Sunday, 28 August 2011

Is there a link between climate patterns and conflict?

Peru's civil war erupted during an El Nino year
Ok, so this summer holidays I had planned to try and link various topics to development but, so far, I havent got very far down my lists of ideas and, as we go back to college fairly soon, I thought I had better start! Here goes for one of my first, the link between climate and civil conflict which, of course has/had a knock-on impact on development.......

A recent study has made the first link between global climate patterns, specifically ENSO, to the onset of civil conflict and, perhaps most interestingly, a factor that is being placed on a par with poverty. Researchers at Princton University have been looking at conflicts that have occured between 1950 and 2004 that killed more than 25 people a year and then compared those years with whether or not we were in a El Nino or La Nina. The analysis included 175 countries and 234 conflicts, with more than half being responsible for 1000 deaths, and concluded that the risk of conflict in tropical countries rose by 3% during La Nina to 6% during El Nino; with this affect being absent in those countries who only experienced a small impact thanks to the climate cycles (essentially countries with a temperate climate). This study has shown that 1/5 of the conflicts that have erupted since 1950 are a result of the cyclical changes in climate which have, primarily, triggered reductions in food production.

Although ENSO has wide and varied effects, I think it is quite unsettling to think that cyclical short term variations in climate can seem to have such an impact when the predicted changes as a result of global climate change are likely to be much more extreme and long lasting - so just how are we going to adapt to those???
Is it just coincidence that cyclical climatic changes have occured
just before the eruption of civil conflict in many developing
countries?
Anyway, this doubling of the risk of conflict is quite large, and the study seems to suggest that the imapct of El Nino is immediate, with the onset of conflict erupting within months of the start of an El Nino event - a correlation independent of other local weather events which are also capable of generating tension. The study related outbreaks of violence in countries from southern Sudan to Indonesia and Peru to the cuts in food production triggered by El Nino. Using southern Sudan as an example, warfare broke out during 1963 (an El Nino year) and then again in 1976 (again an El Nino year) and then in 1983 (a very intense El Nino year), with the conflict lasting for more than 20 years and leaving more that 2 million people dead and millions displaced. In contrast, Australia, whose climate is also controlled to some extent by ENSO has had no civil conflicts which suggests that less developed countries lack the resourcse to adapt to the varability generated by these cyclical climate changes and so are more vulnerable to its impacts - a fact that suggests that climate still hinders the development of countries today.....

Hopefully provides a general idea of the varying
impacts of El Nino on the climates of many
countries
So, what is it about El Nino that increases the risk of conflict? Well, the study is yet to explain this and doing so is going to be hard due to the global variability in the impacts of El Nino. Best guesses, at present, seem to point towards increased temperatures in some regions leading to droughts, thus reducing crop yields which, in turn, would provoke a hike in global food prices - something that, thanks to the international market, would spread the climate signal around the world. Although most believe it is the impact on food production that triggers the violene, other ideas include a rise in unemployment and an increase in natural disasters.

This seems to be the first clear link between civil conflict and climatic cycles and I think it only reinforces the idea of our dependency on climate and the dictatorial role it has played and, perhaps, continues to play in terms of development (post on this idea hopefully on its way soon!). I must admit that it does concern me that if ENSO, an example of a short term cyclical climatic change which we are forever understanding and predicting better, can have such an impact on social unrest; how is mankind going to cope with the sea-level rises, droughts, famines, more natural disasters etc. that are predicted to accompany global climate change - a change in climate whose impacts are going to be much further reaching...........

Wednesday, 24 August 2011

Earthquake hits East Coast of America.......Could it have been caused by fracking???

Yesterday, a magnitude 5.8 earthquake hit Virginia, with tremors being felt in Washington D.C. and New York City. Although in comparison to the earthquake that hit Japan this year it sounds rather small, for this region, it was quite large and is currently being classed as a 'rare but significant event for the region'. Earthquakes rarely strike this region, primarily due to its distance from any tectonic plate boundaries (closest being about several hundred miles away in the Altantic), and when they do occur they are generally less severe - although the risk is not insignificant. In contrast, California experiences more severe and frequent earthquakes as the San Andreas fault runs practically straight through it.

(I have ratherly cheekly copied the video that Millie posted on the FB page)

Despite this being the largest earthquake to hit this area since the 31st May 1897, and the fact that it was above 5.5 in magnitude (kind of like the threshold above which it becomes a concern in relation to structural damage), it is believed that the impacts will be relatively minor. At 5.8, it is just below the magnitude required for liquefaction to occur, something that often causes significant damage, and structurally, the earthquake is only believed to have caused a few cracks in buildings and a few collapsed chimneys etc. The two nuclear power plants in the region where successfully shutdown.

So, what caused this earthquake???

Well, some scientists believe that it could be caused by the release of stress from a small thrust fault in the region. The impact of the earthquake was then increased by the fact that, because it occured far away from major plate boundaries, the continental rock is much older (bedrock beneath Virginia is believed to have formed when the continents collided to form a supercontinent about 500-300 million years ago) and denser, so more like a solid sheet of bedrock, and so the seismic waves were permitted to travel further.

Another suggestion is that fracking could have caused the earthquake. Now I don't personally know that much about fracking but I will try and explain why some believe that a recent rise in fracking could have provoked the earthquake. Correct me if I am wrong but I believe that fracking, or hydraulic fracturing, is the man-made splintering of underground rocks to speed up the exploitation of natural resources and, since its inception in 2004, has become increasing popular as it can allow for the recovery of oil and gas supplies. Due to the impact that fracking can have on the geological make-up of the Earth many are starting to insinuate that it could cause earthquakes. In locations were fracking occurs, the waste salt water produced is injected back into the earth (after the fractures have been created) and some estimate that, in each well, 3 million gallons of waste is injected.  With reference to the East of USA, earthquakes, as previously mentioned are rare, but the surrounding area has experienced 8 minor tremors last year alone - an area that has also seen an increase in fracking operations over the past few years.

This is not the only earthquake that some are suggesting has been caused by fracking. The USGS have said that "Earthquakes induced by himan activity have been documented in a few locations in the United States, Japan and Canada" with "The cause the injection of fluids into deep wells for waste disposal and secondary recovery of oil and the use of reservoirs for water supplies". Geologists have more recently blamed fracking for the 20 tremors witnessed in the state of Arkansas in one day; also similar size earthquakes have been experienced in Texas, New York and Oklohoma, all of which are not normally likely locations for epicentres but have experienced a significant increase in fracking over the last few years. What is quite interesting is that the multi-stage fracking being held responsible (it drills several miles deep into the Earth), has only recently, over the past 2 years, become prevalent in the above mentioned areas, all of which have seen a rise in tremors, and have since banned fracking - an action that seems to have been followed by a reduction in size and frequency of tremors. Since this, more states are now reviewing their current legislation on fracking.

So, what do you think? Is it possible that these earthquakes are really being caused by fracking and if so, along with some of its other detrimental impacts, is this reason to prevent it from being utilised in the future? Do you actually think that we would ever place a global ban on it, due to our increasing hunger for energy and dwindling supplies of oil? On the other hand, do you feel that a release of stress from the thrust boundary is a more logical explanation? My knowledge on this is a bit limited so if anyone knows are more I would love to hear about it! Let me know what you think.........

Whilst on the topic of earthquakes, I read this other blog that is related to geography (kind of more human geography I suppose and is one that Millie suggested) written by this person from Sheffield University, and he produces these really interesting maps as a graphical way of presenting data (they are a bit different to maps I have ever seen before!). He wrote a post yesterday on the earthquake, although it focuses a bit more generally just on earthquakes as a whole and the impacts, which is definetly worth a read. Magnitude 5.9: Earthquakes revisited I do try and keep some sort of balance between my human and physical geography posts but if you are ever looking for something human related to read, his posts are often quite interesting - it is included on my (extremely short!) blogs I read list at the bottom of the blog so keep an eye out for it in the future! If you ever come across anyother earth science related blogs you think are worth reading just let me know - I am always looking for different things to read!

Monday, 22 August 2011

Hurricane Irene becomes first hurricane of the Atlantic in 2011

It could, perhaps, be said that hurricane season has offically begun with the first hurricane of the year forming over the Atlantic. Hurricane Irene is currently heading towards the Dominican Republic and the east coast of America, after hitting Puerto Rico earlier today.

So far, the hurricane has sustained winds of 80mph, accompanied by torrential rain. Many in Puerto Rico's capital had to seek emergency shelter ahead of the storm. The islands main airport was overwhelmed with people trying to get off the island before Irene hit earlier today and, due to flight cancellations, many holiday makers have been left stranded. It also cut power to more than a million people, flooded the streets and brought down trees. As of yet, no deaths or serious injuries have been reported but a state of emergeency has been declared warning people to stay indoors.

However, the biggest threat currently seems to lie on the island on Hispaniola (the island shared between Haiti and the Dominican Republic), as, thanks to last year's earthquake, 600,000 people still live without shelter and, due to the deforestation that has occured, the area to more prone to flooding and landslides. As a result, the Dominican Republic has a hurricane warning in effect, with a hurricane watch in effect in northern Haiti and the Bahamas. It is expected that latter in the week Irene may hit Florida, Georgia and the Carolinas in the US.




23-08-2011
Hurricane Irene strengthens as it swirls over the Caribbean

Geography Picture of the Day - Formation of the Gulf Stream


I have spent some time this afternoon trying to create a way of representing the formation and journey of the Gulf Stream with minimal text. I am really bad at writing succintly so this has been a bit of a challenge and there is still way too much text on it, but I thought I would share it with you all anyway (any feedback on it would be great!) as I think, when it comes to the climate module, we do have to know a little bit about ocean circulation and this particular current, along with the North Atlantic Deep Water (NADW), play an influential role in moderating our climate.

Saturday, 20 August 2011

Has this blog been useful?

I first started writing this blog after my January skills exam and seeing as we only just got our AS results the other day (I hope everyone got the grade they wanted/needed!) and this is offically my 100th post, I thought I would write a little bit of feedback about my experience and whether or not I think this helped me with my exam.

Well, I was rather relieved on Thursday to find out that I did well enough in my Geography exam and honestly I think that part of the reason is because of this blog. It has really helped me with my writing (especailly writing essays faster!) and it was an invaluable revision tool, something different to the other revision methods I use. Due to writing it, I found it so much easier to link what we got taught in lessons to the geography that was currently happening around world and to recall facts/statistics from the case studies. I even think it helped slightly in some of my other subjects as I have had to learn (and am still learning) to structure what I write, get straight to the point so as to write more succintly (as evident from some rather long posts I am still trying to master this!) and to stay as focused as possible on what I am supposed to be writing about. I am really hoping that it has been beneficial to atleast some of you too, especially during the revision period leading up to the exam.  Whilst on the topic of my exam results, I would like to say a huge thank you to the Geography department as they helped me so much over the course of the year! Nikki and Nick  marked loads and loads of my essays/work over the past year and probably got a bit fed up with seeing me in workshops with a pile of essays in my hand, accompanied by a long list of questions! Millie, well what can I say, all year she has put up with my endless question asking (I think my curosity may have been bordering on annoyance at times - I do apologise! ), she has taught me so much about the world of geograhpy, helped me start to improve my writing style, encouraged me to always further my knowledge outside of the classroom, ignited an enthusiasm/passion for the subject (although she may regret/be regretting this!), made me realise that I can actually be quite good a geography when I want to be and so perhaps should be pursuing it in the future and finally got me to start blogging!!! So, thank you, all three of you, as there is no way that I would have progressed as far, in terms of my geography skills, or done as well in my exam without you and I look forward to the year ahead!

As I have found writing this blog so useful, and it keeps me out of trouble, I am planning on continuing to write it. I have been looking back at some of my posts and I realise that I need to try and reduce the amount I write and include some more pictures so that they look at bit more interesting at first glance. I have a tendency to get a bit carried away and write a lot, sometimes in too much detail, but I am going to try my best to stop doing this - no promises though! I thought I might try and do a few of those video posts that Millie has done in the past as, firstly, I personally found that really beneficial and, secondly,  it may be a welcomed break from lots of text. I am also going to try and maintain a bit more consistency in my blogging as I realise that sometimes I may not write anything for a week or so and then the next minute I write like 5 posts in a day and most importantly I am going to make sure that I actually write about what my title suggests - what I learn in lessons not just all the stuff I learn outside (although that will still greatly feature!).

What would be really good to know is whether or not any of you have found this blog useful? Do you think you would benefit if I carry on writing it? Is there anything you think I should do more or less of? Basically any feedback would be great and not just on my blog. I know Millie would probably really appreciate some feedback on all this social media in education stuff she it doing. There is a discussion group set up on the FB where you can leave comments, or on her blog. I personally think what she is trying to do is really amazing and that it makes the learning, consoldiation and revision processes for us students so much easier as there is always somewhere for us to go to find out what has been taught, something to read, somewhere to discuss and debate and somwhere to ask questions or ask for help. So, let us know what you think!

Inertia Currents

You may have got the impression from some of more recent blog posts that I have been spending quite a lot of my summer holidays trying to learn some of the basics of oceanography. Unfortunately, as our EPQ's can only be 5000 words long and have to be very specific, there are lots of interesting things, especially with regards to the thereotical side of physical oceanography, that I have to leave out. Instead I thought I would perhaps do a few more posts on here about some of the stuff I have been learning as, you never know, it may come in handy when we do the climate module as the oceans and atmosphere are very closely linked. So, first up is inertia currents........

Winds are not always constant in strength or direction and so when a wind that has been driving a current ceases to provide sufficient energy to do so, inertia currents are created. Momentum will not leave the water immediately as, in open ocean, it takes a while to dissipate and whilst in motion, frictional forces and Coriolis force will continue to act upon them, thus resulting in a circular motion that characterises inertia currents. The extent of this circular motion is determined by the influence of Coriolis over other forces with the most circular inertia currents being generated when Coriolis is the only horizontally acting force on a current whose journey involves minimal latitudinal movement. The energy in the oceans is both kinetic, by virtue of its motion, and potential due to the displacement of isopycnic and isobaric surfaces and it is this huge store of potential energy in the oceans that ensures that the ocean circulation would take a few decades to completely cease if global winds stopped blowing.
Various possible paths for inertia currents

There is, as with oceanography as a whole, an awful lot of maths involved with inertia current to calculate things like the centripetal force (which is essentially the Coriolis force in this case) so you can then move on to work out the period of the inertia current. I will spare you all the maths - I am currently staring at a bunch of equations that work this all out in a textbook and trust me it doesn't look very pleasant at all!!!
Plan view demonstrating inertial motion in the
Northern Hemisphere

Anyway, apparently the equations demonstrate that, in an ideal situation, the only variable affecting the period of the inertia current (basically the time taken for a water parcel to complete one circuit) is latitude so, approximately, at latitude 45 degrees, it theorectically, the period of the inertia current is 17 hours whereas, at the Equator, it becomes infinite.
Thats some of the theory, but these currents have actually be identified and observed in real life from the current measurements taken in many parts of the oceans. Here is an example of one observed in the Baltic Sea. The wind-driven current flowing to the north-north-west has been superimposed on by the inertial motion which, at this latitude, has a period of about 14 hours and, therefore, the inertia current died out after around 9 or 10 rotations.
Plan view showing the inertial motion
observed in the Baltic Sea
So, I think thats about it really on inertia currents - I hope some of you found it interesting!

Geography Picture of the Day - Could seawater solve the freshwater crisis?

By 2025, it has been predicted that 1.8 billion people will live in areas of extreme water scarity and so, desalination (the removal of salt from water) is increasingly being proposed as a solution to this huge problem. However, before desalination can make the impact required to solve the looming water crisis, much worl needs to be done to overcome the obstacles that make it an expensive and inefficient process......
Desalination plants such as the U.K.'s Thames Gateway facility use
reverse osmosis technology.

Scientists predict that by 2016, the amount of fresh water produced by desalination plants will exceed 10 billion gallons (38 million cubic meters) a year, or double the rate in 2008. Modern desalination plants use a technology called reverse osmosis,  which involves pressing salty water through really thin, semipermeable plastic membranes. Unable to pass through, large molecules or ions, such as salt, are filtered out, so fresh water flows out the other side. This method wastes much less energy than earlier desalination techniques, such as heating seawater and harvesting fresh water from the steam. However a typical reverse osmosis plant can still spend up to 40 percent of its operating costs on generating electricity to run the system—a big reason engineers are searching for ways to cut costs and make plants more efficient, starting at the membrane level.

Sounds like this technology, especially if the amount of electricity required can be reduced and the efficiency increased, could be used a lot in the future to try and secure water supplies. However, I am sure that it has other disadvantages, like the environmental impacts on oceans and ecosystems. Also what would you do with the salt as I am guessing if it is on a large scale then quite a bit of salt will be produced? Linking it to my EPQ, I am unaware of how much salt would be produced but by dumping the waste salt back in the oceans, whilst removing large volumes of water, the salinity of the oceans will be affected - something intrinsic to the stability of the thermohaline circulation..........

Some external forcing factors with the ability to distrupt the general ocean circulation

As I have briefly discussed before, with reference to Heinrich events, the current ocean circulation pattern that exisits has not always do so and alterations to it in the past have resulted in huge shifts in the worlds climate. As well as those previously mentioned, there are some other external forcing factors that have the ability to affect the oceanic and atmospheric circulation. I think some of this stuff, like volcanic influence and Milankovich, comes up in the A2 syllabus although I don't know how much detail we go into - probably a bit more than I have done here, but hopefully the basics will still be useful!

At varying points in time, external forcing factors have and will continue to provoke variability in the ocean circulation. Understanding them is, again, crucial as some explain the past changes that occurred, whilst others endorse future predictions.

There are two types of Precession: this diagram illustrates Axial Precession
 and this alters the hemispheric distribution of insolation. For more on
Milankovich and the individual cycles see seperate blog post on
The race for a million year old ice sample 
Many proxy-climate records suggest that the Milankovich ‘pacemaker’ has driven alterations in the oceans, atmosphere and the cryosphere; due to the moderation in the hemispheric distribution of insolation provoked by the three cycles, precession (23ka and 19ka), obliquity (41ka) and eccentricity (100ka). The spectral analysis of d18O variations present in marine carbonates over the last 10Ma, contain signals of all three cycles moderating high northern latitude insolation variations.  Milankovich used this to explain the initiation and termination of ice ages and his theory states that the alterations in high-latitude insolation in the Northern Hemisphere are crucial in regulating the survival of snow through successive summers to warrant ice accumulation; a theory authenticated by the coincidence of glacial terminations and rapid increases in the solar insolation values of high latitudes in the Northern Hemisphere. The control Milankovich cycles exercise over hemispheric insolation distribution therefore dictates, although on a delayed timescale, the extension/shrinkage of ice masses (whether that be sea ice or ice-sheet/shelves) and it is because of this that they alter ocean circulation; although it is believed that precession has the largest influence. Generally speaking, the cycles range between two extremes, one favouring glaciation and the other deglaciation. When they favour glaciation, the THC is forced to downwell further south and thereby reduces northwards heat transfer and the associated ablation processes, to only further accelerate cooling. During glacial termination, the opposite is true and baseline increases in NADW intensity, beginning approximately 18ka, that parallel increasing Northern Hemisphere insolation, have been inferred from the RC11-83 South Atlantic Ocean floor sediment core. Many believe that it is the alterations provoked by this extrinsic forcing factor to the thermohaline circulation that drives, all atleast contributes, to the temperature changes that occur during transitions between glacial and interglacials.

Spectral analysis of variations of the chemical composition of ice cores have revealed that cycles shorter than those of Milankovich have occurred (periodicities of 11100, 6100 and 1470 years); with these sub-Milankovich cycles believed to be overtones generated within the climate system due to the influence longer cycles. The sub-Milankovich cycles can also be classed as an external forcing factor and can be attributed to shorter, abrupt alterations to the oceanic circulation. Precessional-driven climate alterations are believed to be linked to the 11100 year cyclicity which is being held responsible for temperature maximums being experienced every 11100ka in continents straddling the tropics. The 6100 year cyclicity seems to have a relationship with Heinrich events and other coolings such as the Little Ice Age and it is thought to only be amplified by ice-sheet presence. The shortest periodicity, because of the lethargic nature of ice-sheets, presumed to communicate readjustment of atmospheric circulation, is possibly due to solar output variations; something suggested by 14C records in tree-rings. When the sun is at its most ‘’energetic’, the Earth’s magnetic field is strengthened, blocking more cosmic rays. 14C is formed when cosmic rays hit plants, therefore measured in tree rings; with high levels of 14C suggesting an ‘inactive’ sun. Bond documented increases in icebergs and ice drift coinciding with the increase in 14C, indicating the sun was weaker at such times. Alterations in the volume of ice-rafted debris, in North Atlantic, also coincide with the 1470 year cyclicity, although are only 1/10 the size of the inconsistencies witnessed during the last glacial. Overall, there is agreement amongst scientists that these millennial-scale cycles, which have also been detected within ENSO, have a solar inception affiliated to the THC.

Volcanic eruptions, principally those that disperse ash and SO2 into the stratosphere which are most commonly high latitude (due to lower tropopause) explosive eruptions, can provoke a period of cooling that can last for a few years; like Pinatubo did after it erupted in 1991, releasing 20 million tonnes of SO2, cooling the Northern Hemisphere 0.5°C over  5 years.  Despite their apparent ability to affect the climate, the effect they have on ocean circulation is debatable due to the variability produced by GCM. Some models show a connection between volcanic eruptions and a reduction in MOC intensity. However, these reductions appear to be small and short term and, this fact combined with other models not picking up the link above, suggest that the impacts of volcanic eruptions on ocean circulation, if there is one at all, is of little consequence and do not seem to pose a threat to the stability of the ocean circulation.


Invictus - a students film review

This is another film based in South Africa and on Nelson Mandela and if you are planning on trying to watch this and the last film, I would advise watching Goodbye Bafana first as it is set beforehand.


So, Invictus follows the story of Mandela after he is released from 27 years of imprisonment for fighting against apartheid. After being released from prision he became the first democraticly elected president of South Africa. Instead of looking to take revenge, he forgave his oppressors and  went in search of a way to unite the greatly divided country. He found the common ground he was searching for in an unlikely place: the rugby field, a place that for many had strong links to aparthied, and this is where the film's main theme lies. Through rugby, Mandela felt he could unite the broken South Africa and so he asked the national rugby team captain, and his underdog team, to win the world cup.

Is it a good geography film? Well, for much the same reasons as Goodbye Bafana, in relation to the Development and Globalisation module, it is pretty good. I think it quite nice to watch both of them as they are closely related to each other and Invictus kind of follows on from Goodbye Bafana. The film provides another look at aparthied, although more specifically some of the resulting problems in the country, and I think that to be able to understand the development of South Africa, you need to have some understand of aparthied and the impacts in had on development. Again, this film provides an insight into the levels of development in South Africa at that time and the problems that Mandela had to solve in order to allow the country to develop more sustainably. There is a bit of geopolitics throughout the film and just some other general geographical references that make it quite a good geography film to watch!

Goodbye Bafana - a student's film review

So, I have been trying further my knowledge of development and globalisation before we go back to college and as I have been doing a lot of reading for my EPQ, and I fancied a bit of a break, I thought I would watch a few films. The first one up is 'Goodbye Bafana'.

Based on an inspirational true story, Goodbye Bafana tracks the unlikely but profound relationship betwen James Gregory, a racist South African jailer, and his prisoner, Nelson Mandela. Gregory is ordered to spy on Mandela because he understands Mandela's native language. No one expected that a friendhsip would grow between these two very different men and through Mandela's influence, Gregory's world changes forever, along with that of every person living in South Africa.

So, is this a good geography film and what did I learn from watching it? Well, any film that is set in another country will instanly provide an insight into that country and this film very clearly depicts what life was like for everyone, not just prisioners, in South Africa at that time. The issue of apartheid is a key theme that runs throughout and is very important in relation to how it affected the development of South Africa. It is because of this that it is a good geography film as it presents some of the reasons for the development of South Africa and why it still experiences many issues today. Due to this, it is definetly a film to watch if you can find the time!

What I taught in Geography this week.........

This was literally meant to be posted about a month ago but I clearly just totally forgot - better late than never I suppose!

I have been writing this blog since mid-January now, from a student's persepective, and so this week I thought that I would try something slightly different. This week I have been helping out the Geography department at my secondary school and so I thought I would write about what I teach...............well, to be honest, it is more like what I observed being taught and then raise it to a slightly more academic level.
Most classes have been learning about hurricanes and the devastation caused by Hurricane Katrina. When asked questions, in reference to their formation, I had to refrain from going into any detail much more that the necessity for warm deep oceans and strong winds. So, after having to contain my enthusiasm all week I thought I would go into a bit more detail now (and anyway I am guessing it might come in handy when we do the climate module!). Hurricanes, tropical cyclones and typhoons are all tropical revolving storms and are named according to their location.  There are a few common characteristics in the development and location of the development tropical revolving storms and they include:-

- Very warm tropical oceans (temperatures need to exceed 26 degrees Celcius), where the ocean has been warmed to a depth of at least 50m. This is necessary to ensure sustained heating over a wide area which, in turn, provides a heat source to create a large mass of warm, unstable air.
- They occur most commonly in autumn as this is when sea temperatures are at their highest as temperatures have been built up over the summer.
- They are found within the trade wind belt as this is where the surface winds warm as they blow towards the equator.
- They are usually located between latitiudes 5-20 degrees north or south of the equator.
- They trael westwards on unpredicatble courses.
- On landfall they move towards the nearest poles and are another way in which surplus energy is tranferred away from the tropics with vertical displacement through the atmosphere.
- Away from their ocean heat source they rapidly lose power and eventually become storms before they are classified as depressions.

Hurricanes in the Atlantic are often over 600km in diameter and are characterised by their relatively uniform temperatures, humidity and pressure. One of the main reasons that they most commonly form in late summer and autumn is because this is when the ITCZ has completed its move to the north of the equator and so large expanses of the ocean, to great depths, are heated and therefore so is the air above it. The convergence of air at low levels and uplift creates the very low pressure and strong winds that are required for the formation of a hurricane.
To develop from a depression into a tropical storm, the rising air currents must be maintained and that requires a constant supply of heat and moisture. As winds sweep over the ocean surface they increase the rate of evaporation and the latent heat needed to transform liquid to vapour is transferred to the rising air. Later, as the moist air rises it will conense to form clouds and heavy rainfall, releasing latent heat and further driving the storm. Once the storm has developed to a mature stage, a central eye develops with a diameter of 30-50km. This is an area of subsiding air, with light winds, clear skies and anomalous high temperatuers. The descending air increases instability by warming and serves to increase the intensity of the storm. wind speeds of 160-300km/hr are not uncommon, with larger hurricanes creating widespread damage and signinficant threat to life. Associated with the high winds are storm surges which are broad waves of water pushed ahead of the storm and excaberated by the rise in sea level allowed by intense low pressure beneath the hurricane. Intense rainfall leading to run-off on land feeds swollen rivers which may have their outlet to the sea impeded by the inundation of seawater driven by storm surges into estuaries and other low-lying land.

Once hurricanes reach land they rapidly decline in terms of energy. This is because the storm loses its source of heat and moisture over land and increased friction slows it down. If it carries on moving away from the tropics over the sea, the increasing cooler waters beneath restrict the amount of energy available and ultimately reduce the pressure difference. The average lifespan of a tropical cyclone is 7-14 days.

So, thats a brief look into hurricanes and their formation. I was going to look, in detail, into Hurricane Katrina but I might save that for another time. What did I learn during this week? Well, firstly that I am really bad at explaining things to others and at targetting what I say at specific year groups - something also proven by my attempt to research and write my EPQ!!!!! This week also made me realise just how much my geographical knowledge as improved and expanded since I first started learning geography in year 7 - even my old teacher (who taught me Geography for 5 years couldn't belive how much I know knew). My writing ability also seems to have flourished although my handwriting, compared to year 7, has shrunk considerably! It was really wierd to see some of my work from back then that my teacher has kept, and even my GCSE coursework. I honestly think that its since I started doing Geography at college that my level of understanding has so rapidly grown - along with my enthusiasm - and I know excatly who to thank for that!

Friday, 19 August 2011

Success in predicting an underwater eruption

Being able to predict any form of natural hazards is an achievement and, for the first time, scientist have successful managed to predict an underwater eruption.

What does the aftermath of an underwater volcanic eruption look like? Well, if you have just watched the above clip you will have noticed that vents are releasing cloudy water months after the blast and the seafloor is covered in hardened lava.

When scientists found this sight, they were not at all surprised by it as they had forecast this event, making it the first successful prediction of an undersea volcanic eruption.  Axial Seamount, off of the Oregon coast, has been discovered to behave in a more predicatable manner than previously thought, and than most other volcanoes. The reason for this is believed to be due to its robust magma supply, accompanied with a thin crust, and location on a mid-ocan ridge spreading centre.

When the volcano last erupted in 1998, the bottom of the crater subsided as magma moved upwards. The team predicted that it would erupt again once it attained the same level again. Based on a series of pressure measurements that showed the volcano was inflating, they forecast that this would happen before 2014. It is believed that the volcano erupted on the 6th April this year. Scientist were able to generate this prediction as it is the only volcano on the seafloor whose surface deformation has been continuously monitored throughout an entire eruption cycle.

Sunday, 14 August 2011

Heinrich Events

Heinrich events were first described in 1988 by the German marine geologist, Hartmut Heinrich, whose study demonstrated that six times during the last glacial huge iceberg armadas discharged from Canada into the North Atlantic, depositing, as they melted, lithic fragments. Peaks in the abundance of these lithic fragments far from land can only be attributed to icebergs melting as sea ice only transports dust and to further support this idea, much of the ice-rafted debris found consists of limestone similar to that exposed in much of Canada today (although lithic fragments from across the North Atlantic do feature). The lithic peaks form layers in sediment cores, known as Heinrich layers, which extend some 3000km across the North Atlantic, and seem to reflect an episodic nature in Heinrich events, with each one lasting approximately 1ka and occurring at intervals of 7-13ka (over the last 100ka).
Laurentide ice sheet during Last Glacial Maximum (LGM)
The six events described by Heinrich are not unique as there are many lesser peaks in the lithic content of sediment cores. They are, however, the largest of the now recognised events in high-resolution core logs. In every event, icebergs were released when the surrounding surface water was cold but then abruptly warmed. All of this can be said with confidence but the exact cause of the periodic surges in the flow of the Laurentide ice-sheet (covered eastern Canada) provides an air of uncertainity as explaining the cause of the characteristic iceberg armadas is slightly harder than identifying them in sediment cores. There are, though, two fundamentally differing models that try to do this.
Denton model for iceberg armadas
The Denton model is essentially climatically driven as it based on global cooling leading to greater snowfall and thus a rapid expansion of ice-sheets/shelves and then marine ablation calving the icebergs from the expanding ice-shelf. Fundamentally the Denton model lays blame with the external cause of ice-sheet/shelf expansion as a result of global cooling as the forcing factor.
Advantages:-
- Evidence supports cooling in the North Atlantic before the Heinrich events
- The model explains the surging of South American glaciers and other global responses without the need for complicated teleconnections, during the same period of time
- Around 1.5ka climate cycles are known to have occured during the last 10ka and, despite them being an order of magnitude smaller than Dansgaard-Oeschger events, they too suggest external forcing over internal forcing
Disadvantages:-
- The model cannot explain the rapidity of events
- Heinrich events do not have consistent cyclicity as early on in the last glacial period they occured every 13ka but then later on they occured every 7ka
The MacAyeal 'binge-purge' model for iceberg armadas
The MacAyeal ‘binge-purge’ model blames an internal cause (ice sheet failure) due to geothermal and frictional heat periodically building up and getting trapped beneath the ice-sheet, thus melting the base and provoking the catastrophic failure of the ice-sheet. So, instead of being climactically driven, it’s reliant on the mechanical failure of ice-sheets due to thermal modification at its base.  MacAyeal suggested that the Laurentide ice-sheet grew whilst its base was frozen solid to both the crystalline rock (currently exposed on land in Canada) and the softer sediments found beneath Hudson Bay, to the south of the ice-sheet. When the base of the ice-sheet was heated enough, by geothermal heat, to cause the sediments to thaw, the rapid ice movement of the purge was initiated. Frictional heating then further increased the temperature, provoking a positive feedback as the ice movement was accelerated further. Despite this, the greater friction at the ice/crystalline rock meeting point prevented the total collapse of the ice sheet. This model highlights the fact that natural systems can display abrupt changes caused by a forcing factor that fails to change with time and so can occur independently of the external forcing factor; one of the reasons for the difficultly in making predictions about the future impacts of climatically driven forcing factors.
 Advantages:-
- The model is able to explain the rapid initiation and termination of Heinrich events - something that the Denton model fails to do
- Due to its dependency on the size of the ice sheet, it can explain the irregular cyclicity of Heinrich events
- Provides an explanation of the large amount of ice-rafted debris, which forms the Heinrich layer, found in the North Atlantic
Disadvantages:-
- Cannot explain the cooling known to have occured before each Heinrich event
- It needs a mechanism, such as the NADW, to transport the 'signal' around the world
Both models have their advantages and disadvantages and as a result there is a lack of consistency in which is favoured by scientists. For some time though, the 'binge-purge' model was favoured by most but then it was revealed that some of the Heinrich layers contained material that could have only came from other ice sheets, other than Laurentide. Attempts to generate a combined model have failed to paint a clearer picture of the mechanism provoking iceberg armadas but have led to further research into the conditions surrounding such events. Some of the sediment in the Heinrich layers has been linked to areas other than those covered by the Laurentide ice-sheet, such as Iceland due to basaltic glass fragments. This suggests that separate ice sheets surged simultaneously, something unlikely unless climatically driven or as a result of increased marine ablation due to eustatic sea-level rise thanks to Laurentide ice-sheet melt. The westward thickening of Heinrich layers, across the Atlantic, and its continuation towards Hudson Bay, point to the latter being correct and it is possible that its break-up triggered a response in other ice-sheets. Evidence insinuates that three gradual advances and rapid retreats of the Laurentide ice-sheet occurred towards the end of the last glacial, with glacial advances culminating before Heinrich events; thus provoking rapid ice discharge into the Atlantic, reducing southward ice flow and resulting in rapid retreat of LIS. There also appears to be synchronicity between the North Atlantic ice-rafting events and ice-sheet growth/ collapse in the Andes and New Zealand; something which supports the idea of strong inter-hemispheric coupling of changes in temperature  and therefore global forcing of climate change. Research into the abundance of left-hand coiling in foraminiferid populations in ocean floor sediment cores, accompanied with studies into the origins of lithic sediments, have indicated that iceberg-calving events have occurred more frequently than first believed (intervals of 2-3ka), albeit on a smaller scale than the six originally identified Heinrich events. Of greater importance, is that many of the fragment peaks coincided with >90% proportions of left-hand coiling foraminiferid, thus revealing that the launching of iceberg armadas corresponded with low North Atlantic SST’s, symbolising stadial periods followed by the prompt warming leading into an interstadials. The use of d18O variations as a proxy record for eustatic sea-level rise and a lack of coherence between evidence of temperature rises in ice-cores from Greenland and Antarctica imply that meltwater discharge pulses, during the above events, originate from the Northern Hemisphere; an inference only endorsed by changes in salinity that are known to have occurred in the North Atlantic. As a result it can be said with confidence that Heinrich events influenced alterations in ocean circulation. 
There exists conflicting views regarding the influence of Heinrich events on THC. Some believe that the AMOC collapsed over the course of the six known Heinrich events, as a result of the influx of freshwater from glaciers interrupting the ‘normal’ circulation. Others suggest that NADW cessed as a result of each Heinrich event as the iceberg armadas placed a freshwater ‘lid’ over the northern North Atlantic. A Heinrich event is estimated to have provided a freshwater input in the order of 0.1Sv to the Atlantic, a volume believed to be sufficient to halt NADW formation, whose magnitude dictates the deep-ocean THC, and thereby explain the cooling observed in proxy data from the mid-latitude Atlantic. Some believe that Heinrich events were actually triggered by a reduction in NADW formation, due to freshwater fluxes to the North Atlantic as a result of the early deglaciation of the Fennoscandian ice-sheet. The reduced NADW formation would generate warmer SST’s, therefore perturb the ice-shelves, thus triggering iceberg armadas, allowing for the additional freshwater to further weaken, ultimately leading to the cessation of the MOC. Alternatively, several think that the collapse is relatively independent of the magnitude and origin of the freshwater input produced by Heinrich events, as long as it is transferred to North Atlantic convection sites; whilst events restricted to the Nordic Seas reduced NADW formation but didn’t provoke the cessation of the global conveyor; thus perhaps partially explaining the cause of Dansgaard-Oeschger events.
This might seem a bit random, but I have just written up a section on the past changes that occured to the ocean circulation across glacial/interglacial and stadial/interstadial and so have mentioned Heinrich events, Dansgaard-Oeschger events and Bond cycles, amongst other things; unfortunately it is beyond the scope of my project to go into any real detail into the models used to suggest the causes of iceberg armadas and so, instead, I thought I would mention them on here. I have one question though, that I would be quite interested in knowing the answer to if anyone knows, what excatly caused the frequency of Heinrich events to change, from 13ka to 7ka, over the course of the last glacial?

Friday, 12 August 2011

The Day After Tomorrow - A student's film review

I have spent rather a lot of time over the past month or so with my head in textbooks and papers etc. to help me try and get to grips with some of the basics of oceanography (trust me, it is literally like a whole new science) and so I fancied a bit of a break from the heavy reading. Therefore I thought I would watch the film The Day After Tomorrow......
This film is based on the events that follow, rather rapidily, the shut down of the Atlantic Meridional Overturning Circulation (AMOC) and a shift in the Gulf Stream as a result of global warming triggering the melt of ice shelves, with the collapse of the Larsen B ice shelf being the example in the film. In the film this leads to the onset of a new Ice Age where tornadoes flatten Los Angeles, tidal waves engulf New York and the entire Northern Hemisphere begins to freeze solid, forcing millions to migrate rather quickly as far south as possible. Stuck in the middle of all of this is a small band of survivors who have to ride out the 'superstorm' in the shelter offered by an old library whilst they wait for the father of one of the survivors, also a climatologist, to come and rescue them.

Now obvisouly this film was produced to be entertaining and so presents the extremes, and perhaps not quite reality and essentially it is this trait that makes it a good film to watch for geography as you can allow it to really test your knowledge. Its one of those films that, from an educational point of view, you have to watch and then point out the geographical mistakes made - quite an interesting challenge really (just do it when you're on your own though as, from experience, I have learnt that not everyone will appreciate an indepth explanation every 5 minutes as to why something would/could probably never happen in real life!). It is because of this that it really helped me consolidate some of the basics that I had learnt so far, in relation to my EPQ, and by doing this I could see the areas I had clearly understood well and others not so well - I might have to look out for films which would allow me to do this for topics on our syllabus as a different way of revising! For now though, I think I will write a little about the science behind the film and hopefully explain the basic priniciples that the film is based on.

At the beginning of the film, you see footage of the collapse of the Larsen B ice shelf. This actually happened in 2002. Larsen B was 200 metres thick, with a surface area of 3,250 square kilometres and all 500 billion tonnes of the ice sheet rapidly disintergrated ; thus making it the closest thing to a modern day Heinrich event we have ever witnessed. Not only did this result in a large freshwater water input as a direct result of the ice shelf collapse but it also resulted in a two-to-six-fold increase in the centreline speed of the four glaciers that flow into the now collapsed section of the Larsen B ice shelf - basically a lot of freshwater entered the sea as a result! It is this event that the film suggests caused the shutdown of the AMOC and although technically the large freshwater input would have had an impact on it, the freshwater from the disintergration of Larsen B didn't really affect the AMOC. This event, therefore, demonstrates the importance of the location of the freshwater input. The most sensitive areas of the THC are those where the sinking occurs, so in the Atlantic, up near Iceland etc.. The freshwater from Larsen B didn't reached this high latitude in the Northern Hemishpere due to the Antarctic circum-polar current which prevented it from spreading that far and therefore from having a large detrimental impact on the general oceanic circulation. Why could a freshwater influx effect the THC? Well, it is all to do with density and a freshwater input would upset the differing densities of the water and so prevent or weaken the formation of deep water and thereby effect the entire thermohaline circulation. In turn, this would alter surface currents, such as the Gulf Stream which dictates our climate, as it would reduce the movement of warmer waters to the higher latitudes in the Northern Hemisphere, allowing for greater sea ice formation and provoke the Gulf Stream to shift southwards. This would have a huge impact on the climate of the Northern Hemipshere and greatly reduce the temperatures experienced in the UK and countries of similar or higher latitiude. However, this change would not occur on the timescale portrayed in the film!!! This is, I suppose, the foundations of the science that the film tries to base itself on, although, as it is a film, scientific content is lacking but I will leave that for you to discover yourself!


So, is it a good geography film? Well, if you approach the film as one to watch with the aim to point out the geographical errors and try to add science to what you see, then yes. There are a few scientific mistakes to be found and the film does portray the extremes of what could happen if the AMOC was to weaken or shut down - a possibility in the future as it has happened in the past. You definitely get the idea that allowing a large volume of freshwater to enter the Atlantic is a dangerous thing! Like I said above, I found watching and then picking out the mistakes, quite a good way to consolidate what I have been trying to teach myself  and doing so was kind of like quite a good revision technique - something I might try again in the future!

Thursday, 4 August 2011

Met Office Work Experience - Day 3 (for Wednesday)

I spent my third day at the Met Office talking to various researchers about the work they are doing, how it relates to my EPQ topic and asking them lots and lots of questions (I did have to apologise to one person as I literally spent an hour quizzing them about the thermohaline circulation!). I am unsure as to how much knowledge some of you will have surrounding ocean circulation so some of this may not make a lot of sense - if you hunt around on the blog though you will find various posts on the basics of ocean circulation.

So, first up I had a very long discussion with someone about the thermohaline circulation. For those of you who don't know much about the thermohaline circulation  it is the driving force behind the deep currents of the ocean that are collectively referred to as the Global Conveyor Belt. This deep circulation is caused by density changes in oceanic water resulting from changes in temperature and salinity, hence its name ‘thermohaline circulation’, which are caused by cold winds cooling surface waters, the input of freshwater from either precipitation or melting ice, the cooling and freezing of seawater into sea ice or the evaporation of sea water. The basic thermohaline circulation is initiated when denser water (predominately the cooler, saltier water) sinks below the more buoyant water (warm, with a low salt content). Convection penetrates to a level where the density of the sinking water matches that of the surrounding water. When this maximum penetration level has been reached, it will gradually spread into the rest of the ocean. Once the dense water masses have spread into the full extent of the ocean, they will slowly upwell to supply the slow return flow to the sinking regions and replace the surface waters lost - thus driving and sustaining this circulatory movement. Anyway, the discussion I had was focused on the likelihood of it weakening or shutting down and the resulting impacts such an event would have on us. In terms of the UK, if the MOC (Meridional Overturning Circulation) was to significantly weaken or shutdown then the UK would get a lot colder as a slower circulation means a slower heat transfer from the Equator to the Poles and thus a warmer tropics but colder high latitudes. Changes in wind patterns and precipitation would also occur although, in terms of precipitation, the biggest changes would be experienced by those who currently have monsoon climates as a change in the ocean circulation would impact on the movement of the ITCZ. Due to the colder poles, more sea ice is likely to form and this is something that would impact the path taken by the Gulf Stream. The warm moist air brought to us by the North Atlantic Current ( a branch of the Gulf Stream) is what allows us to have a temperate climate, one far milder than countries of the same latitude. However, if the MOC stopped then the path of the Gulf Stream would be altered and it would split at a much lower latitude in the North Atlantic and so we would not get the warm water and moist air that dictates the climate we currently experience. Therefore this would amplify  the effects of an MOC shutdown and further cool our climate. When you then factor in the predicted changes due to global climate change, it becomes slightly more complicated. To some extent it is believed that global climate change could, to a certain extent, offset the effects of an MOC shutdown and so they could act to cancel each other out in most of the world. In the Northern Hemisphere though, due to the reduction in speed of the meridional heat transfer, the UK and areas above it would stay cold or perhaps even get colder! So, what would be needed to cause a shutdown or weakening? Well, something that will upset the delicate density differences and so the most likely thing to do this would be an input of freshwater. They are a few possible sources of freshwater that could do this. First is the collapse of ice sheets/shelves in Greenland due to rising sea and air temperatures as not only would you get the obvious freshwater input from that but after ice shelf collapse glacial flow is also increased. Another possibility is the melt of pack ice in the Arctic and the finally possibility is an increase in precipitation as a result of global warming. It is debatable which poses the greatest threat to the MOC as little is known about the stability of ice sheets and shelves in Greenland etc (lots of research is being done at present) and so many think that the most likely threat could come from an increase in precipitation - something that I realised would have an impact but was surprised to know was believed to have the biggest impact in the near future. A question I was quite interested to know the answer to was how much freshwater would be needed to shutdown the MOC and on what time scale would a shutdown be likely to occur. However, no one really knows and research into this is currently being conducted around the world. One thing that was said for certain was that a shutdown is unlikely in the near future and that one would not occur on the time scale portrayed in The Day After Tomorrow (film review on its way soon!)!!! To try and answer these questions lots of models are being used to try and calculate what state the MOC is currently in.
This graph is rather simple but does help when trying to explain some of the theory behind the response of the MOC to freshwater and how it may recover from an input - another area that really intrigues me. So basically along the x-axis is the volume of freshwater and along the y-axis the strength of the MOC/THC. The idea that many have is that the MOC, despite an input of freshwater, will maintain a constant strength until a certain point is reached. At this point, a rapid decline in its strength will be witnessed and then the MOC will fall off its 'track' (kind of onto the bottom line). Therefore, for it to re-initiate, a decline in freshwater would need to occur, which I suppose is like a reversal of the current pattern, for it to get back on 'track'. The idea of this graph originates from some of the thinking behind how the oceans would respond to an input of freshwater and the contrasting ideas produced by models.
The first comes from  more complex models which seem to suggest a more gradually weakening in response to a freshwater input. The simple models, upon which the first graph I showed you is based on, suggest something different.
The rapid decline in strength after a certain point has been reached is something that many believe would have in reality.

The same graph as the first one, but based on the response results produced by the complex models, is slightly different.

This graph suggests that a gradually response would occur to an input and that, therefore, a gradual return to normal would occur as freshwater was removed and the density differences restored. Excatly which model is correct has yet to be decided but validating one of thiese models is crucial if we are to understand how the THC/MOC will respond and how it is likely to be re-started. Understanding this is also likely to help with calculating just how much freshwater the MOC can 'cope' with before weakening/shutting down.

Another area that is being researched is what feedback system the oceans are currently in. All of these ideas tie in together and understanding the mechanisms is vital if we are to gain a better understanding of how the ocean responds to different factors.
The negative feedback loop represented, rather simply, above is the state that the models used suggest that the oceans are in; which is the idea that freshwater goes in to the North Atlantic, sinks, and then salt water emerges in the South. However, scientists actually believe that the oceans are in a state of positive feedback instead......
Work into which one the oceans is in is currently being done as by understanding this, it is hoped that more reliable predictions for the future will be able to be produced. Just as kind of a side note, scientists think that the oceans may be able to switch between the two feedbacks  mechanisms with this switch being provoked by changes caused to the basic circulation pattern of the oceans, in repsonse to freshwater input.

I realise that this is a bit all over the place but I hope by now you have got the idea that a freshwater input could cause a shutdown or weakening of the MOC and this would have a large impact on the climate of the UK, amongst other countries. Hopefully you we also be able to understand how the alterations of our climate would effect other factors that affect us and other aspects of our lives like, for example, agriculture and food production. Something else though that needs to be taken into account when talking about a possible shutdown is the location of the freshater input. An exact location which would have the largest impact is yet known, but in general, it is believed that any input into the North Atlantic could have a major impact, especially in comparison to the Pacific or Indian Ocean. Again, understanding some of the things above will help aid the discovery of where is the key point in terms of the MOC and this just demonstrates how interlinked all of these things are. During this discussion we covered loads more, hopefully some of which will appear in my EPQ, but I have probably talked about this all a bit too much already! There is some other really interesting stuff that I might right about in a couple days that we also covered - in reflection I do feel a bit sorry for the woman who kindly gave up a lot of her time to talk to me about all of this stuff as I literally bombared her with hundreds of questions!!!

Once last thing I need to mention, which is related to the above, may be of general interest. I don't know if any of you have ever read anything about the thermohaline circulation or meridional overturning circulation but whilst doing research for my EPQ it has confused me how some people switch frequently between THC and MOC and was excatly the difference is. So, I thought who better to ask then the very intelligent scientists at the Met Office! Well, here is the answer............. the MOC is used as to represent the integral across an ocean basin of the meridional flow (south to north movement hence why it is often used to describe the THC in the Atlantic). Given a flow field, the MOC can be precisely defined as a function of depth, or potential density, and latitude. On the other hand, the THC is a less precise concept and is used to describe the whole Global Conveyor Belt circulation. The THC is generally, broadly, taken to mean the part of the circulation that is directly and solely driven by density differences rather than wind stress. However, it is important to note that there are thereotical difficulties in disentangling which forcings are responsbile for a specific part of the circulation and in many cases the MOC is not purely a result of the THC. In many cases, though, the conceptual difficulties may be less severe when considering the changes to the circulation rather than determining the causes of the circulation. Therefore, the reason for some papers alternating between the two is that whilst there are some differences, in some circumstances, both terms are appropriate for use - I hope that explains the small difference!

Then, to finish off what has been an amazing three days, I had a chat with two scientists who are researching the impact of climate change on the ocean ecosystem. These guys were in the Biogeochemistry working group meeting I talked about earlier in the week and so they do a lot of work into CO2 uptake etc. and the idea that phytoplankton can control temperature. Our discussion included many things such as the way in which they model ocean ecosystems and how the models have developed over the years, some of the basics of the cycles involved in the ocean ecosystems and how excatly climate change is likely to alter the delicate ecosystems. This meant that the discussion moved on to the issue of ocean acidification and how studies are being conducted into the impacts this has on ecosystems, especially fish and corals. This is a rather large topic and so, again, I think I will write a seperate post on this over the next few days. At some point in conversation (can't really remember when!) we moved on to a discussion about Daisyworld and the Gaia hypothesis/books. Daisyworld is one of the ways in which James Lovelock tried to represent the ability of the Earth to self-regulate and for a quick idea of what Daisyworld is all about follow the link - Daisyworld animation - its a bit simple but portrays the general idea. I have read the first one and have nearly finished the second one (thanks Millie for getting me to read them as it enabled be to fully participate in the discussion!) and it was quite interesting to get the view of two scientists on the book which is written for the non-scientists about some of the work they are researching.

Anyway, so thats what I got up to during my 3 days at the Met Office (sorry that the posts have been all over the place and written a bit late). I had an incredible time and met some really lovely and highly intelligent people who were more than willing to answer my questions, talk about the work they are doing and offer lots of general advice. There are so many people I need to thank for helping me get into the Met Office, preparing me for the priviledge, allowing me in in the first place, organising many things for me to participate in, for giving up their time to talk to me, allowing me to bombard them with questions and for just being so welcoming whilst I was their. I learnt so much from the experience and its given me a lot to think about in terms of what I want/need to do in the future - I have a lot of thinking to do! It has also reinforced the fact that I know so little about the world of Geography and so I have a lot of reading to do to try and cover as many of the things I didn't quite understand as possible and just expand me knowledge (I will say sorry in advance as a lot of writing is likely to appear on here over the next few weeks!) - I relish the challenge!!! So, all that is left for me to say, apart from another thanks to everyone who has helped make this possible, is that I can't wait to hopefully go back at the end of August!


Wednesday, 3 August 2011

Met Office Work Experience - Day 2 (for Tuesday)

My second day at the Met Office and I think I am starting to get used to being here - well what I really mean to say is that didn't get lost!

So, what did I learn today? As to be expected an awful lot - although again much of it went over my head and so I need to go away and do some more reading on some of the areas. First thing this morning I had a really interesting chat to a researcher who is currently running and then analysising the results of various models linked to the changes he estimates will happen to the contiental shelf, temperature and salinity of the oceans, risk of storm surges and sea level in the future. They have been running loads of these simulations in the hope that they will be able to provide a better and more reliable picture of future conditions to several organisations so that they can take the appropriate steps so that they can effectively adapt to the predicted changes. The majority of this session was spent going over the idea of Ensemble modelling anf forecasting (or atleast I think that is what it is called). Over the next few days I will try and explain the basics but first I need to either locate or draw some diagrams etc to help aid the explanation as it will be tricky enough without them. It is actually really interesting as by understanding the basics (and I refer to the real basics as all this modelling stuff soon gets really complex - just trust me on that one!) of the modelling system, you can see how various factors are linked to or provoke a certain reaction and start to understand why there is often much variablility and uncertainity over future projections. Listening to how and why he was doing the research he is doing at present (and I mean like right now - the plots etc he showed be had literally on that morning been completed!) was really interesting and some of the stuff he was looking into really fascinated me. This talk really demonstrated how the some of the work completed help to guide government policy on various topics. I was given a copy of the last MCCIP Annual Report Card which has some interesting regional snapshots of Marine Climate Change Impacts and various impacts, accompained by the risk of them occuring. Here is the link to the summary report which you can read online http://www.mccip.org.uk/media/7562/mccip-report-2010-2011.pdf ; it is quite interesting to read and not that hard to understand as it was written for people and politicians who may not have a great deal of previous knowledge of the topic. We also discussed UKCP90 and went over loads of graphs, plots and data linked to various changes that are likely to occur due to climate change. Again here is the link to their webpage http://ukclimateprojections.defra.gov.uk/content/view/12/689/ and if you click on 'Quick Downloads' you can download the pdf files of the report they produced which I worked through quite a bit of with this researcher. If anyone is doing an EPQ related to climate change they might find the stats, plots, graphs and diagrams included useful to use in their write up or presentation - I may try and sneak a few in!

After this, I attended another seminar but this time on "Climate sensitivity and ocean heat uptake" by Geoff Vallis of Princeton University, USA. I struggled to follow this seminar as, again, it involved lots of models, lots of acronyms I had never come across before, some horribly complicated looking equations and it kind of jumped around a bit. However I got some of the basics of what he was trying to show with his models and equations so I will go for explaining that - like I did with the other seminar. Essentially the overall sensitivity of the climate was discussed, with particular reference to surface temperature, to an increase in greenhouse gas emissions. You probably got this from the title but it focused on the role of the ocean in all of this - remember that the atmosphere and oceans are coupled and they talk to each other (this is what all the scientists at the Met Office refered to the relationship as) and also that the oceans are both a source and sink of gases like carbon dioxide. The main basis of the seminar was on the speed of responses and so say if carbon dioxide instantaneously doubled then an aspect of the climate system would respond rapidly, with a thermal inertia (describes the ability of a given volume of a substance to store internal energy while undergoing a given temperature change, but without undergoing a phase change, so is said to be resistant to temperature change) which is determined by the mixed layer in the oceans.When you then look at long timescales there is a slower element to global warming, one that many consider is effectively irreverisble even if emissions would cease. A fast response, which is commonly classed as the 'transient climate sensitivity' ( I have been picking up some new words and phrases over the last few days!), on the other hand, is only relevant to a response timescale of a decade to century. So basically the seminar was about responses to different factors by the climate and the oceans and the speed of the responses (something which when asked about seemed to divide the conference room in two!). It included links to not only anthropogenic greenhouse gas emissions but also links to volcanic eruptions and ENSO and various other things which he included in his models. The last aspect of this seminar was to look at the model which he referred to as being "embarrasingly simple" and used observational evidence of global warming over the past century to estimate the parameters(although it didn't really look that simple to me - but  the people I was with said that in terms of the equations used and parameters set it was quite simple) and compare it to the results from more complex models and show that the simple model had less uncertainity surrounding it and so is perhaps the better one to use. Over the last few days, one of the many things I have learnt, is that none of these models are perfect - something that was demonstrated in the 'Oceans and Iced Tea' meeting I attended in the afternoon - and that the scientists spend much of their time developing, refining, running and then criticising the models due to the uncertainities that they produce and the errors they sometimes generate. However, these models are crucial as they provide us a insight into the possible future conditions as the variables can be changed and things messed around with a bit to see how different factors provoke different responses. I have got so much I want to write about but I just have to find the time! Hopefully something on modelling (it will be the most simplistic explanation of the basics ever) and on climate sensitivity will appear over the next week.


The afternoon 'Oceans and Iced Tea' meeting was a bit easier to follow (perhaps as my knowledge of terminology on this topic is slightly better) and it was on the topic of erroneous eddies that were appearing on ocean models and why. The reasons discussed including the lack of bathymetry included in the models and the idea of the influence of continental shelves and the shelf currents. Work is always being down to improve the models that they use as they are used to generate data for some may things. Something that surprised me was that many of the models used across the different departments were quite similar and has only small adaptions to make the predictions generated more specific to certain areas.

I also had a rather long chat with some of the summer placement students who are doing like 12 weeks paid work experience at the Met Office where they get to do some proper research using on the models and stuff. These students were all at either the end of their degrees, doing masters or phd's but this scheme is something that I would strongly recommend you keep an eye out for if and when you get to that stage. They all said it was a really great and beneficial thing to do and, in reference to going into this line of work in the future, they all said excatly the same thing - you NEED to have evidence of have done some high level maths or physics from your degree and modelling work!

It was, again, another incredible day and I learnt loads and got a lot of good advice from various different people who definetly gave me a look to think about in terms my future!