|From||"Roger Brugge" <firstname.lastname@example.org>|
|Date||Tue, 22 May 2012 11:49:13 +0000|
http://www.shef.ac.uk/geography/phd/shinecentre2012 Shine Centre Studentship The Northern Hemisphere polar jet stream and its effect on regional climate change during 1871-2100 The key motivation for this study is that over the last decade a tendency has developed for a more meridional jet-stream pattern than previously, which has led to unusual regional climate anomalies with severe socio-economic impacts across the Northern Hemisphere, including in 2010 record floods in Pakistan, intense heat waves and forest fires in Russia, and some enigmatically cold winter spells on both sides of the Atlantic in 2010 and 2011 (e.g. December 2010 was the coldest December since 1890 in the Central England Temperature record) which caused severe socio-economic disruptions in the UK. While these regional climate anomalies are directly attributable to changes in the jet stream, the ultimate drivers of the changes in the jet stream itself have not been fully quantified. One of the main aims of the current project is to advance mathematical modelling (analytical and numerical) in order to make a leap forward in the understanding of jet streams and their effects on climate. At the same time, Arctic sea-ice coverage - most notably in late summer - has reached and remained at record low levels. This may be linked with what Professor James E Overland, an international leading expert of the field, has dubbed 'Warm Arctic Cold Continents' - whereby, as a result of the polar amplification of global warming and thinning Arctic sea-ice, more heat is released from the polar ocean to the overlying atmosphere, which reduces the meridional surface temperature gradient and tends to weaken the mid-latitude westerly winds, with resulting jet-stream changes as noted above. Note however that Arctic Sea Ice is not the only driver of changes in the jet stream. Contemporaneous changes in solar output, the Pacific Ocean's El Nino - Southern Oscillation cycle, the state of the Atlantic Ocean and other factors linked to Northern European climate are all known to have additional impacts on the northern hemisphere jet stream and thereby impact Europe and other regional climates. Fluctuations in these additional factors are superimposed on top of the recent Arctic Sea Ice decline in the historical record and these varying drivers need to be unravelled for a more complete picture. This is a second main aim of the proposed project. This project will analyse in details the historic observational records for evidence of similar sea ice changes to the recent period during the previous Arctic warm period of the 1930s/40s, to ascertain to what extent there is a consistent response and to what extent recent changes in the jet stream might be caused by natural climate variability. This will also allow us to constrain the likely future changes in jet-stream behaviour, and therefore regional disparities of climate change in the generally densely populated mid-latitude Northern Hemisphere continents during the coming decade and indeed the remainder of the Twenty First Century. The project will also analyse and model changes in the polar front jet stream configuration and strength in the Northern Hemisphere mid-high latitude atmosphere in response to ongoing climate change from global warming and other relevant factors. It will do so using state-of-the-art climate analyses including: Twentieth Century Reanalysis (1871-2008) and ECMWF ERA-40 and Interim Reanalysis (1957-2012) sea level pressure, winds, temperatures and geopotential height fields, and also the IPCC AR5 suite of GCM projections. The project will include analysis of Met Office climate model simulations: both backwards to 1871 (to assess GCM reliability against the observational record and for validating purposes our modelling) and forwards to 2100 and will interact with the Met Office's long range forecasting and climate change projection programs through active collaboration. The project is a collaboration between Dr Edward Hanna (PI, Dept of Geography, email@example.com<mailto:firstname.lastname@example.org>) and Prof Robert von Fay-Siebenburgen (CoI, SoMaS, email@example.com<mailto:firstname.lastname@example.org>). Please direct informal queries to either of the above two people. The project will also have an external CoI, Dr Adam Scaife (Head, Monthly to Decadal Prediction; Met Office). During the project the student will spend the a short period of time at the Met Office in order to acquire the modelling skills necessary for a successful outcome. Deadline: Tuesday 5th June 2012 or until filled. How to apply: This project is administered through SOMAS<http://www.sheffield.ac.uk/maths>. You can apply online<http://www.sheffield.ac.uk/postgraduate/research/apply> for admission to the university, choosing SOMAS as your department of study.
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