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SUMMARY:Symposium on Polar Tropical Teleconnections - Lesley Gray (Univers
 ity of Oxford)\, Matt Collins (University of Exeter)\, Liz Thomas (British
  Antarctic Survey)\, Andrew Turner (University of Reading)
DTSTART:20191016T130000Z
DTEND:20191016T163000Z
UID:TALK127006@talks.cam.ac.uk
CONTACT:Dr Mario Krapp
DESCRIPTION:The Cambridge Centre for Climate Science kindly invites you to
  its symposium on polar tropical teleconnections.\n\nCome join us for an e
 xciting and diverse range of talks.\n\n\nSchedule:\n\n14:00 - 14:45\nLesle
 y Gray\, University of Oxford\nTropical - Extratropical Teleconnections in
 volving the Stratosphere\n\n14:45 - 15:30\nMatt Collins\, University of Ex
 eter\nThe El Nino Southern Oscillation and its Teleconnections Under a\nCh
 anging Climate\n\n15:30 - 16:00 pm tea and coffee break\n\n16:00 - 16:45\n
 Liz Thomas\, British Antarctic Survey\, Cambridge\nTropical Pacific influe
 nce on West Antarctica - evidence from ice\ncores\n\n16:45 - 17:30\nAndrew
  Turner\, University of Reading\nBITMAP: Better understanding of Interregi
 onal Teleconections for\nprediction in the Monsoon and Poles\n\n\n17:30 Wi
 ne reception\n\nAbstracts:\n\nLesley Gray\, University of Oxford: Tropical
  -- Extratropical Teleconnections involving the Stratosphere\n\nThere is n
 ow plenty of evidence that stratospheric dynamics can impact the troposphe
 re below. This is especially true in NH winter when we see a shift to a ne
 gative North Atlantic Oscillation (NAO) index for up to ~60 days following
  an extreme polar vortex event known as a Sudden Stratospheric Warming (SS
 W). Some winters have one\, or even two\, SSWs while others have none. Und
 erstanding what influences their occurrence is really interesting\, and in
 volves large-scale teleconnections within the ocean - troposphere - strato
 sphere system and between equatorial and high latitudes. We have a rough u
 nderstanding of some of the factors that influence SSWs\, such as ENSO\, t
 he QBO\, the solar cycle and these can help to provide statistical predict
 ions. But forecasting an individual SSW\, especially its timing during win
 ter - which is what is needed to be really useful - has proved a real chal
 lenge for seasonal forecasters. The talk will give an overview of the fact
 ors influencing SSWs and describe some UM experiments where we explore the
  timing of SSWs using a couple of case studies. The results are surprising
  and point to the importance of a relatively neglected region of the strat
 osphere where improvements could help to substantially improve SSW forecas
 ts.\n\n\nMat Collins\, University of Exeter -- The El Nino Southern Oscill
 ation and its Teleconnections Under a Changing Climate\n\nProjections of c
 limate change indicate an increasing frequency of extreme El Nino Southern
  Oscillation (ENSO) events in the future\, even under low emissions scenar
 ios. This talk will review recent literature on changes in ENSO and its te
 leconnections under climate change. The robustness of the physical mechani
 sms for the increase in frequency of extreme ENSO will be discussed. Futur
 e teleconnection changes are complex\, with interactions between mean clim
 ate change and wet/dry teleconnections in both the tropics and midlatitude
 s. The role of vegetation in controlling those changes will be highlighted
 .\n\n\nLiz Thomas\, British Antarctic Survey\, Cambridge -- Tropical Pacif
 ic influence on West Antarctica – evidence from ice cores\n\nAntarctica 
 has experienced dramatic climate change in recent decades. Warming surface
  temperatures and changing wind patterns have resulted in ice shelf collap
 se and accelerated melting of glaciers\, particularly in West Antarctica. 
 In this talk\, I present ice core records from West Antarctica and the Ant
 arctic Peninsula\, highlighting the tropical teleconnection that exists ov
 er centennial time scales. I explore the influence of the tropical pacific
  in driving climate change in West Antarctica and demonstrate the importan
 ce of large-scale modes of atmospheric variability on Antarctic mass balan
 ce\, especially during the late 20th century.\n\n \n\n\nAndrew Turner\, Un
 iversity of Reading -- BITMAP: Better understanding of Interregional Telec
 onections for prediction in the Monsoon and Poles\nIn the BITMAP project (
 funded by JPI-Climate and the Belmont Forum)\, we set out to understand mo
 re about connections between high latitudes and the South Asia region.  Th
 e topic is of particular interest since we expect\, under Arctic ice melt 
 and tropical tropospheric warming\, the meridional temperature gradient to
  weaken which may have implications for the subtropical jetstream\, the mo
 nsoons and the ITCZ in general.  Work in BITMAP has focused in particular 
 on Western Disturbances\, a type of storm that can affect northern India a
 nd Pakistan during wintertime\, supplying rainfall and sometimes extreme e
 vents.  In recent years\, there has been some suggestion of Western Distur
 bances interacting with tropical lows during the summer\, leading to a rap
 id monsoon onset and extreme flooding.  This therefore motivates us to und
 erstand how Western Disturbances have changed in the past and how they may
  change in the future\, and to examine the basis for any change.  This tal
 k examines the structure of Western Disturbances in the ERA-Interim datase
 t based on a feature tracking algorithm designed at Reading\, and their ro
 le in providing extreme rainfall.  Next\, we compare trends in Western Dis
 turbance activity in the historical record with those in CMIP5 experiments
  of the 20th century\, before examining projections of intensity and storm
  count in RCP future projections of CMIP6.  Finally\, we examine the chang
 ing background state responsible for these changes.
LOCATION:Small Lecture Theatre\, Department of Geography
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