BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:A Lagrangian analysis of the seasonal and interannual variability 
 in Greenland precipitation sources - Johannes de Leeuw\, Utrecht Universit
 y
DTSTART:20180611T101500Z
DTEND:20180611T111500Z
UID:TALK106198@talks.cam.ac.uk
CONTACT:Dr Gillian Young
DESCRIPTION:Precipitation is a key element when studying the polar climate
  as it directly effects the ice sheet mass balance. Additionally\, its iso
 topic composition\, which is stored in ice cores\, can be used to reconstr
 uct local temperatures on much longer timescales than available from direc
 t observations. Nonetheless\, making a robust temperature reconstruction r
 emains a challenging task\, as a large number of physical processes can al
 ter the isotopic composition of the precipitation. For example\, a correct
  representation of the environmental conditions under which the moisture e
 vaporates into the atmosphere at the source regions is crucial. Critical q
 uantities like surface temperature and relative humidity are known to be a
 lso spatially heterogeneous and consequently\, a shift in source regions c
 ould have a large impact on the initial isotopic composition as well.\n\nT
 o investigate the importance of source variability for Greenland\, we stud
 ied the variability of the moisture source regions for Greenland on both i
 nterannual and seasonal timescales between 1987-2016\, using an offline tr
 ajectory model (ROTRAJ) forced with reanalysis data (ERA-Interim). Using t
 he reanalysis data\, it is found that there exists a strong seasonal varia
 bility in the moisture uptake locations for the precipitation observed ove
 r Greenland. During winter\, moisture sources are mainly located over the 
 Atlantic Ocean\, while the largest contributor of moisture for Greenland p
 recipitation during summer is the North American continent. Interestingly\
 , the detailed source locations in winter are highly dependent on the circ
 ulation patterns\, while in summer source regions are more constant and ma
 inly vary in strength. These results suggest that changes in precipitation
  seasonality as well as changes in atmospheric circulation can have a larg
 e influence on the isotope signature of Greenland precipitation and should
  therefore be considered carefully when reconstructing temperatures from i
 ce cores.
LOCATION:British Antarctic Survey\, Seminar Room 187
END:VEVENT
END:VCALENDAR