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SUMMARY:Is the Halley temperature record homogeneous? - Prof. John King\, 
 British Antarctic Survey
DTSTART:20201023T130000Z
DTEND:20201023T140000Z
UID:TALK153307@talks.cam.ac.uk
CONTACT:Dr Hua Lu
DESCRIPTION:Commencing in 1956\, observations made at Halley Research Stat
 ion provide one of the longest continuous series of near-surface temperatu
 re observations from the Antarctic continent. The record does not\, howeve
 r\, come from a single location but is a composite of observations from a 
 sequence of seven stations\, all situated on the Brunt Ice Shelf\, that ra
 nge from around 10 km to 50 km distance from the ice shelf coast. Until re
 cently it was generally assumed that temperature data from all of these st
 ations could be combined into a single composite record with no adjustment
 . In this talk I will report on recent research that suggests that this as
 sumption of homogeneity is incorrect. Application of an objective statisti
 cal change-point detection algorithm indicates that there is at least one 
 sudden downward jump in temperature associated with relocation of the stat
 ion\, which is large enough to introduce a spurious cooling trend into the
  composite record. Analysis of observations from a network of automatic we
 ather stations and data from a run of a high-resolution regional atmospher
 ic model confirm the existence of mean temperature gradients across the ic
 e shelf which are large enough to explain the jumps seen in the record. Th
 ese temperature gradients are largely driven by the advection of maritime 
 air masses across the cold surface of the ice shelf. I will discuss the im
 plications of these findings for local and regional climate studies that m
 ake use of the Halley record and will consider whether it might be possibl
 e to create a homogenised record.
LOCATION:https://ukri.zoom.us/j/94856318028?pwd=UHJCckFwNUlVMmZJaURCQlF4Sj
 BKdz09
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