Is the dramatic surface warming observed in the Antarctic Peninsula also present throughout the troposphere?

Meteorological surface observations from the Antarctic Peninsula began in the mid-1940s. The most reliable long-term (~50 years) temperature record from this region has been obtained from Faraday station on the western side of the Peninsula (Fig. 1). The annual surface temperature trend for the 50-years from 1951- 2000 is +0 .0562 ± 0.0429°C a"', which is significant at the 1% level. Hansen et al. (1999) demonstrated that from 1950-98 the Peninsula underwent the greatest warming anywhere in the Southern Hemisphere, which was of a similar magnitude to the largest coincident global temperature rises, observed in regions of the Arctic (cf. their Plate 4a) . Seasonally, the greatest warming at Faraday has occurred during the austral winter (JJA) - +0.1089 ± 0.0880°C ã' - and has been linked to a decrease in winter sea-ice extent in the Bellingshausen Sea west of the Peninsula (Jacobs and Comiso 1997; King and Harangozo 1998), with resultant changes in the regional marine ecosystem (Fraser et a(. 1992). However, it is the smaller summer (DJF) temperature increase of +0 .0244 ± 0.0168°C ã' that is principally responsible for the widely publicized disintegration of many ice shelves fringing the northern Peninsula (Vaughan and Doake 1996).

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