Central West Antarctica among the most rapidly warming regions on Earth

Abstract

There is clear evidence that the West Antarctic Ice Sheet is contributing to sea-level rise. In contrast, West Antarctic temperature changes in recent decades remain uncertain. West Antarctica has probably warmed since the 1950s, but there is disagreement regarding the magnitude, seasonality and spatial extent of this warming. This is primarily because long-term near-surface temperature observations are restricted to Byrd Station in central West Antarctica, a data set with substantial gaps. Here, we present a complete temperature record for Byrd Station, in which observations have been corrected, and gaps have been filled using global reanalysis data and spatial interpolation. The record reveals a linear increase in annual temperature between 1958 and 2010 by 2.4±1.2 • C, establishing central West Antarctica as one of the fastest-warming regions globally. We confirm previous reports of West Antarctic warming, in annual average and in austral spring and winter, but find substantially larger temperature increases. In contrast to previous studies, we report statistically significant warming during austral summer, particularly in December-January, the peak of the melting season. A continued rise in summer temperatures could lead to more frequent and extensive episodes of surface melting of the West Antarctic Ice Sheet. These results argue for a robust long-term meteorological observation network in the region.

Identification of Air Masses Responsible for Warm Events on the East Antarctic Coast

“…For example, warming trends observed in the Antarctic Peninsula (AP) and West Antarctica (WA) in the past decades (Vaughan et al 2003;Bromwich et al 2012) have been associated with increase in mass loss Sutterley et al 2014). Present available observation dataset, however, is of insufficient length to address that these warming trends are anthropogenically forced, because natural interannual to multi-decadal variability may obscure these warming trends (Jones et al 2016).…”

“…This warm westerly flow travels over mountain ranges on the AP, causing additional temperature increase by adiabatic warming as the air descends on the east side of the AP that is called a foehn warming (e.g., Elvidge et al 2015Cape et al 2015;Grosvenor et al 2014). The increase in poleward marine air advection is also known to have contributed to summer warming at Byrd Station through most of the late 1980s, though it can not solely explain long-term trends in West Antarctica (Bromwich et al 2012). Changes in the frequency, duration and magnitude of marine air intrusions therefore are expected to play a major role on the occurrence of melt on the coast of the East Antarctic ice sheet.…”

Absence of 21st century warming on Antarctic Peninsula consistent with natural variability

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While global mean surface air temperature (SAT) has increased over recent decades, the rate 28 of regional warming has varied markedly 10 , with some of the most rapid SAT increases 29 recorded in the polar regions [11][12][13] . In Antarctica, the largest SAT increases have been 30 observed in the Antarctic Peninsula (AP) and especially on its west coast 1 : in particular, 31

Vernadsky (formerly Faraday) station (Fig.

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Study of the active layer at the Spanish Antarctic station “Gabriel de Castilla”, Deception Island, Antarctica

“…Sin embargo, el espesor de la capa activa y su gradiente de temperatura pueden verse incrementados si el balance de energía en la superficie del suelo es positivo, como está ocurriendo en la actualidad por efecto del calentamiento global, y del que la Antártida es un claro ejemplo (ej., Steig et al, 2009;Bromwich et al, 2013). El incremento del espesor de la capa activa y su temperatura conlleva que parte del permafrost que está situado inmediatamente por debajo de ella se vaya fundiendo, es decir, se vaya degradando.…”