Research press release


Nature Communications

Climate sciences: Antarctic glaciers in hot water



今回、Ala Khazendarたちは、米国航空宇宙局(NASA)のオペレーション・アイスブリッジで収集された航空探査データを用いて、アムンゼン海の湾内にある3つの南極氷河(スミス、ポープ、コーラー)の融解速度と接地線の位置を調べた。Khazendarたちは、2002~2009年に氷河の融解が急速かつ不均一に起こり、スミス氷河で減少した氷厚の累計が約0.5キロメートルとなり、年平均で最大70メートルの速さで氷が失われたことを報告している。その後2009~2014年には暖かい海水の流入量が減り、ポープ氷河とコーラー氷河からの氷減少は鈍化したが、スミス氷河の接地線は後退して深い谷を形成し、大量の氷の減少の継続に寄与した。


Hundreds of metres of solid ice were lost from West Antarctica’s glaciers between 2002 and 2009, according to a study published in Nature Communications this week. The findings support the hypothesis that the influx of warm ocean water beneath ice shelves in the Amundsen Sea embayment significantly increased during the mid-2000s.

The Amundsen Sea embayment of West Antarctica hosts some of the fastest melting glaciers on the planet. Warm ocean waters flow across the continental shelf into sub-ice shelf cavities where they slowly erode the ice, especially near the glaciers’ grounding lines - where the glacier meets the sea. However, until now the exact magnitude of this ice loss has remained poorly quantified.

Ala Khazendar and colleagues use airborne data collected as part of NASA’s Operation IceBridge to examine the variations in melting rates and grounding line positions of three Antarctic glaciers in the Amundsen Sea embayment: Smith, Pope, and Kohler. The authors report intense, unbalanced melting of the glaciers between 2002 and 2009, with Smith Glacier losing as much as 70 metres per year, and almost half a kilometre of ice thickness in total. Between 2009 and 2014 a reduction in the influx of warm ocean water led to less ice loss from Pope and Kohler; however, the grounding line of Smith Glacier retreated into a deep trough, contributing to continued intense ice loss.

These findings demonstrate that the position of the retreating glaciers, along with the variability of oceanic heat influx, modulate the observed melting rates.

doi: 10.1038/ncomms13243

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