Eighteen-year record of circum-Antarctic landfast-sea-ice distribution allows detailed baseline characterisation and reveals trends and variability
Eighteen-year record of circum-Antarctic landfast-sea-ice distribution allows detailed baseline characterisation and reveals trends and variability
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DOI：
10.5194/tc-15-5061-2021
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发表时间：
2021-11
期刊：
影响因子：
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通讯作者：
A. Fraser;R. Massom;M. Handcock;P. Reid;K. Ohshima;M. Raphael;J. Cartwright;A. Klekociuk;Zhaohui Wang;R. Porter-Smith
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作者：
A. Fraser;R. Massom;M. Handcock;P. Reid;K. Ohshima;M. Raphael;J. Cartwright;A. Klekociuk;Zhaohui Wang;R. Porter-Smith
抽象的。固定在陆地上的海冰（固定冰）是南极大陆架冰冻圈的一个重要组成部分，但人们对其了解甚少，它在大气-海洋-冰盖相互作用以及耦合的生态和地球化学过程中发挥着关键作用。在这里，我们提出了第一个深入的基线分析的变异性和变化，在环南极坚冰分布（包括其与测深的关系），基于一个新的高分辨率卫星派生的时间序列为2000年至2018年。这表明：（a）总体趋势为-882 824 km 2 yr−1（-0.19 0. 18% yr−1）;（B）就坚冰覆盖范围和形成模式而言，有8个不同的区域。其中，四个国家在18年期间呈现积极趋势，四个国家呈现消极趋势。在东南极洲和别林斯高晋海可以看到积极的趋势，该地区的积极趋势最大，为+1198 <$359 km 2 yr−1（+1.10 <$0.35% yr−1）。这四个负趋势主要发生在南极洲西部，最大的负趋势为-1206 277 km 2 yr−1（-1.78 0. 41% yr−1），发生在罗斯海西部的维多利亚和奥茨地地区。所有的趋势都很重要。这一新的基线分析表明，我们对全球冰冻圈和复杂的南极沿海系统现状的了解有了重大进展，这两个系统都容易受到气候多变性和变化的影响。它还将为广泛的其他研究提供信息。
Abstract. Landfast sea ice (fast ice) is an important though poorly understood component of the cryosphere on the Antarctic continental shelf, where it plays a key role in atmosphere–ocean–ice-sheet interaction and coupled ecological and biogeochemical processes. Here, we present a first in-depth baseline analysis of variability and change in circum-Antarctic fast-ice distribution (including its relationship to bathymetry), based on a new high-resolution satellite-derived time series for the period 2000 to 2018. This reveals (a) an overall trend of -882±824 km2 yr−1 (-0.19±0.18 % yr−1) and (b) eight distinct regions in terms of fast-ice coverage and modes of formation. Of these, four exhibit positive trends over the 18-year period and four negative. Positive trends are seen in East Antarctica and in the Bellingshausen Sea, with this region claiming the largest positive trend of +1198±359 km2 yr−1 (+1.10±0.35 % yr−1). The four negative trends predominantly occur in West Antarctica, with the largest negative trend of -1206±277 km2 yr−1 (-1.78±0.41 % yr−1) occurring in the Victoria and Oates Land region in the western Ross Sea. All trends are significant. This new baseline analysis represents a significant advance in our knowledge of the current state of both the global cryosphere and the complex Antarctic coastal system, which are vulnerable to climate variability and change. It will also inform a wide range of other studies.