Getz Ice Shelf melting response to changes in ocean forcing
Getz Ice Shelf melting response to changes in ocean forcing
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DOI：
10.1002/jgrc.20298
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发表时间：
2013-09-01
影响因子：
3.6
通讯作者：
Mouginot, J.
中科院分区：
文献类型：
--
作者：
Jacobs, S.;Giulivi, C.;Mouginot, J.
庞大而复杂的盖茨冰架沿着阿蒙森海的西南极洲海岸线延伸近半，与大多数其他太平洋区域的冰架相比，它所处的海洋环境变化更为多样。此处利用在其冰下空洞开口附近获取的海洋温度、盐度和溶解氧剖面，来估算海水输送量和融水比例。2000年和2007年更完整的数据覆盖了1994年至2011年间观测到的大部分变化情况，而在一个冰前沿附近长达一年的记录，支持了利用夏季剖面来确定年度底部融化速率。我们发现，平均融化速率分别为1.1米/年和4.1米/年，2007年的速率更高，当时有更大体积的温暖深水占据了邻近的大陆架，且海洋环流更为强劲。研究结果与相对于冰架吃水深度的温跃层深度变化以及向邻近大陆架的物质输送变化相一致。我们还根据2003年至2008年冰流量的卫星测量数据、模拟积累量和变薄情况，计算出2007 - 2008年稳态融化速率和实际融化速率分别为2.5米/年和4.6米/年。这意味着2000年质量平衡为正，但在2007年为负，当时盖茨冰架产生的融水量比任何更大、融化更慢或更小、融化更快的冰架都要多。
The large and complex Getz Ice Shelf extends along nearly half of the West Antarctic coastline in the Amundsen Sea and is exposed to a more variable ocean environment than most other Pacific sector ice shelves. Ocean temperature, salinity, and dissolved oxygen profiles acquired near its sub-ice cavity openings are used here to estimate seawater transports and meltwater fractions. More complete coverage during 2000 and 2007 brackets most of the variability observed from 1994 to 2011, and yearlong records near one ice front support the use of summer profiles to determine annual basal melt rates. We find area average rates of 1.1 and 4.1 m/yr, higher in 2007 when a larger volume of warmer deep water occupied the adjacent continental shelf, and the ocean circulation was stronger. Results are consistent with changes in thermocline depths relative to ice shelf draft and mass transports onto the adjacent continental shelf. We also calculate steady state and actual melting of 2.5 and 4.6 m/yr in 2007-2008 from satellite measurements of ice flux, modeled accumulation, and thinning from 2003 to 2008. This implies a positive mass balance in 2000, but negative in 2007, when the Getz was producing more meltwater than any of the larger, slower melting or smaller, faster-melting ice shelves.