Inter-annual water mass variations from GRACE in central Siberia
Inter-annual water mass variations from GRACE in central Siberia
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DOI：
10.1007/s00190-012-0597-9
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发表时间：
2013-03
影响因子：
4.4
通讯作者：
S. Vey;H. Steffen;Jürgen Müller;J. Boike
中科院分区：
文献类型：
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作者：
S. Vey;H. Steffen;Jürgen Müller;J. Boike
我们的研究分析了以Lena分水岭为中心的雅库茨克地区的卫星和陆地观测结果，该地区主要以持续的永久冻土为特征。利用重力恢复和气候实验卫星任务的月度解，我们发现从2002年到2007年西伯利亚中部的质量增加，并在2007年到2011年之间逆转为质量减少。在整个观察期内，没有明显的群体性趋势。为了进一步量化这种行为，详细研究了不同的质量信号分量：(1)大气质量的年际变化，(2)冰川均衡调整(GIA)的可能影响，以及(3)水文质量变化。在标准处理中，大气质量信号是基于来自数值天气预报模式的数据来减少的。我们使用地面气压观测来验证这种大气减少。在年际时间尺度上，模式预报的大气质量信号与地面气压观测的大气质量信号之间的当量水高相差4毫米。利用全球冰模式和球对称、可压缩、Maxwell粘弹性地球模式计算了GIA对西伯利亚上空质量信号的影响。计算表明，对于研究区来说，可以排除GIA的任何影响。因此，信号的主要部分可以归因于水文质量的变化。我们简要讨论了潜在的水文影响，如降水、河流流量、地表和地下蓄水量的变化。
Our study analyses satellite and land-based observations of the Yakutsk region centred at the Lena watershed, an area characterised mainly by continuous permafrost. Using monthly solutions of the Gravity Recovery And Climate Experiment satellite mission, we detect a mass increase over central Siberia from 2002 to 2007 which reverses into a mass decrease between 2007 and 2011. No significant mass trend is visible for the whole observation period. To further quantify this behaviour, different mass signal components are studied in detail: (1) inter-annual variation in the atmospheric mass, (2) a possible effect of glacial isostatic adjustment (GIA), and (3) hydrological mass variations. In standard processing the atmospheric mass signal is reduced based on the data from numerical weather prediction models. We use surface pressure observations in order to validate this atmospheric reduction. On inter-annual time scale the difference between the atmospheric mass signal from model prediction and from surface pressure observation is4 mm in equivalent water height. The effect of GIA on the mass signal over Siberia is calculated using a global ice model and a spherically symmetric, compressible, Maxwell-viscoelastic earth model. The calculation shows that for the investigated area any effect of GIA can be ruled out. Hence, the main part of the signal can be attributed to hydrological mass variations. We briefly discuss potential hydrological effects such as changes in precipitation, river discharge, surface and subsurface water storage.