Estimating northern hemisphere snow water equivalent for climate research through assimilation of space-borne radiometer data and ground-based measurements
Estimating northern hemisphere snow water equivalent for climate research through assimilation of space-borne radiometer data and ground-based measurements
复制标题
DOI：
10.1016/j.rse.2011.08.014
复制
发表时间：
2011-12
影响因子：
13.5
通讯作者：
M. Takala;K. Luojus;J. Pulliainen;C. Derksen;J. Lemmetyinen;Juha-Petri Kärnä;J. Koskinen;B. Bojkov-
中科院分区：
文献类型：
--
作者：
M. Takala;K. Luojus;J. Pulliainen;C. Derksen;J. Lemmetyinen;Juha-Petri Kärnä;J. Koskinen;B. Bojkov-
雪水当量是描述全球季节积雪的关键变量。然而，可靠的信息半球尺度的变化SWE是缺乏的，因为传统的方法，如地面测量插值和独立的算法应用于星载观测是高度不确定的雪团的空间分布及其演变。本文利用卫星被动微波辐射计资料同化天气站雪深资料的算法，得到了北方半球30年的季节性雪深时间序列。该数据集使用来自俄罗斯、前苏联、芬兰和加拿大的独立SWE参考数据进行验证。SWE时间序列的验证表明，当SWE <150 mm时，总体上具有较强的检索性能，均方根误差低于40 mm。当SWE高于此阈值时，检索不确定性增加。SWE估计也比较了一个典型的独立的卫星被动微波算法所获得的结果。这种比较表明了新开发的同化方法的好处。此外，在卫星被动微波测量的时代，北方半球雪团的趋势和年际变化。
The key variable describing global seasonal snow cover is snow water equivalent (SWE). However, reliable information on the hemispheric scale variability of SWE is lacking because traditional methods such as interpolation of ground-based measurements and stand-alone algorithms applied to space-borne observations are highly uncertain with respect to the spatial distribution of snow mass and its evolution. In this paper, an algorithm assimilating synoptic weather station data on snow depth with satellite passive microwave radiometer data is applied to produce a 30-year-long time-series of seasonal SWE for the northern hemisphere. This data set is validated using independent SWE reference data from Russia, the former Soviet Union, Finland and Canada. The validation of SWE time-series indicates overall strong retrieval performance with root mean square errors below 40mm for cases when SWE <150mm. Retrieval uncertainty increases when SWE is above this threshold. The SWE estimates are also compared with results obtained by a typical stand-alone satellite passive microwave algorithm. This comparison demonstrates the benefits of the newly developed assimilation approach. Additionally, the trends and inter-annual variability of northern hemisphere snow mass during the era of satellite passive microwave measurements are shown.