Validation and trend analysis of ECV soil moisture data on cropland inNorth China Plain during 1981–2010
Validation and trend analysis of ECV soil moisture data on cropland inNorth China Plain during 1981–2010
复制标题
1981—2010年华北平原农田ECV土壤水分数据验证及趋势分析
DOI：
10.1016/j.jag.2015.10.010
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发表时间：
2016
影响因子：
7.5
通讯作者：
Shi hu
中科院分区：
文献类型：
--
作者：
Sisi Wang;Xingguo Mo;Suxia Liu;Zhonghui Lin;Shi hu
欧洲空间局气候变化计划正在利用被动和主动卫星微波传感器建立全球土壤水分时间序列。本研究旨在验证ECV SM数据集的可靠性，并尝试分析农田SM的趋势。首先，利用1992 - 2010年全国228个测站和华北平原21个测站作物生长季的实测数据，对ECV SM产品进行了验证。在此基础上，分析了1981 - 2010年华北平原冬小麦（4 - 6月）和夏玉米（7 - 9月）生育期ECV SM的时空变化特征。最后，探讨了植被指数与降水、蒸散量的关系。结果表明，ECV SM能较好地捕捉到季节性的SM动态。ECV SM在中国的平均三重配置随机误差为0.052 m3 m − 3，而在农田中的误差范围为0.003 - 0.156 m3 m −3。ECV SM与气象观测值的平均斯皮尔曼相关系数在中国为0.42（p< 0.01），在华北平原农田为0.43（p< 0.01）。从空间上看，小麦季大部分地区ECV SM呈下降趋势，玉米季华北平原ECV SM呈南正北负的趋势，与降水量的变化趋势一致。总体而言，ECV SM可能适用于NCP的趋势分析，其验证和分析将有助于进一步增强ECV SM产品。
Global time series of the Essential Climate Variable (ECV) soil mositure (SM) is being developed from passive and active satellite microwave sensors at a coarse spatial resolution with Climate Change Initiative program funded by European Space Agency. This study aims to validate the reliability of ECV SM dataset, and attempts are made to analyze SM trends in cropland. Firstly,in-situSM measurements during crop growing seasons from 1992 to 2010 for 228 stations across China and 21 stations over cropland of North China Plain (NCP) were employed to validate ECV SM product. Then, the spatiotemporal variations of ECV SM were analyzed during growing period of winter wheat (April–June) and summer maize (July–September) from 1981 to 2010 in NCP. Finally, the possible relationship between SM, precipitation, evapotranspiration and NDVI were explored. Results showed that ECV SM could generally capture the seasonal SM dynamics. The average triple collocation random error of ECV SM in China was 0.052 m3m−3while the error in cropland ranged from 0.003 to 0.156 m3m−3. The averaged Spearman correlation coefficient between ECV SM and allin-situobservations was 0.42 (p< 0.01) in China and 0.43 (p< 0.01) for cropland over NCP. Spatially, ECV SM was decreasing in most areas during wheat season, whereas the trends of ECV SM were positive in south and negative in north during maize season in NCP, being consistent with the precipitation fluctuation. Overall, ECV SM is potentially suitable for trend analysis in NCP and its validations and analysis will be helpful for further enhancement of the ECV SM product.