Validation of SMAP surface soil moisture products with core validation sites
Validation of SMAP surface soil moisture products with core validation sites
复制标题
DOI：
10.1016/j.rse.2017.01.021
复制
发表时间：
2017-03-15
影响因子：
13.5
通讯作者：
Yueh, S.
中科院分区：
文献类型：
--
作者：
Colliander, A.;Jackson, T. J.;Yueh, S.
NASA土壤湿度主被动（SMAP）任务利用了一组核心验证点作为评估土壤湿度检索算法性能的主要方法。这些站点在不同条件和位置的SMAP产品网格像素内提供校准良好的原位土壤湿度测量。基于原位测量的SMAP产品网格像素内的平均土壤湿度估算，如果对传感器进行了特定位置的校准，并且在空间域上有足够的复制，并且基于使用土壤湿度分布的独立估计的分析的上尺度函数，则更可靠。SMAP通过Cal/Val合作伙伴计划满足了这些要求。本文介绍了SMAP任务前11个月34个候选核心验证点的结果。在获得SMAP数据之前对这些站点进行了筛选，在34个候选站点中，有18个站点（至少）满足其中一个分辨率尺度的所有要求。其余的站点在算法评估中用作次要信息。结果表明：基于SMAP辐射计的土壤水分数据产品满足0.04 m(3)/m(3)体积土壤水分（无偏均方根误差）的预期性能；雷达-辐射计组合产品接近其0.04 m(3)/m(3)的预期性能，雷达-辐射计组合产品满足其0.06 m(3)/m(3)的目标精度（由于SMAP雷达故障，组合产品和雷达-辐射计组合产品的长度被截断为10周左右）。在完成任务的密集Cal/Val阶段后，SMAP项目将继续与Cal/Val伙伴合作，通过继续比较现有的核心验证地点和包含可以解决缺点的候选地点，继续增强主要和扩展地理领域的产品。(C) 2017爱思唯尔公司版权所有。
The NASA Soil Moisture Active Passive (SMAP) mission has utilized a set of core validation sites as the primary methodology in assessing the soil moisture retrieval algorithm performance. Those sites provide well calibrated in situ soil moisture measurements within SMAP product grid pixels for diverse conditions and locations. The estimation of the average soil moisture within the SMAP product grid pixels based on in situ measurements is more reliable when location specific calibration of the sensors has been performed and there is adequate replication over the spatial domain, with an up-scaling function based on analysis using independent estimates of the soil moisture distribution. SMAP fulfilled these requirements through a collaborative Cal/Val Partner program. This paper presents the results from 34 candidate core validation sites for the first eleven months of the SMAP mission. As a result of the screening of the sites prior to the availability of SMAP data, out of the 34 candidate sites 18 sites fulfilled all the requirements at one of the resolution scales (at least). The rest of the sites are used as secondary information in algorithm evaluation. The results indicate that the SMAP radiometer-based soil moisture data product meets its expected performance of 0.04 m(3)/m(3) volumetric soil moisture (unbiased root mean square error); the combined radar-radiometer product is close to its expected performance of 0.04 m(3)/m(3), and the radar-based product meets its target accuracy of 0.06 m(3)/m(3) (the lengths of the combined and radar-based products are truncated to about 10 weeks because of the SMAP radar failure). Upon completing the intensive Cal/Val phase of the mission the SMAP project will continue to enhance the products in the primary and extended geographic domains, in co-operation with the Cal/Val Partners, by continuing the comparisons over the existing core validation sites and inclusion of candidate sites that can address shortcomings. (C) 2017 Elsevier Inc. All rights reserved.