Assessment of CYGNSS Wind Speed Retrieval Uncertainty
Assessment of CYGNSS Wind Speed Retrieval Uncertainty
复制标题
DOI：
10.1109/jstars.2018.2825948
复制
发表时间：
2019-01
影响因子：
5.5
通讯作者：
C. Ruf;S. Gleason;D. McKague
中科院分区：
文献类型：
--
作者：
C. Ruf;S. Gleason;D. McKague
对由 GNSS-R 卫星组成的旋风全球导航卫星系统 (CYGNSS) 星座进行的近地表风速测量进行了评估，并通过两种方式评估其不确定性。自下而上的评估从工程测量误差模型开始，并通过风速检索算法分析传播该误差。自上而下的评估对 CYGNSS 测量值和风速的一致“地面实况”测量值进行统计比较。比较两种方法的结果。通过自上而下的方法确定的总体性能，使用自下而上的方法分解为其误差来源。当风速低于 20 m/s 时，CYGNSS 反演的总体均方根 (RMS) 不确定性为 1.4 m/s。在风速较高时，反演误差的增加主要是由于海洋散射截面对风速变化的敏感性降低造成的。在热带气旋中，由于未考虑到完全发展的海洋状态的偏离，检索错误变得更加复杂。当风速高于 20 m/s 时，CYGNSS 反演的总体 RMS 不确定性为 17%。
Measurements of near surface wind speed made by the Cyclone Global Navigation Satellite System (CYGNSS) constellation of GNSS-R satellites are evaluated and their uncertainty is assessed in two ways. A bottom-up assessment begins with a model for the error in engineering measurements and propagates that error through the wind speed retrieval algorithm analytically. A top-down assessment performs a statistical comparison between CYGNSS measurements and coincident “ground truth” measurements of wind speed. Results of the two approaches are compared. Overall performance, as determined by the top-down method, is decomposed using the bottom-up approach into its contributing sources of error. Overall root mean square (RMS) uncertainty in the CYGNSS retrievals is 1.4 m/s at wind speeds below 20 m/s. At higher wind speeds, an increase in the retrieval error is primarily caused by a decrease in the sensitivity of the ocean scattering cross section to changes in wind speed. In tropical cyclones, retrieval errors are compounded by unaccounted departures from a fully developed sea state. Overall RMS uncertainty in the CYGNSS retrievals is 17% at wind speeds above 20 m/s.