利用浮标和NWP风场对HY-2散射计联合定标验证

本文对海洋二号卫星微波散射计(Haiyang-2 Scatterometer,HY-2 SCAT)进行了海洋定标算法研究,并使用数值天气预报模型风场(Numerical Weather Prediction,NWP)和浮标数据对定标后反演风场进行联合验证.通过匹配2012年12月份的HY-2 SCAT反演风场、NWP风场及浮标的观测数据,共得到无降雨条件下的3112个25km分辨率的匹配数据.对匹配数据进行分析时,采用基于变量的误差分析方法能够得到比传统线性回归方法更精确的验证结果.选取在风场U、V分量进行联合验证能得到较在风速、风向上更为有利的验证结果.验证结果表明,经过海洋定标法之后的HY-2 SCAT测量后向散射系数的误差残余小于0.15dB,其反演风场与浮标及NWP数据相吻合,U、V分量相对浮标及NWP数据偏差均小于0.23m/s,验证了该定标算法的有效性及定标后反演风场的高精度.

Calibration and Validation of HY-2 Scatterometer Using NWP and Buoy Data

The scatterometer onboard HY-2 satellite is calibrated using Numerical Ocean Calibration and its retrieval winds after calibration are validated from 130 global buoys and winds from the European Centre for Medium-Range Weather Foresting Numerical Weather Prediction model using triple-collocation during December 2012,resulting in 3112 collocated triplets.The KNMI QC flag is used to collocate the data without rain efforts.It is found that functional relationship employing the error-in-variables method is more accuracy than that using linear regression for the validation of retrieval wind from HY-2 scatterometer.Moreover,using the wind component domain is confirmed to be favourable.It is shown that the uncertainties after ocean calibration is less than 0.15dB,resulting in 0.2m/s systematic wind effects.For both zonal and meridional winds,the similar wind fields comparing with buoys and ECMWF indicate that the effective of the calibration and high quality of the retrieval winds.