Based on the radiosonde data from 15 stations located on islands,accuracy of the total precipita-ble water (TPW)measurements over oceans made by WindSat from 2007 to 2015 is assessed in this paper, and the cause of the differences between the two measurements is analyzed.It is shown that the satellite retrievals over ocean scenes agree well with the radiosonde measurements,with a total mean bias of -0.43 mm,root-mean-square-error of 3.14 mm,standard deviation of 3.11 mm and correlation coefficient of about 0.98.The satellite retrieval algorithm has a good performance in the middle and high latitudes,with the root-mean-square-errors of less than 3 mm,while the accuracy of the satellite retrievals in low latitudes is much poor,with a root-mean-square-errors of more than 5 mm.Low wind speed has the significant in-fluence on the TPW retrievals,while the TPW product shows little relationship with the SST and cloud water.The accuracy of the TPW retrievals deteriorates distinctly as the latitude decreases.Radiosonde TPW data obtained by sounding at daytime is plagued by a dry bias.%利用时空匹配的15个海岛站的探空资料对WindSat 2007—2015年的海洋大气可降水量产品(total precip-itable water,TPW)进行了检验,并分析了造成两者差异的原因.结果表明:WindSat反演的海洋大气可降水量产品与探空比对的一致性较好,两者平均偏差为-0.43 mm,均方根误差为3.14 mm,标准偏差为3.11 mm,相关系数达到了0.98;WindSat在中高纬度地区反演效果较好,均方根误差在各个站点均小于3 mm;在低纬度地区 WindSat反演精度较差,均方根误差大于5 mm.低风速对 WindSat可降水反演精度影响较大;海面温度和云中液态水含量与大气可降水量产品之间无明显相关关系;WindSat反演精度随纬度降低下降明显;利用白天探空释放所得到的水汽数据存在干性偏差.
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