Satellite retrieval of atmospheric water vapor is intended to further understand the role played by the energy and water cycle to determine the Earth's weather and climate.The algorithm for operational retrieval o...Satellite retrieval of atmospheric water vapor is intended to further understand the role played by the energy and water cycle to determine the Earth's weather and climate.The algorithm for operational retrieval of total precipitable water (TPW) from the visible and infrared radiometer (VIRR) onboard Fengyun 3A (FY-3A) employs a split window technique for clear sky radiances over land and oceans during both day and night.The retrieved TPW is compared with that from the moderate resolution imaging spectroradiometer (MODIS) onboard the Terra satellite and data from radiosonde observations (RAOB).During the study period,comparisons show that the FY-3A TPW is in general agreement with the gradients and distributions from the Terra TPW.Their zonal mean difference over East Asia is smaller in the daytime than at night,and the main difference occurs in the complex terrain at mid latitude near 30°N.Compared with RAOB,the zonal FY-3A and the Terra TPW have a moist bias at low latitudes and a dry bias at mid and high latitudes;in addition,the FY-3A TPW performs slightly better in zonal mean biases and the diurnal cycle.The temporal variation of the FY-3A and the Terra TPW generally fits the RAOB TPW with the FY-3A more accurate at night while Terra TPW more accurate during the daytime.Comparisons of correlations,root mean square differences and standard deviations indicate that the FY-3A TPW series is more consistent with the RAOB TPW at selected stations.As a result,the FY-3A TPW has some advantages over East Asia in both spatial and temporal dimensions.展开更多
本文对我国第二代极轨气象卫星风云三号C星(Fengyun-3C,FY-3C)上的可见光红外扫描辐射计(Visible and Infra-Red Radiometer,VIRR)测得的西北太平洋地区的海表温度数据精度进行了评估,该评估结果可为风云卫星遥感资料的使用提供参考。将...本文对我国第二代极轨气象卫星风云三号C星(Fengyun-3C,FY-3C)上的可见光红外扫描辐射计(Visible and Infra-Red Radiometer,VIRR)测得的西北太平洋地区的海表温度数据精度进行了评估,该评估结果可为风云卫星遥感资料的使用提供参考。将FY-3C/VIRR Level-2(二级数据)海表温度数据与实测浮标海表温度数据进行比较,两者匹配的时间窗口为1 h,空间窗口为0.01°,分别对FY-3C/VIRR全样本和质量等级为优的海表温度数据进行评估。FY-3C/VIRR全样本海表温度数据白天平均偏差为-0.12℃(FY-3C/VIRR海表温度减去实测海表温度),标准偏差为0.79℃;夜晚平均偏差为0.03℃,标准偏差为0.76℃。FY-3C/VIRR最优样本海表温度数据白天平均偏差为-0.01℃,标准偏差为0.64℃;夜晚平均偏差为0.16℃,标准偏差为0.58℃。针对部分云漏检及温度梯度大区域卫星与实测海表温度空间不匹配的问题,对匹配点周围3×3网格的有效海表温度数据进行统计分析,统计结果表明FY-3C/VIRR海表温度数据在质量为优、且匹配点周围3×3网格数据的局部标准偏差在阈值为0.3℃时,白天匹配数据的平均偏差为0.03℃,标准偏差为0.51℃;夜晚匹配数据的平均偏差为0.23℃,标准偏差为0.55℃。结果表明FY-3C/VIRR测得的海表温度数据精度较高,可用于全球变化与海气相互作用等研究。展开更多
基金supported by the National High Technology Research and Development Program of China(Grant No. 2007AA12Z144)the Professional Projects (Grant Nos.GYHY200706005 and GYHY200906036)the China Meteoro-logical Administration New Technology Promotion Project (GrantNo. CMATG2008Z04)
文摘Satellite retrieval of atmospheric water vapor is intended to further understand the role played by the energy and water cycle to determine the Earth's weather and climate.The algorithm for operational retrieval of total precipitable water (TPW) from the visible and infrared radiometer (VIRR) onboard Fengyun 3A (FY-3A) employs a split window technique for clear sky radiances over land and oceans during both day and night.The retrieved TPW is compared with that from the moderate resolution imaging spectroradiometer (MODIS) onboard the Terra satellite and data from radiosonde observations (RAOB).During the study period,comparisons show that the FY-3A TPW is in general agreement with the gradients and distributions from the Terra TPW.Their zonal mean difference over East Asia is smaller in the daytime than at night,and the main difference occurs in the complex terrain at mid latitude near 30°N.Compared with RAOB,the zonal FY-3A and the Terra TPW have a moist bias at low latitudes and a dry bias at mid and high latitudes;in addition,the FY-3A TPW performs slightly better in zonal mean biases and the diurnal cycle.The temporal variation of the FY-3A and the Terra TPW generally fits the RAOB TPW with the FY-3A more accurate at night while Terra TPW more accurate during the daytime.Comparisons of correlations,root mean square differences and standard deviations indicate that the FY-3A TPW series is more consistent with the RAOB TPW at selected stations.As a result,the FY-3A TPW has some advantages over East Asia in both spatial and temporal dimensions.
