目前的降水产品依然存在较大的不确定性,采用多源降水数据融合可以更准确地估计降水量和空间分布情况。为实现无资料地区的数据融合,本文在不使用任何先验信息的前提下,通过整合站点插值、卫星遥感和再分析的降水产品,基于贝叶斯三角帽(...目前的降水产品依然存在较大的不确定性,采用多源降水数据融合可以更准确地估计降水量和空间分布情况。为实现无资料地区的数据融合,本文在不使用任何先验信息的前提下,通过整合站点插值、卫星遥感和再分析的降水产品,基于贝叶斯三角帽(Bayesian-Three Cornered Hat, BTCH)法,融合多源降水数据,探究不同输入数量的降水产品对于融合数据精度的影响以及每个降水产品对于融合数据精度的贡献率,并在黄河源区进行应用。结果表明:在月尺度上,融合数据性能优于原始降水产品;在日尺度上,融合数据性能明显高于卫星遥感和再分析降水产品,但低于基于站点的降水产品CHM_PRE;2套基于站点的降水产品CN05.1和CHM_PRE对于融合数据有最大的贡献率。在黄河源区的应用表明,该数据融合方法确实能够更准确地估计降水量,可应用于无实测降水资料地区,为数据融合分析及应用提供参考。展开更多
重力恢复与气候实验(gravity recovery and climate experiment,GRACE)卫星已成为观测冰盖质量变化的主要手段之一,但不同机构发布的GRACE数据在估计格陵兰冰盖质量变化上存在较大差异,在研究长期变化趋势时会产生很大不一致性。针对此...重力恢复与气候实验(gravity recovery and climate experiment,GRACE)卫星已成为观测冰盖质量变化的主要手段之一,但不同机构发布的GRACE数据在估计格陵兰冰盖质量变化上存在较大差异,在研究长期变化趋势时会产生很大不一致性。针对此问题,先分析了用不同GRACE数据估算的格陵兰冰盖质量变化数据之间的差异,再用三角帽(three-cornered hat,TCH)方法对其进行不确定性分析,并通过数据融合消除了不同数据间的不一致性。展开更多
Microwave Radiometer Imager(MWRI) is a key payload of China’s second generation polar meteorological satellite, i.e., Fengyun-3 series(FY-3). Up to now, 5 satellites including FY-3A(2008), FY-3B(2010), FY-3C(2013), F...Microwave Radiometer Imager(MWRI) is a key payload of China’s second generation polar meteorological satellite, i.e., Fengyun-3 series(FY-3). Up to now, 5 satellites including FY-3A(2008), FY-3B(2010), FY-3C(2013), FY-3D(2018), and FY-3E(2021) have been launched successfully to provide multiwavelength, all-weather, and global data for decades. Much progress has been made on the calibration of MWRI and a recalibrated MWRI brightness temperature(BT) product(V2) was recently released. This study thoroughly evaluates the accuracy of this new product from FY-3B, 3C, and 3D by using the simultaneous collocated Global Precipitation Measurement(GPM)Microwave Imager(GMI) measurements as a reference. The results show that the mean biases(MBEs) of the BT between MWRI and GMI are generally less than 0.5 K and the root mean squares(RMSs) between them are less than1.5 K. The previous notable ascending and descending difference of the MWRI has disappeared. This indicates that the new MWRI recalibration procedure is very effective in removing potential errors associated with the emission of the hot-load reflector. Analysis of the dependence of MBE on the latitude and earth scene temperature shows that MBE decreases with decreasing latitude over ocean. Furthermore, MBE over ocean decreases linearly with increasing scene temperature for almost all channels, whereas this does not occur over land. A linear regression fitting is then used to modify MWRI, which can reduce the MBE over ocean to be within 0.2 K. The standard deviation of error of GMI, FY-3B, and FY-3D MWRI BT data derived by using the three-cornered hat method(TCH) shows that GMI has the best overall performance over ocean except at 10.65 GHz where its standard deviation of error is slightly larger than that of FY-3D. Over land, the standard deviation of error of FY-3D is the lowest at almost all channels except at 89V. MWRI onboard FY-3 series satellites would serve as an important passive microwave radiometer member of the constellation to monitor key surface and atmospheric properties.展开更多
文摘目前的降水产品依然存在较大的不确定性,采用多源降水数据融合可以更准确地估计降水量和空间分布情况。为实现无资料地区的数据融合,本文在不使用任何先验信息的前提下,通过整合站点插值、卫星遥感和再分析的降水产品,基于贝叶斯三角帽(Bayesian-Three Cornered Hat, BTCH)法,融合多源降水数据,探究不同输入数量的降水产品对于融合数据精度的影响以及每个降水产品对于融合数据精度的贡献率,并在黄河源区进行应用。结果表明:在月尺度上,融合数据性能优于原始降水产品;在日尺度上,融合数据性能明显高于卫星遥感和再分析降水产品,但低于基于站点的降水产品CHM_PRE;2套基于站点的降水产品CN05.1和CHM_PRE对于融合数据有最大的贡献率。在黄河源区的应用表明,该数据融合方法确实能够更准确地估计降水量,可应用于无实测降水资料地区,为数据融合分析及应用提供参考。
基金National Natural Science Foundation of China (42030608 and 42075079)。
文摘Microwave Radiometer Imager(MWRI) is a key payload of China’s second generation polar meteorological satellite, i.e., Fengyun-3 series(FY-3). Up to now, 5 satellites including FY-3A(2008), FY-3B(2010), FY-3C(2013), FY-3D(2018), and FY-3E(2021) have been launched successfully to provide multiwavelength, all-weather, and global data for decades. Much progress has been made on the calibration of MWRI and a recalibrated MWRI brightness temperature(BT) product(V2) was recently released. This study thoroughly evaluates the accuracy of this new product from FY-3B, 3C, and 3D by using the simultaneous collocated Global Precipitation Measurement(GPM)Microwave Imager(GMI) measurements as a reference. The results show that the mean biases(MBEs) of the BT between MWRI and GMI are generally less than 0.5 K and the root mean squares(RMSs) between them are less than1.5 K. The previous notable ascending and descending difference of the MWRI has disappeared. This indicates that the new MWRI recalibration procedure is very effective in removing potential errors associated with the emission of the hot-load reflector. Analysis of the dependence of MBE on the latitude and earth scene temperature shows that MBE decreases with decreasing latitude over ocean. Furthermore, MBE over ocean decreases linearly with increasing scene temperature for almost all channels, whereas this does not occur over land. A linear regression fitting is then used to modify MWRI, which can reduce the MBE over ocean to be within 0.2 K. The standard deviation of error of GMI, FY-3B, and FY-3D MWRI BT data derived by using the three-cornered hat method(TCH) shows that GMI has the best overall performance over ocean except at 10.65 GHz where its standard deviation of error is slightly larger than that of FY-3D. Over land, the standard deviation of error of FY-3D is the lowest at almost all channels except at 89V. MWRI onboard FY-3 series satellites would serve as an important passive microwave radiometer member of the constellation to monitor key surface and atmospheric properties.
