Evaluation Of Satellite Climate Data Record And Its Application In The Study Of Climate

Using the China surface climate data, the monthly mean data of ISCCP (International Satellite Cloud Climatology Project) D2and radiosonde data, EAGSCDR—FY2and GMS Geostationary Satellite Climate Data Record over East Asia were validated and evaluated in this paper. The results, which the distributions of annual mean total cloud amounts from the three kinds of data were analyzed and compared, show that all the distributive patterns of cloud amounts agree well, however, total cloud amounts from ISCCP and Geostationary satellite data sets of climate are higher than that given by station observations in the north of40°N. Furthermore, it is indicated that about72.15%cloud detection product samples of EAGSCDR agree with surface weather observations, and the overall miss detected rate and false detected rate is respectively4.45%and23.40%over China; the conclusion of the lower accuracy in fall and winter was obtained by the study in different seasons, and the clear sky was mistaken for cloud in autumn and winter was the main reason; gave monthly variation properties of accuracy, miss detected rate and false detected rate over5regions of China, thus the seasonal changes were found in their time sequence curve. Therefore, we should pay attention to the influence of different seasons and different regions on precision in the use of EAGSCDR. The cloud amount of EAGSCDR and ISCCP both are obtained from satellite data, and their major differences come from different algorithms. The analysis from this study shows that the cloud product precision of EAGSCDR is higher than that of ISCCP, and the time resolution could reach1hour, the spatial resolution is up to10km. To sum up the above arguments, the cloud product of EAGSCDR has an advantage over ISCCP. Furthermore, comparing with precipitable water based on the radiosonde data, the rationality of EAGSCDR precipitable water product was validated. The deviation of EAGSCDR from the radiosonde data was evaluated by setting the radiosonde result as standards. The results show that as follows, the error in summer and autumn was lower than that in winter and spring, the values of precipitable water based on the EAGSCDR were slightly smaller than that on the radiosonde data in July, however, the values of precipitable water based on the EAGSCDR in the north of China were higher than that on the radiosonde data other time; the ocean error was less than the land. We also discussed the climate characters of total cloud amount in different regions, gave monthly, daily variation properties of cloud amount over China; we also analyzed the period of cloud amount by using wavelet analysis, and the existing characteristics time scales were obtained from the sequence of total cloud amount.