Abstract: Compared with the precipitation data from meteorological stations,the precipitation products based on remote sensing can be used to well present the spatial distribution of precipitation,whereas the accuracy of remote sensing products generally cannot match that of the meteorological stations.Thus it is necessary to evaluate the common used precipitation products.In this paper,the reliability of two satellites precipitation products ITPCAS and CMORPH with high spatial-temporal resolution over Shaanxi Province was evaluated using the observed data from 36 national and 23 regional meteorological stations.Analysis based on the indexes including the detection rate of precipitation events,capture rate over all precipitation magnitudes and errors of precipitation at different spatial-temporal scales were adopted in the evaluation.Results showed that the ITPCAS was accurate for the Shaanxi region because of its low bias of average daily precipitation,low false alarming ratio and missed ratio,high capture rate of precipitation for grades higher than moderate magnitude,good presentation of the distribution and variation pattern of the precipitation.The spatial distribution and change pattern of precipitation in the Shaanxi region could be well presented by ITPCAS precipitation.CMORPH also showed the spatial distribution pattern of precipitation in the Shaanxi region.However,the errors were comparatively higher as CMORPH did not merge any data from meteorological stations.Further revisions of the CMORPH are needed to ensure the accuracy of the products.

Key words: CMORPH, ITPCAS, remote sensing, precipitation product, applicability, Shaanxi Province