ITPCAS和CMORPH两种遥感降水产品在陕西地区的适用性

Applicability of ITPCAS and CMORPH Precipitation Datasets over Shaanxi Province

与气象站观测数据相比,遥感降水产品能够更好地反映降水的空间分布特征。利用36个国家标准气象站点以及23个区域气象站点的观测数据,通过对降水事件的探测能力、不同降水量级的捕捉率和不同时空尺度的降水量误差等指标的分析,评估ITPCAS和CMORPH两种高时空分辨率的遥感降水产品在陕西地区的适用性。结果表明：ITPCAS在多年平均日降水误差、空报率、漏报率、中雨及以上降水等级的捕捉率、多年平均年降水的空间分布及站点误差等方面,均显著好于CMORPH,能够较好地体现陕西地区降水的空间分布特征和变化趋势。

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 from36 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.