APHRODITE高分辨率逐日降水资料在中国大陆地区的适用性

Assessing the Quality of APHRODITE High-Resolution Daily Precipitation Dataset over Contiguous China

日本APHRODITE(Asian Precipitation-Highly Resolved Observational Data Integration Towards Evaluation of Water Resources)研究计划建立了一套高分辨率的逐日亚洲陆地降水数据集(简称APHRO),时间从1951年到2007年,空间分辨率为0.25°×0.25°。本文从气候态、不同等级降水量分布以及长期变化等方面分析,通过与中国559个台站观测资料对比,考察了该降水资料在中国地区的适用性。结果表明:(1)气候态分布方面,APHRO降水量与台站资料一致,并且可以准确表征雨带的季节性移动;但是,与台站资料相比,这套资料的降水强度偏小,而降水频率偏大。(2)考察不同等级降水量的分布发现,APHRO资料的暴雨年降水量相对偏少,而小雨和中雨的年降水量偏多。(3)APHRO资料揭示的近50年降水量的变化趋势与台站资料大致相同,并能反映年平均降水频率"西增东减"的趋势;两套资料近50年的年平均降水强度在东南沿海和西北部等区域都呈增加趋势,但APHRO在华北、东北和江淮区域的降水强度变化趋势与台站资料差异显著。此外,在年代际变化方面,APHRO资料对中国东部降水夏季"南涝北旱"和"江南春旱"强度的描述与台站资料有所不同,降水量的变化趋势偏弱。

A daily gridded precipitation dataset （APHRO） for Asia was created by the Asian Precipitation-Highly Resolved Observational Data Integration Towards the Evaluation of Water Resources （APHRODITE） project in Japan. The resolution of this dataset is 0.25°×0.25°, and the length is from 1951 to 2007. This study aims to assess the quality of the APHRO rainfall in contiguous China from the perspective of climatological mean, rainfall classes, and long-term trend. Daily rainfall records observed by 559 rain gauges are used for the comparison. The results are as follows：（1） For the mean states, the APHRO shows similar distribution of precipitation amount to station data, and can accurately characterize the seasonal migration of rain-belt. However, compared with station data, this dataset underestimates precipitation intensity, but overestimates precipitation frequency.（2） For the distribution of different classes of precipitation, annual mean precipitation amount for heavy rainfall derived from the APHRO data is lower, while the amounts for light and moderate rainfall are higher than the station data.（3） The trends of precipitation amount in China during 1956-2005 derived from two dataset are identical, the trends of precipitation frequency are also highly consistent, and both show an ＂increase in the west but decrease in the east＂ pattern. A large difference between the two datasets is found in the spatial pattern of precipitation intensity trends. The precipitation intensity derived from station data shows an increasing trend throughout the Chinese mainland in the past 50 years; the APHRO data exhibit a similar trend in the southeastern coastal region and northwestern China, but a different pattern in northern China, northeastern China, and Jianghuai region. In addition, analysis on the seasonality of interdecadal variability indicates that the characteristics of ＂southern China food and northern China drought＂ and ＂Jiangnan late spring drought＂ derived from the APHRO data are different from those derived from station data. The APHRO data tend to underestimate the trends.