摘要
This study employs a newly defined regional-rainfall-event （RRE） concept to compare the hourly charac- teristics of warm-season （May September） rainfall among rain gauge observations, China merged hourly pre- cipitation analysis （CMPA-Hourly）, and two commonly used satellite products （TRMM 3B42 and CMORPH） By considering the rainfall characteristics in a given limited area rather than a single point or grid, this method largely eliminates the differences in rainfall characteristics among different observations or measure- ments over central-eastern China. The results show that the spatial distribution and diurnal variation of RRE frequency and intensity are quite consistent among different datasets, and the performance of CMPA- Hourly is better than the satellite products when compared with station observations. A regional rainfall coefficient （RRC）, which can be used to classify local rain and regional rain, is employed to represent the spatial spread of rainfall in the limited region defining the RRE. It is found that rainfall spread in the selected grid box is more uniform during the nocturnal to morning hours over central-eastern China. The RRC tends to reach its diurnal maximum several hours after the RRE intensity peaks, implying an in- termediate transition stage from convective to stratiform rainfall. In the afternoon, the RRC reaches its minimum, implying the dominance of local convections on small spatial scale in those hours, which could cause large differences in rain gauge and satellite observations. Since the RRE method reflects the overall features of rainfall in a limited region rather than at a fixed point or in a single grid, the widely recognized overestimation of afternoon rainfall in satellite products is more reliable in representing sub-daily variation of rainfall a reasonable method to compare satellite products with which also has great potential to be used in evaluating the numerical models. not obvious, and thus the satellite estimates are from the RRE perspective. This study proposes rain gauge observations on the sub-daily scale, spatiotemporal variation of cloud and rainfall in
This study employs a newly defined regional-rainfall-event （RRE） concept to compare the hourly charac- teristics of warm-season （May September） rainfall among rain gauge observations, China merged hourly pre- cipitation analysis （CMPA-Hourly）, and two commonly used satellite products （TRMM 3B42 and CMORPH） By considering the rainfall characteristics in a given limited area rather than a single point or grid, this method largely eliminates the differences in rainfall characteristics among different observations or measure- ments over central-eastern China. The results show that the spatial distribution and diurnal variation of RRE frequency and intensity are quite consistent among different datasets, and the performance of CMPA- Hourly is better than the satellite products when compared with station observations. A regional rainfall coefficient （RRC）, which can be used to classify local rain and regional rain, is employed to represent the spatial spread of rainfall in the limited region defining the RRE. It is found that rainfall spread in the selected grid box is more uniform during the nocturnal to morning hours over central-eastern China. The RRC tends to reach its diurnal maximum several hours after the RRE intensity peaks, implying an in- termediate transition stage from convective to stratiform rainfall. In the afternoon, the RRC reaches its minimum, implying the dominance of local convections on small spatial scale in those hours, which could cause large differences in rain gauge and satellite observations. Since the RRE method reflects the overall features of rainfall in a limited region rather than at a fixed point or in a single grid, the widely recognized overestimation of afternoon rainfall in satellite products is more reliable in representing sub-daily variation of rainfall a reasonable method to compare satellite products with which also has great potential to be used in evaluating the numerical models. not obvious, and thus the satellite estimates are from the RRE perspective. This study proposes rain gauge observations on the sub-daily scale, spatiotemporal variation of cloud and rainfall in
作者
CHEN Haoming
YU Rucong
SHEN Yan
陈昊明;宇如聪;沈艳(State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081 National Meteorological Information Center, Beijing 100081)
基金
Supported by the Outstanding Tutors for Doctoral Dissertations of S&T Project in Beijing(20138005801)
National Natural Science Foundation of China(41375004)
Basic Scientific Research and Operation Foundation of the Chinese Academy of Meteorological Sciences(2014R013)
