Validation of GPM IMERG Extreme Precipitation in the Maritime Continent by Station and Radar Data

Earth and Space Science

Nicolas A. DaSilva¹  Benjamin G. M. Webber¹  Adrian J. Matthews²  Thorwald H. M. Stein³  Matthew M. Feist³  Christopher E. Holloway³  Muhammad F. A. B. Abdullah⁴ 

[1] Centre for Ocean and Atmospheric Sciences School of Environmental Sciences University of East Anglia Norwich UK;Centre for Ocean and Atmospheric Sciences School of Environmental Sciences and School of Mathematics University of East Anglia Norwich UK;Department of Meteorology University of Reading Reading UK;Malaysian Meteorological Department Petaling Jaya Malaysia;

关键词: precipitation evaluation;    IMERG;    Maritime Continent;    South East Asia;    radar precipitation;   

DOI  :  10.1029/2021EA001738

来源: DOAJ

【 摘 要 】

Abstract The Maritime Continent (MC) is a region subject to high impact weather (HIW) events, which are still poorly predicted by numerical weather prediction (NWP) models. To improve predictability of such events, NWP needs to be evaluated against accurate measures of extreme precipitation across the whole MC. With its global spatial coverage at high spatio‐temporal resolution, the Global Precipitation Measurement (GPM) data set is a suitable candidate. Here we evaluate extreme precipitation in the Integrated Multi‐Satellite Retrieval for GPM (IMERG) V06B product against station data from the Global Historical Climatology Network in Malaysia and the Philippines. We find that the high intragrid spatial variability of precipitation extremes results in large spatial sampling errors when each IMERG grid box is compared with individual co‐located precipitation measurements, a result that may explain discrepancies found in earlier studies in the MC. Overall, IMERG daily precipitation is similar to station precipitation between the 85th and 95th percentile, but tends to overestimate above the 95th. IMERG data were also compared with radar data in western Peninsular Malaysia for sub‐daily timescales. Allowing for uncertainties in radar data, the analysis suggests that the 95th percentile is still suitable for NWP evaluation of extreme sub‐daily precipitation, but that the rainfall rates diverge at higher percentiles. Hence, our overall recommendation is that the 95th percentile be used to evaluate NWP forecasts of HIW on daily and sub‐daily time scales against IMERG data, but that higher percentiles (i.e., more extreme precipitation) be treated with caution.

【 授权许可】

Unknown