Abstract

A comparison was made between seasonal and diurnal variations in the Integrated Multi-Satellite Retrievals for Global Precipitation Measurement (IMERG) version 06B Final run and TRMM Multi-Satellite Precipitation Analysis (TMPA) 3B42 version 7 products from April 2014 to March 2019. As for earlier IMERG versions, systematic differences between IMERG version 06B precipitation and TMPA precipitation data were larger over the oceans than over land. Systematic annual mean differences between the IMERG and TMPA data over the oceans were smaller for IMERG version 06B than for earlier IMERG versions, possibly because of updated calibration processes. The mean differences between the IMERG version 06B and TMPA data for tropical oceans were relatively smtropical Pacific for all four seasons were not. The diurnal amplitudes of the IMERG were smaller than those of the TMPA over most continents, and the differences increased with mean diurnal amplitudes. The diurnal amplitudes of the IMERG were larger than those of the TMPA data over the oceans. The differences between the phases of the precipitation diurnal harmonics in the IMERG and TMPA datasets varied widely in all four seasons, but the mean phases were almost the same over both the oceans and the land. The sources of the differences in diurnal precipitation amplitudes in the Bay of Bengal and along the west coast of Central America, which showed large diurnal ranges and rather different diurnal amplitudes, were assessed. Differences in seasonal means caused differences in diurnal amplitudes in the Bay of Bengal, but for Central America, differences in diurnal amplitudes were associated with seasonal mean diurnal amplitudes.

Highlights

  • As an important element in the global hydrological cycle, precipitation affects clouds, water vapor, and the atmosphere through the exchange of latent heat, and it influences oceanic circulation through its effect on seawater salinity, as well as changing the surface reflectance by regulating the cryoconite cover [1,2,3]

  • The TMPA and IMERG datasets have different spatial resolutions, so the data in each dataset were interpolated to 1° × 1° grids using a linear interpolation method to allow comparison of seasonal and diurnal variations in the two precipitation products at the global scale

  • We have shown larger diurnal cycle differences between two satellite datasets tended to occur over ocean than over land

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Summary

Introduction

As an important element in the global hydrological cycle, precipitation affects clouds, water vapor, and the atmosphere through the exchange of latent heat, and it influences oceanic circulation through its effect on seawater salinity, as well as changing the surface reflectance by regulating the cryoconite cover [1,2,3]. Accurate measuring of precipitation is important for researches on the global energy balance. Satellite remote sensing precipitation products have been used commonly in climate studies and applications in recent decades. These satellite products are based mainly on microwave and infrared (IR) retrieval data [4,5,6,7]. Whereas most microwave sensors can provide precipitation data with a good degree of accuracy but poor coverage and low temporal resolution, IR sensors afford better coverage and temporal resolution but provide less accurate estimates of precipitation [4, 8, 9].

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