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The summertime diurnal cycle of precipitation derived from IMERG

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journal contribution
posted on 21.08.2019, 09:13 by Daniel Watters, Alessandro Battaglia
The Integrated Multi-satellitE Retrievals for GPM (IMERG) precipitation product derived from the Global Precipitation Measurement (GPM) constellation offers a unique opportunity of observing the diurnal cycle of precipitation in the latitudinal band 60°N-S at unprecedented 0.1° × 0.1° and half-hour resolution. The diurnal cycles of occurrence, intensity and accumulation are determined using four years of data at 2° × 2° resolution; this study focusses on summertime months when the diurnal cycle shows stronger features. Harmonics are fitted to the diurnal cycle using a non-linear least squares method weighted by random errors. Results suggest that mean-to-peak amplitudes for the diurnal cycles of occurrence and accumulation are greater over land (generally larger than 25% of the diurnal mean), where the diurnal harmonic dominates and peaks at ~16-24 LST, than over ocean (generally smaller than 25%), where the diurnal and semi-diurnal harmonics contribute comparably. Over ocean, the diurnal harmonic peaks at ~0-10 LST (~8-15 LST) over open waters (coastal waters). For intensity, amplitudes of the diurnal and semi-diurnal harmonics are generally comparable everywhere (~15-35%) with the diurnal harmonic peaking at ~20-4 LST (~3-12 LST) over land (ocean), and the semi-diurnal harmonic maximises at ~5-8 LST and 17-20 LST. The diurnal cycle of accumulation is dictated by occurrence as opposed to intensity.


Daniel Watters was funded by a Natural Environment Research Council studentship awarded through the Central England NERC Training Alliance (CENTA; grant reference NE/L002493/1) and by the University of Leicester. The work by A. Battaglia was funded by ESA in the frame of the RAINCAST project (ESA Contract No. 4000125959/18/NL/NA). Acknowledgments: The version-5 level-3 IMERG data were provided by the NASA/Goddard Space Flight Center and PPS, which develop and compute the V05 level–3 IMERG data as a contribution to GPM, and archived at the NASA GES DISC. This research used the SPECTRE High Performance Computing Facility at the University of Leicester.



Remote Sensing, 2019, 11 (15), 1781

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/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy


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