frequency, intensity, and diurnal cycle of precipitation in surface and satellite observations over low- and mid-latitudes
Global precipitation data sets with high spatial and temporal resolution are needed for many applications, but they were unavailable before the recent creation of several such satellite products. Here, we evaluate four different satellite data sets of hourly or 3-hourly precipitation (namely CMORPH,...
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| Published in: | Climate dynamics 2007-12, Vol.29 (7-8), p.727-744 |
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| Main Authors: | , , |
| Format: | Article |
| Language: | eng |
| Subjects: | |
| Online Access: | Get full text |
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| Summary: | Global precipitation data sets with high spatial and temporal resolution are needed for many applications, but they were unavailable before the recent creation of several such satellite products. Here, we evaluate four different satellite data sets of hourly or 3-hourly precipitation (namely CMORPH, PERSIANN, TRMM 3B42 and a microwave-only product referred to as MI) by comparing the spatial patterns in seasonal mean precipitation amount, daily precipitation frequency and intensity, and the diurnal and semidiurnal cycles among them and with surface synoptic weather reports. We found that these high-resolution products show spatial patterns in seasonal mean precipitation amount comparable to other monthly products for the low- and mid-latitudes, and the mean daily precipitation frequency and intensity maps are similar among these pure satellite-based precipitation data sets and consistent with the frequency derived using weather reports over land. The satellite data show that spatial variations in mean precipitation amount come largely from precipitation frequency rather than intensity, and that the use of satellite infrared (IR) observations to improve sampling does not change the mean frequency, intensity and the diurnal cycle significantly. Consistent with previous studies, the satellite data show that sub-daily variations in precipitation are dominated by the 24-h cycle, which has an afternoon-evening maximum and mean-to-peak amplitude of 30-100% of the daily mean in precipitation amount over most land areas during summer. Over most oceans, the 24-h harmonic has a peak from midnight to early morning with an amplitude of 10-30% during both winter and summer. These diurnal results are broadly consistent with those based on the weather reports, although the time of maximum in the satellite precipitation is a few hours later (especially for TRMM and PERSIANN) than that in the surface observations over most land and ocean, and it is closer to the phase of showery precipitation from the weather reports. The TRMM and PERSIANN precipitation shows a spatially coherent time of maximum around 0300-0600 local solar time (LST) for a weak (amplitude |
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| ISSN: | 0930-7575 1432-0894 |