Journal article
Measurements of drop size distribution in the southwestern Amazon basin
Journal of Geophysical Research: Atmospheres, Vol.107(D20), pp.LBA 19-1-LBA 19-15
10/27/2002
DOI: 10.1029/2001JD000355
Abstract
Simultaneous observations of an optical and an impact type disdrometer and their application in radar rainfall estimation are evaluated. The disdrometers and two collocated rain gauges were operated in the southwest Amazon region of Brazil in 1999 as part of a NASA Tropical Rainfall Measuring Mission (TRMM) field campaign and the hydro‐meteorological component of the Large Scale Biosphere–Atmosphere Experiment (LBA). During the experiment, we observed large drops with diameters greater than 5 mm. These large drops were not adequately detected by the impact disdrometer and resulted in differences in drop size distribution and integral rain parameters derived from the two sensors. Considering coincident observations, we calculated that the impact disdrometer recorded about 11% lower rainfall accumulations than the optical disdrometer. In addition, radar rainfall algorithms, which we derived from the impact and optical disdrometer measurements, showed instrument dependency. Out of four radar rainfall algorithms that we considered, rain rate derived from specific differential phase has the least dependency, while the rain rate derived from reflectivity at horizontal polarization and differential reflectivity combined exhibited the largest. We also observed the characteristics of rainfall and drop size distribution in two distinct wind regimes present during the TRMM–LBA field campaign. Rain was heavier in the easterly regime, with more large drops being present.
Details
- Title: Subtitle
- Measurements of drop size distribution in the southwestern Amazon basin
- Creators
- Ali Tokay - University of Maryland Baltimore CountyAnton Kruger - University of IowaWitold F Krajewski - University of IowaPaul A Kucera - University of IowaAugusto Jose Pereira Filho - University of São Paulo
- Resource Type
- Journal article
- Publication Details
- Journal of Geophysical Research: Atmospheres, Vol.107(D20), pp.LBA 19-1-LBA 19-15
- DOI
- 10.1029/2001JD000355
- ISSN
- 0148-0227
- eISSN
- 2156-2202
- Number of pages
- 15
- Language
- English
- Date published
- 10/27/2002
- Academic Unit
- Civil and Environmental Engineering; Electrical and Computer Engineering
- Record Identifier
- 9983991939802771
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