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Rainfall estimation from ESMIR-5 measurements and application to El NinoAn algorithm to estimate monthly 5 deg x 5 deg area-averaged rain rate over the oceans from January 1973 to December 1976 using single-channel microwave data from the Nimbus-5 satellite has been developed. This study extends the work of Shin et al. by including the full width of scan angles (from -50 deg to 50 deg) in order to reduce sampling error. The scan-angle dependence of the estimated rain rate due to variable antenna sidelobe effects, surface emissivity, and propagation pathlength is eliminated using a statistical method. A globally uniform beam-filling correction factor of 2.2 is applied in this study. Comparison with island station rainfall measurements over the Pacific shows a remarkably high correlation between two data in the equatorial dry zone and South Pacific convergence zone (SPCZ) but a low correlation in the extratropics and equatorial western Pacific. It is also proved that the retrieved rain rates are statistically significant. The rainfall deviations from non-El Nino years April 1973 to December 1975 reveal the temporal and spatial variations produced by the 1972-73 and 1976-77 El Nino episodes. We observe an increase of rainfall over the eastern and central equatorial Pacific Ocean and a decrease over the equatorial western Pacific Ocean and eastern Australia during these events. Consistent with previous work, the rainfall anomaly of the 1972-73 El Nino was much stronger than that of the 1976-77 El Nino.
Document ID
19950047982
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Lim, Hyo-Suk
(Texas A&M University College Station, TX, United States)
Graves, C. E.
(Saint Louis University St Louis, MO, United States)
North, G. R.
(Texas A&M University College Station, TX, United States)
Wilheit, T. T.
(Texas A&M University College Station, TX, United States)
Date Acquired
August 16, 2013
Publication Date
February 1, 1995
Publication Information
Publication: Journal of Applied Meteorology
Volume: 34
Issue: 2
ISSN: 0894-8763
Subject Category
Meteorology And Climatology
Accession Number
95A79581
Distribution Limits
Public
Copyright
Other

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