An improved microwave radiative transfer model for tropical oceans /
In preparation for the launch of TRMM, new algorithms must be
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1995.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=742744951&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | In preparation for the launch of TRMM, new algorithms must be created that take advantage of the combined data from radar and microwave radiometers that will be on board the satellite. A microwave radiative transfer algorithm with a one-dimensional cloud model is created that incorporates data from radar and radiometers using data obtained from TCM90 and TOGA-COARE flown over the western Pacific in 1990 and 1993, respectively. First, a convective cloud model (CCM) was created that contained a CLW distribution and vertical rain rate structure that were common in previous studies. The brightness temperature - rain rate (T-R) relationships generated by the CCM are shown to produce warmer brightness temperatures at low rain rates and lower brightness temperatures at high rain rates than the Wilheit et al. (1977) model (WILM) and TOGA-COARE observations. Next, a hybrid cloud model (HCM) was developed using observations from TOGA-COARE, TCM-90, and other field projects. Observations changed the cloud model in four ways. First, stratiform clouds with low rain rates were shown to have a low CLW content (< 0.1 g M-3). Second, radar data showed a linear decrease in the logarithm of the backscatter of ice particles above the freezing level. Third, tropical clouds contained more small drops and fewer large drops than predicted by the Marshall - Palmer drop-size distribution (DSD). Last, the reflectivity of ocean surface appears to be specular. The T-R relationships generated by the HCM are different from the CCM. The HCM predicts colder brightness temperatures at low rain rates than in the CCM because of a low CLW content in the cloud at rain rates < 5 mm h-1. At higher rain rates, the vertical precipitation structure and DSD above the freezing level in the HCM make the cloud transparent to microwave radiation resulting in warmer upwelling brightness temperatures at each frequency. The brightness temperatures generated by the HCM closely agree with observations from TOGA-COARE. This study shows that a plane-parallel microwave radiative transfer algorithm coupled with a cloud model based on microphysical observations can accurately simulate rainfall observed in the tropics. |
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| Item Description: | Vita. "Major Subject: Meteorology". |
| Physical Description: | viii, 87 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |