Date of Award

3-1997

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Engineering Physics

First Advisor

Clifton E. Dungey, PhD

Abstract

The USAF operational cloud model, the Real-Time Nephanalysis (RTNEPH), requires infrared and visual scene scans as well as input from the Special Sensor Microwave Imager (SSM/I), featured on the Defense Meteorological Satellite Program (DMSP) polar orbiters. Additionally, SSM/I provides input to the Air Force Global Weather Center (AFGWC) surface temperature model (SFCTMP). The global surface temperatures are required for identifying which pixel of a scene is cloud and which is ground and as a first guess input to initialize NWP models. The SSM/I provides brightness temperatures sampled at four discrete: frequencies and dual polarizations to produce surface temperatures. Two algorithms are operationally available: one currently in use at AFGWC called TMPSMI, which feeds RTNEPH and SFCTMP; the other: an earlier model created by the U.S. Navy during the calibration/validation of the SSM/I sensor, aptly named the CAL/VAL temperature algorithm. Using SSM/I brightness temperatures for the CONUS from days in August and October 1996, this study runs both algorithms and compares the output with observations collected at U.S. reporting sites. The results indicate both models produce similar output, exhibiting a cold bias with respect to the observed surface temperature. Furthermore, the CAL/VAL temperatures approached the observed temperature values more closely than did the SFCTMP output.

AFIT Designator

AFIT-GM-ENP-97M-02

DTIC Accession Number

ADA323190

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