Date of Award

6-17-2010

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Engineering Physics

First Advisor

Steven T. Fiorino, PhD.

Abstract

The ability to accurately describe the atmospheric conditions around us is not only important to the Air Force, but to anyone involved in signal propagation. The programs currently utilized to describe the atmosphere take into account a variety of measures. The LEEDR (Laser Environmental Effects Definition and Reference) program in particular, allows the user to select a location, aerosol and molecular effects model, numerous cloud and precipitation events, as well as other features. Even with the control that the user has, the output that the program provides can vary from actual conditions on a day to day basis. This is due to LEEDR‟s dependence on averaged climatological data. In order to make the output more specific for deterministic conditions, two additions to the LEEDR program have been proposed. The incorporation of calculated or measured ground level characteristics will allow the program to extrapolate data from scenario-specific anchor points, leading to a more realistic depiction of conditions below the boundary layer for the scenario of interest. After making this modification to the LEEDR program, differences were observed in several of the output variables throughout the boundary layer. Also, after interpolating sounding data from a location near the LEEDR site to model ground level conditions, LEEDR was able to more accurately model upper air measurements. In addition, a Correlated-k band model has been developed to augment the line-by-line LEEDR calculation in order to reduce the computation time required to describe atmospheric transmission bands of the spectrum. This allows the implementation of fast calculating path radiance computations. As a stand-alone module, the Correlated-k method is able to calculate transmission for the band interval studied, assuming a homogeneous atmosphere on average, 170% faster than the current transmission method in LEEDR.

AFIT Designator

AFIT-GAP-ENP-10-M12

DTIC Accession Number

Not in DTIC

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