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Multi-wavelength radar target detection in an extreme advection duct event

Published online by Cambridge University Press:  04 April 2011

Robert E. Marshall  and
Katherine L. Horgan
Robert E. Marshall*
Affiliation:
Naval Surface Warfare Center, 18444 Dahlgren Road, Suite 330, Dahlgren, Virginia, USA. Phone: 5406534751
Katherine L. Horgan
Affiliation:
Naval Surface Warfare Center, 18444 Dahlgren Road, Suite 330, Dahlgren, Virginia, USA. Phone: 5406534751
*
Corresponding author: R. E. Marshall Email: [email protected]
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Abstract

Near sea surface radio frequency (RF) refraction is four dimensional (4D) and can significantly impact the performance of radar systems. The refractivity field is dictated by the vertical thermodynamic structure of the constantly evolving marine atmospheric boundary layer (MABL). Logistical and budgetary restraints on meteorological measurements over water to capture the spatio-temporal structure of refractivity fields influencing radar performance have limited the knowledge of how and why radar performance is azimuth, range, and time dependent. Rapidly increasing computer processing speeds and decreasing memory capacity costs have supported the horizontal and vertical resolution requirements for mesoscale numerical weather prediction (NWP) models to resolve the thermodynamic structure in the MABL. Once modeled, refractivity structure is easily calculated from the thermodynamic structure. Mesoscale NWP models coupled with modern parabolic equation radar performance models can support the prediction of 4D radar performance in challenging non-homogeneous, near surface refractivity fields at the time and location of the modeler's choice. The NWP modeling presented in this paper demonstrates how large-scale offshore flow of warm and dry air over colder seas produces strong near surface RF trapping. Large land-sea temperature differences can produce near shore sea breezes and surface-based ducts. This paper describes modeled radar performance in such a complex ducting structure over the Persian Gulf during large-scale northwest atmospheric flow. The refractivity field was resolved by the Coupled Ocean/ Atmosphere Mesoscale Prediction System (COAMPS® is a registered trademark of the Naval Research Laboratory) and the notional radar performance was modeled by the advanced refractive effects prediction system (AREPS). The results indicate strong spatial and wavelength-dependent enhancements and degradations in radar performance relative to a standard atmosphere.

Keywords

refractionradio frequency propagation
Type
Research Papers
Information
International Journal of Microwave and Wireless Technologies , Volume 3 , Special Issue 3: Special Issue on European Microwave Week 2010 , June 2011 , pp. 373 - 381
Copyright
Copyright © Cambridge University Press and the European Microwave Association 2011

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References

REFERENCES

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