2.6
Mesoscale Forecasting of the EM Propagation Environment and Dust Storms in the Persian Gulf
Tracy Haack, NRL, Monterey, CA; and M. Liu, D. L. Westphal, A. L. Walker, and S. D. Burk
Two important concerns for Naval operations in the Persian Gulf involve 1) mesoscale variability in electromagnetic propagation affecting target/ship detection, and 2) visibility degradation due to aerosols. During the Fall transitional season, atmospheric conditions are known for their abrupt pattern reversals in this region. Using the Navy's COAMPS™ model, we analyze a five day period at the end of October 2000 during which time Shamal winds produce two separate dust storms. The spatial and temporal evolution of refractivity parameters: duct strength, thickness and evaporation duct height are examined to determine sensitivity to the Shamal event. The more subtle influences of local diurnal and topographic forcing are also studied. While the adjacent Zagros Mountains, oriented NW-SE along the eastern side of the Persian Gulf, are found to be a weakly contributing factor, considerable mesoscale detail occurs in the ducting properties associated with the passage of an upper level disturbance. The abrupt transition to Shamal winds also plays a significant role in the generation of dust storms along the Tigris-Euphraties Valley reducing visibility over the Gulf for 500 km downwind. The COAMPS™ embedded aerosol tracer module forecasts 3-dimensional fields of aerosol concentration which are compared to daily SeaWiFS satellite imagery. Although sparse in this region, additional observations of meteorological conditions are used for model validation, including infrequent DMSP and AVHRR satellite imagery, 6 hrly surface station data and three rawinsonde sites reporting once daily.
Session 2, Case Studies II
Monday, 12 August 2002, 1:30 PM-3:00 PM
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