Mesoscale GEM-LAM modeling of atmospheric refractivity in coastal environments

Radio frequency (RF) propagation depends strongly on the structure of the coastal marine atmospheric boundary layer which can occasionally create anomalous propagation conditions. Both observations and numerical weather prediction modeling have shown that littoral propagation conditions change rapidly during transitions due to diurnal, mesoscale, or synoptic-scale circulations, leading to enhanced or attenuated naval surface sensor and communication system performance.

The ABCANZ (America/Britain/Canada/Australia/New Zealand) Working Group has established a need for diagnostic and prognostic refractivity modeling capabilities to support littoral naval operations. Since 2007, a mesoscale modeling collaboration between these countries has been going on to develop such capabilities that would be exploitable by all ABCANZ countries.

The presentation will highlight current work within the ABCANZ Group using the GEM-LAM model at mesoscale resolutions to simulate seven days of the Wallops 2000 Microwave Propagation Measurement Experiment that took place in April-May 2000. Another project involving GEM-LAM aims at modeling the New Zealand Sea Breeze Trial that took place in February-March 2009. The detailed meteorological observations and RF propagation data were obtained for both projects. Comparison between the observed and modeled refractivity and propagation properties will be discussed.