Modeling and Simulation of Notional Future Radar in Non‐Standard Propagation Environments Facilitated by Mesoscale Numerical Weather Prediction Modeling

Abstract

Normal near surface radio‐frequency (RF) propagation in the littorals across the land–sea boundary is rare due to the land–sea temperature difference, coastline shape, ground cover, urban density, coastal topography, and soil moisture content. The resulting frequent existence of coastal non‐standard vertical profiles of refractivity and the resulting RF propagation has a profound impact on the performance of Navy ship‐borne radars operating within 100 nm of the shore. In addition, these non‐standard RF propagation conditions are spatio‐temporally inhomogeneous. These spatial and time dependent propagation conditions and the resulting radar engineering implications cannot be revealed by a single vertical profile of refractivity taken near the ship borne radar. The results from single profile analysis techniques provide no spatiotemporal information and may lead to overly conservative radar design. Mesoscale numerical weather prediction (NWP) is a rapidly maturing technology with a strong operational Navy history that can provide a vertical profile of refractivity every 1 km in the battle space and every hour, up to 48 h, in the future. The Sensor Division at NSWCDD has applied mesoscale NWP for the last 2 years to better understand the performance of prototype radar in realistic four‐dimensional (4D) coastal environments. Modern RF parabolic equation models are designed to model specific radar designs and to employ 3D refractivity fields from mesoscale NWP models. This allows for a radar design to be tested in realistic littoral non‐standard atmospheres produced by stable internal boundary layers, sea breeze events, and the more rare sub‐refractive events. Mesoscale NWP is currently qualitative for this purpose, but a research and development program focused on sea testing of prototype radars is described with the purpose of developing a more quantitative mesoscale NWP technology to support radar acquisition, testing, and operations.

Refractivity estimation from sea clutter: An invited review

“…Numerical weather prediction (NWP) systems have undergone substantial development in the last decade. There currently exist capabilities to extract 48 h radar forecast based on output from NWP [ Marshall et al , 2008]. These forecasts are used now to predict the radar performance [ LeFurjah et al , 2010].…”

Duct occurrence and characteristics for Bulgarian Black sea shore derived from ECMWF data

“…P.452-11, 2003;Kerans et al, 2002;Milas and Constantinou, 2005;Sirkova and Mikhalev, 2004). The trapping results in: missed target detection (Anderson, 1995;Marshall et al, 2010) and wrong target position estimation by surveillance radars; false precipitation echo for weather radars (Fornasiero et al, 2006;Mesnard and Sauvageot, 2010;Ryzhkov and Zrnic, 1998); performance alteration of shipborne radars (Marshall. et al, 2008).…”

Brief review on PE method application to propagation channel modeling in sea environment

“…The generated refractivity profiles may be used as input to the PE model [12,39,122]. It should be noted that the current state-of-the-art mesoscale NWP models, as applied to the refractivity field modeling, still provide rather qualitative predictions of duct height and strength; intensive [122]. The varied topics of Section 2, together with the most appropriate literature references to each topic, are summarized in Table 2.…”

“…The above discussed evaporation duct model applied to an open ocean. To account for the spatio-temporal development of the ducting layers in the littoral zones [3,39,120], mesoscale numerical weather prediction (NWP) modeling [121,122] has been used to generate 4D refractivity fields. The generated refractivity profiles may be used as input to the PE model [12,39,122].…”

“…To account for the spatio-temporal development of the ducting layers in the littoral zones [3,39,120], mesoscale numerical weather prediction (NWP) modeling [121,122] has been used to generate 4D refractivity fields. The generated refractivity profiles may be used as input to the PE model [12,39,122]. It should be noted that the current state-of-the-art mesoscale NWP models, as applied to the refractivity field modeling, still provide rather qualitative predictions of duct height and strength; intensive [122].…”