| || Ray-Trace of an Abnormal Radar Echo Using Geographic Information System
Author : Chen, Chi-Nan;Wang, Jian-Liang;Chu, Chang-Min;Lu, Fang-Chuan
Source : Defence Science Journal ; Vol:59(1) ; 2009 ; pp 63-72
Subject : 621.396.9 Radars
Keywords : Atmospheric refractivity;Geographic Information System (GIS);Weather research and forecast model (WRF);Common Operational Picture (COP)
Abstract : Weather radar plays a key role in natural disaster mitigation just as surveillance radar does in detecting objects that threaten homeland security. Both together comprise an instrumental part of radar observation. Therefore, quality control of the data gathered through radar detection is extremely important. However, radar waves propagate in the atmosphere, and an anomalous echo can occur if there are significant discontinuities in temperature and humidity in the lower boundary layer. The refractive curvature of the earth makes some errors in observation inevitable. On the night of July 3, 2003, Next Generation Radar (NEXRAD) weather radar detected an abnormal echo. The Weather Research and Forecast (WRF) model was utilized to simulate the atmospheric conditions. Radar propagation was simulated using the Advanced Refractivity Engineering Prediction System (AREPS) as well as the GIS. The results show the feasibility of establishing an abnormal propagation early-warning system and extending the application of the GIS in serving as the foundation of a Common Operation Picture (COP). Furthermore, the parameters of the boundary layer near the sea's surface in the numerical weather forecasting model need remodification.