Evaluation of networked based attenuation correction in CASA IP1 testbed

Monitoring of precipitation using higher frequency radar systems such as X-band is becoming popular. At X-band frequency, weather radar signals are attenuated along their paths due to precipitation. Most attenuation impact is occurred by rain medium. However attenuation by melting ice or ice particles is also critical at higher frequencies such as X-band.

Since Hitchfeld and Borden (1954) proposed the attenuation correction technique based on empirical relationship of reflectivity versus specific attenuation, many attenuation correction algorithms have developed. For ground radars with polarimetric capability, a simple attenuation correction method using differential phase was discussed in Bringi et al. (1990). Subsequently, a constrained solution for path-integrated attenuation (PIA) derived from differential propagation phase shift (Φdp) was proposed (Testud et al. 2000). This algorithm is sensitive to the specific attenuation versus specific differential phase parameterization. To eliminate this problem, Bringi and Chandrasekar (2001) suggested a self-consistent algorithm combining differential phase shift and differential reflectivity constraint. In addition, Gorgucci et al. (2008) has developed a self consistent attenuation correction procedure. However these Φdp based algorithm has a limitation within rain medium. Chandrasekar and Lim (2008) proposed a methodology for reflectivity retrieval in a networked radar environment. A solution for the specific attenuation distribution is provided by solving the integral equation for reflectivities from networked radars. The network approach is not constrained to rain medium.

In this paper the network based attenuation correction will be evaluated by CASA IP1 data during 2007-2009 filed experiments. The preliminary results show that the networked based attenuation correction algorithm retrieves reflectivity properly.