[M-IS14] Atmospheric Electricity

[MIS14-11] Development of precipitation attenuation correction technique in a dual-pol radar network

*Shigeharu Shimamura¹, Tomoo Ushio¹, Eiichi Yoshikawa², V. Chandrasekar³ (1.Subarea of Electromagnetic Compatibility. Division of Electrical, Electric and Information Engineering. Graduate School of Engineering, Osaka University, 2.Japan Aerospace eXploration Agency, 3.Colorado State University)

Keywords:meteorological radar, rain

Dense radar network systems with low power transmitters at X-band has been proposed which can fill in observation gaps in low altitudes and have good accuracy and resolution. An X-band dual polarization radar network is the main stream of weather observation to make rapid scanning at low altitude. The dual polarization products such as differential reflectivity (Z_DR), specific differential phase (K_DP) and correlation coefficient (ρ_hv) provide us with detailed information about drop size distribution (DSD) and rainfall rate estimation. K_DP can be calculated from differential phase Φ_DP.
On the other hand, a weather radar, especially with transmitting short-wavelength pulses, is affected by precipitation attenuation. Various attenuation correction techniques for horizontal reflectivity (ZH) and Z_DR using Φ_DP and K_DP were proposed. However, measured differential phase Ψ_DP consists of Φ_DP and backscattered phase shift δ_co.
Especially at C-, or X-band, contamination due to delta cannot be ignored. Some δ_co removing techniques were proposed. Scarchilli et al. (1993) suggested recursive algorithm to remove delta from Ψ_DP in an individual radar using δ_co - Z_DR relationship. They assumed coefficients in the power-law relationship. However, the relationship actually depends on DSD. In this paper, probabilistic attenuation correction technique based on the Bayesian theory in multiple dual polatimetric radar network, is proposed. The proposed technique considering δ_co effects also derive coefficients of relationships.