255 Variability of parameters for Attenuation Correction over mid-latitude extreme precipitating events

Thursday, 17 September 2015
Oklahoma F (Embassy Suites Hotel and Conference Center )
Paola Salio, Ciudad Univ., Buenos Aires, Argentina; and L. Pappalardo, S. W. Nesbitt, L. Vidal Sr., M. D. L. M. Alvarez imaz, and A. Scardilli

Argentina is installing a C-Band dual polarization radar network under a precipitation regime principally dominated by heavy precipitating mesoscale convective systems. Nearly 80% of warm precipitation is contributed by these systems. In order to obtain accurate quantitative precipitation estimation (QPE), algorithms for attenuation correction must be evaluated in the region focused on extreme precipitation events and often the presence of hail. A linear relationship between the specific differential phase (KDP) and both the specific horizontal reflectivity attenuation (AH) and specific differential attenuation (ADP) has been demonstrated by many authors. However, AH/KDP (α) and ADP/KDP (β) shows large variability during highly precipitating events where large raindrops and hail produce non-Rayleigh resonance scattering. The present paper proposes to quantify the variability of these coefficients for classical attenuation correction algorithm considering multiple experiments over mid-latitude extreme precipitating events during warm season events.

The Midlatitude Continental Convective Clouds Experiment (MC3E), conducted in Oklahoma, multiple field campaigns over central Argentina, and the project Cloud processes of tHe main precipitation systems in Brazil: A contribUtion to cloud resolVing modeling and to the GPM (CHUVA), conducted in Santa Maria, southern Brazil, will provide measurements in intense precipitation mixed with hail in order to constrain polarimetric attenuation correction relationships. T-matrix simulations will be used to explore coefficients in these relationships which strongly depend on hydrometeor phase and drop size distribution (DSD) measurements. Different wavelengths including C, S and X band are considered in the evaluation in order to understand the effects of varying microphysical properties on these relationships. Comparisons are made amongst different DSD sensors, including laser sensors (Particle Size Velocity first and second generation, Thies), two-dimensional video disdrometers to examine instrument-dependent impacts on the attenuation corrections. The impact on differences will be analyzed over a sample of cases over in order to understand possible contribution to total QPE estimations using commonly used algorithms for attenuation correction.

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