Author(s): Matias Ezequiel Suarez; Denis Poffo; Ignacio Montamat; Raul Comes; Jorge Saffe; Ricardo Ingaramo; Edgardo Pierobon; Lucia Sandalio; Andres Lighezzolo; Giorgio Caranti; Andres Rodriguez

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Keywords: Hydrological; Calibration; Weather; Radar; RMA1

Abstract: Quantitative precipitation estimates (QPE) is an important tool for generating meteorological and hydrological warnings of severe weather events and flood forecasts. In particular, weather radars can provide QPE with high spatial (typically in the order of a few hundreds of meters in range and ~1° of angular resolution) and time resolution (~10 min) over large ground areas (>30 000 km²). QPE can be obtained through empirical relationships between weather radar measurements and ground rainfall rate. Some of these empirical relationships are of the form R=aZ^b and R=aZ^bZdr^c where Z is the equivalent reflectivity factor, Zdr the differential reflectivity, R the rainfall rate, and a, b and c are empirically determined constants. In this work, we present a new method to determine the Z-R and Z-Zdr-R relationships for the weather radar RMA1 located in Córdoba, Argentina. This new technique is based on the Window Correlation Matching Method (WCMM) and the Window Matching Method (WMM). The proposed method consists of matching an R-value, measured by a rain gauge, with a Z and Zdr values obtained from a weighted average of a 3x3 radar bins window centered over the rain gauge. The weighted average will be calculated in such a way as to assign a proportional weight to the cells of the 3x3 window that exceeds a certain minimum value of the Pearson correlation coefficient. In order to compare this technique with other methods commonly cited, the Z-R and Z-Zdr-R relationships were constructed using WCMM, WMM, and TMM (Traditional Matching Method). The Z-R and Z-Zdr-R relationships were derived using a dataset from storms that occurred during 2019 in Córdoba Province, Argentina.

DOI: https://doi.org/10.3850/IAHR-39WC252171192022734

Year: 2022