The Kinetic Energy of Hailfalls. Part I: Hailstone Spectra

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  • 1 Atmospheric Physics, ETH, 8093 Zürich, Switzerland
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Abstract

The relationship between radar reflectivity and kinetic energy flux (Z-Ė) is investigated by means of analyses of hailstone size distributions measured with hail spectrometers. Semi-empirical relations assuming monodisperse or exponential and untruncated hailstone size distributions are compared with real relations obtained from 175 measured spectra. It is found that 1) the semi-empirical relations agree very well with real ones, the deviation in Ė in the case of exponential spectra being less than 15% for Z values between 50 and 70 dBZ, 2) the Z-Ė relations from different storms show a surprisingly similar behavior, and 3) the total kinetic energy in one point calculated from radar reflectivity factors agrees with the real energy value to better than 25%.

Abstract

The relationship between radar reflectivity and kinetic energy flux (Z-Ė) is investigated by means of analyses of hailstone size distributions measured with hail spectrometers. Semi-empirical relations assuming monodisperse or exponential and untruncated hailstone size distributions are compared with real relations obtained from 175 measured spectra. It is found that 1) the semi-empirical relations agree very well with real ones, the deviation in Ė in the case of exponential spectra being less than 15% for Z values between 50 and 70 dBZ, 2) the Z-Ė relations from different storms show a surprisingly similar behavior, and 3) the total kinetic energy in one point calculated from radar reflectivity factors agrees with the real energy value to better than 25%.

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