An Approach for the Estimation of Hydrometeorological Variables Towards the Determination of Z-R Coefficients

An attempt is made to estimate the basic hydrometeorological variables, namely the rainfall concentration for each bin per m3, the radar reflectivity factor Z and the rainfall intensity R, and consequently to determine coefficient "a" and exponent "b" of the power law relationship Z = aRb. Data used were recorded in a period of almost 10 years, with a Joss-Walvogel RD-69 disdrometer (JWD), located in the meteorological station of the campus of National Technical University of Athens. A number of rainfall events were selected based on the following criteria: the total rainfall depth of each event was greater than 24.0 mm and the average rainfall intensity exceeded 5.0 mm/h, in order to only study events with increased flash flooding probability. Initially, Drop Size Distributions (DSDs) were calculated for these rainfall events and processed for the derivation of Z-R relationships. Such Z-R relationships were finally derived for the overall spectra of R > 5.0 mm/h and for each event separately and were compared with other Z-R relationships found in the literature. © 2015 Springer International Publishing Switzerland.