Evaluation of methods of comparative analysis of sums of atmospheric precipitation measured with the classical method and with a contact-less laser rain gauge

Abstract

Abstract Evaluation of methods of comparative analysis of sums of atmospheric precipitation measured with the classical method and with a contact-less laser rain gauge. The paper concerns on the evaluation of a preliminary method of comparing data on diurnal sums of atmospheric precipitation acquired with the classic method and by means of Thies Clima laser precipitation monitor - disdrometer. The objective of the study was realized with the use of results of measurements of diurnal sum of precipitation conducted from 1 July to 31 August 2012, in the area of the Faculty Agro and Hydrometeorology Observatory of the Wroclaw University of Environmental and Life Sciences. Information about precipitation measured by means of disdrometer and processed by the authors’ software DisPre led to the development of three variants of precipitation totals counting (1 - data processed by means of the program supplied as standard by the manufacturer of the disdrometer, 2 - totals calculated from the volume of particular hydrometeors - 11 classes, and 3 - totals calculated basing on droplets’ diameters - 22 classes). The tests showed that the totals processed by the program supplied by the manufacturer proved to be the closest to the measurements taken with the Hellmann rain gauge as the method of precipitation calculation during a 24-hour period. The reason for the divergences of the observed values should be certainly sought in the method of measurement itself. Due to the high sensitivity of disdrometer on the external factors, it is absolutely necessary to conduct daily checks of cleanliness of the instrument - especially in the summer period.