The wind-induced loss of thunderstorm precipitation measurements

Paired elevated and ground level recording precipitation gauges of the electronic weighing type with a resolution of 0.01 mm/min were tested during the 3-year field experiments at two sites in Slovakia. The wind-induced loss, defined as the difference between the ground level and the elevated gauge measurements, is related to the average wind speed and the average intensity of precipitation during a particular time interval. Two intervals of 15 and 60 min of total number of 1611 and 736 precipitation events, respectively, were used in the analysis. The events are divided according to the type of clouds into two groups. The cumuliform cloud group is representative for heavy (convective) precipitation and the stratiform cloud group for all other types of (non-convective) precipitation. The results show a non-linear dependence of the wind-induced loss on intensity of precipitation and wind speed. The wind-induced losses are smaller for the convective precipitation as compared with the non-convective precipitation. There are also differences between the results for the two time intervals. The smaller interval shows larger wind-induced losses than the greater one. The results agree well with the previous findings of the authors and these obtained by the numerical simulation. Using a threshold value of precipitation intensity i ≤ 8 mm h −1 instead of the cloud genesis to separate the non-convective precipitation from the convective one resulted in different wind-induced losses for the group of so defined “non-convective” precipitation. The wind-induced losses differ by up to ± 15%.