Measuring drop size distribution and kinetic energy of rainfall using a force transducer

Abstract

Abstract:The relatively high cost of commercially available raindrop spectrometers and disdrometers has inhibited detailed and intensive research on drop size distribution, kinetic energy and momentum of rainfall which are important for understanding and modelling soil erosion caused by raindrop detachment. In this study, an approach to ®nd the drop size distribution, momentum and kinetic energy of rainfall using a relatively inexpensive device that uses a piezoelectric force transducer for sensing raindrop impact response is introduced. The instrument continuously and automatically records, on a time-scale, the amplitude of electrical pulses produced by the impact of raindrops on the surface of the transducer. The size distribution of the raindrops and their respective kinetic energy are calculated by analysing the number and amplitude of pulses recorded, and from the measured volume of total rainfall using a calibration curve. Simultaneous measurements of the instrument, a rain gauge and a dye-stain method were used to assess the performance of the instrument. Test results from natural and simulated rainfalls are presented.

Rain Drop Measurement Techniques: A Review

“…marine environments, however difficulties remained during high rainfall intensity measurement. Jayawardena and Rezaur [83] [86], Bagree [98] and Vaisala [82] (Figure 3).…”

“…The combination of drop size distribution and drop velocity can provide an estimation of kinetic energy, however there have been several previous attempts to take measurements directly [83][84][85]. This has been done using either acoustic or displacement methods.…”

“…Based on the relationship between kinetic energy and drop size calculations [53,69], this electrical signal is converted to kinetic energy via the measured acoustic energy [73,[83][84][85][86][87][88][89][90][91][92][93][94][95].…”

“…Jayawardena and Rezaur [83] also successfully modified the acoustic disdrometers, and improved drop size distribution, rain intensity and kinetic energy measurement accuracy. Other commercial devices have been successfully developed by Salmi and Ikonen [97], Salmi and Elomaa [84], Winder and Paulson [86], Bagree [98] and Vaisala [82] (Figure 3).…”

Impact of Rainfall Microstructure on Erosivity and Splash Soil Erosion Under Simulated Rainfall

“…For this reason, several indices have been suggested to estimate the rainfall erosivity from common rainfall parameters (rainfall macro-structure), such as daily, and monthly rainfall data. Raindrop erosivity can be determine directly by using piezoelectric transducer where the measured water drop kinetic energy or momentum related with output voltage from the transducer due to the drop impact (Madden et al, 1998;Jayawardena and Rezaur, 2000b;Abd Elbasit et al, 2007;Abd Elbasit et al, 2010;Abd Elbasit et al, 2011). Anologously, optical methods have, also been utilized, where raindrop size and velocity are monitored simultaneously and then the erosivity indices are calculated directly from these two parameters (Salles and Poesen, 2000;Nanko et al, 2004).…”