The effect of reported high-velocity small raindrops on inferred drop size distributions and derived power laws 1Hydrology and Quantitative Water Management Group, Department of Environmental Sciences, Wageningen University, Droevendaalsesteeg 4, 6708 PB Wageningen, The Netherlands
*current address: Royal Netherlands Meteorological Institute, Wilhelminalaan 10, 3732 GK De Bilt, The Netherlands
Received: 02 Feb 2010 – Published in Atmos. Chem. Phys. Discuss.: 09 Apr 2010 Abstract. It has recently been shown that at high rainfall intensities, small
raindrops may fall with much larger velocities than would be expected
from their diameters. These were argued to be fragments of recently
broken-up larger drops. In this paper we quantify the effect of this
phenomenon on raindrop size distribution measurements from a Joss-Waldvogel
disdrometer, a 2-D Video Distrometer, and a vertically-pointing Doppler radar.
Probability distributions of fall velocities have been parameterized, where
the parameters are functions of both rainfall intensity and drop size. These
parameterizations have been used to correct Joss-Waldvogel disdrometer
measurements for this phenomenon. The effect of these corrections on
fitted scaled drop size distributions are apparent but not major. Fitted
gamma distributions for three different types of rainfall have been used
to simulate drop size measurements. The effect of the high-velocity small
drops is shown to be minor. Especially for the purpose of remote sensing
of rainfall using radar, microwave links, or optical links, the errors
caused by using the slightly different retrieval relations will be masked
completely by other error sources.
Revised: 16 Jul 2010 – Accepted: 19 Jul 2010 – Published: 23 Jul 2010
Citation: Leijnse, H. and Uijlenhoet, R.: The effect of reported high-velocity small raindrops on inferred drop size distributions and derived power laws, Atmos. Chem. Phys., 10, 6807-6818, doi:10.5194/acp-10-6807-2010, 2010.