The raindrop size distribution (DSD) is crucial for understanding the relationships which link the radar reflectivity factor to rainfall rate. In this study, we propose a dimensionless gamma probability density function (pdf ) with two parameters to model the general distribution of the DSD. A relationship between two parameters in the gamma pdf is derived based on self-consistency. As a result, only one shape parameter, called, is necessary to describe the variability of the general distribution. For each DSD spectrum, we apply a new method, which uses the ratio of consecutive moments to estimate. For the whole DSD time series data, with a global value of, this gamma pdf model can be easily adapted to both the one- and two-moment normalisation approach presented in the literature. Our theory has been implemented for a four-month DSD time series observed in the Cévennes region, France. Results - show the gamma pdf and its self-consistency to be a good approximation to the observed general distribution. The uncertainty in the moment estimations (e.g. the Z-R relationship) is partly explained by the variability of the general distribution. Thus, a classification of the DSD spectra by can improve the quality of moment estimation. Further research is needed to investigate the physical meaning of the variability of the general distribution.
|Publication status||Published - 2011|
|Event||EGU General Assembly 2011 - Vienna, Austria|
Duration: 3 Apr 2011 → 8 Apr 2011
|Conference||EGU General Assembly 2011|
|Period||3/04/11 → 8/04/11|
Yu, N., Delrieu, G., Boudevillain, B., & Uijlenhoet, R. (2011). The parameterization of the general raindrop size distribution by the gamma probability density function. Paper presented at EGU General Assembly 2011, Vienna, Austria.