P2.63 Deep Convective Clouds Precipitation Particles Spectrum Distribution Observation and its Characteristic Analysis

Wednesday, 30 June 2010
Exhibit Hall (DoubleTree by Hilton Portland)
Jiangping Pu, PLA University of Science & Technology, Nanjing, Jiangsu Province, China; and G. Zheng and M. Lv

Using OTT-Parsivel Laser Particle Spectrometer at Yangtze River Plain region in East China with 2 years, several times rain droplet scale & velocity spectral data aquatic from isolated Mountain Lushan stations (elevation 1300m) and the plains of Nanjing surface observation (elevation 8 meters) were observed and analyzed. Compared to the plain deep convective clouds precipitation, the rain droplet size distribution (DSD) with two elevation of deep convective cloud precipitations were significant features. As the Lushan station located at 1300 meters above sea level on an isolated hilltop, at the observation moments, the authors felt was the development of a strong convective cloud, the sky darkened can hear thunder, clouds with strong wind enveloped in the station. It can be observed in large-scale rain droplets by eyes. The pictures using digital camera directly show the big rain particles. It can be judged, the DSD information of observed the precipitation is almost the bottle of the deep convective raining clouds. General DSD observations on the surface station is that the droplets in clouds fall running thought after several kilometers with cloud outside the dry air environment, warming and melting, touching and broken, evaporation, etc., after the whereabouts of the status of the process. Contrast these two types of DSD data for the study of deep convective clouds in the rain system, the distribution of particle structure is very useful. Based on deep convective clouds at different altitudes precipitation particles on the scale spectrum and velocity spectrum of information, respectively M-P distribution and Gamma distribution fitting method of statistical analysis of the various stages of precipitation DSD and rain particles micro-physical parameters of a comparative analysis was the convective cloud precipitation DSD and velocity spectra at different heights on the difference. The results showed that the width of DSD at bottom of deep convective clouds is much wider than the width of DSD on surface observation, mountain station, the observed spectral width of DSD in general exceeds 11mm (V.S. ground routine observations of the maximum rain particles diameter of less than 8mm), and the drop rate of the same scale particles in the initial cloud bottom moment were greater than their speed reach ground. The number concentration of raindrops falling at the cloud bottom is always greater than they landing to the ground. DSD at various stages, smaller particle concentration which diameter were less than 1mm located in the bottom cloud is than the concentration of particle spectra above the ground about an order of magnitude. Various stages of precipitation particle spectra, located in the cloud is less than 1mm at the bottom of the particle number concentration is the concentration of particle spectra above the ground about an order of magnitude, but large particle number concentration at cloud bottom is the concentration of particle spectra above the ground about two orders of magnitude, which the particle number concentrations of the diameter from 1.5mm to 2.5mm is basically the same. This shows that the rain droplet concentration produced by the cloud physical processes is larger than the concentration we obtain of conventional on ground-based observations and can generate a lot of big droplets than we realize that deep convective clouds that may exist in larger particles. Conjecture is due to deep convective clouds of ice-phase process in the formation of large-scale ice, snow and graupel particles in the melting process of the formation of large drops, however, this suppose remains to be confirmed by direct the aircraft cloud physical parameters measurement.
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