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Numerical simulation of convective cloud hygroscopic catalysis research

Author: YangZongZhen
Tutor: ChenBaoJun
School: Nanjing University
Course: Meteorology
Keywords: Right convective cloud Initial CCN Hygroscopic catalytic Numerical Simulation
CLC: P426.5
Type: Master's thesis
Year: 2011
Downloads: 25
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Abstract

In this paper, two-dimensional sub-file convective modes, respectively, in the Three Rivers region numerically simulated convective cold and wet, warm CHRV convective background, different initial cloud condensation nuclei (CCN) number concentration on convective cloud and precipitation formation and development effects. Meanwhile, the combination of these different initial CCN number concentration situations, numerical simulation on the Three Rivers region of the hygroscopic catalytic wet cold convective clouds and warm CHRV convective precipitation affected. Through macro and micro structure and convective precipitation analysis, the results showed that: 1) Three Rivers region to ice-phase convective process mainly graupel precipitation process of development in a dominant role, mainly in the Huaihe River basin convective warming Cloud-based process, liquid precipitation total precipitation during a major proportion; 2) in the same initial thermal and dynamic conditions, low concentrations of CCN in the case of convective development and maturation stage to more effectively produce rain, ice and graupel, forming a stronger radar reflectivity. With increasing concentration of the initial CCN, CCN large particle cloud droplet growth limiting, and in the cold cloud graupel process for inhibiting the formation, particle generation is not conducive to precipitation, the precipitation delay, less precipitation; 3) Initial Number CCN concentration on convective precipitation and nonlinear response of precipitation begins with the initial CCN number concentration increases to about 500cm-3 reached a maximum after the initial CCN number concentration greater convective precipitation less. Hygroscopic catalyzed through numerical simulation and sensitivity test, the results showed that: a) in the Three Rivers region convective cold wet backdrop initial CCN number concentration higher catalytic effect on convective hygroscopic most obvious; early stage of development in the cloud (10-14min), in the main cloud base updraft area (center 15km), seeding height 900m altitude, the catalytic effect is better, play a decisive role on the catalytic results are coarse particles (gt; 1μm), small particles catalysis (lt; 1μm) play negative effects on precipitation. 2) in the Huaihe River basin of warm convective clouds background, early development in the cloud (20-24min), in the main cloud base updraft area (center 15km), seeding height 1800m altitude, the use of coarse particles (gt; 1μm) , to achieve better catalytic effect, the amount of precipitation also with the increase of sowing, and precipitation occurs earlier. 3) In the same initial CCN concentration and catalytic programs, different thermal environments on the catalytic effect of the specific process is different, cold and wet catalytic primarily affects convective warm cloud and cold clouds, warm catalytic largely convective cold cloud warm cloud processes through the process to have an impact.

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CLC: > Astronomy,Earth Sciences > Atmospheric science (meteorology ) > Meteorological elements,atmospheric phenomenon > Water vapor,condensation,and precipitation > Cloud
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