气象学报(英文版)
氣象學報(英文版)
기상학보(영문판)
ACTA METEOROLOGICA SINICA
2013年
6期
832-848
,共17页
陆春松%刘延刚%牛生杰%赵丽娟%于华英%程穆宁
陸春鬆%劉延剛%牛生傑%趙麗娟%于華英%程穆寧
륙춘송%류연강%우생걸%조려연%우화영%정목저
fog microphysics%microphysical relationships%physical processes%observations
In this paper, the microphysical relationships of 8 dense fog events collected from a comprehensive fog observation campaign carried out at Pancheng (32.2?N, 118.7?E) in the Nanjing area, China in the winter of 2007 are investigated. Positive correlations are found among key microphysical properties (cloud droplet number concentration, droplet size, spectral standard deviation, and liquid water content) in each case, suggesting that the dominant processes in these fog events are likely droplet nucleation with subsequent condensational growth and/or droplet deactivation via complete evaporation of some droplets. The abrupt broadening of the fog droplet spectra indicates the occurrence of the collision-coalescence processes as well, although not dominating. The combined effects of the dominant processes and collision-coalescence on microphysical relationships are further analyzed by dividing the dataset according to visibility or autocon-version threshold in each case. The result shows that the specific relationships of number concentration to volume-mean radius and spectral standard deviation depend on the competition between the compensation of small droplets due to nucleation-condensation and the loss of small droplets due to collision-coalescence. Generally, positive correlations are found for different visibility or autoconversion threshold ranges in most cases, although negative correlations sometimes appear with lower visibility or larger autoconversion thresh-old. Therefore, the compensation of small droplets is generally stronger than the loss, which is likely related to the su?cient fog condensation nuclei in this polluted area.