An investigation into the relationship between liquid water content and cloud number concentration in the stratiform clouds over north China

Abstract

The determination of the relationship between liquid water content (LWC) and cloud number concentration (Nc) is significant in the cloud microphysical parameterization. A statistical analysis of cloud microphysical properties has been performed based on the in-situ observations from the North China Cloud Physics Detection Project (NCCPDP) during the period from 1980 to 1982. From the statistical results, the relationship between LWC and Nc was investigated. The results show that: (1) LWC of 34.2% of the clouds is quite low (less than 0.100gm−3), and only about 25.7% of the observations show LWC greater than 0.500gm−3; LWC varies widely from 0.0012 to 4.940gm−3, with an overall average of 0.462gm−3; (2) Nc of more than 42.9% of these cases is less than 250.0cm−3 with only about 15.1% of the cases having Nc larger than 2000.0cm−3, and the percentiles of 25%, 50%, 75%, and 90% of the values of Nc are 93.0cm−3, 395.0cm−3, 1444.0cm−3, and 4672.0cm−3, respectively; and (3) the relationship between LWC and Nc can be expressed as log10Nc=0.7941∗log10LWC+3.1820. These results are expected to be useful for improving the microphysical parameterizations in climate and weather forecasting models.