OBSERVATION ON CHEMICAL COMPOSITION OF SUPERCOOLED CLOUD AND SNOW

The rime ice samples of seven cold-cloud events,including the snow samples of two events,were collected at Huangshan Mountain Summit (1840m in elevation) in the January of 1986 and 1987.The results of analyses of the chemical composition of the rime ice and the falling snow for the events showed that the cloud water under the prevailing wind of SW,W and NW had a less pH than 5.6 while the snow and the local clouds had a larger pH than 7.0.SO42- was the dominant ion that influenced the cold-cloud events.The maximum value of pH and the minimum value of SO42- appeared at the middle part of the cold-clouds.Compared with the cold-cloud water,the snow had a characteristic of larger pH and lower ion concentrations.The variation of the ion concentrations in precipitation may be partially due to higher percentage of the solid precipitation.