THE PHYSICAL AND CHEMICAL CHARACTERISTICS OF A SPRING FRONTAL RAINFALL IN GUANGZHOU

Through layer-by-layer observational analysis to a typical case of frontal sheetcloud rainfall, some of its physical and chemical characteristics are obtained, which show that:(1) modest raindrops concentration and small drop diameter account for a light raininess;(2) the pH value(4. 78 in average) is low and NH4+,SO4-,and NO3- are the dominant composition of ions with Cl- and Na+ next to them:(3) with the fall of raindrops at the near-surface layers, ion lvels and pH values increase:(4) the pH value rises in fluctuation at the onset of the rainfall coupled with a consistent desent afterwards.Cl- well relates with Na+.