Analysis of acid rain's characteristics and variation tendency in longli experimental plot, guizhou.
From April 2007 to December 2008,the rainfalls had been collected and measured at Longli experimental plot in Guizhou Province.The acidity and chemical composition of rainwater were analyzed with statistical methods to reveal the characteristics and seasonal tendency of local acid rain.76.7% of the total capacity of rainwater were acidic with an average pH value of 4.70 and the frequency of acid rain accounted for 70.1% during the study period.Meanwhile,the concentrations of SO42-,NO3-,NH4+,Ca2+ of rainwater were higher in spring with much more occurrences of acid rain.As a conclusion,the wet depositions of sulfur and nitrogen did not exceed the critical loads estimated by the other studies.