Characteristics of inorganic ions in precipitation at different altitudes in the Yulong Snow Mountain, China

The present study investigated the chemical composition of summer precipitation at different altitudes in Yulong Snow Mountain, hoping to obtain some basic information about the chemical characteristics of precipitation. A couple of precipitation samples at different altitudes in the Yulong Snow Mountain area in southeastern China were collected from July 26 to July 31, 2005 for chemical analyses. Sea-salt tracer analysis showed that Cl− and Na+ had high proportion from marine sources, while the other ions mainly were from non-marine sources. Statistics showed that the cation concentrations ranged from 0.51 to 5.26 mg L−1 and anion concentrations ranged from 0.99 to 4.90 mg L−1. Further analysis showed that terrestrial ions, especially from the proximal terrestrial sources, largely affected the ion concentrations in precipitation. Ion concentrations of precipitation were correlated significantly with local atmospheric circulation at altitude 2,950–4,800 m, and also correlated closely with human activities at altitude 2,400–2,950 m. Limestone, the majority of local rocks, caused high cation concentrations in precipitation, such as Ca2+ and Mg2+. The majority of vapors in the region came from the Indian Ocean whereas parts came from the eastern Pacific. The inorganic ions in precipitation increased significantly in the Yulong Snow Mountain area during this century. Compared with most of the high altitude Mountains in China, the precipitations in the Yulong Snow Mountain area had higher concentrations of inorganic ions and low acidic ion concentrations. The conclusions can provide a basis for study of regional climate characteristics, environment and ecological characteristics of Yulong Snow Mountain area.