Mapping Critical Loads Of Acid Deposition For Northeast Asia

Eastern Asia is one of the largest acid rain areas in the world, following Europeand North America. Acid deposition is an important air pollution issue, of which thetransboundary environment impact caused a wide spread attention. Regional aciddeposition control has been a hot topic for researchers, Especially in Europe, lots ofstudy on transboudary air pollution have been done, which have been paid muchattention to by Eastern Asia Recently. Critical load is the quantitatie estimation of thesensitivity of ecosystem to acid deposition, which is widely used in Europe and NorthAmerica. Therefore, the critical loads of acid deposition for Northeast Asia weremapped and the distribution of the ecosystem sensitivity in this area were studied,which could be fundamental data for transboundary pollution impact analysis andco-emission reduction negotiation.First of all, soil, vegatation and deposition parameter were discussed, then aciddeposition of Northeast Asia (Northeast of China, Japan and Korean Peninsula) werecompiled through Simple Mass Balance(SMB) method with the resolution of0.1°(latitude)×0.1°(longitute). The thesis focused on discussion of the method and dataunification of soil base cation weathering rates and vegetation uptakes of base cationand nitrogen. Base cation weathering rates were derived by the former findings in BCwsurvey of China and the formation of soil reference system. Vegetation uptakes werecalculated by multiplying net primary production and element content of dominant plantof each vegetation type which were concluded through comprehensive literature survey.NAQPMS model were used for regional base cation deposition simulation to get apreciser distribution information. Critical loads of acidity, sulfur and nitrogen ofNortheast Asia were mapped. As can be seen from the critical load map of acidity, thelowest critical load area were in Daxinganling Mountain with Podzolic soiland thesouthwest of Honshu in Japan(<0.5keqha-1yr-1) with a high base cation uptake, thenfollowed by Xiaoxinganling Mountain, Changbai Mountain and south of KoreanPeninsula with a critical load range of0.5-1.0keqha-1yr-1. Highest critical loadsoccurred in volcanic zone of Japan, Sanjiang Plain and the neighborhood of InnerMongolia Autonomous Region (>2.0keqha-1yr-1), which was in accord with their high base cation weathering rates. The critical load map of sulfur differed with the criticalload map of acidity on northeast of China and North Korea, due to high base cationdeposition rates. The critical loads of nitrogen in Northeast Asia were mostly above1.0keqha-1yr-1(1.4gm-2yr-1), increasing from west to east, Japan had the highest criticalloads of nitrogen with climate conditions suitable for vegetation growth.