Abstract
Wet deposition of nss-sulfate, nitrate, ammonium and hydrogen ion in Kyushu, Japan was estimated on the basis of measurements of precipitation chemistry at 27 sites and rainfall amounts at 118 AMeDAS stations. The spatial distribution of the deposition obtained with γ-2-interpolation scheme was compared with avaible measurements of precipitation chemistry and rainfall amounts to confirm acceptable accuracy of the estimaing scheme. The obtained distributions of seasonal ionic deposition strongly suggested that: 1) the deposition of nss-sulfate was rainfall limited, 2) that of nitrate was influenced by local emissions, and 3) ammonium deposition is dominated by rainfall amount and local emissions. Spatial distribution of nss-sulfate discerned that southwesterly airflow in Baiu and summer transported sulfur species emitted from Sakurajima, a volcano located in the southernmost of Kyushu, over 150 km to Kyushu Sanchi mountains, whereas sulfur from the Asian Continent significantly contributed the deposition in winter months over northern Kyushu due to northwesterly monsoon.
