Enhanced Wet Deposition of Nitrogen Induced by a Landfalling Typhoon over East Asia: Implications for the Marine Eco- Environment

Wet deposition of reactive nitrogen (Nr) induced by typhoons has significant eco-environmental impacts on the oceans, especially under the growing frequency of landfalling typhoons in East Asia. However, little is known about the mechanism of how anthropogenic activities influence the ocean ecosystem by interacting with landfalling typhoons. Based on the Nested Air Quality Prediction Modeling System, the Nr wet deposition induced by landfalling typhoon Hagupit 2020 and the ecological response were explored. The Nr wet deposition over both the Yellow Sea and the Sea of Japan after landfall was found to have increased by up to 1000 times that of the prelandfall ocean influenced by the typhoon. This high Nr wet deposition was mainly due to the "pumping effect" mechanism of the typhoon, where strong uplifts of the typhoon rapidly carried surface air pollutants up to high altitudes from the land, following a large wet deposition through long-range transport toward the downwind ocean, finally leading to a high-concentration chlorophyll-a bloom. This study improves our understanding of Nr wet deposition induced by landfalling typhoons and helps in the establishment of effective and active measures and to reveal marine ecology damaged by extremely strong convective weather systems.