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Abstract：
East Asian oceans are possibly affected by a high nitrogen (N) burden because of the intense anthropogenic emissions in this region. Based on high-resolution regional chemical transport modeling with horizontal grid scales of 36 and 12 km, we investigated the N burden into East Asian oceans via atmospheric deposition in 2010. We found a high N burden of 2-9 kg N ha-1 yr-1 over the Yellow Sea, East China Sea (ECS), and Sea of Japan. Emissions over East Asia were dominated by ammonia (NH3) over land and nitrogen oxides (NOx) over oceans, and N deposition was dominated by reduced N over most land and open ocean, whereas it was dominated by oxidized N over marginal seas and desert areas. The verified numerical modeling identified that the following processes were quantitatively important over East Asian oceans: the dry deposition of nitric acid (HNO3), NH3, and coarse-mode (aerodynamic diameter greater than 2.5 μm) NO3-, and wet deposition of fine-mode (aerodynamic diameter less than 2.5 μm) NO3- and NH4+. The relative importance of the dry deposition of coarse-mode NO3- was higher over open ocean. The estimated N deposition to the whole ECS was 390 Gg N yr-1; this is comparable to the discharge from the Yangtze River to the ECS, indicating the significant contribution of atmospheric deposition. Based on the high-resolution modeling over the ECS, a tendency of high deposition in the western ECS and low deposition in the eastern ECS was found, and a variety of deposition processes were estimated. The dry deposition of coarse-mode NO3- and wet deposition of fine-mode NH4+ were the main factors, and the wet deposition of fine-mode NO3- over the northeastern ECS and wet deposition of coarse-mode NO3- over the southeastern ECS were also found to be significant processes determining N deposition over the ECS.
摘要：
由于该地区人为排放大量，东亚海洋可能受到高氮（N）负担的影响。基于水平网格尺度为36和12km的高分辨率区域化学输运模型，我们在2010年调查了通过大气沉积进入东亚海洋的氮负担。我们在黄海上发现了2-9kgNha-1yr-1的高N负荷，东海(ECS),日本海。东亚的排放主要由陆地上的氨（NH3）和海洋上的氮氧化物（NOx）主导，在大多数陆地和公海上，氮的沉积以减少的氮为主，而边缘海和沙漠地区的氧化氮占主导地位。经过验证的数值模型确定，以下过程在东亚海洋中具有重要的定量意义：硝酸（HNO3）的干沉积，NH3和粗模式（空气动力学直径大于2.5μm）NO3-，和细模式（空气动力学直径小于2.5μm）NO3-和NH4的湿沉积。在公海上，粗模式NO3-的干沉降的相对重要性更高。估计整个ECS的氮沉积为390GgNyr-1；这与从长江到ECS的流量相当，表明大气沉降的显著贡献。基于ECS上的高分辨率建模，发现了西部ECS高沉积和东部ECS低沉积的趋势，并估计了各种沉积过程。粗模式NO3-的干沉积和细模式NH4+的湿沉积是主要因素,还发现东北ECS上的细模式NO3-的湿沉积和东南ECS上的粗模式NO3-的湿沉积是决定ECS上N沉积的重要过程。
