Campbell Patrick C, Bash Jesse O, Nolte Christopher G, Spero Tanya L, Cooter Ellen J, Hinson Kyle, Linker Lewis
National Academies/National Research Council (NRC) Fellowship Participant at National Exposure Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA.
National Exposure Research Laboratory, U.S. Environmental Protection Agency Research Triangle Park, North Carolina, USA.
J Geophys Res Biogeosci. 2019 Dec 26;12(11):3307-3326. doi: 10.1029/2019JG005203.
Atmospheric deposition is among the largest pathways of nitrogen loading to the Chesapeake Bay Watershed (CBW). The interplay between future climate and emission changes in and around the CBW will likely shift the future nutrient deposition abundance and chemical regime (e.g., oxidized vs. reduced nitrogen). In this work, a Representative Concentration Pathway (RCP) from the Community Earth System Model is dynamically downscaled using the Weather Research and Forecasting (WRF) and Community Multiscale Air Quality (CMAQ) model coupled to the agro-economic Environmental Policy Integrated Climate (EPIC) model. The relative impacts of emission and climate changes on atmospheric nutrient deposition are explored for a recent historical period and a period centered on 2050. The projected regional emissions in CMAQ reflect current federal and state regulations, which use baseline and projected emission years 2011 and 2040, respectively. The historical simulations of 2-m temperature and precipitation have cool and dry biases, and temperature and precipitation are projected to both increase. Ammonium wet deposition agrees well with observations, but nitrate wet deposition is underpredicted. Climate and deposition changes increase simulated future ammonium fertilizer application. In the CBW at 2050, these changes (along with widespread decreases in anthropogenic nitrogen oxide and sulfur oxide emissions, and relatively constant NH emissions) decrease total nitrogen deposition by 21%, decrease annual average oxidized nitrogen deposition by 44%, and increase reduced nitrogen deposition by 10%. These results emphasize the importance of decreased anthropogenic emissions on the control of future nitrogen loading to the Chesapeake Bay in a changing climate.
大气沉降是切萨皮克湾流域（CBW）氮负荷的最大途径之一。CBW及其周边地区未来气候与排放变化之间的相互作用可能会改变未来养分沉降的丰度和化学状态（例如，氧化态氮与还原态氮）。在这项研究中，利用天气研究与预报（WRF）模型和社区多尺度空气质量（CMAQ）模型，并耦合农业经济环境政策综合气候（EPIC）模型，对社区地球系统模型中的代表性浓度路径（RCP）进行了动态降尺度处理。研究探讨了排放和气候变化对近期历史时期以及以2050年为中心的时期大气养分沉降的相对影响。CMAQ中预测的区域排放反映了当前的联邦和州法规，分别使用2011年的基线排放年和2040年的预测排放年。2米高度处气温和降水的历史模拟存在冷偏差和干偏差，预计气温和降水都将上升。铵态湿沉降与观测结果吻合良好，但硝态湿沉降预测值偏低。气候和沉降变化增加了模拟的未来铵肥施用量。在2050年的CBW，这些变化（以及人为氮氧化物和硫氧化物排放的普遍减少，以及相对稳定的氨排放）使总氮沉降减少21%，年平均氧化态氮沉降减少44%，还原态氮沉降增加10%。这些结果强调了在气候变化背景下，减少人为排放对于控制未来切萨皮克湾氮负荷的重要性。
