A Multiyear Constraint on Ammonia Emissions and Deposition Within the US Corn Belt
A Multiyear Constraint on Ammonia Emissions and Deposition Within the US Corn Belt
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DOI：
10.1029/2020gl090865
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发表时间：
2021-03-28
影响因子：
5.2
通讯作者：
Czarnetzki, Alan C.
中科院分区：
文献类型：
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作者：
Hu, Cheng;Griffis, Timothy J.;Czarnetzki, Alan C.
美国玉米带是全球大气氨 (NH3) 的热点地区，这种气体会对环境和人类健康产生不利影响。我们将每小时高塔 (100 m) 测量值和来自氨监测网络的每两周一次、空间分布、地面观测与美国国家排放清单 (NEI) 和 WRF-Chem 模拟相结合，以限制 2017 年 4 月至 9 月至 2019 年 9 月的 NH3 排放。我们发现：（1）NH3排放量在5月至7月达到峰值，是年NEI平均值的1.6-1.7倍； (2) 农业用地的平均生长季 NH3 排放量多年来非常相似 (3.27-3.64 nmol m(-2) s(-1))，但显示出由气象和土地管理驱动的显着的间歇性变化； (3)干沉降占农业用地总排放量的40%，超过自然用地总排放量的100%。我们的研究结果为评估未来 NH3 排放和减排工作提供了重要基准。
The US Corn Belt is a global hotspot of atmospheric ammonia (NH3), a gas known to adversely impact the environment and human health. We combine hourly tall tower (100 m) measurements and bi-weekly, spatially distributed, ground-based observations from the Ammonia Monitoring Network with the US National Emissions Inventory (NEI) and WRF-Chem simulations to constrain NH3 emissions from April to September 2017-2019. We show that: (1) NH3 emissions peaked from May to July and were 1.6-1.7 times the annual NEI average; (2) average growing season NH3 emissions from agricultural lands were remarkably similar across years (3.27-3.64 nmol m(-2) s(-1)), yet showed substantial episodic variability driven by meteorology and land management; (3) dry deposition was 40% of gross emissions from agricultural lands and exceeded 100% of gross emissions in natural lands. Our findings provide an important benchmark for evaluating future NH3 emissions and mitigation efforts.