Seasonal changes in the transport of pollutants into the Arctic troposphere‐model study
Seasonal changes in the transport of pollutants into the Arctic troposphere‐model study
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DOI：
10.1029/2002jd002199
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发表时间：
2003-02
影响因子：
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通讯作者：
A. Klonecki;P. Hess;L. Emmons;Lesley Smith;J. Orlando;D. Blake
中科院分区：
文献类型：
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作者：
A. Klonecki;P. Hess;L. Emmons;Lesley Smith;J. Orlando;D. Blake
[1]结合春分前后对流层臭氧生成（TOPSE）测量活动，利用一个区域性情景化学输送模式研究了污染物从北方半球排放区向对流层其它区域输送的季节机制。该模型模拟了CO和碳氢化合物的强季节性循环，与TOPSE测量结果吻合良好。在这项研究中，我们使用等熵的角度来分析运输在不同的季节和不同的排放区域。用诊断示踪剂进行模拟，以量化（1）不同排放区域对示踪剂分布的贡献和（2）交叉等熵输运的重要性。在冬季高纬度地区，与以前的研究一致，欧洲和西伯利亚的排放源是最大的贡献者诊断示踪剂分布在对流层低层由于大规模的环流模式，低温的来源和存在的冷稳定的边界层，有利于非绝热冷却。北美的排放位于更南部，通常在极锋以南，平均而言，排放的潜在温度较高。由于它们主要在相对温暖的大西洋上传输，它们由于空气柱的普遍不稳定和风暴路径中的强降水而经历强烈的非绝热加热。在夏季，来自所有排放区域的污染物更有可能被非绝热地输送到更高的潜在温度并被稀释。此外，由于大尺度环流模式的差异，夏季污染物直接输送到北极的频率较低。
[1] In association with Tropospheric Ozone Production about the Spring Equinox (TOPSE) measurement campaign a regional episodic chemical transport model is used to study the seasonal mechanisms of transport of pollutants from their Northern Hemisphere emission regions into the remainder of the troposphere. The model simulates the strong seasonal cycle for CO and hydrocarbons that agrees well with TOPSE measurements. In this study we use the isentropic perspective to analyze transport during different seasons and from different emission regions. Simulations with diagnostic tracers are conducted to quantify (1) the contribution of different emission regions to tracer distribution and (2) the importance of cross-isentropic transport. In the high latitudes during winter, in agreement with previous studies, the European and Siberian emission sources are the largest contributors to the diagnostic tracer distributions in the lower troposphere due to large-scale circulation patterns, low temperatures at the source and presence of a cold stable boundary layer that facilitates diabatic cooling. North American emissions are located further south, often south of the polar front, and are on average emitted at higher potential temperatures. Owing to their predominant transport over the relatively warm Atlantic, they experience strong diabatic heating due to the general instability in the air column and heavy precipitation in the storm track. During the summer months the pollution from all emission regions is more likely to be diabatically transported to higher potential temperatures and diluted. In addition, direct transport of pollutants into the Arctic is less frequent during summer due to the differences in the large-scale circulation patterns.