Horton Daniel E, Diffenbaugh Noah S
Department of Environmental Earth System Science, Stanford University, Stanford, CA, USA.
Environ Res Lett. 2012;7(4). doi: 10.1088/1748-9326/7/4/044034.
Stagnant atmospheric conditions can lead to hazardous air quality by allowing ozone and particulate matter to accumulate and persist in the near-surface environment. By changing atmospheric circulation and precipitation patterns, global warming could alter the meteorological factors that regulate air stagnation frequency. We analyze the response of the National Climatic Data Center (NCDC) Air Stagnation Index (ASI) to anthropogenically enhanced radiative forcing using global climate model projections of late-21(st) century climate change (SRES A1B scenario). Our results indicate that the atmospheric conditions over the highly populated, highly industrialized regions of the eastern United States, Mediterranean Europe, and eastern China are particularly sensitive to global warming, with the occurrence of stagnant conditions projected to increase 12-to-25% relative to late-20(th) century stagnation frequencies (3-18+ days/year). Changes in the position/strength of the polar jet, in the occurrence of light surface winds, and in the number of precipitation-free days all contribute to more frequent late-21(st) century air mass stagnation over these high-population regions. In addition, we find substantial inter-model spread in the simulated response of stagnation conditions over some regions using either native or bias corrected global climate model simulations, suggesting that changes in the atmospheric circulation and/or the distribution of precipitation represent important sources of uncertainty in the response of air quality to global warming.
停滞的大气状况会使臭氧和颗粒物在近地表环境中积聚并持续存在，从而导致空气质量恶化。全球变暖通过改变大气环流和降水模式，可能会改变调节空气停滞频率的气象因素。我们利用21世纪末气候变化的全球气候模型预测（SRES A1B情景），分析了国家气候数据中心（NCDC）的空气停滞指数（ASI）对人为增强的辐射强迫的响应。我们的结果表明，美国东部、欧洲地中海地区和中国东部人口密集、工业化程度高的地区的大气状况对全球变暖特别敏感，预计停滞状况的发生频率相对于20世纪末的停滞频率（每年3 - 18 +天）将增加12%至25%。极锋急流的位置/强度变化、微风的出现以及无降水天数的变化，都导致这些高人口地区在21世纪后期空气质量停滞更为频繁。此外，我们发现，使用原始或偏差校正的全球气候模型模拟，一些地区停滞状况的模拟响应在不同模型之间存在很大差异，这表明大气环流和/或降水分布的变化是空气质量对全球变暖响应中不确定性的重要来源。
