Multimodel ensemble simulations of present-day and near-future tropospheric ozone
Multimodel ensemble simulations of present-day and near-future tropospheric ozone
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DOI：
10.1029/2005jd006338
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发表时间：
2006-04
影响因子：
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通讯作者：
D. Stevenson;F. Dentener;M. Schultz;K. Ellingsen;T. Noije;O. Wild;G. Zeng;M. Amann;C. Atherton-C.-Ath
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文献类型：
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作者：
D. Stevenson;F. Dentener;M. Schultz;K. Ellingsen;T. Noije;O. Wild;G. Zeng;M. Amann;C. Atherton-C.-Ath
作为臭氧对空气质量和气候作用的更广泛研究的一部分，对26个最先进的大气化学模式集合的全球对流层臭氧分布、收支和辐射强迫进行了相互比较和综合。2030年三种排放情景的结果，大致代表乐观、可能和悲观的选择，与基准年2000年的模拟结果进行了比较。这一基本情况真实地反映了目前全球对流层臭氧的分布情况。进一步的一组模拟考虑了气候变化在同一时期的影响，通过强迫中央排放情景，地表变暖约0.7K。大型多模型集成的使用使我们能够识别不确定性的关键区域，并提高结果的鲁棒性。在2000年至2030年期间，3种情景对流层臭氧负荷的总体平均变化范围从减少5%到增加6%，再到增加15%。与这些值相关的模式间不确定性（±1标准差）约为±25%。模型异常值对集合均值结果没有显著影响。结合臭氧和甲烷的变化，这三种情景产生的辐射强迫分别为-50、180和300 mW m-2，而co2强迫在同一时期的辐射强迫为800-1100 mW m-2。这些值表明空气污染排放在中短期气候强迫中的重要性，以及严格/宽松控制措施改善/恶化未来气候强迫的潜力。臭氧对气候变化的模式敏感性因模式而异，但通过各种反馈机制，特别是涉及水蒸气和平流层-对流层交换的反馈机制，将纬向平均混合比调节了±5 ppbv。这种程度的气候变化也使甲烷的寿命减少了约4%。总体平均2000年对流层臭氧收支表明化学生产、化学破坏、干沉积和平流层输入通量分别为5100、4650、1000和550 Tg（O 3）年-1。这些值与政府间气候变化专门委员会（IPCC）第三次评估报告（TAR）记录的平均预算有显著差异。平均臭氧负担（340 Tg(O 3)）比IPCC第三次评估报告的估计高10%，而平均臭氧寿命（22天）短10%。单个模式的结果显示了臭氧负担与寿命之间的相关性，并且每个模式的臭氧负担和寿命在不同的排放情景中以相似的方式响应。对气候变化的反应就不那么一致了。模式显示，与中纬度地区相比，热带地区的变化更大。模式中一些最不确定的区域包括对热带深层对流的处理，包括闪电NO x的产生；植物异戊二烯排放及异戊二烯降解化学stratosphere-troposphere交流;生物质燃烧;水蒸气浓度。版权归美国地球物理联盟所有。
Global tropospheric ozone distributions, budgets, and radiative forcings from an ensemble of 26 state-of-the-art atmospheric chemistry models have been intercompared and synthesized as part of a wider study into both the air quality and climate roles of ozone. Results from three 2030 emissions scenarios, broadly representing optimistic, likely, and pessimistic options, are compared to a base year 2000 simulation. This base case realistically represents the current global distribution of tropospheric ozone. A further set of simulations considers the influence of climate change over the same time period by forcing the central emissions scenario with a surface warming of around 0.7K. The use of a large multimodel ensemble allows us to identify key areas of uncertainty and improves the robustness of the results. Ensemble mean changes in tropospheric ozone burden between 2000 and 2030 for the 3 scenarios range from a 5% decrease, through a 6% increase, to a 15% increase. The intermodel uncertainty (±1 standard deviation) associated with these values is about ±25%. Model outliers have no significant influence on the ensemble mean results. Combining ozone and methane changes, the three scenarios produce radiative forcings of -50, 180, and 300 mW m-2, compared to a CO 2 forcing over the same time period of 800-1100 mW m-2. These values indicate the importance of air pollution emissions in short- to medium-term climate forcing and the potential for stringent/lax control measures to improve/worsen future climate forcing. The model sensitivity of ozone to imposed climate change varies between models but modulates zonal mean mixing ratios by ±5 ppbv via a variety of feedback mechanisms, in particular those involving water vapor and stratosphere-troposphere exchange. This level of climate change also reduces the methane lifetime by around 4%. The ensemble mean year 2000 tropospheric ozone budget indicates chemical production, chemical destruction, dry deposition and stratospheric input fluxes of 5100, 4650, 1000 and 550 Tg(O 3 ) yr-1, respectively. These values are significantly different to the mean budget documented by the Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report (TAR). The mean ozone burden (340 Tg(O 3 )) is 10% larger than the IPCC TAR estimate, while the mean ozone lifetime (22 days) is 10% shorter. Results from individual models show a correlation between ozone burden and lifetime, and each model's ozone burden and lifetime respond in similar ways across the emissions scenarios. The response to climate change is much less consistent. Models show more variability in the tropics compared to midlatitudes. Some of the most uncertain areas of the models include treatments of deep tropical convection, including lightning NO x production; isoprene emissions from vegetation and isoprene's degradation chemistry; stratosphere-troposphere exchange; biomass burning; and water vapor concentrations. Copyright 2006 by the American Geophysical Union.