Simulations of anthropogenic change in the strength of the Brewer-Dobson circulation
Simulations of anthropogenic change in the strength of the Brewer-Dobson circulation
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DOI：
10.1007/s00382-006-0162-4
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发表时间：
2006-12-01
期刊：
影响因子：
4.6
通讯作者：
Sigmond, M.
中科院分区：
文献类型：
--
作者：
Butchart, N.;Scaife, A. A.;Sigmond, M.
气候变化对布鲁尔-多布森环流的影响，特别是对流层和平流层之间的大尺度季节性平均输送，在若干大气环流模式中进行了比较。所有模式都再现了观测到的穿过热带对流层顶的上升流，通过外热带的下升流来平衡，尽管在一些模式中上升流的季节周期更像是半年而不是一年。所有模型还一致预测，质量交换率会随着温室气体浓度的增加而增加，而不管模型是否包括相互作用臭氧化学。平均趋势为11kt / s（-1）年（-1）或每十年约2%，但不同模式之间差异很大。在所有模式中，除了一个模式外，物质交换的增加贯穿全年，尽管通常在北方冬季趋势更大。平均而言，60%以上的平均质量通量可以用向下控制原理的ep -通量发散来解释。从ep -通量散度得出的年平均质量通量趋势也解释了对流层-平流层质量交换率在所有模式上的平均趋势的60%。除了两个模式外，推导出的向下控制的年际变率与实际质量通量的年际变率总体上与年平均值有很好的相关性。
The effect of climate change on the Brewer-Dobson circulation and, in particular, the large-scale seasonal-mean transport between the troposphere and stratosphere is compared in a number of middle atmosphere general circulation models. All the models reproduce the observed upwelling across the tropical tropopause balanced by downwelling in the extra tropics, though the seasonal cycle in upwelling in some models is more semi-annual than annual. All the models also consistently predict an increase in the mass exchange rate in response to growing greenhouse gas concentrations, irrespective of whether or not the model includes interactive ozone chemistry. The mean trend is 11 kt s(-1) year(-1) or about 2% per decade but varies considerably between models. In all but one of the models the increase in mass exchange occurs throughout the year though, generally, the trend is larger during the boreal winter. On average, more than 60% of the mean mass fluxes can be explained by the EP-flux divergence using the downward control principle. Trends in the annual mean mass fluxes derived from the EP-flux divergence also explain about 60% of the trend in the troposphere-to-stratosphere mass exchange rate when averaged over all the models. Apart from two models the interannual variability in the downward control derived and actual mass fluxes were generally well correlated, for the annual mean.