Effect of trends of middle atmosphere gases on the mesosphere and thermosphere
Effect of trends of middle atmosphere gases on the mesosphere and thermosphere
复制标题
中层大气气体趋势对中间层和热层的影响
DOI：
10.1002/jgra.50354
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
R. Roble
中科院分区：
文献类型：
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作者：
L. Qian;D. Marsh;A. Merkel;S. Solomon;R. Roble
我们进行了模式模拟，以研究中层大气中放射性活性微量气体浓度的变化如何影响高层大气的长期变化。我们将模型研究的重点放在1983年至2003年间二氧化碳（CO2）、甲烷（CH4）和水蒸气（H2O）增加和臭氧（O3）减少的影响上。在本研究中，我们使用了美国国家大气研究中心的全大气群落气候模式和热层-电离层-中间层-电动力学环流模式，即全球平均模式。模式模拟表明，CO2是热层长期变化的主要强迫机制，O3、CH4和H2O的影响较小。在400 km高度，全球平均热层中性密度由于CO2单独强迫而下降了~4.5%，而由于所有四种气体的联合强迫而下降了~4.8%。O3耗竭导致平流层和中间层的降温（最大降低0.5 K），这是由于吸收太阳紫外线辐射的减少，但在热层几乎没有降温作用。然而，由于平流层和中间层的热收缩，O3耗损导致热层中性密度小幅度下降约0.25%。由于化学加热和太阳紫外线辐射的吸收增加，CH4和H2O的增加可能使上层中间层和热层略微变暖。
We conducted model simulations to examine how changes in concentration of radiatively active trace gases in the middle atmosphere affect long‐term changes in the upper atmosphere. We focused our model study on the impact of increases in carbon dioxide (CO2), methane (CH4), and water vapor (H2O), and decreases in ozone (O3) between 1983 and 2003. We used both the National Center for Atmospheric Research Whole Atmosphere Community Climate Model and the Thermosphere‐Ionosphere‐Mesosphere‐Electrodynamics General Circulation Model, global mean version, in this study. The model simulations indicate that CO2 is the main forcing mechanism of long‐term changes in the thermsophere, with minor influences from O3, CH4, and H2O. At 400 km altitude, global mean thermospheric neutral density decreased by ~4.5% due to CO2 forcing alone, whereas it decreased by ~4.8% due to the combined forcing from all four gases. O3 depletion caused cooling in the stratosphere and mesosphere (maximum decrease of 0.5 K) due to reduced absorption of solar ultraviolet radiation, but had nearly no cooling effect in the thermosphere. However, due to thermal contraction in the stratosphere and mesosphere, O3 depletion caused a small decrease in thermospheric neutral density of ~0.25%. Increases in both CH4 and H2O may slightly warm the upper mesosphere and thermosphere due to increased chemical heating and absorption of solar ultraviolet radiation.