ON SURFACE-TEMPERATURE, GREENHOUSE GASES, AND AEROSOLS - MODELS AND OBSERVATIONS
ON SURFACE-TEMPERATURE, GREENHOUSE GASES, AND AEROSOLS - MODELS AND OBSERVATIONS
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DOI：
10.1175/1520-0442(1995)008
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发表时间：
1995-10-01
影响因子：
4.9
通讯作者：
SENIOR, CA
中科院分区：
文献类型：
--
作者：
MITCHELL, JFB;DAVIS, RA;SENIOR, CA
利用与混合层海洋耦合的Hadley中心大气模式的一个版本，研究了大气二氧化碳浓度和硫酸盐气溶胶的变化对近地表温度的影响。硫酸盐气溶胶对太阳光的散射表现为适当地增强了地表反照率。大气二氧化碳浓度加倍时，全球平均气温增加了5.2K。再加上二氧化碳增加39%，得出自1900年以来温室气体增加导致的辐射加热估计变化，产生了2.3K的平衡变暖，即使考虑到海洋惯性，这也明显高于同期观测到的变暖。此外，模拟表明，各地都在大幅变暖，而观测结果表明，包括中纬度大陆北部部分地区在内的孤立地区正在降温。加上对当前工业气溶胶散射影响的估计(至少不确定3倍)，导致与北部大陆上观察到的变化模式的一致性提高，并使全球平均变暖减少了约30%。加倍的气溶胶强迫产生的模式仍然与观测结果一致，但进一步增加会导致中纬度地区不切实际的大范围降温。由于二氧化碳的增加，大部分北部温带地区的地表温度日较差减小，这与最近的观测结果一致。目前的工业气溶胶的加入对模式中的日变化范围几乎没有可检测到的影响，因为表面太阳加热减少的直接影响与冷却的间接影响大致平衡。因此，日较差的减少与平均变暖的比率增加了，这与观测结果更接近。尽管夏季气溶胶强迫在北部中纬度地区达到最大值，但由于海冰反馈放大了冬季的冷却，因此全年的响应相当均匀。随着气溶胶载量的增加，全球平均日温差持续增加，与平均气温降低有关，但在气溶胶载量最大的地方，日温差略有减小。对二氧化碳增加的反应与其他模型的反应进行了比较。
The effect of changes in atmospheric carbon dioxide concentrations and sulphate aerosols on near-surface temperature is investigated using a version of the Hadley Centre atmospheric model coupled to a mixed layer ocean. The scattering of sunlight by sulphate aerosols is represented by appropriately enhancing the surface albedo.On doubling atmospheric carbon dioxide concentrations, the global mean temperature increases by 5.2 K. An integration with a 39% increase in CO2, giving the estimated change in radiative heating due to increases in greenhouse gases since 1900, produced an equilibrium warming of 2.3 K, which, even allowing for oceanic inertia, is significantly higher than the observed warming over the same period. Furthermore, the simulation suggests a substantial warming everywhere, whereas the observations indicate isolated regions of cooling, including parts of the northern midlatitude continents. The addition of an estimate of the effect of scattering by current industrial aerosols (uncertain by a factor of at least 3) leads to improved agreement with the observed pattern of changes over the northern continents and reduces the global mean warming by about 30%. Doubling the aerosol forcing produces patterns that are still compatible with the observations, but further increase leads to unrealistically extensive cooling in the midlatitudes.The diurnal range of surface temperature decreases over most of the northern extratropics on increasing CO2, in agreement with recent observations. The addition of the current industrial aerosol had little detectable effect on the diurnal range in the model because the direct effect of reduced solar heating at the surface is approximately balanced by the indirect effects of cooling. Thus, the ratio of the reduction in diurnal range to the mean warming is increased, in closer agreement with observations.Results from further sensitivity experiments with larger increases in aerosol and CO2 are presented. Although the aerosol forcing is a strong maximum in the northern midlatitudes in summer, the response is fairly even throughout the year because sea ice feedbacks amplify the cooling in winter. Increasing the aerosol loading produces a consistent increase in the globally averaged diurnal temperature range, associated with the mean reduction in temperature, though the diurnal range decreases slightly where the aerosol loading is greatest. The response to increased CO2 is compared with that in other models.