Evaluation of multidecadal variability in CMIP5 surface solar radiation and inferred underestimation of aerosol direct effects over Europe, China, Japan, and India
Evaluation of multidecadal variability in CMIP5 surface solar radiation and inferred underestimation of aerosol direct effects over Europe, China, Japan, and India
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DOI：
10.1002/jgrd.50426
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发表时间：
2013-06-27
影响因子：
4.4
通讯作者：
Wild, M.
中科院分区：
文献类型：
--
作者：
Allen, R. J.;Norris, J. R.;Wild, M.
全球能源平衡档案的观测表明，从大约 20 世纪 50 年代到 1980 年代，所有天空表面太阳辐射出现区域性下降，随后在 1990 年代有所增加。这些时期通常分别称为变暗和变亮。从所有天空表面太阳辐射中消除云量变化的辐射影响会产生称为晴空代理辐射的量，其中可以更明显地看到数十年趋势，表明气溶胶辐射强迫是一个可能的原因。先前的研究表明，耦合模型比对项目 3 (CMIP3) 的气候模型普遍低估了这些趋势的严重程度，特别是在中国和印度。在这里，我们对参与新 CMIP5 的 42 个气候模型的 173 个模拟进行了类似的分析。结果显示，相对于 CMIP3 的改进可以忽略不计，因为欧洲、中国、印度和日本四个地区的 CMIP5 调光趋势均被低估。印度和中国的这种偏差最大，多模式平均值导致晴空代理辐射分别减少 -1.3 +/- 0.3 和 -1.2 +/- 0.2Wm(-2)decade(-1)，而观测到的减少量为 -6.5 +/- 0.9 和 -8.2 +/- 1.3Wm(-2)decade(-1)。对日本观测到的变暗现象也存在类似的低估，CMIP5 平均变暗程度约为观测到的 20%。此外，没有任何一个模拟能够再现所观察到的这三个区域的调光趋势的幅度。相对于调光，CMIP5 模型更好地模拟了观察到的增亮，但中国和日本都存在严重低估。总体而言，没有哪个模型在所有四个地区都表现得特别好。模型偏差似乎与处方气雾剂与预后气雾剂的使用或气雾剂的间接影响无关。然而，模型显示晴空代理辐射与几个气溶胶相关场之间存在显着相关性，最显着的是气溶胶光学深度 (AOD) 和吸收 AOD。这表明模型对观察到的趋势的低估与气溶胶直接辐射强迫和/或气溶胶排放清单不足的估计有关。
Observations from the Global Energy Balance Archive indicate regional decreases in all sky surface solar radiation from approximate to 1950s to 1980s, followed by an increase during the 1990s. These periods are popularly called dimming and brightening, respectively. Removal of the radiative effects of cloud cover variability from all sky surface solar radiation results in a quantity called clear sky proxy radiation, in which multidecadal trends can be seen more distinctly, suggesting aerosol radiative forcing as a likely cause. Prior work has shown climate models from the Coupled Model Intercomparison Project 3 (CMIP3) generally underestimate the magnitude of these trends, particularly over China and India. Here we perform a similar analysis with 173 simulations from 42 climate models participating in the new CMIP5. Results show negligible improvement over CMIP3, as CMIP5 dimming trends over four regionsEurope, China, India, and Japanare all underestimated. This bias is largest for both India and China, where the multimodel mean yields a decrease in clear sky proxy radiation of -1.3 +/- 0.3 and -1.2 +/- 0.2Wm(-2)decade(-1), respectively, compared to observed decreases of -6.5 +/- 0.9 and -8.2 +/- 1.3Wm(-2)decade(-1). Similar underestimation of the observed dimming over Japan exists, with the CMIP5 mean dimming approximate to 20% as large as observed. Moreover, not a single simulation reproduces the magnitude of the observed dimming trend for these three regions. Relative to dimming, CMIP5 models better simulate the observed brightening, but significant underestimation exists for both China and Japan. Overall, no individual model performs particularly well for all four regions. Model biases do not appear to be related to the use of prescribed versus prognostic aerosols or to aerosol indirect effects. However, models exhibit significant correlations between clear sky proxy radiation and several aerosol-related fields, most notably aerosol optical depth (AOD) and absorption AOD. This suggests model underestimation of the observed trends is related to underestimation of aerosol direct radiative forcing and/or deficient aerosol emission inventories.