SGER: Evaluation of Surface Solar Irradiance in Coupled Climate Models

将对卫星观测和地面下沉流辐照度的现场测量结果进行分析，并与世纪末和世纪运行的全球大气环流耦合模式模拟结果进行比较，以评价模式的气候学、变率以及云和气溶胶效应。在表面的入射短波辐照度是海洋/冰和陆地子模型的一个驱动机制，虽然它直接受到大气中的物理作用，如云，气溶胶，水蒸气，臭氧和其他气体的影响，但它只受到海洋/冰/陆地的间接影响。因此，气溶胶和云的变化对下沉流短波地面辐照度有很强的直接信号，这是很容易解释的。与此同时，地表太阳辐照度及其与云和气溶胶的联系是云反馈回路的一个关键部分。此外，科学界对地表入射太阳辐照度的长期变化越来越感兴趣。观测表明，从1961-1990年，全球各站的太阳辐照度最近下降了约4%，这可能是由于气溶胶浓度和云的变化。这被描述为全球变暗效应。目前的研究（来自卫星观测）表明，从1980年代末到1990年代，这种影响发生了逆转。PI将使用两个数据集，这两个数据集代表两种不同类别的数据检索方法，分别来自卫星和现场测量。他们将把观测到的地表下沉短波通量的气候学和变异性与四个耦合气候模型进行比较，这四个耦合气候模型是戈达德空间研究所模型和两个海洋子模型，即地球物理流体动力学实验室模型和国家大气研究中心社区气候系统模型。由于这些模式使用不同的气溶胶数据集和云参数化（有些使用间接的云-气溶胶效应），对地面太阳辐照度的模式间比较将对每个模式表示云和气溶胶影响的质量具有指导意义。主要研究者将：（a）评估模型在地面下沉短波通量的长期变化和趋势，并将其与观测结果进行比较;（B）评估模型中的气溶胶和云的影响;（c）审查模型模拟具体事件（火山爆发和厄尔尼诺现象）的能力。 更广泛的影响：这项研究很重要，因为它有可能提高气候预测模型的质量，这将有利于社会活动，如环境管理和决策。这是美国气候变化科学计划的气候变化和可预测性计划（CLIVAR）下的一项资助。

Observations from satellites and in situ measurements of surface downwelling irradiance will be analyzed and compared with global general circulation coupled model simulations of the late 19th century and 20th century runs to evaluate the model climatology, variability and cloud and aerosol effects. The incoming shortwave irradiance at the surface is one driving mechanism of the ocean/ice and land submodels and while it is directly affected by the physics in the atmosphere, such as clouds, aerosols, water vapor, ozone and other gases, it is only indirectly affected by the ocean/ice/land. Hence, aerosol and cloud variations have a strong direct signal on the downwelling shortwave surface irradiance, which can be easily interpreted. At the same time, surface solar irradiance and its link to clouds and aerosols represents one crucial part of the cloud feedback loop. Furthermore, there has been increased interest in the scientific community regarding the long-term variability of the surface incoming solar irradiance. Observations show that solar irradiance has recently been decreasing in stations worldwide by about 4% from 1961-1990, possibly due to changed aerosol concentrations and cloud variations. This has been described as a global dimming effect. Current research (from satellite observations) shows a reversal of this effect from the late 1980s and during the 1990s. The PIs will use two data sets, which represent two different classes of data retrieval methods, from satellites and in situ measurements. They will compare the observed climatology and variability of the surface downwelling shortwave flux to four coupled climate models, the Goddard Institute for Space Studies (GISS) model with two ocean submodels, the Geophysical Fluid Dynamics Laboratory (GFDL) model and the National Center for Atmospheric Research (NCAR) Community Climate System Model (CCSM-3), on all resolved temporal and spatial scales. Since the models use different aerosol datasets and cloud parameterizations (some use indirect cloud-aerosol effects) the inter-model comparisons of the solar irradiance at the surface will be instructive of the quality of each models' representation of cloud and aerosol impacts. The PIs will a) assess the long-term variability and trend of the model downwelling shortwave flux at the surface and compare it to observations, b) assess the aerosol and cloud effects in the models and, c) examine the models' capability in simulating specific events (volcanic eruptions and El Nino conditions). Broader Impacts: This research is important because it has the potential to improve the quality of climate prediction models, which would be a benefit to societal activities, such as, environmental management and decision-making.This is a grant under the U.S. Climate Change Science Program's, Climate Variability and Predictability Program (CLIVAR).