Parameterization of instantaneous global horizontal irradiance: Cloudy‐sky component
Parameterization of instantaneous global horizontal irradiance: Cloudy‐sky component
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DOI：
10.1029/2012jd017557
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发表时间：
2012-07
影响因子：
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通讯作者：
Zhian Sun;Jing-miao Liu;X. Zeng;H. Liang
中科院分区：
文献类型：
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作者：
Zhian Sun;Jing-miao Liu;X. Zeng;H. Liang
[1]在全球数值天气预报和气候模式中，为了减少计算量，辐射计算通常以3小时为间隔进行。这种处理可能导致不正确的太阳辐射在地球表面，这可能是在模拟对流和降水的误差来源之一。为了改善太阳辐射日循环的模拟，已经开发了一个快速的计划，详细的辐射传输计算的基础上，为广泛的大气条件，并可用于确定在每个模型的积分时间步长的表面太阳辐射与负担得起的成本。该方案分为晴空和多云条件下的组件。晴空部分已在一份配套文件中作了说明。本文介绍了云天空分量。该方案所需的输入变量都可以在数值预报和气候模式中获得，或者可以从卫星观测中获得。因此，该方案可用于全球模式，以确定表面GHI。它也可以用作离线方案，使用卫星测量数据计算地表GHI。利用美国建立的三个大气辐射观测站（ARM）的观测资料，对SNOLUX方案进行了检验。S.能源部。结果表明，全天空条件下GHI的半小时平均相对误差小于7%。该方案的一个重要应用是全球气候模式。本文利用卫星LUX和ARM观测资料，研究了由于辐射计算不频繁而引起的辐射采样误差。结果发现，由于忽略了云的影响，地表净太阳辐照度的误差非常大，在许多非辐射时间步超过800 W m− 2。使用Snowlux方案可以将这些误差降低到小于50 W m−2。
[1] Radiation calculations in global numerical weather prediction (NWP) and climate models are usually conducted in 3-hourly time interval in order to reduce the computational cost. This treatment can lead to an incorrect solar radiation at the Earth's surface which could be one of the error sources in modeled convection and precipitation. In order to improve the simulation of the diurnal cycle of solar radiation a fast scheme has been developed based on detailed radiative transfer calculations for a wide range of atmospheric conditions and can be used to determine the surface solar radiation at each model integration time step with affordable costs. This scheme is divided into components for clear-sky and cloudy-sky conditions. The clear-sky component has been described in a companion paper. The cloudy-sky component is introduced in this paper. The input variables required by this scheme are all available in NWP and climate models or can be obtained from satellite observations. Therefore, the scheme can be used in a global model to determine the surface GHI. It can also be used as an offline scheme to calculate the surface GHI using data from satellite measurements. SUNFLUX scheme has been tested using observations obtained from three Atmospheric Radiation Measurements (ARM) stations established by the U. S. Department of Energy. The results show that a half hourly mean relative error of GHI under all-sky conditions is less than 7%. An important application of the scheme is in global climate models. The radiation sampling error due to infrequent radiation calculations is investigated using the SUNFLUX and ARM observations. It is found that errors in the surface net solar irradiance are very large, exceeding 800 W m−2at many non-radiation time steps due to ignoring the effects of clouds. Use of the SUNFLUX scheme can reduce these errors to less than 50 W m−2.