An infrared radiative scheme for the numerical models of weather and climate
An infrared radiative scheme for the numerical models of weather and climate
复制标题
天气和气候数值模型的红外辐射方案
DOI：
10.1029/jd094id12p14923
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发表时间：
1989
影响因子：
--
通讯作者：
T. Aoki
中科院分区：
文献类型：
--
作者：
K. Shibata;T. Aoki
本文在多参数随机模式的基础上，发展了一个精确而计算速度快的红外辐射传输方案，用于气候和数值预报模式。整个红外光谱分为四个光谱区，20-550，550-800，800-1200和1200-2200 cm−1，包括H2O旋转和6.3 μm波段，CO2 10-和15-μm波段，以及O3 9.6-和14-μm波段。H2O的连续吸收被纳入所有的光谱区域。均匀路径在每个区域的平均漫透射率计算由一个线的方法，它们近似与一个简单的指数函数，其中包含10或12个参数。通过非均匀大气的透射率计算采用改进的Godson方法，该方法将Godson方法独立地用于透射函数的线部分和翼部分。该方法在保持相同精度的前提下，比现有的龙芯方法节省了计算时间。用该方案计算的模式大气加热率误差在对流层和平流层小于0.3K/d，在平流层顶以上小于0.8K/d。辐射通量的误差在地球表面和大气顶部都小于0.8W/m2。它还表明，该计划的准确性不会降低时，CO2浓度增加一倍。指出在20-550 cm−1范围内包含H2O连续谱，在550-800 cm−1范围内包含14 μm的O3，在800-1200 cm−1范围内包含10μm的CO2显著影响辐射通量和冷却速率。
An accurate but computationally fast scheme of the infrared radiative transfer is developed based upon the multiparameter random model to be used in climate and numerical prediction models. The entire infrared spectrum is divided into four spectral regions, 20–550, 550–800, 800–1200, and 1200–2200 cm−1, including the H2O rotation and 6.3-μm bands, the CO2 10- and 15-μm bands, and the O3 9.6- and 14-μm bands. The continuum absorption of H2O is incorporated in all the spectral regions. The mean diffuse transmittances in each region for homogeneous paths are calculated by a line-by-line method, and they are approximated with a simple exponential function which contains 10 or 12 parameters. The transmittance calculations through inhomogeneous atmospheres are carried out by the modified Godson method, which independently uses the Godson method to the line and wing parts of the transmission function. This method is found to be more economical in computation time than the current Godson method, keeping the same precision. The errors in heating rates calculated by this scheme for the model atmospheres are less than 0.3 K/d in the troposphere and stratosphere, and less than 0.8 K/d above the stratopause. The errors in radiative fluxes are less than 0.8 W/m2 both at the Earth's surface and the top of the atmosphere. It is also shown that the accuracy of this scheme does not degrade when the CO2 concentration is doubled. It is pointed out that the inclusion of the H2O continuum in 20–550 cm−1, O3 14 μm in 550–800 cm−1, and CO2 10μm in 800–1200 cm−1 significantly affects radiative flux and cooling rate.