A Three-Dimensional Radiative Transfer Model to Investigate the Solar Radiation within a Cloudy Atmosphere. Part II: Spectral Effects
A Three-Dimensional Radiative Transfer Model to Investigate the Solar Radiation within a Cloudy Atmosphere. Part II: Spectral Effects
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用于研究多云大气中太阳辐射的三维辐射传输模型。
DOI：
10.1175/1520-0469(1998)055
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发表时间：
1998
影响因子：
3.1
通讯作者：
C. Gautier
中科院分区：
文献类型：
--
作者：
W. O'Hirok;C. Gautier
提出了一种新的基于蒙特卡罗的高光谱和空间分辨率的三维（3D）辐射传输模型。它用于研究 3D 和 1D 计算之间多云大气中宽带太阳辐射吸收、大气层顶部上升流和表面下降太阳辐射的差异。对不同波长的这些相同辐射成分（吸收、上升流和下降流）的空间变化以及路径长度分布进行分析，以描述工作的主要物理机制。该模型包含所有重要的大气和表面辐射成分。它包括瑞利散射、云滴和气溶胶的吸收和散射，以及主要大气气体的吸收。输入包括 3D 液态水场、气溶胶以及气体分布、类型和浓度。使用热带云场的卫星图像作为输入，模型结果表明，与 3D 计算相比，各种平面平行 (1D) 假设可能会低估大气吸收。这种差异是由气体吸收、云滴吸收和太阳天顶角的复杂相互作用造成的。通过敏感性分析，作者证明最重要的因素是云场的形态，其次是水汽的垂直分层。
A new Monte Carlo‐based three-dimensional (3D) radiative transfer model of high spectral and spatial resolution is presented. It is used to investigate the difference in broadband solar radiation absorption, top-of-theatmosphere upwelling, and surface downwelling solar radiation in a cloudy atmosphere between 3D and 1D calculations. Spatial variations of these same radiation components (absorption, upwelling, and downwelling), together with pathlength distributions, are analyzed for different wavelengths to describe the main physical mechanisms at work. The model contains all of the important atmospheric and surface radiative constituents. It includes Rayleigh scattering, absorption and scattering by both cloud droplets and aerosols, and absorption by the major atmospheric gases. Inputs include 3D liquid water fields, aerosols, and gas distribution, type, and concentrations. Using satellite imagery of a tropical cloud field as input, model results demonstrate that various plane-parallel (1D) assumptions can underestimate atmospheric absorption when compared to 3D computations. This discrepancy is caused by a complex interaction of gaseous absorption, cloud droplet absorption, and the solar zenith angle. Through a sensitivity analysis, the authors demonstrate that the most important factor is the morphology of the cloud field, followed by the vertical stratification of water vapor.