大气模式与气溶胶模型对辐射传输计算的影响

Influence of atmospheric model and aerosol type on radiation transfer calculation

大气模式与气溶胶模型选择是影响定量遥感应用的辐射传输计算的重要因素。人们一般凭感性认识去进行选择,有一定随意性,对其带来的影响程度关注甚少。以太阳辐射计测量为依据,对大气模式与气溶胶模型选择方法作了研究,并利用经辐射定标过的光谱辐射计地面测量对辐射传输计算精度进行了验证。在昆明进行的试验表明,在0.50-0.68μm范围内,选择中纬度冬季大气模式和大陆型气溶胶,经辐射传输计算后得到的光谱辐射亮度与光谱辐射计测量结果一致性很好,差别在3.3%以内;变换大气模式对辐射传输计算产生明显影响,差别达10%左右;选择不同的气溶胶模型对辐射传输计算影响也很大,差别达11%左右。基于辐射计测量的大气模式与气溶胶模型选择避免了主观选择的不可靠性,有益于减少辐射传输计算或卫星遥感大气订正的误差。

The selection of atmospheric model and aerosol type is very important in the radiation transfer calculation of quantitative remote sensing.However,the selection is commonly empiric,and its influence on the calculation is usually neglected.Thus a method based on the measurement of sun photometer was proposed to study the selection of atmospheric model and aerosol type.Meanwhile,a calibrated spectral radiometer was used to measure the spectral radiance to check the results above at the ground level.Experiments have been done in Kunming.Choosing middle altitude summer atmospheric and land aerosol type,the relative error between calculation and measurement is below 3.3% in the spectral range of 0.50 to 0.68 μm.Changing atmospheric model only,the relative error can be up to 10%,while changing the aerosol type only,the relative error can be up to 11%.Selecting atmospheric model and aerosol type based on radiometer measurement can avoid uncertainty caused by subjective selection,which can reduce radiation transfer calculation error or limit calibration uncertainty of satellite remote sensing.