RTTOV中模拟亮温对垂直插值方案的敏感性研究

Sensitivity of Simulated Brightness Temperature to Vertical Interpolation Scheme in RTTOV

以搭载在风云3号D星上的红外高光谱探测仪HIRAS为例,研究了目前广泛使用的快速辐射传输模式RTTOV中模拟辐射值对垂直插值方案的敏感性。以逐线LBLRTM模式模拟亮度温度为基准,分析发现:当输入大气状态参数廓线层数比RTTOV系数层数多时,各插值方案在窗区、水汽通道模拟结果差异不大;当大气廓线层数比模式系数层稀疏时,方案1在多数通道上比其它插值方案偏差大,但5种插值方案之间差异较小。在输入大气廓线层数少于系数层数时,温度Jacobian和湿度Jacobian矩阵垂直分布较为平滑,各插值方案结果相近;但当输入廓线层层密于系数层数时,使用插值方案2得到的水汽Jacobian矩阵表现出强烈的振荡。

The paper is sensitivity of the simulated radiation values to the vertical interpolation scheme in the fast radiation transfer mode RTTOV. This study is evaluated by taking HIRAS uploaded on China Fengyun polar orbiting meteorological satellite as an example. Using the LBLRTM as benchmark, the analysis finds that: When the number of input atmospheric state parameter contour layers is more than the number of RTTOV coefficient layers, the interpolation schemes do not differ significantly in the simulation results for the window area and water vapour channels;when the number of atmospheric contour layers is sparser than the model coefficient layers, Scheme 1 deviates more than the other interpolation schemes in most channels, but the differences between the five interpolation schemes are small. When the number of input atmospheric profile layers is less than the number of coefficient layers, the vertical distribution of the temperature Jacobian and humidity Jacobian matrices is smoother and the results of the interpolation schemes are similar;however, when the number of input profile layers is denser than the number of coefficient layers, the water vapour Jacobian matrix obtained using interpolation scheme 2 shows strong oscillations.