Spectral Kernel

The dataset comprises two NetCDF files containing spectral kernels computed under different atmospheric conditions: spectral_kernel_monthly_climatology_clearsky.nc — clear-sky conditions spectral_kernel_monthly_climatology_allsky.nc — all-sky conditions Each file provides the partial derivatives of spectral radiance (computed at nadir) with respect to seven key atmospheric variables: Surface temperature - unit [mW/(m²·cm⁻¹· sr ·K) ] Air temperature - unit [mW/(m²·cm⁻¹· sr ·K ) ] Water vapor concentration - unit [mW/(m²·cm⁻¹·sr ppmv) ] Ozone - unit [mW/(m²·cm⁻¹·sr ppmv) ] Carbon dioxide - unit [mW/(m²·cm⁻¹·sr ppmv) ] Methane - unit [mW/(m²·cm⁻¹·sr ppmv) ] Nitrous oxide - unit [mW/(m²·cm⁻¹·sr ppmv) ] The kernels were computed using the RTTOV radiative transfer model, based on monthly mean ERA5 atmospheric profiles and standard forcing datasets used for historical CMIP6 simulations for the years 2008, 2009, and 2010. These results were then averaged over the three years to produce monthly climatological mean spectral kernels, spanning the spectral range of the IASI instrument. The spectral resolution is 10 cm⁻¹, covering the IASI range from 650 to 2750 cm⁻¹. In addition to the regular spectral grid, the dataset includes high-resolution spectral kernels for a selected set of IASI channels that are particularly sensitive to specific climate variables at different atmospheric levels (667.75, 700.25, 710.25, 721.25, 728.50, 739.00, 871.25, 901.50, 1014.50, 1041.00, 1326.75, 1381.75, 1400.50, 1596.25 cm⁻¹).These channels were selected to capture sensitivity to climate-relevant variations across different altitudes.本数据集包含两份网络通用数据格式（NetCDF）文件，存储了不同大气条件下计算得到的光谱核函数： spectral_kernel_monthly_climatology_clearsky.nc — 晴空条件月度气候态光谱核函数文件 spectral_kernel_monthly_climatology_allsky.nc — 全天空条件月度气候态光谱核函数文件 每份文件均提供了天底方向计算的光谱辐亮度对7种关键大气变量的偏导数，各变量及对应单位如下： Surface temperature（地表温度）：单位为[mW/(m²·cm⁻¹·sr·K)] Air temperature（大气温度）：单位为[mW/(m²·cm⁻¹·sr·K)] Water vapor concentration（水汽浓度）：单位为[mW/(m²·cm⁻¹·sr·ppmv)] Ozone（臭氧）：单位为[mW/(m²·cm⁻¹·sr·ppmv)] Carbon dioxide（二氧化碳）：单位为[mW/(m²·cm⁻¹·sr·ppmv)] Methane（甲烷）：单位为[mW/(m²·cm⁻¹·sr·ppmv)] Nitrous oxide（一氧化二氮）：单位为[mW/(m²·cm⁻¹·sr·ppmv)] 该光谱核函数通过RTTOV辐射传输模型计算得到，基于2008、2009及2010年的ERA5大气月均廓线，以及历史耦合模式比较计划第六阶段（CMIP6）模拟所用的标准强迫数据集。随后将这三年的数据进行平均，得到覆盖红外大气探测干涉仪（IASI）光谱范围的月度气候态平均光谱核函数。 该数据集的光谱分辨率为10 cm⁻¹，覆盖IASI仪器650~2750 cm⁻¹的光谱范围。除常规光谱网格外，本数据集还包含针对一组精选IASI通道的高分辨率光谱核函数，这些通道对不同大气高度层的特定气候变量具有较高灵敏度，具体通道波数为：667.75、700.25、710.25、721.25、728.50、739.00、871.25、901.50、1014.50、1041.00、1326.75、1381.75、1400.50、1596.25 cm⁻¹。选取上述通道旨在捕捉不同高度下与气候相关的变化灵敏度。