FY-2水汽通道光谱响应测量大气污染评估和订正
发布时间：2018-11-03 07:51
【摘要】：由于无法实现真空测量,大气吸收作用会对实验室光谱响应(SRF)测量产生污染。为了提高光谱定标精度,通过敏感性试验定量评估了大气污染对水汽通道实验室光谱响应测量的影响,并以FY-2D为例进行了光谱响应污染订正,分析了光谱污染带来的通道辐射计算误差。不同测量环境的敏感性模拟结果表明:大气吸收导致光谱测量曲线产生显著波动,强吸收光谱处的响应减弱,致使依赖于SRF的通道辐射计算结果被高估。光谱污染带来的通道亮温偏差随着水汽含量的增加呈指数增长趋势,偏差大于0.5K且仅在等效水平路径小于1m相对湿度低于15%的干燥环境下小于1K。4m水平路径35%相对湿度的情况下,亮温偏差可大于4K。FY-2系列卫星水汽通道的光谱响应都存在不同程度的大气污染现象。利用水平大气透过率光谱,通过光谱比值的方法,对FY-2D的SRF进行订正。订正后SRF的异常波动被基本消除,曲线分布更加光滑合理。理论分析结果表明:大气污染导致FY-2D在典型大气条件下大气层顶的通道亮温模拟偏高2.2K,黑体辐射进而辐射定标高估7.6%。大气吸收对实验室光谱定标的影响非常显著,不仅对水汽通道对所有气体吸收通道都不能忽略。实验室光谱定标不能忽略大气吸收的影响,应该通过扣除大气透过率的影响的方式对测量光谱响应进行订正。
[Abstract]:Because the vacuum measurement can not be realized, the atmospheric absorption will pollute the spectrum response (SRF) measurement in the laboratory. In order to improve the accuracy of spectral calibration, the influence of air pollution on the measurement of spectral response of water vapor channel laboratory was quantitatively evaluated by sensitivity test. The spectral response pollution correction was carried out with FY-2D as an example. The calculation error of channel radiation caused by spectral pollution is analyzed. The sensitivity simulation results of different measuring environments show that atmospheric absorption results in significant fluctuations in the spectral measurement curve and weakens the response at the strong absorption spectra, which results in overestimation of the channel radiation calculation results dependent on SRF. The channel brightness temperature deviation caused by spectral pollution increases exponentially with the increase of water vapor content. The deviation is greater than 0.5 K and is only less than 35% relative humidity of 1K.4m horizontal path in dry environment where the equivalent horizontal path is less than 1m and less than 15% RH. The brightness temperature deviation can be larger than the spectral response of 4K.FY-2 series satellite water vapor channel. The SRF of FY-2D was revised by using horizontal atmospheric transmittance spectrum and spectral ratio method. The abnormal fluctuation of SRF is basically eliminated, and the curve distribution is more smooth and reasonable. The results of theoretical analysis show that atmospheric pollution results in high brightness temperature simulation of the atmospheric top of FY-2D under typical atmospheric conditions, and the blackbody radiation and radiation calibration overestimate 7.6kg. The influence of atmospheric absorption on the calibration of laboratory spectra is very significant, not only for the water vapor channel, but also for all the gas absorption channels. The influence of atmospheric absorption should not be ignored in the calibration of spectra in laboratory, and the spectral response should be revised by deducting the influence of atmospheric transmittance.
【作者单位】： 国家卫星气象中心中国遥感卫星辐射测量与定标重点开放实验室;
【基金】：国家自然科学基金项目(41471304,41505029,41475031) 中国气象局气候变化专项(CCSF201623)资助
【分类号】：X87
，
本文编号：2307167
[Abstract]:Because the vacuum measurement can not be realized, the atmospheric absorption will pollute the spectrum response (SRF) measurement in the laboratory. In order to improve the accuracy of spectral calibration, the influence of air pollution on the measurement of spectral response of water vapor channel laboratory was quantitatively evaluated by sensitivity test. The spectral response pollution correction was carried out with FY-2D as an example. The calculation error of channel radiation caused by spectral pollution is analyzed. The sensitivity simulation results of different measuring environments show that atmospheric absorption results in significant fluctuations in the spectral measurement curve and weakens the response at the strong absorption spectra, which results in overestimation of the channel radiation calculation results dependent on SRF. The channel brightness temperature deviation caused by spectral pollution increases exponentially with the increase of water vapor content. The deviation is greater than 0.5 K and is only less than 35% relative humidity of 1K.4m horizontal path in dry environment where the equivalent horizontal path is less than 1m and less than 15% RH. The brightness temperature deviation can be larger than the spectral response of 4K.FY-2 series satellite water vapor channel. The SRF of FY-2D was revised by using horizontal atmospheric transmittance spectrum and spectral ratio method. The abnormal fluctuation of SRF is basically eliminated, and the curve distribution is more smooth and reasonable. The results of theoretical analysis show that atmospheric pollution results in high brightness temperature simulation of the atmospheric top of FY-2D under typical atmospheric conditions, and the blackbody radiation and radiation calibration overestimate 7.6kg. The influence of atmospheric absorption on the calibration of laboratory spectra is very significant, not only for the water vapor channel, but also for all the gas absorption channels. The influence of atmospheric absorption should not be ignored in the calibration of spectra in laboratory, and the spectral response should be revised by deducting the influence of atmospheric transmittance.
【作者单位】： 国家卫星气象中心中国遥感卫星辐射测量与定标重点开放实验室;
【基金】：国家自然科学基金项目(41471304,41505029,41475031) 中国气象局气候变化专项(CCSF201623)资助
【分类号】：X87
，
本文编号：2307167
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