FY-2水汽通道光譜響應(yīng)測量大氣污染評估和訂正
發(fā)布時間：2018-11-03 07:51
【摘要】：由于無法實現(xiàn)真空測量,大氣吸收作用會對實驗室光譜響應(yīng)(SRF)測量產(chǎn)生污染。為了提高光譜定標(biāo)精度,通過敏感性試驗定量評估了大氣污染對水汽通道實驗室光譜響應(yīng)測量的影響,并以FY-2D為例進(jìn)行了光譜響應(yīng)污染訂正,分析了光譜污染帶來的通道輻射計算誤差。不同測量環(huán)境的敏感性模擬結(jié)果表明:大氣吸收導(dǎo)致光譜測量曲線產(chǎn)生顯著波動,強吸收光譜處的響應(yīng)減弱,致使依賴于SRF的通道輻射計算結(jié)果被高估。光譜污染帶來的通道亮溫偏差隨著水汽含量的增加呈指數(shù)增長趨勢,偏差大于0.5K且僅在等效水平路徑小于1m相對濕度低于15%的干燥環(huán)境下小于1K。4m水平路徑35%相對濕度的情況下,亮溫偏差可大于4K。FY-2系列衛(wèi)星水汽通道的光譜響應(yīng)都存在不同程度的大氣污染現(xiàn)象。利用水平大氣透過率光譜,通過光譜比值的方法,對FY-2D的SRF進(jìn)行訂正。訂正后SRF的異常波動被基本消除,曲線分布更加光滑合理。理論分析結(jié)果表明:大氣污染導(dǎo)致FY-2D在典型大氣條件下大氣層頂?shù)耐ǖ懒翜啬M偏高2.2K,黑體輻射進(jìn)而輻射定標(biāo)高估7.6%。大氣吸收對實驗室光譜定標(biāo)的影響非常顯著,不僅對水汽通道對所有氣體吸收通道都不能忽略。實驗室光譜定標(biāo)不能忽略大氣吸收的影響,應(yīng)該通過扣除大氣透過率的影響的方式對測量光譜響應(yīng)進(jìn)行訂正。
[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.
【作者單位】： 國家衛(wèi)星氣象中心中國遙感衛(wèi)星輻射測量與定標(biāo)重點開放實驗室;
【基金】：國家自然科學(xué)基金項目(41471304,41505029,41475031) 中國氣象局氣候變化專項(CCSF201623)資助
【分類號】：X87
，
本文編號：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.
【作者單位】： 國家衛(wèi)星氣象中心中國遙感衛(wèi)星輻射測量與定標(biāo)重點開放實驗室;
【基金】：國家自然科學(xué)基金項目(41471304,41505029,41475031) 中國氣象局氣候變化專項(CCSF201623)資助
【分類號】：X87
，
本文編號：2307167
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