光谱学与光谱分析
光譜學與光譜分析
광보학여광보분석
Spectroscopy and Spectral Analysis
2015年
11期
2979-2984
,共6页
吕春光%王维和%杨文博%田庆久%卢山%陈赟
呂春光%王維和%楊文博%田慶久%盧山%陳赟
려춘광%왕유화%양문박%전경구%로산%진빈
臭氧总量%TOMS V8算法%地球紫外后向散射%太阳天顶角%观测天顶角%DU
臭氧總量%TOMS V8算法%地毬紫外後嚮散射%太暘天頂角%觀測天頂角%DU
취양총량%TOMS V8산법%지구자외후향산사%태양천정각%관측천정각%DU
Total ozone%TOMS V8 algorithm%Earth ultraviolet backscatter%Solar zenith angle%View zenith angle%DU
新型高光谱大气臭氧传感器大多计划搭载地球静止轨道平台,其对大视场范围和时间范围内的臭氧总量提取提出了更高的需求。TOMSV8算法在低轨卫星大气臭氧传感器得到广泛的应用和发展,但其在大观测几何条件下的提取精度不足,因此如何提高TOMS算法在新型传感器上的提取精度是当前亟待解决的问题。利用MODTRAN大气辐射传输模型模拟了晴空场景 TOMS算法标准廓线各观测几何条件下的地球紫外后向散射辐射,分析了各观测几何条件下后向散射辐射亮度与臭氧总量拟合模型,并根据模型拟合精度情况,得到了不同观测几何条件下后向散射辐射随臭氧总量的变化关系,提出了改进的臭氧总量初值估算模式。对改进模式与传统模式的臭氧总量初估结果表明,传统模式依赖于指数模型的拟合精度,而改进模式依赖于对数模型的拟合精度,指数模型和对数模型均表现出高的拟合精度,但对数模型的拟合精度比指数模型在整个臭氧浓度范围内平均高约0.9%。改进模式使臭氧总量初估的总体精度得到改善,RMSE降低约0.087%~0.537%,并且在较大观测几何和臭氧总量低值区(175~275 D U )间则更加显著。在臭氧总量低值区间以及较大观测天顶角和太阳天顶角条件下,改进模式具有更高的估算精度和更大的适用范围。该改进的臭氧总量初值估算模式可为日后TOMS算法的更新提供支持和参考依据。
新型高光譜大氣臭氧傳感器大多計劃搭載地毬靜止軌道平檯,其對大視場範圍和時間範圍內的臭氧總量提取提齣瞭更高的需求。TOMSV8算法在低軌衛星大氣臭氧傳感器得到廣汎的應用和髮展,但其在大觀測幾何條件下的提取精度不足,因此如何提高TOMS算法在新型傳感器上的提取精度是噹前亟待解決的問題。利用MODTRAN大氣輻射傳輸模型模擬瞭晴空場景 TOMS算法標準廓線各觀測幾何條件下的地毬紫外後嚮散射輻射,分析瞭各觀測幾何條件下後嚮散射輻射亮度與臭氧總量擬閤模型,併根據模型擬閤精度情況,得到瞭不同觀測幾何條件下後嚮散射輻射隨臭氧總量的變化關繫,提齣瞭改進的臭氧總量初值估算模式。對改進模式與傳統模式的臭氧總量初估結果錶明,傳統模式依賴于指數模型的擬閤精度,而改進模式依賴于對數模型的擬閤精度,指數模型和對數模型均錶現齣高的擬閤精度,但對數模型的擬閤精度比指數模型在整箇臭氧濃度範圍內平均高約0.9%。改進模式使臭氧總量初估的總體精度得到改善,RMSE降低約0.087%~0.537%,併且在較大觀測幾何和臭氧總量低值區(175~275 D U )間則更加顯著。在臭氧總量低值區間以及較大觀測天頂角和太暘天頂角條件下,改進模式具有更高的估算精度和更大的適用範圍。該改進的臭氧總量初值估算模式可為日後TOMS算法的更新提供支持和參攷依據。
신형고광보대기취양전감기대다계화탑재지구정지궤도평태,기대대시장범위화시간범위내적취양총량제취제출료경고적수구。TOMSV8산법재저궤위성대기취양전감기득도엄범적응용화발전,단기재대관측궤하조건하적제취정도불족,인차여하제고TOMS산법재신형전감기상적제취정도시당전극대해결적문제。이용MODTRAN대기복사전수모형모의료청공장경 TOMS산법표준곽선각관측궤하조건하적지구자외후향산사복사,분석료각관측궤하조건하후향산사복사량도여취양총량의합모형,병근거모형의합정도정황,득도료불동관측궤하조건하후향산사복사수취양총량적변화관계,제출료개진적취양총량초치고산모식。대개진모식여전통모식적취양총량초고결과표명,전통모식의뢰우지수모형적의합정도,이개진모식의뢰우대수모형적의합정도,지수모형화대수모형균표현출고적의합정도,단대수모형적의합정도비지수모형재정개취양농도범위내평균고약0.9%。개진모식사취양총량초고적총체정도득도개선,RMSE강저약0.087%~0.537%,병차재교대관측궤하화취양총량저치구(175~275 D U )간칙경가현저。재취양총량저치구간이급교대관측천정각화태양천정각조건하,개진모식구유경고적고산정도화경대적괄용범위。해개진적취양총량초치고산모식가위일후TOMS산법적경신제공지지화삼고의거。
New hyperspectral sensor to detect total ozone is considered to be carried on geostationary orbit platform in the future , because local troposphere ozone pollution and diurnal variation of ozone receive more and more attention .Sensors carried on geo‐stationary satellites frequently obtain images on the condition of larger observation angles so that it has higher requirements of to‐tal ozone retrieval on these observation geometries .TOMS V8 algorithm is developing and widely used in low orbit ozone detec‐ting sensors ,but it still lack of accuracy on big observation geometry ,therefore ,how to improve the accuracy of total ozone re‐trieval is still an urgent problem that demands immediate solution .Using moderate resolution atmospheric transmission ,MODT‐RAN ,synthetic UV backscatter radiance in the spectra region from 305 to 360 nm is simulated ,which refers to clear sky ,multi angles (12 solar zenith angles and view zenith angles) and 26 standard profiles ,moreover ,the correlation and trends between at‐mospheric total ozone and backward scattering of the earth UV radiation are analyzed based on the result data .According to these result data ,a new modified initial total ozone estimation model in TOMS V8 algorithm is considered to be constructed in order to improve the initial total ozone estimating accuracy on big observation geometries .The analysis results about total ozone and simulated UV backscatter radiance shows :Radiance in 317.5 nm (R317.5 ) decreased as the total ozone rise .Under the small solar zenith Angle (SZA) and the same total ozone ,R317.5 decreased with the increase of view zenith Angle (VZA) but increased on the large SZA .Comparison of two fit models shows :without the condition that both SZA and VZA are large (>80°) ,expo‐nential fitting model and logarithm fitting model all show high fitting precision (R2 >0.90) ,and precision of the two decreased as the SZA and VZA rise .In most cases ,the precision of logarithm fitting mode is about 0.9% higher than exponential fitting model .With the increasing of VZA or SZA ,the fitting precision gradually lower ,and the fall is more in the larger VZA or SZA . In addition ,the precision of fitting mode exist a plateau in the small SZA range .The modified initial total ozone estimating model (ln(I) vs .Ω) is established based on logarithm fitting mode ,and compared with traditional estimating model (I vs .ln(Ω)) , that shows :the RMSE of ln(I) vs .Ωand I vs .ln(Ω) all have the down trend with the rise of total ozone .In the low region of total ozone (175~275 DU) ,the RMSE is obvious higher than high region(425~525 DU) ,moreover ,a RMSE peak and a trough exist in 225 and 475 DU respectively .With the increase of VZA and SZA ,the RMSE of two initial estimating models are overall rise ,and the upraising degree is ln(I) vs .Ωobvious with the growing of SZA and VZA .The estimating result by modi‐fied model is better than traditional model on the whole total ozone range (RMSE is 0.087% ~0.537% lower than traditional model) ,especially on lower total ozone region and large observation geometries .Traditional estimating model relies on the preci‐sion of exponential fitting model ,and modified estimating model relies on the precision of logarithm fitting model .The improve‐ment of the estimation accuracy by modified initial total ozone estimating model expand the application range of TOMS V8 algo‐rithm .For sensor carried on geostationary orbit platform ,there is no doubt that the modified estimating model can help improve the inversion accuracy on wide spatial and time range This modified model could give support and reference to TOMS algorithm update in the future .