基于辐射传输模型的GOCI晨昏时段数据的可用性分析

Usability Analysis GOCI Twilight Periods Radiative Transfer Model Data

GOCI作为首颗静止轨道海洋水色卫星搭载的地球同步海色成像仪,每日获取8个时相的海表观测数据,成为监测晨昏时段海洋现象的重要遥感数据源。GOCI高频次连续观测的数据已广泛用于海面流场反演、水色要素日变化分析等近海应用。针对目前GOCI数据验证与质量评价较少涉及晨昏时段数据,本文基于GOCI传感器参数,利用OSOAA、HydroLight和6SV等辐射传输模型比较中午时段、晨昏时段的GOCI数据及其GDPS软件处理结果的差异。研究表明:HydroLight和6SV辐射传输模型的耦合结果略好于OSOAA辐射传输模型,两种算法基于GDPS软件处理结果的光谱模拟数值与卫星观测值的比较差异均小于10%,且两者差异随波长不同而变化。北京时间9点半、13点半的GOCI两个时刻的比较结果与中午时段的差异并不明显,412-680波段的偏差范围为5%~10%,745nm、865 nm波段的偏差为10%~15%;而8点半、14点半和15点半等3个时刻的660nm、680nm、745nm、865nm波段的差异显著,接近或高于20%。

GOCI,as the first geosynchronous sea color imager carried by the geostationary orbit ocean color satellite,acquires sea surface observation data in 8 phases every day,and has become an important remote sensing data source for monitoring marine phenomena during the twilight period.The high-frequency continuous observation data of GOCI has been widely used in offshore applications such as sea surface flow field inversion and daily analysis of water color.In view of the fact that GOCI data verification and quality evaluation rarely involve twilight period data,this paper uses the GOCI sensor parameters to compare the difference between the noon and twilight periods of GOCI data and its GDPS software processing results using OSOAA,HydroLight and 6SV radiation transfer models.It is shown that the coupling result of HydroLight and 6SV radiation transfer model is slightly better than that of OSOAA radiation transfer model.The difference between the spectral simulation values of the two algorithms based on the GDPS software processing result and the satellite observation value is less than 10%,and the difference between the two varies with wavelength.The difference between the GOCI time at 9:30 and 13:30 Beijing time and the noon time is not obvious.The deviation range of the 412-680 band is 5%〜10%,and the deviation of the 745 nm and 865 nm bands is 10%〜15%.The differences in the 660 nm,680 nm,745 nm,and 865 nm bands at 8:30,14:30 and 15:30 are significant,close to or higher than 20%.