春季辽东湾静止轨道海洋水色遥感产品的真实性检验

Validation of the Remote Sensing Products Retrieved by Geostationary Ocean Color Imager in Liaodong Bay in Spring

静止轨道海洋水色成像仪(GOCI)拥有高时间分辨率(1 h)和高空间分辨率(500 m×500 m)的观测优势。为了保证GOCI应用的可靠性,对其遥感产品进行检验极为重要。利用辽东湾春季航次观测数据,对4种二类水体大气校正算法[Korea Ocean Satellite Center(KOSC)校正算法、management unit mathematics models(MUMM)校正算法、紫外(UV)校正算法和近红外(NIR)校正算法]获得的GOCI遥感反射率产品及GOCI标准叶绿素浓度、悬浮物浓度遥感产品进行了真实性检验,并探讨了不同观测时相的稳定性。结果表明:KOSC算法在辽东湾具有最高的校正精度,各波段遥感反射率平均绝对百分比误差(APD)为27.16%(412 nm)、16.03%(443 nm)、13.73%(490 nm)、15.99%(555 nm)、12.83%(660 nm)、12.35%(680 nm)、27.68%(745 nm)、42.81%(865 nm);叶绿素浓度、悬浮物浓度产品的平均绝对百分比误差分别为29.75%和26.40%。相比于临近中午观测时的结果,GOCI早上和下午观测时反演的结果(包括遥感反射率、叶绿素浓度、悬浮物浓度)与实测值偏差显著增大。

The geostationary ocean color imager（GOCI） can provide high temporal resolution（1 h） and spatial resolution（500 m×500 m） observations. Validation of the GOCI-derived ocean color products is a key for the application of the GOCI data. Based on matched-up in-situ measurements in Liaodong Bay during spring, the GOCIderived remote sensing reflectance is retrieved by four atmospheric correction algorithms,including Korea Ocean Satellite Center（KOSC）correction, management unit mathematics models（MUMM） correction,ultraviolet correction（UV-correct） and near infrared correction（NIR-correct）, and the GOCI standard chlorophyll-a concentration and suspended particulate matter concentration are validated. In addition, the stability of the GOCI-derived ocean color remote sensing products under different observing time is evaluated. The results show that the remote sensing reflectance retrieved by KOSC algorithm has the best agreement with the values of in-situ observations, with mean absolute percentage deviations（APDs） of 27.16%（412 nm）, 16.03%（443 nm）, 13.73%（490 nm）, 15.99%（555 nm）,12.83%（660 nm）, 12.35%（680 nm）, 27.68%（745 nm）, 42.81%（865 nm）. The APDs of chlorophyll-a and suspended particulate matter products are respectively 29.75% and 26.40%. Moreover, compared with the ocean color products obtained from 10∶30 to 12∶30（Beijing time）, the consistency of GOCI-derived ocean color data obtained between in situ and in other observing time is much poorer.