基于MODIS卫星数据的台湾海峡南部水体漫衰减系数时空分布特征研究

Spatiotemporal distribution characteristics from MODIS diffuse attenuation coefficient in the southern parts of Taiwan Straits

利用中分辨率呈像光谱仪(Moderate Resolution Imaging Spectroradiometer,MODIS)的多波段遥感反射率(Remote sensing reflectance,R rs)组合,反演获取2009—2019年台湾海峡南部490 nm波段处水体漫衰减系数(K d(490))的遥感影像。基于此,分析该海域K d(490)的年平均、季节变化与逐月变化的时空分布特征。结果表明:K d(490)多年平均与相应标准偏差的高值区主要位于沿岸水域,而低值区则分布在海域中心,即随着离岸距离的增加K d(490)逐渐降低。此外,K d(490)的季节变化与逐月变化趋势较为一致,即K d(490)值在冬季时段内最高,春、秋两季次之,夏季最低。此外,人类经济活动、大陆径流、水体层结稳定度以及海流等因素均对K d(490)的时空变化起到一定的作用。

Diffuse attenuation coefficient at 490 nm(K d(490))between 2009 and 2019 in the southern of Taiwan Strait was retrieved based on the remote sensing(R rs)from Moderate Resolution Imaging Spectroradiometer(MODIS).The characteristics of spatial-temporal distributions of K d(490)s mean annual,seasonal and monthly maps were analysed.Results showed that the mean annual of K d(490)and corresponding standard deviation(STD)is higher in the coastal water while lower in the central of the studied area,that is,with the increase of the offshore distance,K d(490)decreases gradually.Besides,the variations of seasonal K d(490)is relatively consistent with that of the changes of months,that is,K d(490)is highest in the winter,lower in the spring and autumn and lowest in the summer.Besides,human economic activities,runoff,the stability of water stratification and currents also play a certain role in the spatial-temporal changes of K d(490).