1998～2010年夏季台湾海峡西部沿岸海水遥感透明度的年际变化

Annual variations of Secchi depth in the nearshore waters of the western Taiwan Strait during the summers of 1998 -2010

通过比较分析不同的透明度卫星遥感算法,提出将一个基于固有光学特性的、适用于沿岸海域的算法应用于台湾海峡西岸海域,反演获得1998～2010年SeaWiFS遥感透明度时间序列.根据这组时间序列数据,发现该海域夏季透明度低值(<4 m)年份出现在1998、2001和2006年,高值(最高值达到10 m)年份出现在1999、2004和2010年.控制这一年际变动的因素,以目前有限的数据来看,主要是径流与上升流共同引发的水华强度的变化.此外,该海域透明度在研究时段内没有呈现一定的变化趋势,甚至在2006年之后,似乎在持续加深,说明海峡西岸活跃的经济活动,在1998～2010的13 a间,暂时没有对沿岸水质产生显著的破坏性的影响.

Comparison and analyses between several satellite remote sensing algorithms for Secchi depth（Zsd）,produced an inherent optical property（IOP） algorithm suitable for the western Taiwan Strait waters;Zsd from SeaWiFS during the summers of 1998～2010 were reproduced from this algorithm.It was found that low Zsd appeared in 1998,2001 and 2006,when Zsd was close to 4 m,peaks of Zsd were observed in 1999,2004 and 2010,which was at maximum up to 10 m.Variations of phytoplankton abundance attributed to run-off and upwelling induced blooms were considered to be the main reason leading to the observed temporal pattern of Zsd.No trend of Zsd change emerged during 1998～2010,suggesting the highly active economic developments alongshore the western Taiwan Strait has not shown significant negative impacts on the local water quality in the last 13 years.