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有色可溶有机物(CDOM)是重要的水色要素之一,在“江苏沿海大开发”背景下,利用遥感分析其时空分布特征对监测近海水质及污染状况有重要的实际意义。用高时间分辨率的韩国静止水色卫星(GOCI)影像,在日、周、月多时间尺度上分析2011年4月至2016年5月江苏近海有色可溶有机物的时空分布特征。结果表明江苏近海CDOM以陆源为主,近岸高于远岸;月平均浓度最大值(0.180~0.206 m~(-1))在长江口最大浑浊带外,南黄海西岸次之(0.167~0.201 m~(-1)),南黄海中南部较低(0.086~0.187 m~(-1),440 nm吸收系数)。结合潮位数据,发现沿岸海域CDOM日变化与潮汐变化一致,但远海区域呈先减后增的特征。利用余弦函数对CDOM月均值进行拟合,发现南黄海月尺度变化周期性明显,其中南黄海中部海域拟合优度为0.823。南黄海主要受黄海冷水团影响,各子区季节变化显著,CDOM在冬春季高于夏秋季;长江口由于冲淡水及其他水团共同影响,情况复杂,冬春季低于夏秋季。月尺度下,CDOM浓度与悬浮物(TSM)呈正相关关系(相关系数r为0.72),且南黄海中部与南部CDOM随TSM的变化趋势较为显著。
Color soluble organic matter (CDOM) is one of the important water color elements. Under the background of “Jiangsu Coastal Development”, using remote sensing to analyze its temporal and spatial distribution characteristics is of great practical significance for monitoring the water quality and pollution status of offshore waters. The spatial and temporal distribution characteristics of the offshore soluble organic matter in Jiangsu from April 2011 to May 2016 were analyzed on the daily, weekly and monthly multi-temporal scales by using high temporal resolution GOCI images. The results show that the offshore CDOM in Jiangsu Province is dominated by terrestrial sources and the nearshore is higher than the far shore. The maximum monthly mean concentration (0.180-0.206 m -1) is outside the maximum turbidity zone in the Yangtze River estuary, followed by the west coast of the South Yellow Sea (0.167-0.201 m -1 and lower in the southern South Yellow Sea (0.086-0.187 m -1, 440 nm). Combined with the tide level data, it was found that the daily variation of CDOM in the littoral waters was consistent with that of the tides, but the characteristics of the CDOM in the distant sea first decreased and then increased. Using the cosine function to fit the monthly mean of CDOM, we found that the monthly scale of the South Yellow Sea has obvious cyclical changes. The goodness of fit of the central South Yellow Sea is 0.823. The South Yellow Sea is mainly affected by the Yellow Sea cold water mass, and the seasonal variation of each sub-region is significant. CDOM is higher in summer and spring than that in summer and autumn. Due to the influence of diluate water and other water masses, the CDOM is complicated and the winter and spring are lower than those in summer and autumn. At the monthly scale, there was a positive correlation between CDOM concentration and TSM (correlation coefficient r = 0.72), and the trend of CDOM with TSM in the middle and southern SCS was significant.