利用2007-2010年MODIS的L2级叶绿素a浓度产品作为数据基础,对叶绿素a浓度年平均和月平均数据进行分级分区处理,研究南海北部海域叶绿素a浓度时空分布特征及其与海洋环境因素的关系。初步研究结果表明:2007-2010年在南海北部海域叶绿素a浓度的高值区(〉5.0mg/m3)主要分布在广东省沿岸河流的入海口,分布范围在夏季最大,在春秋次之,在冬季最小;叶绿素a浓度的次高值区(1.0~5.0mg/m3)主要分布在海岸线到50m等深线之间的海域,分布范围夏冬较大,能扩展到50m等深线附近,而春秋较小,会退缩到50m等深线以内;叶绿素a浓度的中值区(0.3~1.0mg/m3)主要分布在50m到100m等深线之间的海域,时空变化复杂;叶绿素a浓度的低值区(〈0.3mg/m3)主要分布在100m等深线以外的海域,其区域平均值夏季最低,春秋次之,冬季最高,同时该区域叶绿素a浓度在春夏秋三季空间分布较均匀,而冬季受季风和黑潮入侵影响空间分布较为复杂。南海北部海域海表叶绿素a浓度的时空变化特征与季风、沿岸河流、海流、海表温度等海洋环境因素的变化有关。
The temporal and spatial distribution of a chlorophyll a (Chl-a) concentration in the northern South China Sea (NSCS) and its relationship with marine environmental factors were studied based on the annually and monthly mean images (January 2007 to December 2010) of the Chl-a concentration , which were obtained from the MODIS chlorophyll a concentration Level 2 products, then classified into seven re- gions based on the isobaths and divided into six grades. The preliminary results showed that during 2007-- 2010 in the NSCS, the highest value area(〉5 mg/m3) of Chl-a concentration was mainly distributed in Guangdong coastal estuaries, and the biggest in summer, followed in spring and autumn, the smallest in winter; The second highest value area(1.0- 5.0 mg/m3) of the Chl-a concentration was mainly in the wa- ters between coastline and 50m isobaths. The distribution range of Chl-a concentration in summer and win- ter was larger , extending to the vicinity the 50 m isobath, smaller in spring and autumn, keeping within 50 m isobath; the mid-value area(0.3-1.0 mg/m3) of the Chl-a concentration mainly distrubuted between 50 and 100 m isobath with complex temporal and spatial variation; the low value area(〈0.3 mg/m3 ) of the Chl-a concentration distributed basically in the waters beyond the 100 m isobath, where the regional aver- age of monthly mean Chl-a concentration was the lowest in summer, followed by spring and autumn, the highest in winter, and where the spatial distributions of the Chl-a concentration were homogeneous in spring, summer and autumn, but due to the monsoon and the intrusion of Kuroshio, became more complex in winter. The temporal and spatial features of the Chl-a concentration in the NSCS were affected by the variations of the marine environmental factors, such as monsoon, coastal rivers, ocean currents, sea sur- face temperature, etc.