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The saline water color component characteristic (chlorophyll-a and chromophoric dissolved organic matter (CDOM)) and
their spatial change tendency in the Pearl River Estuary from the In-situ data in December of 2006 was studied. Based on
the experimental results, the mixing behavior of CDOM in the Shawan-Humen Watercourse was analyzed. The mixing
behavior was controlled by topography, hydrological and biological factors, and the relationships among absorption
characteristics of CDOM (at 400 nm, ag400). Contained is a discussion of chlorophyll-a concentration and salinity. The
chlorophyll-a concentration decreases with increasing CDOM absorption under a salinity of 10, while the chlorophyll-a
concentration decreases with increasing salinity. The salinity becomes less aggressive towards the Lingding Bay in the
saltwater intrusion reach of Shawan-Humen, and a low chlorophyll-a concentration area occurs in the Shiziyang riverway
where the salinity is greater than 20. The highest chlorophyll-a concentration of surface water was observed in the
Dadaoshawei site of the Shawan tributary reach- where the saltwater and freshwater interface. The slope distribution of
the CDOM spectral absorption curve in the Shawan-Humen watercourse was increased towards the Lingding Bay
direction. The spectral slope S value of CDOM varied from 0.0107 to 0.0121 nm-1 with an average value of 0.0116 nm-1.
This was an indication that the terrestrial river input was the main resource of CDOM in the Shawan-Humen
watercourse. The high correlation (R2=0.9458)of surface water and bottom water (-7.5m ) salinity showed that salinity
can be monitored by remote sensing. The ag400 in the saltwater intrusion reach showed conservative behavior, indicating
strong characteristics of the CDOM it reflected. There was a correlative relationship between ag400, chlorophyll-a
concentration and the salinity, showing that a water color analysis technique can be used to study the distribution and
behavior of salinity, as well as saltwater intrusion to a certain extent.
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