Freshwater discharge from rivers into the ocean is an important element of the dynamics in coastal areas. River discharge from land that includes chlorophyll a, nutrients, sediments and pollutants have been identified as one of the major causes of deterioration of the coastal water. The objective of this study was to examine the relationship between river discharge and variability of chlorophyll a concentration in plume area using satellite imagery. Satellite ocean color and Sea Surface Temperature (SST) imagery were used to present the synoptic quantification of chlorophyll a variability on seasonal and interannual timescales for the plume area of Tokachi River, Japan. Five years (1998 to 2002) of SeaWiFS local area coverage, AVHRR imagery and surface wind were analyzed using default NASA coefficients and community-standard algorithms as implemented by SeaDAS. The chlorophyll a climatology seasonal pattern showed seasonal cycles, first peak in spring and second peak in late summer to early autumn. Elevated chlorophyll a concentration demonstrates seasonal cycles and interannual variability are present around plume area associated with variation of river discharge. Elevated chlorophyll a concentration in offshore area was seen to be influenced by low sea surface temperature and wind stress.