Seasonal and interannual variability of SeaWiFS-derived chlorophyll-a concentrations in waters off the southwest coast of India, 1998-2003

Abstract

Seasonal and interannual variability in satellite-derived estimates of near-surface chlorophyll-a concentrations were examined in the four regions off the southwest coast of India from 1998-2003. Wind-induced upwelling predominates in late spring and summer, coinciding with the maximum in solar radiation, leading to increased accumulations of phytoplankton biomass. Chlorophyll concentrations varied from 2 to 10 mg/m 3 and were generally lower in January-April and maximal in May-September. Chlorophyll concentrations along the coast followed a similar seasonal pattern (ranging from 0.5 to 4 mg/m 3 ); however, concentrations were always greater on the Trivendrum and Cochin coast compared to the Calicut and Mangalore coast. The southwest coast is often cloud covered; data density maps provide an index of confidence in the 'regional' applicability of the summary statistics. One consequence of the 1997-1998 El Nino appears to be a reduction in chlorophyll concentration off Trivendrum and Cochin in 1998. An increased frequency of El Nino events may lead to a reduction in offshore carbon in this dynamic upwelling region. Six-month median chlorophyll concentrations were maximal in 2002 off Trivendrum and Cochin.

Bio-physical Changes in the Eastern Arabian Sea due to Ocean-Atmospheric Teleconnections

“…One consequence of the 1997-1998 El Niño appears to be a reduction in Chl-a off the southwest coast of India in 1998. An increased frequency of El Niño events may lead to a reduction in offshore carbon in this dynamic upwelling region [18]. The Indian Ocean Dipole (IOD) is one of the dominant modes of the interannual variability of the Indian Ocean SST [19].…”

Spatial–temporal dynamics of NDVI and Chl-a concentration from 1998 to 2009 in the East coastal zone of China: integrating terrestrial and oceanic components

“…Chauhan et al (2002) suggested that the information of the Chl-a concentration on a global scale is important to study the biogeochemical cycles of carbon, nitrogen, and sulfur. Later, the mesoscale variability (Uz and Yoder 2004) and the seasonal and interannual variability of Chl-a concentrations (Sackmann et al 2004;Hyde et al 2007;Krishna 2008) were studied widely.…”