El-Nino signal in the Arabian Sea Chlorophyll Concentration as Estimated from the SeaWiFS Observations
Rajeev
Mudgal, Indian Institute of Technology,Kharagpur India, rajeev@coral.iitkgp.ernet.in
(Presenting)
Mihir
Kumar
Dash, Indian Institute of Technology,Kharagpur India, mihir@coral.iitkgp.ernet.in
Prem
Chand
Pandey, Indian Institute of Technology,Kharagpur India, pcpandey@coral.iitkgp.ernet.in
The biological process in World Ocean is mainly controlled by the presence of phytoplankton, which forms the base of the food chain, and is responsible for CO2 fixation, hence act as the major sink of Carbon Dioxide. In the increased greenhouse scenario the study of oceanic carbon cycle is of paramount importance. The demand of studying the phytoplankton population, yellow substances in the ocean and sediment transport give rise to the science of ocean optics. Marine biologist and physicists work together on optics, light and colour to study the fundamental properties of phytoplankton population in the ocean. Ocean colour is a key parameter for understanding the biological and physical processes of the ocean. The development in space technology has revolutionized the study of the abundance of ocean biota on a global scale through the ocean colour sensor.
The observation of the ocean biota from space had started with the observation of the ocean surface through the coastal zone colour scanner (CZCS) onboard SEASAT and Nimbus - 7 both launched by NASA.. Since then it attracted the scientific community to study the primary productivity of the ocean using the space borne remote sensing observations. It is followed by the Ocean colour temperature scanner (OCTS), Sea-viewing Wide Field-of-view Sensor (SeaWiFS), Moderate Imaging sensor (MODIS) to provide quantitative data on global ocean bio-optical properties to the Earth science community.
The Indian Ocean is the only ocean in the world which is affected by the periodic reversal of the trade wind in a year. Particularly the primary productivity in the Arabian Sea and the Bay-of-Bengal is affected by both the short term global climate change, the El-Nino Southern Oscillation, and the reversal of trade-wind, the Monsoonal circulation. In this study we have attempted to study the variability of the chlorophyll -a concentration in the Arabian Sea from the SeaWiFS observations. It is found that during the El-Nino period (1997 - 1998) the mean chlorophyll concentration is very low compared to the La-Nina year (1998 - 1999). We propose the hypothesis that there is a teleconnection between chlorophyll-a and El Nino phenomena which give rise to less wind stress over the study region during the El-Nino compared to that during the La-Nina.
NASA Carbon Cycle & Ecosystems Active Awards Represented by this Poster:
Award: 281945.02.65.01.10 and 547714.04.06.02.01 Start Date: 2003-11-01