Comparison of global chlorophyll concentrations using MODIS data Swarvanu Dasgupta a , Ramesh P. Singh b, * , Menas Kafatos c a Center for Earth Observation and Space Research, George Mason University, Fairfax, VA 22030, USA b Department of Physics, Computational Science and Engineering, Chapman University, One University Drive, Orange, CA 92866, USA c College of Science, Chapman University, One University Drive, Orange, CA 92866, USA Received 4 March 2008; received in revised form 6 November 2008; accepted 7 November 2008 Abstract Chlorophyll concentrations derived from satellite borne ocean color sensors data provide an idea of the distribution of phytoplank- tons across the oceans which help us in understanding the spatial and temporal dynamics of phytoplanktons. The changes in the patterns of distribution and abundance of the planktons have significant impact on the entire ecosystem and play a key role in the global carbon cycle. In this paper, we have analyzed annual and seasonal chlorophyll concentrations retrieved from MODIS data for the periods March 2000–October 2003, which reveal the spatial and seasonal distribution of chlorophyll concentrations across the global oceans. Chloro- phyll concentrations anomaly indicate that chlorophyll concentrations in almost all ocean regions responded similarly. Ó 2008 COSPAR. Published by Elsevier Ltd. All rights reserved. Keywords: Seawifs; Chlorophyll; Remote sensing; Ocean 1. Introduction About 70% parts of the globe is covered by the ocean, which surrounds different continents. The ocean is full of natural resources which are very useful to the human kinds. Oceans play a very important role in controlling the long and short term changes in weather conditions. In the ocean, the physical, chemical and biological processes are linked in an intimate manner (Tang et al., 2002). The pres- ence of phytoplankton and its spatial distribution control the entire ecosystem and also play a key role in the global carbon cycle. In the contemporary ocean, photosynthetic carbon fixation by marine phytoplankton leads to forma- tion of 45 gigatons of organic carbon per annum, of which 16 gigatons are exported to the ocean interior. The export of carbon can strongly influence atmospheric CO 2 levels (and hence climate) on geological time scales, as well as set upper bounds for sustainable fisheries harvest (Fal- kowski et al., 1998). Atmospheric carbon dioxide is absorbed equally by land vegetation and phytoplankton. The greenhouse effect is likely to increase without the pho- tosynthetic buffering by the phytoplanktons, which affects carbon dioxide levels. The phytoplankton account for approximately 50% of the photosynthesis on the earth and over 99.9% of all the carbon dioxide that has been bur- ied over geologic time, and thus, provide information about atmospheric carbon. The interaction of the natural ocean resources and biochemical processes is relevant to global climate change and the carbon cycle (Bahamon et al., 2003). Recently, Singh et al. (2008) have found enhancement in chlorophyll concentrations associated with dust storms in the Arabian ocean. With the multi ocean color monitor sensors, the monitoring of oceans is being carried out and numerous studies have revealed annual, intra-annual, seasonal and inter-seasonal variability of chlorophyll concentrations in different oceanic zones. Long term ocean color satellite monitoring provides an impor- tant tool for better understanding of the marine processes, ecology, and the coastal environmental changes (GEO- HAB, 1998, Kawamura and OCTS team, 1998, Yoder et al., 1993; Tang et al., 1998, 1999, 2002). Gregg and Conkright (2002) have studied the decadal changes in global ocean using Coastal Zone Color Scanner 0273-1177/$36.00 Ó 2008 COSPAR. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.asr.2008.11.009 * Corresponding author. Tel.: +1 714 289 2037; fax: +1 714 289 2041. E-mail address: rpiitkanpur@gmail.com (R.P. Singh). www.elsevier.com/locate/asr Available online at www.sciencedirect.com Advances in Space Research 43 (2009) 1090–1100