Scaling in global ocean chlorophyll fluctuations

Abstract

Nine years of weekly Sea-viewing Wide Field-of-view Sensor (SeaWiFS) data from 1998 to 2006 are used to investigate the temporal correlations in chlorophyll fluctuations by means of detrended fluctuation analysis. Chlorophyll fluctuations are found to exhibit scaling behavior on time scales from several weeks to more than two years over the global ocean between 50°S and 50°N. The scaling exponent varies in a wide range from 0.51 to 1.26, with an average value of 0.83. Long range correlated fluctuations occur over large parts of the ocean, while uncorrelated random fluctuations tend to concentrate in the western margins of the Pacific and Atlantic. The global distribution of the scaling exponent is similar to that of the ratio of interannual to total variability. A greater percentage of interannual to total variability is generally associated with a larger scaling exponent and hence stronger long range correlation. Copyright 2008 by the American Geophysical Union.