Scaling Behaviors of Global Sea Surface Temperature

Temporal scaling properties of the monthly sea surface temperature anomaly (SSTA) in global ocean basins are examined by the power spectrum and detrended fluctuation analysis methods. Analysis results show that scaling behaviors of the SSTA in most ocean basins (e.g., global average, South Pacific, eastern and western tropical Pacific, tropical Indian Ocean, and tropical Atlantic) are separated into two distinct regimes by a common crossover time scale of 52 months (i.e., 4.3 yr). It is suggested that this crossover is modulated by the El Niño/La Niña–Southern Oscillation (ENSO), indicating different scaling properties at different time scales. The SSTA time series is nonstationary and antipersistent at the small scale (i.e., crossover). It is, however, stationary and long range correlated at the large scale (i.e., crossover). For both time scales, scaling behaviors of SSTA are heterogeneously distributed over the ocean, and the fluctuation of SSTA intensifies with decreasing latitude. Stronger fluctuation appears over the tropical regions (e.g., central-eastern tropical Pacific, tropical Atlantic, tropical Indian Ocean, and South China Sea), which are directly or indirectly linked to ENSO. Weaker fluctuation and stronger persistence are found in mid- and high-latitude areas, coinciding with the “reemergence” areas.