Long term persistence in the sea surface temperature fluctuations

TL;DR

This paper investigates the long-term correlations in sea surface temperature fluctuations in the Atlantic and Pacific, revealing distinct short-term nonstationary and long-term stationary regimes with specific decay behaviors.

Contribution

It introduces a method to analyze SST correlations, identifying two regimes and quantifying their decay exponents, highlighting differences from land temperature dynamics.

Findings

Short-term SST fluctuations are nonstationary up to 10 months.

Long-term correlations decay as s^{-0.4} in both oceans.

SST persistence differs from atmospheric land temperature patterns.

Abstract

We study the temporal correlations in the sea surface temperature (SST) fluctuations around the seasonal mean values in the Atlantic and Pacific oceans. We apply a method that systematically overcome possible trends in the data. We find that the SST persistence, characterized by the correlation $C(s)$ of temperature fluctuations separated by a time period $s$, displays two different regimes. In the short-time regime which extends up to roughly 10 months, the temperature fluctuations display a nonstationary behavior for both oceans, while in the asymptotic regime it becomes stationary. The long term correlations decay as $C(s) \sim s^{-\gamma}$ with $\gamma \sim 0.4$ for both oceans which is different from $\gamma \sim 0.7$ found for atmospheric land temperature.