Asymmetric long-term persistence analysis in sea surface temperature anomaly

The first evidence of asymmetric upward and downward persistence in the global sea surface temperature anomaly (SSTA) is revealed from the observations with the asymmetric detrended fluctuation analysis (A-DFA) method. Global distributions of the scaling exponents which quantify the degree of memory on time scales in the range from 10 months to 20 years, show that the strong general long-term persistence of SSTA forms a thwartwise letter “V” over the tropical Pacific Ocean. The strong upward and downward long-term persistence only exists in particular half of the letter “V”.