Abstract:

NOAA Extended Reconstructed Sea Surface Temperature V3b dataset (ERSST) and Hadley Centre Sea Ice and Sea Surface Temperature dataset (HadISST) were used in this paper for analyzing the observed ENSO intensity changes during 1900-2015. It is demonstrated that ENSO amplitude changed clearly over the past more than 100 years. From the beginning of the 20th century to the 1950s, ENSO intensity weakened while it strengthened significantly from the 1950s to the late 1990s, especially after the 1970s. After 2000, the intensity declined slightly. The weakest ENSO intensity occurred from the 1920s to the 1950s, during which the northsouth width of ENSO spatial pattern narrowed and the maximum sea surface temperature anomaly (SSTA) center had a westward shift. In contrast, the width was the widest and the maximum SSTA center had an eastward shift after the late 1970s when ENSO intensity kept a strong magnitude. And then the width and the center had an opposite changing tendency after 2000.

Key words: the last hundred years, ENSO, intensity change