An Examination of the Link between Decadal Changes in Precipitation, Winds, and Sea Surface Heights in the Tropical Indo-Pacific during the Period 1993–2010

Climate change has contributed to global sea level rise. However, in situ measurements and satellite observations indicate that this increase is not uniform over the tropical Indo-Pacific basin. Further, satellite altimetry data documented large-scale decadal variations in sea level over much of the tropical Indo-Pacific basin, such that sea level trends underwent a decadal change around 1999/2000. Large-scale reversals in sea level trends are associated with fluctuations in the Indo-Pacific branch of the Walker cell. This research examined the nature of decadal sea level change over the tropical Indo-Pacific basin and how these changes relate to low frequency variations in the strength of the Walker circulation. Understanding the causes of decadal sea level variability will aid in adaptation. The relationship between the decadal changes of sea surface heights and zonal wind stress was investigated for 1993-1999 and for 2000-2010 in three regions showing distinct decadal phase reversals near 1999/2000. Changes in the large-scale circulation associated with the Walker circulation were inferred from decadal changes in the precipitation over the Indo-Pacific warm pool and changes in the zonal winds in both the tropical Pacific and Indian Oceans. To isolate the decadal variability in the three variables, five year centralized running means were used. The results showed a decadal change in the strength of the Walker circulation and a strong correlation to winds and sea levels in the tropical Indian and western Pacific. Variability in the western Pacific and Indian Ocean appeared to be strongly influenced by ENSO.