A seasonal scale analysis correlating total cloud amount anomalies with ENSO over the tropical Pacific.

The seasonal patterns of total cloud amount (TCA) responsible for El Niño/La Niña-Southern Oscillation (ENSO) Sea Surface Temperature (SST) anomalies were investigated using the ISCCP-D2 cloud and NOAA OI.v2 SST datasets for the period of July 1983 to June 2008. The results show three main ENSO-sensitive regions obtained by spatial overlapping of seasonal correlations, two in the western tropical Pacific and one in the central tropical Pacific. These regions were named WTP1, WTP2, and CTP. In all three regions, except the JJA (June-August) WTP2, the TCA changes were significantly correlated with the Niño 3.4 anomalies during the four seasons (December-January-February (DJF), March-April-May, JJA, and September-October-November (SON)). Remarkable differences in the seasonal variability of TCA were observed in these regions. In the WTP1, the DJF TCA always remained the highest value among the four seasons in all years. In the WTP2, the maximum TCA occurred during JJA in most years. In the CTP, the extreme value of TCA was mainly observed in DJF or SON near the peak time of ENSO. Seasonal cross-correlation analyses also showed significant relations between TCA and Niño 3.4 SST in these regions, which may be helpful for forecasting the evolution of ENSO. [ABSTRACT FROM AUTHOR]