May 2022 Sea Surface Temperature Assessment
A. Niño Regions
Niño sea surface temperature (SST) Indices are based on the average of SST anomalies across the given regions: Niño 1+2 (0-10S, 90W-80W), Niño 3 (5N-5S, 150W-90W), Niño 3.4 (5N-5S, 170W-120W) and Niño 4 (5N-5S, 160E-150W). These indices are used to monitor the conditions in the Tropical Pacific for the occurrence of El Niño or La Niña.
Sea surface temperature anomalies (SSTAs) across the central and eastern equatorial Pacific remained below average (-0.5ºC to -1.0ºC) but weakened during the month. However, most of the the western Pacific near the Maritime continent was observed to be near to slightly warmer than average (0°C to 1.0°C), while the South China Sea was observed to be slightly cooler than average.
B. Indian Ocean Dipole (IOD)
The Indian Ocean Dipole mode Index (DMI) is defined as the difference between the SST anomalies (ºC) of Western (10ºS-10ºN & 50ºE-70ºE) and Eastern (10ºS-0ºN & 90ºE-110ºE) Equatorial Indian Ocean regions (WEST-EAST). The DMI values represent the intensity of the Indian Ocean Dipole (IOD); DMI values above +0.4 °C is referred as the positive IOD, DMI values below −0.4 °C is referred as the negative IOD and DMI values between +0.4 °C and -0.4 °C is referred as the neutral IOD.
The average IOD value was within neutral levels for the month, although values observed were below zero.
