August 2023 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 were above average (1.0ºC - 2.5ºC anomaly) during the month. The strong warming at the eastern equatorial Pacific were still observed but slightly cooled down and had expanded westward. However, the SSTAs in the western Pacific and over most of the maritime continent were also near 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.
Positive IOD values were observed in August, as the western equatorial Indian Ocean was observed to be warmer than average while the eastern equatorial Indian Ocean was observed to be cooler than average.
