On 1 July 2025, NIWA merged with GNS Science to become Earth Sciences New Zealand.

Souther_Annular_Mode

Positive SAM: A schematic of the positive phase of the SAM. Areas of above normal pressure are shaded in red while areas of below normal pressure are shaded in blue.

Negative SAM: A schematic of the negative phase of the SAM. Areas of above normal pressure are shaded in red while areas of below normal pressure are shaded in blue.