Meeting Documents

Decadal Variability of Marine Heatwaves in the Southwest Indian Ocean

Abstract

Marine HeatWaves (MHWs) have a wide range of impacts, from destruction of local marine ecosystems to extreme precipitation events via teleconnections. Anthropogenic warming has been shown to increase the frequency and intensity of MHWs of the world’s oceans. By analyzing satellite and reanalysis datasets we show that in a large region of the southwest Indian Ocean, the frequency and cumulative intensity of MHWs have significantly increased from 2004-2023 compared to 1982-2003, even after removing the linear trend for sea surface temperature. To explore the causes of this decadal variation, we carry out mixed layer heat budget analysis using the ECCO reanalysis product. Our results show that changes in surface heat flux, particularly shortwave and latent heat, and the mixed layer depth are the major drivers controlling the decadal variability of MHWs. These changes and their relationships to climate modes are being explored.