The South Pacific Convergence Zone is the main source of rainfall for a thousand islands in the South Pacific. Understanding future changes in this region is crucial for local vulnerable populations.
Global climate models can be used to assess the climate response to increasing anthropogenic emissions. These models suggest a significant precipitation decrease in the south-eastern Pacific but no significant changes in the south-western Pacific.
Unfortunately, these projections contain high uncertainties due to long-standing sea surface temperature biases.
For this reason, other studies investigating the future evolution of precipitation use forced high-resolution atmospheric models and apply a correction to present-day sea-surface temperatures to account for these biases. However, these corrections do not consider potential biases in future sea surface temperature changes.
CLEX researchers found that applying a statistical correction to projected sea surface temperatures has a major impact on changes to rainfall with global warming, leading to a 25% reduction in future precipitation projected for the south-western Pacific. They found this large decrease in precipitation is linked to a change in circulation and moisture transport due to future increasing gradients of sea-surface temperatures.
- Paper: Dutheil, C., Bador, M., Lengaigne, M. et al. Impact of surface temperature biases on climate change projections of the South Pacific Convergence Zone. Clim Dyn (2019). https://doi.org/10.1007/s00382-019-04692-6