Science Source

How will precipitation change in extratropical cyclones as the planet warms? Insights from a large initial condition climate model ensemble

Investigates the extratropical precipitation response to global warming within a 30-member initial condition climate model ensemble
States that, as in observations, modeled cyclonic precipitation contributes a large fraction of extratropical precipitation, especially over the ocean and in the winter hemisphere
When compared to present day, the ensemble projects increased cyclone-associated precipitation under twenty-first century business-as-usual greenhouse gas forcing
While the cyclone-associated precipitation response is weaker in the near-future (2016–2035) than in the far-future (2081–2100), both future periods have similar patterns of response
Finds that although cyclone frequency changes are important regionally, most of the increased cyclone-associated precipitation results from increased within-cyclone precipitation
Finds that cyclone-centric composites show statistically significant precipitation increases in all cyclone sectors
Decomposition into thermodynamic (mean cyclone water vapor path) and dynamic (mean cyclone wind speed) contributions shows that thermodynamics explains 92 and 95% of the near-future and far-future within-cyclone precipitation increases respectively
Finds the influence of dynamics on future cyclonic precipitation changes is negligible and that the forced response exceeds internal variability in both future time periods
Results suggest that future cyclonic precipitation changes will result primarily from increased moisture availability in a warmer world, with secondary contributions from changes in cyclone frequency and cyclone dynamics