Global warming precipitation accumulation increases above the current-climate cutoff scale.

Area of Science:

• Climate Science
• Atmospheric Science
• Hydrology

Background:

• Precipitation accumulation is influenced by storm intensity and duration.
• Predicting changes in precipitation accumulation under global warming remains a challenge.
• Understanding these changes is crucial for assessing societal impacts.

Purpose of the Study:

• To develop a theoretical framework for predicting changes in precipitation accumulation probability density functions (pdf).
• To evaluate these predicted changes using global climate model simulations.
• To understand how global warming affects the scale of extreme precipitation events.

Main Methods:

• Developed a theory for the probability density function (pdf) of precipitation accumulations.
• Analyzed changes in the pdf under projected global warming.
• Evaluated the theory using global climate model simulations.

Main Results:

• The theory predicts exponential increases in the frequency of large precipitation accumulations above a physical cutoff scale.
• This cutoff scale, influenced by moisture convergence and precipitation loss, is predicted to increase with global warming.
• Climate models confirm that projected warming (3°C) leads to substantial increases (hundreds to over 1,000%) in the probability of extreme precipitation accumulations.

Conclusions:

• Global warming extends the cutoff scale for precipitation accumulations, making currently rare large events more probable.
• The findings suggest that future climates will experience significantly more frequent and intense extreme precipitation events.
• The theoretical framework and model simulations provide a robust understanding of future precipitation extremes.