Understanding changes in extreme precipitation

Typography

Most climate scientists agree that heavy rainfall will become even more extreme and frequent in a warmer climate. This is because warm air can hold more moisture than cold air, resulting in heavier rainfall.

However, the involved mechanisms are complex and the increase in extreme precipitation varies in space, as noted by Stephan Pfahl, climate scientist at ETH Zurich and lead author of a paper just published in the journal Nature Climate Change: “The level of atmospheric moisture is just one factor influencing the distribution and intensity of extreme precipitation. Other factors also play a key role – especially when it comes to regional variability.”

Most climate scientists agree that heavy rainfall will become even more extreme and frequent in a warmer climate. This is because warm air can hold more moisture than cold air, resulting in heavier rainfall.

However, the involved mechanisms are complex and the increase in extreme precipitation varies in space, as noted by Stephan Pfahl, climate scientist at ETH Zurich and lead author of a paper just published in the journal Nature Climate Change: “The level of atmospheric moisture is just one factor influencing the distribution and intensity of extreme precipitation. Other factors also play a key role – especially when it comes to regional variability.”

Analysis of contributing factors

To better understand regional variations in extreme precipitation, Stephan Pfahl and his co-authors Erich Fischer and Paul O’Gorman from the Massachusetts Institute of Technology (MIT) therefore decomposed the existing projections into their individual components: the contribution of increasing atmospheric moisture on the one hand, and the contribution of weaker or stronger vertical wind velocities on the other hand. This approach gave the researchers a deeper understanding of the changes in extreme precipitation predicted by the models for individual regions.

Continue reading at ETH Zurich

Image: McKay Savage via Wikimedia Commons