Articles | Volume 6, issue 1
https://doi.org/10.5194/wcd-6-231-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/wcd-6-231-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| Highlight paper
| 
24 Feb 2025
Research article | Highlight paper |
| 24 Feb 2025
| 24 Feb 2025
Sensitivity of tropical orographic precipitation to wind speed with implications for future projections
Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, USA
now at: Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland
William R. Boos
Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, USA
Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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This preprint is open for discussion and under review for Weather and Climate Dynamics (WCD).
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Heatwaves are intensifying at a fast pace, and how much further they can strengthen is unknown. Our study seeks to estimate a physical upper limit to surface air temperature. We show that, unlike what recent work suggested, the intensity of the most extreme heatwaves is not constrained by the onset of thunderstorms. Instead, the limit is set by the development of a several-kilometer-deep layer of well-mixed air above the ground, and modulated by a very hot and unstable near-surface layer.
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Heatwaves are intensifying at a fast pace, and how much further they can strengthen is unknown. Our study seeks to estimate a physical upper limit to surface air temperature. We show that, unlike what recent work suggested, the intensity of the most extreme heatwaves is not constrained by the onset of thunderstorms. Instead, the limit is set by the development of a several-kilometer-deep layer of well-mixed air above the ground, and modulated by a very hot and unstable near-surface layer.
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In this study we investigate why climate change is amplified in mountain regions, a phenomenon known as elevation-dependent warming (EDW). We examine EDW using observations and models and assess the roles of radiative forcing vs. internal variability in driving the historical signal. Using a forcing–feedback framework we also quantify for the first time the processes driving EDW on large scales. Our results have important implications for understanding future climate change in mountain regions.
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Atmospheric rivers (ARs) are extreme weather events that can alleviate drought or cause billions of US dollars in flood damage. We train convolutional neural networks (CNNs) to detect ARs with an estimate of the uncertainty. We present a framework to generalize these CNNs to a variety of datasets of past, present, and future climate. Using a simplified simulation of the Earth's atmosphere, we validate the CNNs. We explore the role of ARs in maintaining energy balance in the Earth system.
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Executive editor
How precipitation over ocean regions changes with global warming is grounded in a well accepted theory, but there is so far no such theory to describe precipitation changes over land. This paper provides important theoretical, numerical and observational evidence for the sensitivity of orographically-induced precipitation in the tropics to background wind changes. The result that tropical orographic rainfall increases with cross-slope winds at a rate of 20-30% (which is more than twice the rate expected from simple "upslope flow” theory) has important implications for constraining future climate change, providing an avenue for reliable projections of continental precipitation without the need for climate models that explicitly resolve convection.
How precipitation over ocean regions changes with global warming is grounded in a well accepted...
Short summary
Rainfall in mountainous regions constitutes an important source of freshwater in the tropics. Yet how it will change with global warming remains an open question. Here, we reveal a strong sensitivity of this rainfall to the speed of prevailing winds. This relationship, validated by theory, simulations, and observational data, suggests that regional wind shifts will significantly influence future rainfall changes in the tropics.
Rainfall in mountainous regions constitutes an important source of freshwater in the tropics....
