Andria et al. (2025) Thermodynamic Versus Large‐Scale Controls on Extreme Precipitation: Temporal Scale Dependence and Clausius‐Clapeyron Scaling Redefined

Identification

• Journal: Geophysical Research Letters
• Year: 2025
• Date: 2025-10-31
• Authors: Santa Andria, Marco Borga, Marco Marani
• DOI: 10.1029/2025gl115204

Research Groups

• Department of Civil, Environmental, and Architectural Engineering, University of Padova, Padova, Italy
• Department of Land, Environment, Agriculture, and Forestry, University of Padova, Padova, Italy
• Research Center on Climate Change Impacts, University of Padova, Rovigo, Italy

Short Summary

This study introduces a framework using the Metastatistical Extreme Value Distribution to precisely define precipitation extremes and investigate their dependence on local thermodynamics and large-scale atmospheric circulation across different temporal scales. It finds that hourly precipitation extremes are primarily controlled by thermodynamics, with rarer events intensifying more sharply, while daily extremes are predominantly influenced by large-scale circulation, challenging conventional Clausius-Clapeyron scaling assumptions.

Objective

• To propose a framework that precisely defines precipitation extremes and explores their dependence on local thermodynamics and large-scale atmospheric circulation at different temporal scales.
• To understand the drivers of change in precipitation extremes at varying event durations and probabilities of occurrence, allowing the entire probability distribution of precipitation intensity to depend on climate forcings.

Study Configuration

• Spatial Scale: Observational stations across the contiguous United States, grouped by Köppen-Geiger climate zones.
• Temporal Scale: Hourly and 24-hourly (daily) precipitation events; analysis of extreme event return periods ranging from 5 to 100 years.

Methodology and Data

• Models used:
  • Metastatistical Extreme Value Distribution (MEVD)
  • Weibull distribution (for ordinary precipitation intensity)
  • Piecewise constant and exponential functional dependencies for Weibull parameters on covariates
  • Maximum Likelihood Estimation (MLE)
  • Akaike Information Criterion (AIC)
  • Linear regression for scaling rate determination
• Data sources:
  • Hourly precipitation data: COOP Hourly Precipitation Data (HPD version 02r02)
  • Daily near-surface air temperature (NSAT): Global Historical Climatology Network Daily (GHCN-d)
  • Dewpoint temperature (DPT): HadISD data set (version v3.4.2.202503p)
  • Large-scale atmospheric variables (500 hPa vertical velocity (ω500), vertically integrated moisture convergence (VIMC)): ERA5 reanalysis (approximately 31 km spatial resolution)

Main Results

• Local thermodynamic controls (temperature, dewpoint temperature) predominantly govern changes in hourly precipitation extremes.
• The rate of increase for hourly precipitation extremes is dependent on the return period, with rarer events (higher return periods) intensifying more sharply, contrasting with the fixed-rate assumption of traditional Clausius-Clapeyron scaling.
• Daily precipitation extremes are primarily controlled by large-scale atmospheric circulation, a factor not captured by Clausius-Clapeyron based approaches.
• The shape parameter (w) of the Weibull distribution for ordinary hourly precipitation shows a marked decreasing trend with increasing temperature and dewpoint temperature, implying an increased likelihood of extreme precipitation (thick-tailed behavior, w < 1) under warmer and moister conditions.
• At the daily aggregation scale, the shape parameter (w) exhibits no systematic variations with temperature or dewpoint temperature, indicating a tendency for thinner tails (w > 1) compared to hourly durations.
• The dependence of Weibull distribution parameters on large-scale circulation (ω500) becomes stronger at the daily duration.
• The dependence of the extreme precipitation scaling rate on the return period is primarily modulated by the moisture dependence of the Weibull shape parameter (w).

Contributions

• Introduces a conceptually consistent framework (MEVD) for linking climate change to changes in the full probability distribution of extreme precipitation, moving beyond predefined quantiles.
• Clarifies the distinct physical mechanisms controlling precipitation extremes at different temporal scales, showing local thermodynamic dominance for hourly events and large-scale circulation dominance for daily events.
• Demonstrates that the intensification rate of extreme precipitation is necessarily dependent on its return period, particularly for hourly events, providing a redefinition of Clausius-Clapeyron scaling.
• Highlights the critical role of the shape parameter of the ordinary event probability distribution in modulating how the scaling rate varies with the return period.
• Provides a more rigorous and practical assessment approach for understanding and quantifying extreme precipitation responses to temperature and atmospheric circulation changes.

Funding

• European Union Next-GenerationEU (National Recovery and Resilience Plan - NRRP, Mission 4, Component 2, Investment 1.3 - D.D. 1243 2/8/2022, PE0000005) - RETURN Extended Partnership
• CARIPARO Foundation Excellence Grant 2021 “RESILIENCE”
• European Union – NextGenerationEU under the PRIN (Progetti di Ricerca di Rilevante Interesse Nazionale) programme (Grant 2022ZC2522) - INTENSE project (raINfall exTremEs and their impacts: from the local to the National ScalE)

Citation

@article{Andria2025Thermodynamic,
  author = {Andria, Santa and Borga, Marco and Marani, Marco},
  title = {Thermodynamic Versus Large‐Scale Controls on Extreme Precipitation: Temporal Scale Dependence and Clausius‐Clapeyron Scaling Redefined},
  journal = {Geophysical Research Letters},
  year = {2025},
  doi = {10.1029/2025gl115204},
  url = {https://doi.org/10.1029/2025gl115204}
}