Identifying source of predictability for vapor pressure deficit variability in the southwestern United States

Abstract Atmospheric vapor pressure deficit (VPD) measures the difference between saturation vapor pressure and actual vapor pressure, and its variability is closely related to fire activity in the western United States (US). Here, we assess the forecast skill of monthly VPD variability using a stat...

Full description

Saved in:
Bibliographic Details
Main Authors: Jiale Lou, Youngji Joh, Thomas L. Delworth, Liwei Jia
Format: Article
Language:English
Published: Nature Portfolio 2025-04-01
Series:npj Climate and Atmospheric Science
Online Access:https://doi.org/10.1038/s41612-025-01028-6
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850201491858522112
author Jiale Lou
Youngji Joh
Thomas L. Delworth
Liwei Jia
author_facet Jiale Lou
Youngji Joh
Thomas L. Delworth
Liwei Jia
author_sort Jiale Lou
collection DOAJ
description Abstract Atmospheric vapor pressure deficit (VPD) measures the difference between saturation vapor pressure and actual vapor pressure, and its variability is closely related to fire activity in the western United States (US). Here, we assess the forecast skill of monthly VPD variability using a state-of-the-art dynamical forecast system and statistical predictions, such as the persistence forecast and model-analog forecasts. In the model-analog framework, we select analog states resembling the observed initial conditions from the model space, and the subsequent evolution of those initial model-analogs yields forecast ensembles. Dynamical forecasts demonstrate skillful predictions of VPD variability in the western US, exceeding the persistence forecast skill, which indicates additional sources of VPD predictability within the climate system. To quantify the contribution of different climate variables to VPD prediction, we develop a weighted model-analog forecast and evaluate its skill in comparison to VPD-only and unweighted forecasts. Our findings suggest that sea surface temperature is a critical source of VPD predictability over the western US. The optimally weighted model-analog exhibits forecast skill for VPD variability comparable to that of the dynamical forecast system.
format Article
id doaj-art-4a59d77bc1c94d1c96fe3add424de9d0
institution OA Journals
issn 2397-3722
language English
publishDate 2025-04-01
publisher Nature Portfolio
record_format Article
series npj Climate and Atmospheric Science
spelling doaj-art-4a59d77bc1c94d1c96fe3add424de9d02025-08-20T02:12:01ZengNature Portfolionpj Climate and Atmospheric Science2397-37222025-04-018111410.1038/s41612-025-01028-6Identifying source of predictability for vapor pressure deficit variability in the southwestern United StatesJiale Lou0Youngji Joh1Thomas L. Delworth2Liwei Jia3Atmospheric and Oceanic Sciences Program, Princeton UniversityGeophysical Fluid Dynamics Laboratory/NOAAGeophysical Fluid Dynamics Laboratory/NOAAGeophysical Fluid Dynamics Laboratory/NOAAAbstract Atmospheric vapor pressure deficit (VPD) measures the difference between saturation vapor pressure and actual vapor pressure, and its variability is closely related to fire activity in the western United States (US). Here, we assess the forecast skill of monthly VPD variability using a state-of-the-art dynamical forecast system and statistical predictions, such as the persistence forecast and model-analog forecasts. In the model-analog framework, we select analog states resembling the observed initial conditions from the model space, and the subsequent evolution of those initial model-analogs yields forecast ensembles. Dynamical forecasts demonstrate skillful predictions of VPD variability in the western US, exceeding the persistence forecast skill, which indicates additional sources of VPD predictability within the climate system. To quantify the contribution of different climate variables to VPD prediction, we develop a weighted model-analog forecast and evaluate its skill in comparison to VPD-only and unweighted forecasts. Our findings suggest that sea surface temperature is a critical source of VPD predictability over the western US. The optimally weighted model-analog exhibits forecast skill for VPD variability comparable to that of the dynamical forecast system.https://doi.org/10.1038/s41612-025-01028-6
spellingShingle Jiale Lou
Youngji Joh
Thomas L. Delworth
Liwei Jia
Identifying source of predictability for vapor pressure deficit variability in the southwestern United States
npj Climate and Atmospheric Science
title Identifying source of predictability for vapor pressure deficit variability in the southwestern United States
title_full Identifying source of predictability for vapor pressure deficit variability in the southwestern United States
title_fullStr Identifying source of predictability for vapor pressure deficit variability in the southwestern United States
title_full_unstemmed Identifying source of predictability for vapor pressure deficit variability in the southwestern United States
title_short Identifying source of predictability for vapor pressure deficit variability in the southwestern United States
title_sort identifying source of predictability for vapor pressure deficit variability in the southwestern united states
url https://doi.org/10.1038/s41612-025-01028-6
work_keys_str_mv AT jialelou identifyingsourceofpredictabilityforvaporpressuredeficitvariabilityinthesouthwesternunitedstates
AT youngjijoh identifyingsourceofpredictabilityforvaporpressuredeficitvariabilityinthesouthwesternunitedstates
AT thomasldelworth identifyingsourceofpredictabilityforvaporpressuredeficitvariabilityinthesouthwesternunitedstates
AT liweijia identifyingsourceofpredictabilityforvaporpressuredeficitvariabilityinthesouthwesternunitedstates