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Atmospheric water status—should I use vapour pressure deficit or atmospheric water potential?

Year: 2026
Type: article
Abstract: The aim of this work has been to investigate the application of two popular atmospheric water status measurements, namely, vapour pressure deficit (VPD) and atmospheric water potential (AWP). These climate measurements are employed in a wide range of applications, including studies into: climate change, ecology, plant and tree water-use, and agricultural research as well as featuring in commercial horticulture applications. Both VPD and AWP employ air temperature and relative humidity readings to provide a measure of the atmospheric water status or the water ‘drying force’ of the atmosphere—an important factor in relation to climate change. In this study VPD and AWP are presented as mathematical functions and compared graphically over a range of temperatures and relative humidities to illustrate the non-linear relationship between these functions. Historical open-access environmental data from Open-Meteo for Cambridge, UK, and Phoenix Arizona, USA have been employed to further assess the relationship between VPD and AWP. The results from this assessment indicate that the selection of VPD or AWP for a specific application should also consider: measurement period, seasonal variations, climate type, and the dominant environmental factors (as functions of air temperature and relative humidity) when developing empirical relationships between the water ‘drying force’ of the atmosphere and other measurement datasets. A further deliverable from this work is that the methodology presented in this paper, using open-access historical global weather data, can be easily replicated for a specified location and period to provide insight into the application of VPD and/or AWP as a precursor to experimental work.
DOI: 10.1088/1361-6501/aeaf0d
Language: English
Open Access status: hybrid
Estimated APC paid: $3,325
OpenAlex ID: W7215050529
FWCI:
Cites: 26
Cited by:
Related to: 10