Temperature influences on evapotranspiration

Temperature is a principal driver of evapotranspiration (ET) in arid and desert regions: as temperature increases, evapotranspiration rates generally rise, provided there is sufficient moisture available456.

Key points:

• Higher temperatures increase potential evapotranspiration by raising the energy available for both evaporation from soil and water surfaces and transpiration from plants56.

• In arid and desert regions, actual evapotranspiration is often limited by water availability, not just temperature. If little or no water is present in the soil, even high temperatures will not translate to higher actual ET6.

• Studies report a positive correlation between temperature and monthly ET in arid areas, with temperature being among the main climatic factors influencing ET variability46.

• Evapotranspiration is seasonally highest during the hottest months, but may not scale linearly with temperature if drought or limited precipitation restricts available soil moisture6.

• “Evaporation paradox”: In some regions, despite rising temperatures, observed evaporation rates have decreased in recent decades. This apparent contradiction is attributed to factors like reduced wind speed, decreased surface water availability, or improved irrigation practices—reducing the aerodynamic drivers of evaporation56.

• Enhanced ET in vegetated (irrigated or oasis) areas may cool local microclimates despite increased air temperature, leading to effects like the "oasis cold island”5.

• Vegetation and land use change can alter ET responses to temperature by changing soil moisture retention and transpiration potential46.

In summary: Temperature is a key environmental control on evapotranspiration in arid environments; higher temperatures increase the potential for evapotranspiration, but actual rates are moderated by water supply, vegetation cover, and other local climatic factors456.

1. https://www.sciencedirect.com/science/article/abs/pii/S0921818111001135
2. https://www.sciencedirect.com/science/article/pii/S1470160X25003759
3. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2024WR038301
4. https://pmc.ncbi.nlm.nih.gov/articles/PMC9956289/
5. https://www.nature.com/articles/srep35418
6. https://iwaponline.com/hr/article/52/1/212/79075/Impacts-of-climate-and-vegetation-on-actual
7. https://www.mdpi.com/2073-4441/13/6/870
8. https://www.usgs.gov/special-topics/water-science-school/science/evapotranspiration-and-water-cycle