Spring irrigation can reduce summer heat wave events

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New research, published in Geophysical Research Letters, has investigated the dampening effect irrigating land in spring can have on the intensity of summer heat waves by retaining higher soil moisture levels between seasons, known as soil moisture memory.

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Dr. Liu and colleagues found that spring irrigation reduced the intensity of summer heat waves by 0.29°C and 2.5 days, and when combined with summer irrigation this extends to a reduction of 1°C and 6.5 days. With the simulated regional means of extreme heat waves being temperatures of 35.8°C and lasting 21.7 days, the combined impact of spring and summer irrigation can have a significant effect, especially on the longevity of the event.

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This research is important as it suggests applying a surplus of water in spring helps to alleviate water stress in the following summer months, and is less wasteful of water resources that evaporate more in summer (especially from the top 1 m of soil), while also supporting regions that experience an imbalance in precipitation through the year.

Though the intensity of extreme heat wave events may be reduced, these climatic challenges will persist in the future, so it is important to apply these results in water resource management and adaptation planning strategies.