Abstract
Groundwater plays an integral role in land-atmosphere interactions by connecting the sub-surface storage of water to transpiration via interactions with the root zone. The role of groundwater in moderating heatwave intensity has rarely been examined in coupled climate simulations, as many models overlook this key component of the water cycle. We use a coupled land-atmosphere model with an explicit representation of groundwater dynamics to analyze three major heatwave events in southeast Australia. Groundwater moistens and cools the land surface, with impacts extending to the top of the atmospheric boundary layer during heatwaves. Associated with the cooling, an increase of net radiation and a reduction in the atmospheric boundary layer height occurred, primarily over areas with a shallow water table depth and woody vegetation. The maximum air temperatures were reduced by up to 3 °C at the surface and up to 1 °C through the atmospheric boundary layer. Our results point to an important influence of groundwater on heatwave intensity, implying the necessity of considering groundwater dynamics in climate models in the future heatwave predications.
| Original language | English |
|---|---|
| Article number | 100479 |
| Journal | Weather and Climate Extremes |
| Volume | 37 |
| DOIs | |
| Publication status | Published - Sept 2022 |
Bibliographical note
Funding Information:The research was funded by the ARC Centre of Excellence for Climate Extremes ( CE170100023 ) and by the New South Wales Department of Planning, Industry and Environment . Mu acknowledges support from the UNSW University International Postgraduate Award (UIPA) scheme, and acknowledges the help from Dr. Annette L. Hirsch and Dr. Claire C. Carouge on NU-WRF set-up. De Kauwe and Pitman acknowledge support from the ARC Discovery Grant ( DP190101823 ) and Ukkola acknowledges support from the ARC Discovery Early Career Researcher Award ( DE200100086 ). De Kauwe acknowledges support from the NSW Research Attraction and Acceleration Program (RAAP) . Ge acknowledges the support from the Natural Science Foundation of China ( 42005096 ). We are grateful to the National Computational Infrastructure at the Australian National University for provision of supercomputing resources.
Publisher Copyright:
© 2022 The Authors
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