EGU24-8856, updated on 08 Mar 2024
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Storm intensification driven by soil moisture gradients in global hotspot regions

Emma Barton1, Cornelia Klein1, Christopher Taylor1, John Marsham2, Douglas Parker2, Ben Maybee2, Zhe Feng3, and L. Ruby Leung3
Emma Barton et al.
  • 1UK Centre for Ecology and Hydrology, Wallingford, United Kingdom of Great Britain – England, Scotland, Wales (
  • 2University of Leeds, Leeds, United Kingdom of Great Britain – England, Scotland, Wales
  • 3Pacific Northwest National Laboratory, Richland, Washington, United States of America

Organised thunderstorm clusters known as Mesoscale Convective Systems (MCSs) can bring high impact hazards such as flash floods, lighting and destructive winds. It is crucial for the forecasting and mitigation of these hazards to understand the processes that influence the characteristics of storms and thereby contribute to extreme events. Soil moisture is known to influence the initiation of MCSs in several regions of the world, but the influence of soil moisture on the later stages of MCS lifecycles is less well understood. Work in West Africa has revealed that dry soil moisture structures on scales > 200 km can increase the scale and longevity of propagating, mature afternoon MCSs, but this has not been investigated for other regions. In the current work we simultaneously analyse seven global MCS hotspot regions where storms may be sensitive to soil moisture, the US Great Plains, China, India, West Africa, Australia, South Africa and South America, to gain a more global perspective of the impact of soil moisture conditions on mature MCS characteristics. Using a combination of global datasets, storm tracks, satellite data, reanalysis data and CMIP6 simulations, we reveal that large-scale soil moisture gradients (100s of km) can intensify storms by driving favourable shear conditions through the strengthening of low-level atmospheric temperature gradients. By separating storms by soil moisture conditions, we show an increase in precipitation feature area and rainfall production on days with favourable gradients compared to days with unfavourable gradients. This is a newly identified mechanism through which soil moisture can influence storm hazards globally, which has implications for the forecasting and future projection of extreme events under climate change.

How to cite: Barton, E., Klein, C., Taylor, C., Marsham, J., Parker, D., Maybee, B., Feng, Z., and Leung, L. R.: Storm intensification driven by soil moisture gradients in global hotspot regions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8856,, 2024.