June 22, 2020 | Published by | ,

Picture: Storm cloud out to sea. Credit: Daniel Bernard Unsplash

Over tropical oceans, individual thunderstorms often cluster together into a collection of thunderstorms. The way in which these thunderstorm clusters are organized is important for many aspects of weather and climate. For example, for line‐organized thunderstorm clusters, whether the line is oriented parallel or perpendicular to the winds is important for how the thunderstorms alter the winds and how their anvils reflect solar radiation.

In this study, we investigate the influence of cold pools, which are evaporatively cooled regions of air near the surface, below thunderstorms, on the orientation of line‐organized thunderstorm clusters using computer model simulations.

We found that line‐organized thunderstorm clusters are oriented parallel to the winds more often when the cold pools are weaker. We also show that cold pools have a larger impact on the orientation of the thunderstorm line when the upper level winds are stronger.

Finally, we showed how the cold pool‐induced changes to line‐organized thunderstorms affect the size of their anvil clouds, which affects their ability to reflect solar radiation and the emission of infrared radiation. These thunderstorm sensitivities and their impact on radiation could influence tropical climate, hence it is important to consider these effects in climate models.

  • Paper: Grant, L. D., Moncrieff, M. W., Lane, T. P., & van den Heever, S. C.. ( 2020). Shear‐Parallel Tropical Convective Systems: Importance of Cold Pools and Wind Shear. Geophysical Research Letters, 47, e2020GL087720. https://doi.org/10.1029/2020GL087720