Research: ’Cloud greenhouse effect’ can help tropical cyclones develop

An FSU meteorology professor and a team of scientists found that cloud cover acting as a "greenhouse" can help intensify developing tropical systems.
Published: Oct. 28, 2020 at 6:45 PM EDT
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TALLAHASSEE, Fla. (WCTV) - Atmospheric scientists have made inroads with hurricane forecasting over the last few decades. For instance, the National Hurricane Center’s forecast track error has decreased by 70 - 75% over the last 30 years. But there is still plenty to learn - especially with intensity forecasting. But a peer-reviewed paper released Monday, co-authored by an Florida State University meteorology professor, may shed more light on that topic.

The researchers found that the intensification of a developing tropical cyclone has something to do with the “cloud greenhouse effect.” Some are aware of the greenhouse effect where gasses naturally (and unnaturally) dispersed can keep the planet warm. The clouds can also act like a greenhouse. That is especially the case with deep, tall thunderstorm clouds associated with a developing tropical system. These clouds can trap heat and moisture, helping to intensify the storm. This is assuming that water temperatures and the environment are sufficiently warm, and there are no external factors such as wind shear and dry air intrusion.

Dr. Allison Wing, a co-author and a FSU meteorology professor, and her team ran two model simulations on each storm: Hurricane Maria from 2017 and Typhoon Haiyan in 2013. On each of the storms, they ran a model without clouds and one with clouds at the time of the storm’s development. The team found that the clouds supported the cloud-radiation feedback.

“With no cloud feedback, the storms either formed much more slowly or didn’t form at all, indicating that the cloud-radiation feedback significantly accelerates [tropical cyclone] development," Wing said in an email. “This was our hypothesis, and the result supported it.”

The research could help with forecast modeling of hurricanes, and help predict the strength of a storm before landfall. This would give residents and emergency management a better idea of what to expect.

“We know that weather and climate models sometimes struggle to simulate clouds correctly, and so focusing more research on constraining the cloud-radiation feedback on TCs in models is a promising avenue for improving TC prediction,” Wing said.

But whether a warmer climate would have an impact on this feedback is still unknown, Wing said.

“We don’t know how TCs might be affected by changes in the distribution of clouds related to climate change, but there is a lot of uncertainty in projections of future TC activity,” she said. “[A] deeper understanding of the processes governing TC development, including this cloud-radiation feedback process, may help us make progress on this issue.”

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