Simple Physics Equations To Estimate Cloud Cover, Critical To Climate Change Predictions

Aug 27, 2018

Clouds like these over Utah Lake are an important factor in better understanding future climate predictions.
Credit Utah Lake Commission

Clouds are an important part of predicting day-to-day weather but, even with cloud cover being a critical piece in climate prediction models, it’s often missing. But a few specific physics equations could make predicting future cloud cover easier.  

Scientists are currently writing many lines of code to run computer simulation models of cloud cover in climate prediction models. But these complex computing models require large amounts of computing power.

According to Tim Garrett, a professor of Atmospheric Sciences at the University of Utah, "it would take around 10,000 computers running full time for one hour just to simulate one meter cubed of air over a period of 10 minutes.”

Garrett and his collaborators discovered that a few simple, but specific physics equations can calculate cloud cover in climate prediction models almost as well as these complex computer simulation models.

“The statistics of cloud shapes and where they are distributed can be determined just using a few lines of physics equations," said Garrett. “The technique I use is purely statistical. It cannot say what is happening at any given place at any given time. It just says on average these are the distributions of clouds that you would expect to see ... We found we were able to reproduce the most complex computer models out there to within an accuracy of about 10 percent.”

According to Garrett, clouds are dynamic and complex parts of climate change predictions and a vital part of climate prediction models.

“It has been identified by the international panel on climate change  . . . as being arguably the most important problem to try to solve is the role of clouds and climate 10, 20, 30, 40 years from now,” said Garett.