The relationship between thunderstorms and global warming

The frequency of clouds is very high in the tropical regions of the Earth - clouds are often associated with violent storms - rising due to global warming, according to a study by scientists at NASA's Jet Laboratory, Pasadena, Calif.

In a presentation at the meeting of the American Geophysical Association in San Francisco, JPL researcher Hartmut Aumann presented the results of a five-year document-based study of infrared atmospheric probes. (AIRS) on NASA's Aqua spacecraft. AIRS data is used to observe a number of tropical clouds related to strong thunderstorms, flooding and hail. The device is capable of detecting about 6,000 such clouds a day. Aumann and his team discovered a correlation between the frequency of clouds and the seasonal variation in seasonal sea surface temperatures in tropical seas.

The sea surface temperature increased by 1 degree C (1.8 degrees F), the team observed that very high cloud frequencies increased by 45%. With the current global warming rate of about 0.13 degrees Celsius (0.23 degrees F) a decade, the team found that the frequency of heavy thunderstorms would increase by about 6 percent a decade.

Very high clouds, known as deep convection clouds, are often associated with intense storms and heavy rain. In the AIRS photo of Hurricane Katrina, taken on August 28, 2006, the day before Katrina entered Louisiana, the eye around the storm was a cluster of 528 deep convection clouds (dark green). The temperature of such clouds is less than 210 degrees Kelvin (-82 degrees F). (Photo: NASA / JPL)

Meteorologists have long predicted that the frequency and intensity of severe storms may increase or may not increase with global warming. Aumann said the results of the study will help improve this hypothesis.

Aumann explains: 'Clouds and rain are the weakest eyes in predicting weather. The interaction between the warming of the sea surface under perfectly normal weather conditions and an increase in the formation of low clouds, high clouds and very heavy rain. "

The high clouds we observed - at a height of 20 km (12 miles) above sea level - represent the greatest difficulty for climate models. These models cannot analyze smaller cloud structures about 250km (155 miles) '.

The results of the study, published in the journal Geophysical Research Letters, are consistent with the study by Frank Wentz and colleagues funded by NASA in 2005. The study found that the overall rainfall rate was 1.5. % a decade within 18 years. This value is five times higher than the prediction of the climate models used in the 2007 report of the multi-government panel on climate change.

JPL manages AIRS project for NASA's rocket science directorate, Washington. For more information about AIRS, visit http://airs.jpl.nasa.gov/.