Tropical heat waves: observations of temperature change support climate models.

The atmosphere over the tropics is warming up, according to new analyses of satellite data. These observations echo the calculations of climate models, which are used to predict future temperature change and the impacts of greenhouse gas.

Previously, discrepancies between observations

However, earlier studies showing a slight cooling of the tropical troposphere in the last quarter century were based on analysis of a single satellite database, according to researchers with the Lawrence Livermore National Laboratory. New satellite and weather balloon data tracking temperature trends in the tropical atmosphere agree with the model results.

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"This strongly suggests that there is no longer any fundamental discrepancy between modeled and observed temperature trends in the tropical atmosphere," says Livermore's Benjamin Santer, lead author of the new study published in Science Express. "The new observational data helps to remove a major stumbling block in our understanding of the nature and causes of climate change."

The research involved nearly 50 simulations performed with 19 different models, all of which showed similar temperature amplification effects caused by the release of heat when the moist tropical air rises and condenses into clouds.

"Our work illustrates that progress toward an improved understanding of the climate system requires a combination of observations, theory, and models," Santer concludes.

Source: Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550. Web site www.llnl.gov.