By Jackie Stolze

Here’s the rainfall forecast for the next hundred years: whatever you’re experiencing now will become more extreme.  A new NASA rainfall study predicts that in the next 100 years, wet areas will receive more very heavy rainfalls, while arid regions will experience more droughts.

The study, which will soon appear in the journal Geophysical Research Letters, used data from 14 global climate models. William Lau, NASA’s deputy director of atmospheric studies and the study’s lead investigator, says the results are “amazing.”

Lau’s study is the first to examine the global rainfall system from a basic science viewpoint. While the global climate models produce differing results for specific locations, one result is clear across the board: as global temperatures rise, the atmosphere can hold more water vapor as moisture. The moisture tends to collect in areas that already receive significant rainfall, while intensifying droughts in already dry areas. For each degree Fahrenheit of global temperature increase, wet areas receive 3.9 percent more heavy rainfall. Meanwhile, droughts increase by 2.6 percent in dry areas.

Iowa Flood Center researcher Gabriele Villarini also conducts research on rainfall based on observational records, although he was not involved in this study. He calls the NASA study fascinating. “These modeling results are consistent with some of the detected changes in rainfall over the Central United States, with a redistribution toward more intense rainfall over the recent past,” Villarini says.

The Iowa Flood Center is partnering with NASA on the Iowa Flood Studies project, also known as IFloodS. IFloodS researchers are collecting ground data across Eastern Iowa as part of NASA’s Global Precipitation Measurement Mission, an international satellite mission that will set a new standard for global precipitation measurements from space. To learn more about GPM, visit http://pmm.nasa.gov/ifloods.