By Andrea Thompson
26 January 2017
(Climate Central) – Across a vast swath of Europe and Asia, rain is increasingly falling in the short, localized bursts associated with thunderstorms, seemingly at the expense of events where a steady rain falls over many hours, a new study finds.
The results fit with rainfall trends already observed in the U.S., as well as model predictions that massive rains associated with thunderstorms could become both more frequent and more intense in the U.S. as the world continues to heat up.
The shift toward more extreme rains could have implications for water management and flooding because the ground is less able to absorb rainwater when it falls all at once.
“These changes should have pretty big impacts on this region,” Andreas Prein, of the National Center for Atmospheric Research in Boulder, Colo., said.
That a warming atmosphere will lead to more extreme rainfall events is one of the basic predictions of climate science, and is linked to the fact that warming leads to more evaporation, which leads to more water vapor in the atmosphere. That means that when rains occur, there’s more water vapor available to dump as rain.
Extreme downpours have already been increasing in the U.S., most notably in the Northeast, where they have increased by 71 percent since mid-century, according to the 2014 National Climate Assessment. [more]
ABSTRACT: Convective precipitation—localized, short-lived, intense, and sometimes violent—is at the root of challenges associated with observation, simulation, and prediction of precipitation. The understanding of long-term changes in convective precipitation characteristics and their role in precipitation extremes and intensity over extratropical regions are imperative to future water resource management; however, they have been studied very little. We show that annual convective precipitation total has been increasing astonishingly fast, at a rate of 18.4%/°C, of which 16% is attributable to an increase in convective precipitation occurrence, and 2.4% is attributable to increased daily intensity based on the 35 years of two (combined) historical data sets of 3-hourly synoptic observations and daily precipitation. We also reveal that annual daily precipitation extreme has been increasing at a rate of about 7.4%/°C in convective events only. Concurrently, the overall increase in mean daily precipitation intensity is mostly due to increased convective precipitation, possibly at the expanse of nonconvective precipitation. As a result, transitional seasons are becoming more summer-like as convective becomes the dominant precipitation type that has accompanied higher daily extremes and intensity since the late 1980s. The data also demonstrate that increasing convective precipitation and daily extremes appear to be directly linearly associated with higher atmospheric water vapor accompanying a warming climate over northern Eurasia.