Featured Research

from universities, journals, and other organizations

Increase in heavy rainfalls over past 60 years in upper Midwest, US

Date:
March 13, 2013
Source:
University of Iowa
Summary:
Heavy rains have become more frequent in the upper Midwest over the past 60 years, according to a new stud. The trend appears to hold true even with the current drought plaguing the region, the study's main author says.

The map shows location of selected rain gauges, with blue (red) triangles depicting sites with significant increasing (decreasing) trends, and white circles showing sites with little or no change.
Credit: Adapted from Villarini et al. (2013)

Heavy rains have become more frequent in the upper Midwest over the past 60 years, according to a study from the University of Iowa. The trend appears to hold true even with the current drought plaguing the region, the study's main author says.

Related Articles


The fact that temperatures over the country's midsection are rising, too, may be more than coincidence.The hotter the surface temperature, which has been the trend in the Midwest and the rest of the world, the more water that can be absorbed by the atmosphere. And the more water available for precipitation means a greater chance for heavy rains, explains Gabriele Villarini, assistant professor in engineering at the UI and lead author of the paper, published in the Journal of Climate, the official publication of the American Meteorological Society.

"We found that there is a tendency toward increasing trends in heavy rainfall in the northern part of the study region, roughly the upper Mississippi River basin," says Villarini, in the civil and environmental engineering department and an assistant research engineer at the IIHR-Hydroscience and Engineering. "We tried to explain these results in light of changes in temperature. We found that the northern part of the study region -- including Minnesota, Wisconsin, Iowa, and Illinois -- is also the area experiencing large increasing trends in temperature, resulting in an increase in atmospheric water vapor."

Villarini notes the current drought affecting the Midwest and other regions of the country has occurred too recently to be included in his study, whose data goes from about 1950 to 2010.

"I'm not looking at the average annual rainfall. I'm studying heavy rainfall events," he says. "We may currently be in deficit for overall rainfall, but we may also be in the normal range when it comes to the number of heavy rainfall days."

Villarini and his colleagues examined changes in the frequency of heavy rainfall through daily measurements at 447 rain gauge stations in the central and southern United States. The states included were: Minnesota, Wisconsin Michigan, Iowa, Illinois, Indiana, Missouri, Kentucky, Tennessee, Arkansas, Louisiana, Alabama, and Mississippi.

Each rain gauge station has a record of at least 50 years. The data cover much of the 20th century and the first decade of this century. For the purposes of the study, heavy rainfall was defined as days in which rainfall exceeded the 95th percentile of the at-site rainfall distribution.

Villarini notes that while his study focused on changes in temperature and the frequency of heavy rainfall over the central United States, other published results have shown rainfall increases to be linked to changes in irrigation over the Ogallala Aquifer, which runs from Nebraska to northern Texas. Based on those studies, he says it is reasonable to assume that changes in land use, land cover and agricultural practice would affect the amount of water vapor in the atmosphere as well.

His colleagues in the study are James Smith, professor at Princeton University; and Gabriel Vecchi, of the National Oceanic and Atmospheric Administration.

The research was funded by NASA and the Willis Research Network.


Story Source:

The above story is based on materials provided by University of Iowa. The original article was written by Gary Galluzzo. Note: Materials may be edited for content and length.


Journal Reference:

  1. Gabriele Villarini, James A. Smith, Gabriel A. Vecchi. Changing Frequency of Heavy Rainfall over the Central United States. Journal of Climate, 2013; 26 (1): 351 DOI: 10.1175/JCLI-D-12-00043.1

Cite This Page:

University of Iowa. "Increase in heavy rainfalls over past 60 years in upper Midwest, US." ScienceDaily. ScienceDaily, 13 March 2013. <www.sciencedaily.com/releases/2013/03/130313182312.htm>.
University of Iowa. (2013, March 13). Increase in heavy rainfalls over past 60 years in upper Midwest, US. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2013/03/130313182312.htm
University of Iowa. "Increase in heavy rainfalls over past 60 years in upper Midwest, US." ScienceDaily. www.sciencedaily.com/releases/2013/03/130313182312.htm (accessed October 24, 2014).

Share This



More Earth & Climate News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Dances With Wolves in China's Wild West

Dances With Wolves in China's Wild West

AFP (Oct. 23, 2014) One man is on a mission to boost the population of wolves in China's violence-wracked far west. The animal - symbol of the Uighur minority there - is under threat with a massive human resettlement program in the region. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
San Diego Zoo's White Rhinos Provide Hope for the Critically Endangered Species

San Diego Zoo's White Rhinos Provide Hope for the Critically Endangered Species

Reuters - Light News Video Online (Oct. 22, 2014) The pair of rare white northern rhinos bring hope for their species as only six remain in the world. Elly Park reports. Video provided by Reuters
Powered by NewsLook.com
Trick-or-Treating Banned Because of Polar Bears

Trick-or-Treating Banned Because of Polar Bears

Buzz60 (Oct. 21, 2014) Mother Nature is pulling a trick on the kids of Arviat, Canada. As Mara Montalbano (@maramontalbano) tells us, the effects of global warming caused the town to ban trick-or-treating this Halloween. Video provided by Buzz60
Powered by NewsLook.com
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins