Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Hard rain - UI study of Midwest finds increase in heavy rainfalls over 60 years

14.03.2013
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.

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.


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. Adapted from Villarini et al., 2013.

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 paper is titled, “Changing Frequency of Heavy Rainfall over the Central United States.” It was first published in January.

The research was funded by NASA and the Willis Research Network.
Contacts
Gabriele Villarini, Engineering, 319-384-0596
Gary Galuzzo, University Communication and Marketing, 319-384-0009

Gary Galluzzo | EurekAlert!
Further information:
http://www.uiowa.edu

More articles from Earth Sciences:

nachricht NASA eyes Pineapple Express soaking California
24.02.2017 | NASA/Goddard Space Flight Center

nachricht 'Quartz' crystals at the Earth's core power its magnetic field
23.02.2017 | Tokyo Institute of Technology

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>