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 In times of climate change: What a lake’s colour can tell about its condition
21.09.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

nachricht Did marine sponges trigger the ‘Cambrian explosion’ through ‘ecosystem engineering’?
21.09.2017 | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: LaserTAB: More efficient and precise contacts thanks to human-robot collaboration

At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.

Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Fraunhofer ISE Pushes World Record for Multicrystalline Silicon Solar Cells to 22.3 Percent

25.09.2017 | Power and Electrical Engineering

Usher syndrome: Gene therapy restores hearing and balance

25.09.2017 | Health and Medicine

An international team of physicists a coherent amplification effect in laser excited dielectrics

25.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>