Best weather predicting models examined: Which best predicted September 2013 Colorado surges?

Two College of Iowa scientists lately examined ale the earth's innovative weather predicting models to calculate the Sept. 9-16, 2013 extreme rain fall that triggered severe flooding in Boulder, Colo.

The outcomes, released within the December 2013 problem from the journal Geophysical Research Letters, indicated the predicting models generally carried out well, but additionally left room for improvement.

David Lavers and Gabriele Villarini, scientists at IIHR -- Hydroscience and Engineering, a UI research facility, examined rain fall predictions from eight different global statistical weather conjecture (NWP) models.

Throughout September 2013, Boulder County and surrounding areas experienced severe flooding and high rain leading to deaths, losing houses and companies, and also the promise of a significant disaster.

Following the storms had gone away, Lavers and Villarini made the decision to look at how good a few of the leading NWP models tried. Like a constantly enhancing science, NWP involves integrating current climate conditions through mathematical types of the climate-sea system to forecast future weather. For his or her study, the scientists selected the particular rain fall predictions produced by eight condition-of-the-art global NWP models for that duration of the Colorado surges.

"In an prime position time for you to the big event, the rain fall predictions unsuccessful to capture the persistent character from the event's rain fall," states Lavers, corresponding author as well as an IIHR postdoctoral investigator. "However, the rain fall predictions from Sept. 9 (the very first day from the event) did provide guidance showing a substantial duration of rain fall in Colorado."

"Overall, these models tended to underestimate rain fall amounts and placed the rain fall within the wrong area, despite the fact that they provided a sign that a time of heavy rain fall would affect areas of Colorado," states Gabriele Villarini, study co-author, assistant professor within the UI College of Engineering Department of Civil and Environment Engineering and assistant research engineer at IIHR.

Within their study, Lavers and Villarini used a relatively coarse (getting a comparatively low quantity of pixels) global model output. The UI scientists stress that greater spatial resolution NWP models will probably have taken the rain fall to some greater extent.

States Lavers: "It's wished the ongoing growth and development of finer resolution NWP appliances resolve the complex atmospheric motions in mountainous terrain, like the Rocky Mountain tops, will have the ability to enhance the predicting abilities of these extreme rain fall occasions."

The paper is formally entitled: "Were global statistical weather conjecture systems able to predicting the ultimate Colorado rain fall of 9-16 September 2013?"

The study was based on IIHR, the Iowa Ton Center, and also the U.S. Military Corps of Engineers Institute for Water Assets.

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Climate change could increase storm surges

Last year's most devastating tropical system -- Hurricane Irene -- was considered by some experts to be a "100-year-event," a storm that comes around only once a century.

Irene lashed the East Coast in August, killing at least 45 people and leading to $7.6 billion in damages.

But a study out this week in Nature Climate Change says that due to global warming, these monster storms could make landfall more frequently, causing destructive storm surges every 3 to 20 years instead of once a century.

The lead author of the study was Ning Lin of the Massachusetts Institute of Technology, who partnered with scientists at Princeton University to undertake the research.

Lin and her colleagues used computer models to simulate future hurricanes, looking at the impact of climate change on storm surges, with New York City as a case study. The team simulated tens of thousands of storms under different climate conditions.

Today, a "100-year storm" has a surge flood of about two meters, on average, in New York City. But with added greenhouse gas emissions due to the burning of fossil fuels, the computer models found that a two-meter surge flood would instead occur once every three to 20 years.

Lin says that knowing the frequency of storm surges may help urban and coastal planners design seawalls and other protective structures.

While the number of hurricanes globally may or may not increase due to global warming, some scientists say that the ones that do form could be more intense than they would be otherwise.

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