New theory aims to explain recent temperature, climate extremes

Jun 12, 2007

Using an ocean of data, sophisticated mathematical models and supercomputing resources, researchers at the Department of Energy's Oak Ridge National Laboratory are putting climate models to the test with particular focus on weather extremes.

Ultimately, the new methodology developed by Auroop Ganguly and colleagues could help determine to what extent there is a connection between human activity and climate change. For now, however, researchers are concentrating on how climate models fare when compared to actual observations recorded between 1940 and 2005 and whether there are any connections between the extremes.

"Once we understand the nature of these connections our hope is that we will be able to determine if there is a relation between two extreme weather events - like heat waves and droughts," said Ganguly, a member of the Computational Sciences and Engineering Division. "We may then be able to determine whether there will be more intense storms, hurricanes or floods, and this information could perhaps be used as an early warning tool or to help develop policies."

While traditional climate models may not be especially useful for predicting extremes in general and rainfall extremes in particular, the statistical approach outlined in the journal Advances in Water Resources represents a big step in the direction of modeling rainfall extremes from observations and climate model simulations. Ganguly, who led the research team, believes the technique opens a world of possibilities.

"The methodology can have widespread use," Ganguly said. "In addition to water resources, hydrologic sciences, climate and ecology, the applications can include geospatial intelligence and security."

Using this new tool, researchers can relate extremes of a space and time variable like a 100-year rainfall at two locations or two time periods as well as relate the extremes of two or more variables such as 100-year precipitation extremes and heat waves. A 100-year event is one of such magnitude that over a long period of time - much longer than 100 years - the average time between such events is equal or greater to 100 years.

"For example," Ganguly said, "if 100-year events at two locations occur simultaneously, and if our measure says they are completely independent, then their simultaneous occurrence becomes a 100 times 100 -- or 10,000-year event -- and therefore can be used to predict change more confidently. If, however, our method says the events at the two locations are completely dependent, then the simultaneous occurrence remains a 100-year event overall."

In the paper, the researchers use this new approach to evaluate the performance of climate model simulations in terms of rainfall extremes, looking specifically at the dependence structure among these extremes. What they found is that while the dependence patterns appear to be visually similar and have significant commonalities, important differences do exist in terms of the magnitude, extent and directionality of the dependence.

Source: ORNL

Explore further: NASA HS3 mission Global Hawk's bullseye in Hurricane Edouard

add to favorites email to friend print save as pdf

Related Stories

UK wind power share shows record rise

1 hour ago

The United Kingdom wind power production has been enjoying an upward trajectory, and on Tuesday wind power achieved a significant energy production milestone, reported Brooks Hays for UPI. High winds from Hurricane Gonzalo were the force behind wind turbines outproducing nuclear power ...

Cloning whistle-blower: little change in S. Korea

2 hours ago

The whistle-blower who exposed breakthrough cloning research as a devastating fake says South Korea is still dominated by the values that allowed science fraudster Hwang Woo-suk to become an almost untouchable ...

Glass maker deals to exit Apple, Arizona plant

2 hours ago

Nearly 2,000 furnaces installed in a factory to make synthetic sapphire glass for Apple Inc. will be removed and sold under a deal between the tech giant and the company that had been gearing up to produce huge amounts of ...

Recommended for you

NASA image: Fires in the southern United States

18 hours ago

In this image taken by the Aqua satellite of the southern United States actively burning areas as detected by MODIS's thermal bands are outlined in red. Each red hot spot is an area where the thermal detectors ...

Software models ocean currents for oil and gas search

19 hours ago

A study involving the use of streamline visualisation has found the technology can help guide electromagnetic transmitter and receiver placements, thereby aiding the search for oil and gas on the seafloor.

User comments : 0