Beating the radar: Getting a jump on storm prediction

Jun 16, 2009
Sample meteorological satellite images like those analyzed during this year’s annual Hazardous Weather Testbed, held from May 4 through June 5. The HWT is organized by the National Oceanic and Atmospheric Administration to accelerate the transition of new meteorological technologies into advance forecasting and warnings for hazardous weather events throughout the U.S. UW-Madison Space Science and Engineering Center.

Satellite observation of cloud temperatures may be able to accurately predict severe thunderstorms up to 45 minutes earlier than relying on traditional radar alone, say researchers at UW-Madison's Space Science and Engineering Center.

Scientists from the Cooperative Institute for Meteorological Satellite Studies (CIMSS) have developed a way to measure temperature changes in the tops of clouds to improve forecast times for rapidly growing storms.

"The value of detecting and analyzing these changes is that we can get up to a 45-minute jump on radar detection of the same storm system. A 'nowcast' becomes a 'forecast,'" says CIMSS scientist Wayne Feltz.

Clouds start cooling long before radar can identify them as storms. As a warm cumulus cloud grows and expands upward into higher altitudes, it will rapidly cool. Rapid cloud-top cooling indicates that a cloud top is rising into the frigid upper reaches of the atmosphere and can reveal the formation of a severe storm.

Cloud temperatures can be measured by the wavelengths of light they radiate in the near-infrared and infrared frequencies. Current geostationary satellites — satellites that stay over the same location on Earth — over the U.S. can discern five different bands in these frequencies, each band revealing a different state of cloud development. Looking down from space, the satellite can determine whether the cloud top consists of liquid water, supercooled water or even ice.

By running high-speed five-minute satellite scans through a carefully designed computer algorithm, the scientists can quickly analyze cloud top temperature changes to look for signs of storm formation. "We are looking for transitions," says Feltz. "Does the cloud top consist of liquid water that is cooling rapidly? That could signal a possible convective initiation."

Feltz and other CIMSS colleagues, including Kris Bedka and National Oceanic and Atmospheric Administration (NOAA) scientist Tim Schmit, demonstrated their "Convective Initiation Nowcast" and "Cloud Top Cooling Rate" products at NOAA's annual Hazardous Weather Testbed (HWT), held May 4-June 5 at the Storm Prediction Center in Norman, Okla.

The HWT is designed to accelerate the transition of promising new meteorological insights and technologies into advance forecasting and warnings for hazardous weather events throughout the United States.

"The Hazardous Weather Testbed brings in outside experts in all areas, a melting pot of people to encourage collaboration and interactions and proposal opportunities," Feltz says. "The point of this is working with forecasters in the field — the Weather Service, the Storm Prediction Center, the Hurricane Center — whoever is interested in looking at more advanced satellite products."

Source: University of Wisconsin

Explore further: Climate researchers measure the concentration of greenhouse gases above the Atlantic

add to favorites email to friend print save as pdf

Related Stories

Fay Comes Ashore in Florida

Aug 19, 2008

(PhysOrg.com) -- NASA's CloudSat and Aqua satellites are just two of NASA's fleet keeping eyes on Tropical Storm Fay. NASA is using these data to see cloud height and cloud temperatures which give hints at ...

Scientists seek clear-sky definition of clouds

Dec 06, 2005

All through the ages, humans have dreamily gazed at those shape-shifting cotton-balls floating gently across the sky-the clouds. Atmospheric scientists-Earth's professional cloud-gazers-have learned a great ...

NASA airborne expedition chases climate, ozone questions

Jun 27, 2007

NASA's Tropical Composition, Cloud and Climate Coupling (TC4) field campaign will begin this summer in San Jose, Costa Rica, with an investigation into how chemical compounds in the air are transported vertically into the ...

Recommended for you

NASA sees last vestiges of Tropical Depression Jack

14 hours ago

Tropical Cyclone Jack had weakened to a tropical depression when NASA and JAXA's Tropical Rainfall Measuring Mission (TRMM) satellite passed above on April 22, 2014 at 1120 UTC/7:20 a.m. EDT.

New discovery helps solve mystery source of African lava

18 hours ago

Floods of molten lava may sound like the stuff of apocalyptic theorists, but history is littered with evidence of such past events where vast lava outpourings originating deep in the Earth accompany the breakup ...

Climate change likely to make Everest even riskier

18 hours ago

Climbing to the roof of the world is becoming less predictable and possibly more dangerous, scientists say, as climate change brings warmer temperatures that may eat through the ice and snow on Mount Everest.

User comments : 0

More news stories

On global warming, settled science and George Brandis

The Australian Attorney General, Senator George Brandis is no stranger to controversy. His statement in parliament that "people do have a right to be bigots" rapidly gained him notoriety, and it isn't hard to understand why ...