While temperatures soared to near 100 degrees, a Lear jet with special thermal imaging devices crisscrossed the skies over the Salt Lake Valley Monday looking for hot and cool spots in the city below.

The jet, based at Stennis Space Flight Center near Bay St. Louis, Miss., took off after an informal press conference near the Salt Lake International Airport's Executive Terminal.Jeff Luvall, senior research scientist at the National Aeronautics and Space Administration's (NASA) Marshall Space Flight Center in Huntsville, Ala., and other scientists met with news media personnel to explain a research study being conducted in the Salt Lake area.

Luvall and others are in Salt Lake City to gather data about surface temperatures and bubblelike accumulations of hot air called "urban heat islands."

The scientists, part of an interagency partnership, are "working to determine which surfaces in the valley are contributing to the urban heat island phenomenon," said Camille Russell of the Utah Office of Energy Services.

Russell, who coordinates a National Department of Energy program called "cool communities," said the phenomenon occurs when the landscape loses its natural ability to cool because vegetation is replaced by roads, buildings and other structures that attract and give off heat.

"Bubblelike accumulations of hot air form over cities. That creates what is called the urban heat island effect. And the consequence for you and I are that we have to run our air conditioners more. There are consequences to air quality, and human comfort is jeopardized," Russell said.

"We're trying to understand which surfaces are (creating the problem) in the hope to (create) cool communities. Such (communities) basically (have lots of) trees and make use of light-colored surfaces to mitigate (problems of heat) and that make our environment a more comfortable place in which to live," she said.

Luvall said the Lear23 jet was equipped with a standard aerial photography camera and a scanner, which creates a digital image. The scanner makes use of the same technology that NASA uses to explore the universe.

As the plane flew over the city, the equipment created a photograph based on temperatures of the city. Infrared photographs "show what parts of the city are warm and what parts of the city are cool. We give the information to planning people. It helps them understand what type of urban planning is required to keep your city cool," Luvall said.

Ambient air temperatures were also taken throughout the Salt Lake Valley while the plane was in flight. That information, coupled with data gathered from the aerial photographs, will be studied for several months.

On Sunday, NASA researchers set up instruments atop three Salt Lake buildings to measure atmospheric conditions. On Monday they launched a weather balloon to measure atmospheric conditions during the jet flight. And students took temperature readings on the ground in various locations.

Luval, who at the press conference discussed an aerial photo and thermal images taken of Atlanta in May 1997 and of Salt Lake City in 1985, said trees and other vegetation show up in the photos as blue or green (cooler areas). Rooftops are white, and road surfaces and the tops of buildings generally show up as yellow and red, depending on the temperature. The redder a color is, the hotter the surface.

Russell said it will take three to six months to more fully analyze information gathered Monday. She said the University of Utah, the Energy and Geoscience Institute and TreeUtah will assist the Office of Energy Services in analyzing the data.

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Additional Information

Homing in on S.L. Valley temperature zones

Here's a few observations gleaned by scientists from aerial photography taken Monday in the Salt Lake area:

- "Real cool" areas include Salt Lake City-County Building grounds.

- Gateway area is "very hot." Area shows up mostly orange or red, with a little white (see adjoining story).

- Temperature registered an estimated 160 degrees early Monday afternoon on the roof of the new Scott M. Matheson Courthouse.

- University of Utah campus is "pretty cool, except for parking lots and new construction" around Rice Stadium, said Jeff Luvall of NASA's Marshall Space Flight Center.

- Generally, the downtown area is much warmer than the area east toward the Wasatch Mountains.

"A lot of building rooftops (should) incorporate materials for keeping buildings cooler, Also, a lot more trees should be planted along streets and in parking lots," Luvall said.