Satellites observed U.S. heat spell

GREENBELT, Md., Sept. 1 (UPI) -- As much of the United States sweated through a record-breaking humid heat wave during July, satellites recorded the unusual weather from above, NASA said.

The Atmospheric Infrared Sounder instrument on the Aqua satellite launched in 2002 recorded highly accurate data about the troposphere, the lowest layer of the atmosphere and the part that most directly affects the climate on Earth, a release from the space agency said Thursday.

Texas and Oklahoma persistently experienced daytime highs above 100 Fahrenheit for the month of July, while nights offered little relief, with low temperatures averaging close to 90 degrees -- about 20 degrees warmer day and night than July temperatures recorded during the past eight years of AIRS observations.

The AIRS data offered clues to what may have caused the persistent heat spell, recording domes of high atmospheric surface pressure over both the Atlantic and Pacific oceans that fueled the heat wave.

While the domes normally intensify in summer months, the AIRS observations showed them to be abnormally strong in July, NASA said.

AIRS data revealed a clockwise vortex of winds driven by the high pressure in the North Atlantic pumping hot and humid air from the tropics through the heart of the Gulf of Mexico and into much of the continental United States throughout July.