Friday, May 9, 2008
April temperature variations in the lower troposphere. (Credit: UAHuntsville)
Global temperature trend since Nov. 16, 1978: +0.14 C per decade
April Temperatures (preliminary)
•Global composite temp.: +0.02 C (about 0.04 degrees Fahrenheit) above 20-year average for April.
•Northern Hemisphere: +0.17 C (about 0.31 degrees Fahrenheit) above 20-year average for April.
•Southern Hemisphere: - 0.14 C (about 0.25° Fahrenheit) below 20-year average for April.
March temperatures (revised)
•Global Composite: + 0.09 C above 20-year average
•Northern Hemisphere: + 0.42 C above 20-year average
•Southern Hemisphere: - 0.25 C below 20-year average
(All temperature variations are based on a 20-year average (1979-1998) for
the month reported.)
The La Nina Pacific Ocean cooling event continues to push temperatures in the tropics downward, with the tropical troposphere chilling for the second consecutive month to its coolest temperature since the La Nina of 1989, according to Dr. John Christy, director of the Earth System Science Center at The University of Alabama in Huntsville.
The average for atmospheric temperatures in the tropics was 0.53 C (about 0.95 degrees Fahrenheit) cooler than seasonal norms in April. That is the coolest departure from seasonal averages since March 1989, when the tropics were 0.73 C (about 1.31 degrees F) cooler than seasonal norms.
University of Alabama Huntsville: http://www.uah.edu/