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) forthe month reported.)

Notes on data released May 7, 2008

Newswise — 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.

Color maps of local temperature anomalies may soon be available on-line at:http://climate.uah.edu/

The processed temperature data is available on-line at:http://vortex.nsstc.uah.edu/data/msu/t2lt/uahncdc.lt

Research notes

As part of an ongoing joint project among UAHuntsville, NOAA and NASA, Christy and Dr. Roy Spencer, a principal research scientist in the ESSC, use data gathered by microwave sounding units on NOAA and NASA satellites to get accurate temperature readings for almost all regions of the Earth. This includes remote desert, ocean and rain forest areas for which reliable climate data are not otherwise available.

The satellite-based instruments measure the temperature of the atmosphere from the surface up to an altitude of about eight kilometers above sea level.

Once the monthly temperature data is collected and processed, it is placed in a "public" computer file for immediate access by atmospheric scientists in the U.S. and abroad.

Neither Spencer nor Christy receives any research support or funding from oil, coal or industrial companies or organizations, or from any private or special interest groups. All of their climate research funding comes from state and federal grants or contracts.

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