Global Temperature Report: April 2011
Global climate trend since Nov. 16, 1978: +0.14 C per decade
April temperatures (preliminary)
Global composite temp.: +0.12 C (about 0.22 degrees Fahrenheit) above 30-year average for April.
Northern Hemisphere: +0.20 C (about 0.36 degrees Fahrenheit) above 30-year average for April.
Southern Hemisphere: +0.04 C (about 0.07 degrees Fahrenheit) above 30-year average for April.
Tropics: -0.23 C (about 0.41 degrees Fahrenheit) below 30-year average for April.
March temperatures (revised):
Global Composite: -0.10 C below 30-year average
Northern Hemisphere: -0.07 C below 30-year average
Southern Hemisphere: -0.13 C below 30-year average
Tropics: -0.34 C below 30-year average
(All temperature anomalies are based on a 30-year average (1981-2010) for the month reported.)
As part of an ongoing joint project between UAHuntsville, NOAA and NASA, Dr. John Christy, a professor of atmospheric science and director of the Earth System Science Center (ESSC) at The University of Alabama in Huntsville, and Dr. Roy Spencer, a principal research scientist in the ESSC, use data gathered by advanced 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 where 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 Christy nor Spencer 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 federal and state grants or contracts.