Globally-Averaged Atmospheric Temperatures
The figure above shows the monthly temperature
deviations from a seasonally adjusted average for the lower stratosphere
- Earth's atmosphere from 14 to 22 km (9 to 14 miles). Red is
an increase in the temperature from the average, and blue is
a decrease in temperature. The large increase in 1982 was caused
by the volcanic eruption of El
Chichon, and the increase in 1991 was caused by the eruption
of Mt. Pinatubo
in the Philippines. November 2000 was the coldest month on record
for stratospheric temperatures. The long-term downward trend in lower
stratospheric temperatures is believed to be the result of ozone depletion
(primarily), and to a lesser extent the increase in carbon dioxide concentrations
due to the burning of fossil fuels.
This chart shows the monthly temperature changes
for the lower troposphere - Earth's atmosphere from the surface
to 8 km, or 5 miles up. The temperature in this region is more
strongly influenced by oceanic activity, particularly the "El Niño"
and "La Niña" phenomena, which originate
as changes in oceanic and atmospheric circulations in the tropical
Pacific Ocean. The overall trend in the tropospheric data is
now +0.08 deg. C/decade (through 2004). Click on the
charts to get the numerical data.
Surface thermometer measurements indicate
that the temperature of the Earth is warming at an average rate close
to +0.20 deg. C/decade since 1979, while the satellite
data shows a warming trend of about half of this. These differences
are the basis for discussions over whether our knowledge of
how the atmosphere works might be in error, since the warming aloft
in the troposphere should be at least as strong as that observed at the surface. A
scientific report on
what this apparent discrepency between the satellite and surface data
means in the context of global warming theory will be completed
in 2005 as part of the
U.S. Climate Change Science Program.
This page, updated approximately monthly, will continue
to provide the latest temperature measurements of various
layers of the Earth's atmosphere from space.
We have a Java-based tool that allows you
to interact with the Global Temperature
Variations Data Set. Using this tool you can examine temperature
variations from average at single locations on the globe or you
may look at region averaged values. You can examine atmospheric
temperature features for both the lower troposphere and the lower
stratosphere in either degrees Fahrenheit or degrees Celsius.
The data used were obtained by the
National Oceanographic and Atmospheric Administration TIROS-N
satellite, and interpreted by scientists Dr.
Roy Spencer (University of Alabama at Huntsville) and Dr. John Christy
(University of Alabama at Huntsville) at the Global
Hydrology and Climate Center (GHCC), a cooperative laboratory
involving NASA, the Alabama Space Science and Technology Alliance,
and private industry.
Global Hydrology and Climate Center Homepage
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Last Updated: January,