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National Oceanic and Atmospheric Administration

The Climate of 1997
Lower Tropospheric and Lower Stratospheric Temperatures

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John R. Christy
University of Alabama, Huntsville


Lower Tropospheric

Lower Tropospheric (surface to 20,000 ft.) monthly anomalies (Global, NH, SH deg C relative to 1982-91).

Nov 97 +0.00 +0.02 -0.02 (rev.)
Dec 97 +0.16 +0.12 +0.19

Trend since 1979: -0.04 deg/decade (Trend adjusted for volcanoes and El Ninos: +0.07 deg C/decade)

December value is the warmest, seasonally adjusted temperature since August 1995 - very warm in tropics so we see the warm tropical Pacific waters of El Nino finally affecting the bulk of the global atmosphere. Temperatures in two large oval regions on either side of the Equator of the eastern tropical Pacific were up to 2 deg C above average for the troposphere, which is the classic depiction of El Nino. Temps in N. Canada were up to 5 deg C above average while northern Siberia was over 3 deg C below average.

December 1990 was the last December that was warmer than December 1997.

For 1997 as a whole:

Global average: 1997 was warmer than 7 and cooler than 11 of the 19 years ... very near the average for 1982-91. (deg C).

Annual Global Average lower troposphere temperature anomalies (actual temperature of this layer is 270K or -3 deg C):

79 +0.03
80 +0.17
81 +0.10
82 -0.13
83 +0.07
84 -0.23
85 -0.26
86 -0.12
87 +0.21
88 +0.21
89 -0.03
90 +0.14
91 +0.14
92 -0.21
93 -0.16
94 -0.03
95 +0.05
96 -0.09
97 -0.08

Lower Stratosphere (17-22 km)

December global anomaly of -0.77 C was coldest individual monthly anomaly in the satellite record, being quite cold in the tropics (another ENSO response). 19-year trend is -0.51 C/decade. The coldest daily value (-0.96) occurred on 31 Dec 97 as the global stratospheric temperature has been steadily dropping since mid-December as recorded by both NOAA-12 and -14.

Annual Global anomalies of channel 4, lower stratosphere relative to 1984-90. (Actual temperature of this layer is 211K)

79 +0.51
80 +0.44
81 +0.41
82 +0.93
83 +0.87
84 +0.20
85 -0.07
86 -0.06
87 -0.10
88 -0.05
89 +0.05
90 +0.03
91 +0.53
92 +0.88
93 -0.01
94 -0.24
95 -0.41
96 -0.56
97 -0.46

Color maps of anomalies are available and updated a day or two later at Color maps of anomalies.


for further information, contact:
John R. Christy
Earth System Science Lab
University of Alabama in Huntsville
Huntsville, AL 35899
voice: 205-922-5763 fax: 205-922-5755

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