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Upper Air ReportSeptember 2006
TroposphereCurrent Month / Year-to-dateTemperatures above the Earth's surface are measured using in-situ balloon-borne instruments (radiosondes) and polar-orbiting satellites (NOAA's TIROS-N). The radiosonde and the satellite records have been adjusted to remove time-dependent biases (artificialities caused by changes in radiosonde instruments and measurement practices as well as changes in satellite instruments and orbital features through time). The radiosonde data used in this global analysis were developed using the Lanzante, Klein, Seidel (2003) ("LKS") bias-adjusted dataset and the First Difference Method (Free et al. 2004). Additional details are available. Satellite data have been adjusted by the Global Hydrology and Climate Center at the University of Alabama in Huntsville (UAH). An independent analysis is also performed by Remote Sensing Systems (RSS) and a third analysis has been performed by Dr. Qiang Fu of the the University of Washington (UW) (Fu et al. 2004)** to remove the influence of the stratosphere on the mid-troposphere value. Global averages from radiosonde data are available from 1958 to present, while satellite measurements began in 1979. |
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Radiosonde measurements indicate that for the January-September year-to-date period, temperatures in the mid-troposphere (approximately 2 to 6 miles above the Earth's surface) were 0.56ยฐC above average, the 3rd warmest January-September since global measurements began in 1958. In a pattern similar to that at the surface, radiosonde measurements indicate that temperatures have risen at a rate of 0.15ยฐC/decade since the late 1950's and 0.17ยฐC/decade since 1979. |
Satellite measurements
provide similar results. Since 1979, the RSS analysis indicates
that January-September temperatures have risen at a rate of
0.13ยฐC/decade, while the UW-RSS analysis shows a faster rate of
0.19ยฐC/decade. (The UAH analysis is unavailable this
month.) Mid-troposphere rankings and anomalies from the satellite analyses for the year-to-date and September periods are available below. These temperatures are for the atmospheric layer centered in the mid-troposphere (approximately 2-6 miles above the Earth's surface) which also includes a portion of the lower stratosphere. (The MSU channel used to measure mid-tropospheric temperatures receives about 25 percent of its signal above 6 miles). For additional information on MSU data used in this report, please see the Microwave Sounding Unit page. All datasets indicate September temperatures were above average. |
September | Anomaly | Rank | Warmest Year on Record | Trend |
---|---|---|---|---|
*RSS mid-trop | +0.22ยฐC/0.40ยฐF | 7th warmest | 1998 (+0.52ยฐC/0.94ยฐF) | +0.17ยฐC/decade |
**UW-*RSS mid-trop | +0.34ยฐC/0.61ยฐF | 6th warmest | 1998 (+0.66ยฐC/1.19ยฐF) | +0.24ยฐC/decade |
*Version 02_1 |
January- September |
Anomaly | Rank | Warmest Year on Record | Trend |
---|---|---|---|---|
*RSS mid-trop | +0.17ยฐC/0.31ยฐF | 7th warmest | 1998 (+0.60ยฐC/1.08ยฐF) | +0.13ยฐC/decade |
**UW-*RSS mid-trop | +0.27ยฐC/0.49ยฐF | 6th warmest | 1998 (+0.73ยฐC/1.31ยฐF) | +0.19ยฐC/decade |
RATPAC | +0.56ยฐC/1.01ยฐF | 3rd warmest | 1998 (+0.79ยฐC/1.42ยฐF) | +0.17ยฐC/decade |
*Version 02_1 |
StratosphereCurrent MonthThe table below summarizes stratospheric conditions for September 2006. On average, the stratosphere is located approximately between 10-14 miles above the Earth's surface. Over the last decade, stratospheric temperatures have been below average in large part due to the depletion of ozone. The large positive anomaly in 1982 was caused by the volcanic eruption of El Chichon in Mexico, and the sharp jump in temperature in 1991 was a result of the eruption of Mt. Pinatubo in the Philippines. Temperatures returned to pre-eruption levels within two years. |
September | Anomaly | Rank | Coolest Year on Record |
---|---|---|---|
UAH stratosphere | -0.70ยฐC (-1.26ยฐF) | 3rd coolest | 2005 (-0.78ยฐC/-1.40ยฐF) |
*RSS stratosphere | -0.47ยฐC (-0.85ยฐF) | 5th coolest | 1996 (-0.74ยฐC/-1.33ยฐF) |
*Version 02_1 |
For additional details on precipitation and temperatures in September, see the Global Hazards page. |
ReferencesChristy, John R., R.W. Spencer, and W.D. Braswell, 2000: MSU Tropospheric Temperatures: Dataset Construction and Radiosonde Comparisons. J. of Atmos. and Oceanic Technology 17 1153-1170.Free M., D.J. Seidel, J.K. Angell, J. Lanzante, I. Durre and T.C. Peterson (2005) Radiosonde Atmospheric Temperature Products for Assessing Climate (RATPAC): A new dataset of large-area anomaly time series, J. Geophys. Res., 10.1029/2005JD006169. Free, M., J.K. Angell, I. Durre, J. Lanzante, T.C. Peterson and D.J. Seidel(2004), Using first differences to reduce inhomogeneity in radiosonde temperature datasets, J. Climate, 21, 4171-4179. Fu, Q., C.M. Johanson, S.G. Warren, and D.J. Seidel, 2004: Contribution of stratospheric cooling to satellite-inferred tropospheric temperature trends. Nature, 429, 55-58. Lanzante, J.R., S.A. Klein, and D.J. Seidel (2003a), Temporal homogenization of monthly radiosonde temperature data. Part I: Methodology, J. Climate, 16, 224 240. Lanzante, J.R., S.A. Klein, and D.J. Seidel (2003b), Temporal homogenization of monthly radiosonde temperature data. Part II: Trends, sensitivities, and MSU comparison, J. Climate, 16, 241 262. Mears, Carl A., M.C. Schabel, F.J. Wentz, 2003: A Reanalysis of the MSU Channel 2 Tropospheric Temperature Record. J. Clim 16, 3650-3664. |