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Upper Air ReportAugust 2009
Contents of this Section:
Troposphere
Temperatures above the Earth's surface are measured within the lower troposphere, middle troposphere, and stratosphere using in-situ balloon-borne instruments (radiosondes) and polar-orbiting satellites (NOAA's TIROS-N). The radiosonde and 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). Global averages from radiosonde data are available from 1958 to present, while satellite measurements date back to 1979.
Lower Troposphere
Current Month | Seasonal | Year-to-date
These temperatures are for the lowest 8 km (5 miles) of the atmosphere. Information on the University of Alabama in Huntsville (UAH) and Remote Sensing Systems (RSS) sources of troposphere data is available.
| August | Anomaly | Rank (out of 31 years) |
Warmest Year on Record | Trend |
|---|---|---|---|---|
| UAH low-trop | +0.23°C/+0.41°F | 7th warmest | 1998 (+0.51°C/+0.92°F) | +0.11°C/decade |
| *RSS low-trop | +0.27°C/+0.49°F | 9th warmest | 1998 (+0.57°C/+1.03°F) | +0.16°C/decade |
*Version 03_0
| June-August | Anomaly | Rank (out of 31 years) |
Warmest Year on Record | Trend |
|---|---|---|---|---|
| UAH low-trop | +0.22°C/+0.40°F | 6th warmest | 1998 (+0.53°C/+0.96°F) | +0.10°C/decade |
| *RSS low-trop | +0.25°C/+0.45°F | 7th warmest | 1998 (+0.58°C/+1.05°F) | +0.15°C/decade |
*Version 03_0
| January- August |
Anomaly | Rank (out of 31 years) |
Warmest Year on Record | Trend |
|---|---|---|---|---|
| UAH low-trop | +0.21°C/+0.38°F | 7th warmest | 1998 (+0.61°C/+1.10°F) | +0.12°C/decade |
| *RSS low-trop | +0.22°C/+0.40°F | 8th warmest | 1998 (+0.64°C/+1.15°F) | +0.15°C/decade |
*Version 03_2
Mid-troposphere
Current Month / Seasonal Year-to-date
These temperatures are for the atmospheric layer centered in the mid-troposphere (approximately 3–10 km [2–6 miles] above the Earth's surface), which also includes a portion of the lower stratosphere. (The Microwave Sounding Unit [MSU] channel used to measure mid-tropospheric temperatures receives about 25 percent of its signal above 10 km [6 miles].) Because the stratosphere has cooled due to increasing greenhouse gases in the troposphere and losses of ozone in the stratosphere, the stratospheric contribution to the tropospheric average, as measured from satellites, may create an artificial component of cooling to the mid-troposphere temperatures. The University of Washington (UW) versions of the UAH and RSS analyses attempt to remove the stratospheric influence from the mid-troposphere measurements, and as a result the UW versions tend to have a larger warming trend than either the UAH or RSS versions. For additional information, please see NCDC's Microwave Sounding Unit page.
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) (RATPAC). 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 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.
Radiosonde measurements indicate that, for the January-August year-to-date period, temperatures in the mid-troposphere were 0.44°C (0.80°F) above average, resulting in the seventh warmest January-August (out of 52 years) since global radiosonde measurements began in 1958. This was the 23rd consecutive January-August period with temperature anomalies warmer than average. Meanwhile, satellite analyses of the January-August year-to-date period for the middle troposphere varied from 10th to 15th warmest in the 31-year satellite record.
Similar to January-August year-to-date, radiosonde measurements indicate that temperatures were 0.51°C (0.93°F) above average during the season, giving June-August a rank of fifth warmest on record. The table below shows that satellite measurements for the season varied from 9th to 12th warmest on record.
The global mid-troposphere temperatures were above average during August 2009. As shown in the table below, satellite measurements for August 2009 ranked seventh warmest to tenth warmest on record.
| August | Anomaly | Rank (out of 31 years) |
Warmest Year on Record | Trend |
|---|---|---|---|---|
| UAH mid-trop | +0.11°C/+0.20°F | 9th warmest | 1998 (+0.45°C/+0.81°F) | +0.05°C/decade |
| *RSS mid-trop | +0.17°C/+0.30°F | 10th warmest | 1998 (+0.50°C/+0.91°F) | +0.10°C/decade |
| **UW-UAH mid-trop | +0.20°C/+0.36°F | 7th warmest | 1998 (+0.60°C/+1.08°F) | +0.10°C/decade |
| **UW-*RSS mid-trop | +0.25°C/+0.45°F | 9th warmest | 1998 (+0.64°C/+1.15°F) | +0.15°C/decade |
*Version 03_2
| June-August | Anomaly | Rank (out of 31 years) |
Warmest Year on Record | Trend |
|---|---|---|---|---|
| UAH mid-trop | +0.06°C/+0.11°F | 12th warmest | 1998 (+0.48°C/+0.86°F) | +0.04°C/decade |
| *RSS mid-trop | +0.12°C/+0.22°F | 10th warmest | 1998 (+0.52°C/+0.94°F) | +0.09°C/decade |
| **UW-UAH mid-trop | +0.15°C/+0.27°F | 10th warmest | 1998 (+0.61°C/+1.09°F) | +0.09°C/decade |
| **UW-*RSS mid-trop | +0.20°C/+0.36°F | 9th warmest | 1998 (+0.64°C/+1.15°F) | +0.14°C/decade |
| RATPAC | +0.51°C/+0.93°F | 5th warmest | 1998 (+0.87°C/+1.57°F) | +0.15°C/decade |
*Version 03_2
| January- August |
Anomaly | Rank (out of 31 years) |
Warmest Year on Record | Trend |
|---|---|---|---|---|
| UAH mid-trop | +0.04°C/+0.07°F | 15th warmest | 1998 (+0.55°C/+0.99°F) | +0.04°C/decade |
| *RSS mid-trop | +0.09°C/+0.16°F | 13th warmest | 1998 (+0.59°C/+1.06°F) | +0.09°C/decade |
| **UW-UAH mid-trop | +0.14°C/+0.25°F | 12th warmest | 1998 (+0.68°C/+1.22°F) | +0.10°C/decade |
| **UW-*RSS mid-trop | +0.17°C/+0.31°F | 10th warmest | 1998 (+0.71°C/+1.28°F) | +0.14°C/decade |
| RATPAC | +0.44°C/+0.80°F | 7th warmest | 1998 (+0.83°C/+1.49°F) | +0.14°C/decade |
*Version 03_2
Note: RATPAC's rank is based on records that began in 1958 (52 years).
Stratosphere
The table below summarizes stratospheric conditions for August 2009. On average, the stratosphere is located approximately 16–23 km (10–14 miles) above the Earth's surface. Over the last decade, stratospheric temperatures have been below average in 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. In both cases the temperatures returned to pre-eruption levels within two years.
| August | Anomaly | Rank (out of 31 years) |
Coolest Year on Record |
|---|---|---|---|
| UAH stratosphere | -0.44°C (-0.79°F) | 7th coolest | 1996 (-0.72°C/-1.30°F) |
| *RSS stratosphere | -0.38°C (-0.69°F) | 8th coolest | 1996 (-0.66°C/-1.18°F) |
*Version 03_2
| June-August | Anomaly | Rank (out of 31 years) |
Coolest Year on Record |
|---|---|---|---|
| UAH stratosphere | -0.49°C (-0.88°F) | 8th coolest | 1996 (-0.71°C/-1.28°F) |
| *RSS stratosphere | -0.41°C (-0.75°F) | 8th coolest | 1996 (-0.64°C/-1.15°F) |
*Version 03_2
For additional details on precipitation and temperatures in August, see the Global Hazards page.
References
Christy, 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.
