NOAA's National Centers for Environmental Information
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Note: Beginning in December 2010, all data are reported here with respect to the 1981–2010 base period. Prior to December 2010, radiosonde data were reported with respect to the 1961–1990 base period and satellite data were reported with respect to the 1979–1998 base period. Remote Sensing Systems continues to provide data to NCDC with respect to the 1979–1998 base period; however, NCDC readjusts the data to the 1981–2010 base period so that the satellite measurements are comparable. This change provides a more consistent comparison between the various datasets.
Note: Effective with the January 2011 report, Remote Sensing Systems (RSS) transitioned to a new version (3.3) of the RSS MSU/AMSU atmospheric temperature datasets. Information about the differences between version 3.2 and 3.3 is available.
Upper Air Highlights
University of Alabama Huntsville satellite analyses report that the lower troposphere March 2011 temperature was 0.10°C (0.18°F) below the 1981–2010 average, the 15th coolest (19th warmest) since satellite records began in 1979.
Remote Sensing Systems satellite analyses report a lower troposphere March temperature anomaly of 0.13°C (0.24°F) below the 1981–2010 average, the 12th coolest (22nd warmest) on record.
University of Alabama Huntsville satellite analyses report a March 2011 mid troposphere temperature anomaly of 0.25°C (0.45°F) below average, the 3rd coolest (31st warmest) such period on record. When these analyses are adjusted to remove stratospheric influence, the anomaly decreases to 0.21°C (0.37°F) below average, the 6th coolest (28th warmest) on record.
Remote Sensing Systems satellite analyses report a March 2011 mid troposphere temperature anomaly of 0.21°C (0.38°F) below average, the 6th coolest (28th warmest) such period on record. When these analyses are adjusted to remove stratospheric influence, the anomaly decreases to 0.17°C (0.31°F) below average, the 10th coolest (24th warmest) on record.
RATPAC radiosonde analysis indicates that the January–March mid troposphere temperature was the 46th coolest (9th warmest) year-to-date in the 54-year period of record, while satellite analyses report that the temperature ranked 14th coolest (20th warmest) to 6th coolest (28th warmest) in the 33-year period of record, depending on the source.
For the lower stratosphere, University of Alabama Huntsville satellite data indicate that March 2011 was the 12th coolest (22nd warmest) March in the 33-year period of record, while Remote Sensing System satellite analyses report that March 2011 was the 13th coolest (21st warmest) March.
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
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.
| March | Anomaly | Rank (out of 33 years) |
Warmest (or Next Warmest) Year on Record | Trend |
|---|---|---|---|---|
| UAH low-trop | -0.10°C/-0.18°F | 19th warmest | 2010 (+0.55°C/+0.99°F) | +0.13°C/decade |
| RSS low-trop | -0.13°C/-0.24°F | 22nd warmest | 2010 (+0.49°C/+0.88°F) | +0.14°C/decade |
| January– March |
Anomaly | Rank (out of 33 years) |
Warmest (or Next Warmest) Year on Record | Trend |
|---|---|---|---|---|
| UAH low-trop | -0.04°C/-0.07°F | 18th warmest | 2010 (+0.54°C/+0.97°F) | +0.13°C/decade |
| RSS low-trop | -0.07°C/-0.13°F | 20th warmest | 1998 (+0.51°C/+0.92°F) | +0.14°C/decade |
Mid-troposphere
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–March year-to-date period, temperatures in the mid-troposphere were 0.16°C (0.29°F) above average, resulting in the 9th warmest January–March (out of 54 years) since global radiosonde measurements began in 1958. Satellite analyses of the January–March year-to-date period for the middle troposphere ranged from 6th coolest (28th warmest) to 14th coolest (20th warmest) in the 33-year satellite record.
The global mid-troposphere temperatures were above average during March 2011. As shown in the table below, satellite measurements ranked from 3rd coolest (31st warmest) to 10th coolest (24th warmest), depending on the source.
| March | Anomaly | Rank (out of 33 years) |
Warmest (or Next Warmest) Year on Record |
Trend |
|---|---|---|---|---|
| UAH mid-trop | -0.25°C/-0.45°F | 31st warmest | 1998 (+0.48°C/+0.86°F) | +0.02°C/decade |
| RSS mid-trop | -0.21°C/-0.38°F | 28th warmest | 2010 (+0.48°C/+0.87°F) | +0.07°C/decade |
| UW-UAH mid-trop | -0.21°C/-0.37°F | 28th warmest | 1998 (+0.55°C/+0.99°F) | +0.08°C/decade |
| UW-RSS mid-trop | -0.17°C/-0.31°F | 24th warmest | 2010 (+0.55°C/+0.99°F) | +0.13°C/decade |
| January– March |
Anomaly | Rank (out of 33 years) |
Warmest (or Next Warmest) Year on Record |
Trend |
|---|---|---|---|---|
| UAH mid-trop | -0.18°C/-0.32°F | 28th warmest | 1998 (+0.54°C/+0.97°F) | +0.02°C/decade |
| RSS mid-trop | -0.13°C/-0.23°F | 23rd warmest | 1998 (+0.51°C/+92°F) | +0.09°C/decade |
| UW-UAH mid-trop | -0.13°C/-0.23°F | 22nd warmest | 1998 (+0.62°C/+1.12°F) | +0.08°C/decade |
| UW-RSS mid-trop | -0.09°C/-0.16°F | 20th warmest | 1998 (+0.58°C/+1.04°F) | +0.14°C/decade |
| RATPAC* | +0.16°C/+0.29°F | 9th warmest | 2010 (+0.79°C/+1.42deg;F) | +0.16°C/decade |
*RATPAC's rank is based on records that began in 1958 (54 years).
Stratosphere
The table below summarizes stratospheric conditions for March 2010. 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.
| March | Anomaly | Rank (out of 33 years) |
Coolest Year on Record |
|---|---|---|---|
| UAH stratosphere | -0.20°C (-0.36°F) | 12th coolest | 1999 (-0.61°C/-1.10°F) |
| RSS stratosphere | -0.14°C (-0.25°F) | 13th coolest | 1999 (-0.55°C/-1.00°F) |
For additional details on precipitation and temperatures in March, 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, CA, FJ Wentz, 2009, Construction of the RSS V3.2 lower tropospheric dataset from the MSU and AMSU microwave sounders. Journal of Atmospheric and Oceanic Technology, 26, 1493-1509.
Mears, CA, FJ Wentz, 2009, Construction of the Remote Sensing Systems V3.2 atmopsheric temperature records from the MSU and AMSU microwave sounders. Journal of Atmospheric and Oceanic Technology, 26, 1040-1056.
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.