Upper Air - August 2011


Contents of this Section:


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 August 2011 temperature was 0.33°C (0.59°F) above the 1981–2010 average, the third warmest August since satellite records began in 1979.


  • Remote Sensing Systems satellite analyses report a lower troposphere August temperature anomaly of 0.16°C (0.34°F) above the 1981–2010 average, the sixth warmest August on record.


  • University of Alabama Huntsville satellite analyses report an August 2011 mid troposphere temperature anomaly of 0.18°C (0.32°F) above average, the sixth warmest such period on record. When these analyses are adjusted to remove stratospheric influence, the anomaly increases to 0.28°C (0.50°F) above average, the fourth warmest on record.


  • Remote Sensing Systems satellite analyses report an August 2011 mid troposphere temperature anomaly of 0.17°C (0.31°F) above average, the seventh warmest such period on record. When these analyses are adjusted to remove stratospheric influence, the anomaly increases to 0.25°C (0.45°F) above average, the fourth warmest on record.


  • RATPAC radiosonde analysis indicates that during the first eight months of 2011 (January–August) the average mid troposphere temperature was the ninth warmest year-to-date in the 54-year period of record, while satellite analyses report that the temperature ranked 10th warmest to 16th warmest in the 33-year period of record, depending on the source.


  • For the lower stratosphere, the Remote Sensing Systems and University of Alabama Huntsville satellite analyses both indicate that August 2011 was the sixth coolest August, the second coolest June–August, and the third coolest January–August in the 33-year period of record.

  • 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 eight kilometers (five 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 Lower Troposphere
    August Anomaly Rank
    (out of 33 years)
    Record Years Decadal Trend
    °C °F Year °C °F °C °F
    UAH +0.33 +0.59 Coolest 31st 1992 -0.46 -0.83 +0.13 +0.24
    Warmest 3rd 1998 +0.45 +0.81
    RSS +0.19 +0.34 Coolest 27th 1992 -0.47 -0.85 +0.15 +0.28
    Warmest 6th 1998 +0.47 +0.85
    June-August Lower Troposphere
    June–
    August
    Anomaly Rank
    (out of 33 years)
    Record Years Decadal Trend
    °C °F Year °C °F °C °F
    UAH +0.34 +0.61 Coolest 31st 1992 -0.37 -0.67 +0.13 +0.23
    Warmest 3rd 1998 +0.47 +0.85
    RSS +0.22 +0.40 Coolest 30th 1985 -0.38 -0.68 +0.15 +0.26
    Warmest 4th 1998 +0.50 +0.90
    Year-to-Date Lower Troposphere
    January–
    August
    Anomaly Rank
    (out of 33 years)
    Record Years Decadal Trend
    °C °F Year °C °F °C °F
    UAH +0.15 +0.27 Coolest 27th 1985 -0.31 -0.56 +0.13 +0.23
    Warmest 6th 1998 +0.53 +0.95
    RSS +0.06 +0.11 Coolest 22nd 1985 -0.39 -0.70 +0.14 +0.25
    Warmest 11th 1998 +0.54 +0.97

    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, August 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.

    The global mid-troposphere temperatures were well above average during August 2011. As shown in the table below, satellite measurements for August 2011 ranked fourth to seventh warmest on record, depending on the data source.

    Radiosonde measurements indicate that mid-tropospheric temperatures were 0.33°C (0.59°F) above average during the Northern Hemisphere summer (Southern Hemisphere winter) season, giving June–August a rank of fifth warmest on record. The table below shows that satellite measurements for the season were third to fifth warmest, depending on the data source.

    Radiosonde measurements indicate that, for the January–August year-to-date period, temperatures in the mid-troposphere were 0.16°C (0.29°F) above average, resulting in the ninth warmest January–August period (out of 54 years). Satellite analyses of the January–August year-to-date period for the middle troposphere was the 10th to 16th warmest in the 33-year satellite record, depending on the data source.

    August Mid-troposphere
    August Anomaly Rank
    (out of 33 years)
    Record Years Decadal Trend
    °C °F Year °C °F °C °F
    UAH +0.18 +0.32 Coolest 28th 1992 -0.31 -0.56 +0.08 +0.14
    Warmest 6th 2010 +0.43 +0.77
    RSS +0.17 +0.31 Coolest 27th 1992 -0.32 -0.58 +0.11 +0.19
    Warmest 7th 1998 +0.44 +0.79
    UW-UAH +0.28 +0.50 Coolest 30th 1992 -0.49 -0.88 +0.14 +0.25
    Warmest 4th 1998 +0.53 +0.95
    UW-RSS +0.25 +0.45 Coolest 30th 1992 -0.49 -0.88 +0.15 +0.28
    Warmest 4th 1998 +0.54 +0.97
    June-August Mid-troposphere
    June–
    August
    Anomaly Rank
    (out of 33 years*)
    Record Years Decadal Trend
    °C °F Year °C °F °C °F
    UAH +0.20 +0.36 Coolest 29th 1989 -0.26 -0.47 +0.07 +0.12
    Warmest 4th 1998 +0.45 +0.81
    RSS +0.17 +0.31 Coolest 29th 1985 -0.35 -0.63 +0.10 +0.17
    Warmest 5th 1998 +0.48 +0.86
    UW-UAH +0.31 +0.56 Coolest 31st 1992 -0.38 -0.68 +0.12 +0.22
    Warmest 3rd 1998 +0.55 +0.99
    UW-RSS +0.27 +0.49 Coolest 31st 1985 -0.39 -0.70 +0.14 +0.26
    Warmest 3rd 1998 +0.56 +1.01
    RATPAC* +0.33 +0.59 Coolest 50th 1965 -0.81 -1.46 +0.16 +0.29
    Warmest 5th 1998 +0.59 +1.06

    *RATPAC rank is based on 54 years of data

    Year-to-Date Mid-troposphere
    January–
    August
    Anomaly Rank
    (out of 33 years*)
    Record Years Decadal Trend
    °C °F Year °C °F °C °F
    UAH 0.00 0.00 Coolest 17th 1989 -0.27 -0.49 +0.04 +0.08
    Warmest 16th 1998 +0.53 +0.95
    RSS +0.01 +0.02 Coolest 17th 1989 -0.29 -0.52 +0.08 +0.15
    Warmest 16th 1998 +0.53 +0.95
    UW-UAH +0.07 +0.13 Coolest 22nd 1989 -0.32 -0.58 +0.10 +0.18
    Warmest 12th 1998 +0.62 +1.12
    UW-RSS +0.08 +0.14 Coolest 23rd 1989 -0.33 -0.59 +0.14 +0.24
    Warmest 10th 1998 +0.61 +1.10
    RATPAC* +0.16 +0.29 Coolest 46th 1965 -0.91 -1.64 +0.16 +0.28
    Warmest 9th 2010 +0.79 +1.42

    *RATPAC rank is based on 54 years of data

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    Stratosphere

    Current Month | Seasonal

    The table below summarizes stratospheric conditions for September 2011. On average, the stratosphere is located approximately 16–23 kilometers (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 Stratosphere
    August Anomaly Rank
    (out of 33 years)
    Record Years Decadal Trend
    °C °F Year °C °F °C °F
    UAH -0.46 -0.83 Coolest 6th 1996 -0.56 -1.01 -0.37 -0.67
    Warmest 27th 1991 +1.29 +2.32
    RSS -0.37 -0.67 Coolest 6th 1996 -0.49 -0.88 -0.27 -0.48
    Warmest 28th 1991 +1.17 +2.11
    June-August Stratosphere
    June–
    August
    Anomaly Rank
    (out of 33 years)
    Record Years Decadal Trend
    °C °F Year °C °F °C °F
    UAH -0.51 -0.92 Coolest 2nd 1996 -0.53 -0.95 -0.36 -0.64
    Warmest 32nd 1982 +1.09 +1.96
    RSS -0.44 -0.79 Coolest 2nd 1996 -0.48 -0.86 -0.27 -0.49
    Warmest 32nd 1982 +0.99 +1.78
    Year-to-Date Stratosphere
    January–
    August
    Anomaly Rank
    (out of 33 years)
    Record Years Decadal Trend
    °C °F Year °C °F °C °F
    UAH -0.40 -0.72 Coolest 3rd 2008, 1996 -0.45 -0.81 -0.36 -0.64
    Warmest 31st 1983 +1.02 +1.84
    RSS -0.35 -0.63 Coolest 3rd 1996 -0.39 -0.70 -0.29 -0.51
    Warmest 31st 1992 +0.99 +1.78

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    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.

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    Citing This Report

    NOAA National Climatic Data Center, State of the Climate: Upper Air for August 2011, published online September 2011, retrieved on December 18, 2014 from http://www.ncdc.noaa.gov/sotc/upper-air/2011/8.