Upper Air - September 2012



Note: University of Alabama in Huntsville scientists advise that the AMSU channel 5 on the AQUA satellite, which has heretofore been the anchor-source of data in the construction of low- and mid-tropospheric temperatures (LT and MT) since 2002, was experiencing gradually increasing noise since 2009. However, a relatively rapid increase in noise in the recent few months to September 2012 generated clearly erroneous values. Therefore, beginning September 2012, these datasets (LT and MT) switched from AQUA to the AMSU channel 5 on NOAA-15 and NOAA-18, replacing AQUA data after 2009 in version 5.5.

Troposphere

Lower Troposphere

September Lower Troposphere
September Anomaly Rank
(out of 34 years)
Record Years Decadal Trend
°C °F Year °C °F °C °F
UAH +0.34 +0.61 Coolest 32nd 1984 -0.61 -1.10 +0.19 +0.34
Warmest 3rd 2010 +0.43 +0.77
RSS +0.27 +0.49 Coolest 30th 1984 -0.57 -1.03 +0.17 +0.31
Warmest 5th 2010 +0.40 +0.72
Year-to-Date Lower Troposphere
January–
September
Anomaly Rank
(out of 34 years)
Record Years Decadal Trend
°C °F Year °C °F °C °F
UAH +0.12 +0.22 Coolest 25th 1984 -0.32 -0.58 +0.13 +0.24
Warmest 10th 1998 +0.50 +0.90
RSS +0.09 +0.16 Coolest 24th 1985 -0.38 -0.68 +0.14 +0.24
Warmest 11th 1998 +0.53 +0.95

Mid-troposphere

September Mid-troposphere
September Anomaly Rank
(out of 34 years)
Record Years Decadal Trend
°C °F Year °C °F °C °F
UAH +0.21 +0.38 Coolest 29th 1984 -0.56 -1.01 +0.12 +0.21
Warmest 6th 2010 +0.39 +0.70
RSS +0.24 +0.43 Coolest 29th 1984 -0.56 -1.01 +0.14 +0.25
Warmest 6th 2010, 1998 +0.40 +0.72
UW-UAH +0.28 +0.50 Coolest 30th 1984 -0.67 -1.21 +0.19 +0.34
Warmest 5th 1998 +0.50 +0.90
UW-RSS +0.31 +0.56 Coolest 30th 1984 -0.63 -1.13 +0.19 +0.34
Warmest 4th 1998 +0.50 +0.90
Ties: 2005
Year-to-Date Mid-troposphere
January–
September
Anomaly Rank
(out of 34 years*)
Record Years Decadal Trend
°C °F Year °C °F °C °F
UAH -0.03 -0.05 Coolest 15th 1993, 1989 -0.25 -0.45 +0.04 +0.08
Warmest 20th 1998 +0.51 +0.92
RSS +0.03 +0.05 Coolest 20th 1985 -0.28 -0.50 +0.08 +0.15
Warmest 15th 1998 +0.52 +0.94
UW-UAH +0.03 +0.05 Coolest 18th 1984 -0.32 -0.58 +0.10 +0.18
Warmest 17th 1998 +0.61 +1.10
UW-RSS +0.09 +0.16 Coolest 23rd 1984 -0.33 -0.59 +0.13 +0.24
Warmest 11th 1998 +0.60 +1.08
Ties: 2011
RATPAC* +0.15 +0.27 Coolest 46th 1965 -0.85 -1.53 +0.15 +0.27
Warmest 10th 2010 +0.57 +1.03

*RATPAC rank is based on 55 years of data

Stratosphere

September Stratosphere
September Anomaly Rank
(out of 34 years)
Record Years Decadal Trend
°C °F Year °C °F °C °F
UAH -0.36 -0.65 Coolest 10th 1996 -0.61 -1.10 -0.40 -0.72
Warmest 25th 1991 +1.64 +2.95
RSS -0.32 -0.58 Coolest 8th 1996 -0.53 -0.95 -0.29 -0.53
Warmest 26th 1991 +1.51 +2.72
Ties: 2003
Year-to-Date Stratosphere
January–
September
Anomaly Rank
(out of 34 years)
Record Years Decadal Trend
°C °F Year °C °F °C °F
UAH -0.44 -0.79 Coolest 3rd 1996 -0.47 -0.85 -0.35 -0.64
Warmest 32nd 1992, 1983 +1.01 +1.82
RSS -0.43 -0.77 Coolest 1st 2012 -0.43 -0.77 -0.29 -0.51
Warmest 34th 1992 +0.99 +1.78

Background Information

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.

The mid-troposphere temperatures are centered in the in the atmospheric layer 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, creates 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.

References

Citing This Report

NOAA National Climatic Data Center, State of the Climate: Upper Air for September 2012, published online October 2012, retrieved on November 28, 2014 from http://www.ncdc.noaa.gov/sotc/upper-air/2012/9.