Tropopsphere

Lower Troposphere

September Lower Troposphere
September Anomaly Rank
(out of 43 years)
Record Years Decadal Trend
°C °F Year °C °F °C °F
UAH +0.42 +0.76 Coolest 38th 1984 -0.50 -0.90 +0.16 +0.29
Warmest 6th 2019 +0.62 +1.12
Year-to-Date Lower Troposphere
January–
September
Anomaly Rank
(out of 43 years)
Record Years Decadal Trend
°C °F Year °C °F °C °F
UAH +0.24 +0.43 Coolest 36th 1985 -0.37 -0.67 +0.13 +0.24
Warmest 7th 2016 +0.57 +1.03
Ties: 2002

Mid-troposphere

September Mid-troposphere
September Anomaly Rank
(out of 43 years)
Record Years Decadal Trend
°C °F Year °C °F °C °F
UAH +0.31 +0.56 Coolest 37th 1984 -0.56 -1.01 +0.13 +0.24
Warmest 7th 2019 +0.59 +1.06
STAR +0.33 +0.59 Coolest 36th 1984 -0.63 -1.13 +0.17 +0.30
Warmest 8th 2019 +0.56 +1.01
Year-to-Date Mid-troposphere
January–
September
Anomaly Rank
(out of 43 years*)
Record Years Decadal Trend
°C °F Year °C °F °C °F
UAH +0.16 +0.29 Coolest 34th 1985 -0.29 -0.52 +0.10 +0.17
Warmest 9th 1998 +0.51 +0.92
Ties: 2005
STAR +0.17 +0.31 Coolest 31st 1984, 1985 -0.34 -0.61 +0.12 +0.22
Warmest 12th 1998 +0.52 +0.94
Ties: 2004, 2013
RATPAC* +0.48 +0.86 Coolest 58th 1965 -0.85 -1.53 +0.18 +0.32
Warmest 7th 2016 +0.88 +1.58

*RATPAC rank is based on 64 years of data

Stratosphere

Lower Stratosphere

September Lower Stratosphere
September Anomaly Rank
(out of 43 years)
Record Years Decadal Trend
°C °F Year °C °F °C °F
UAH -0.41 -0.74 Coolest 13th 2020 -0.75 -1.35 -0.29 -0.53
Warmest 31st 1991 +1.52 +2.74
STAR -0.42 -0.76 Coolest 12th 2020 -0.70 -1.26 -0.27 -0.49
Warmest 32nd 1991 +1.50 +2.70
Year-to-Date Lower Stratosphere
January–
September
Anomaly Rank
(out of 43 years)
Record Years Decadal Trend
°C °F Year °C °F °C °F
UAH -0.43 -0.77 Coolest 6th 2016 -0.53 -0.95 -0.26 -0.47
Warmest 37th 1992 +1.01 +1.82
Ties: 2008
STAR -0.35 -0.63 Coolest 7th 2016 -0.47 -0.85 -0.21 -0.38
Warmest 37th 1992 +0.99 +1.78

Background

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 NCEI'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 Centers for Environmental Information, State of the Climate: Upper Air for September 2021, published online October 2021, retrieved on December 5, 2021 from https://www.ncdc.noaa.gov/sotc/upper-air/202109.

Metadata

https://data.nodc.noaa.gov/cgi-bin/iso?id=gov.noaa.ncdc:C00762