Satellite temperature measurement

{{see also|Sea surface temperature#Weather satellites}}

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| image1 = MOD LSTAD M.ogv

| caption1 = Land surface temperature anomalies for a given month compared to the long-term average temperature of that month between 2000-2008.{{Cite web|url = http://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=MOD_LSTAD_M|title = Land Surface Temperature Anomaly|date = 31 December 2019|access-date = 28 January 2014|archive-date = 12 February 2014|archive-url = https://web.archive.org/web/20140212035240/http://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=MOD_LSTAD_M|url-status = live}}

| image2 = AMSRE SSTAn M.ogv

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| caption2 = Sea surface temperature anomalies for a given month compared to the long-term average temperature of that month from 1985 through 1997.{{Cite web| url=http://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=AMSRE_SSTAn_M| title=Sea Surface Temperature Anomaly| date=31 August 2011| access-date=28 January 2014| archive-date=30 April 2014| archive-url=https://web.archive.org/web/20140430152354/http://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=AMSRE_SSTAn_M| url-status=live}}

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Infrared radiation can be used to measure both the temperature of the surface (using "window" wavelengths to which the atmosphere is transparent), and the temperature of the atmosphere (using wavelengths for which the atmosphere is not transparent, or measuring cloud top temperatures in infrared windows).

Satellites used to retrieve surface temperatures via measurement of thermal infrared in general require cloud-free conditions. Some of the instruments include the Advanced Very High Resolution Radiometer (AVHRR), Along Track Scanning Radiometers (AASTR), Visible Infrared Imaging Radiometer Suite (VIIRS), the Atmospheric Infrared Sounder (AIRS), and the ACE Fourier Transform Spectrometer (ACE‐FTS) on the Canadian SCISAT-1 satellite.

Weather satellites have been available to infer sea surface temperature (SST) information since 1967, with the first global composites occurring during 1970.{{cite journal |doi=10.1175/1520-0493(1972)100<0010:GSTDDF>2.3.CO;2 |title=Global Sea-Surface Temperature Distribution Determined from an Environmental Satellite |journal=Monthly Weather Review |volume=100 |issue=1 |pages=10–4 |year=1972 |last1=Krishna Rao |first1=P. |last2=Smith |first2=W. L. |last3=Koffler |first3=R. |bibcode=1972MWRv..100...10K |s2cid=119900067 }} Since 1982,{{cite book|url=https://books.google.com/books?id=qzYrAAAAYAAJ&pg=PA2|page=2|author=National Research Council (U.S.). NII 2000 Steering Committee|title=The unpredictable certainty: information infrastructure through 2000; white papers|publisher=National Academies|year=1997|isbn=9780309060363|access-date=25 September 2016|archive-date=8 March 2020|archive-url=https://web.archive.org/web/20200308133745/https://books.google.com/books?id=qzYrAAAAYAAJ&pg=PA2|url-status=live}} satellites have been increasingly utilized to measure SST and have allowed its spatial and temporal variation to be viewed more fully. For example, changes in SST monitored via satellite have been used to document the progression of the El Niño-Southern Oscillation since the 1970s.{{cite book|url=https://books.google.com/books?id=8-UbmSxLWlUC&pg=PA31|page=31|title=Climate variability and the global harvest: impacts of El Niño and other oscillations on agroecosystems|author1=Cynthia Rosenzweig|author2=Daniel Hillel|year=2008|publisher=Oxford University Press United States|isbn=978-0-19-513763-7|access-date=25 September 2016|archive-date=18 August 2020|archive-url=https://web.archive.org/web/20200818210325/https://books.google.com/books?id=8-UbmSxLWlUC&pg=PA31|url-status=live}}

Over land the retrieval of temperature from radiances is harder, because of inhomogeneities in the surface.{{cite journal |doi=10.1175/BAMS-85-4-587 |title=Analysis of Land Skin Temperature Using AVHRR Observations |journal=Bulletin of the American Meteorological Society |volume=85 |issue=4 |pages=587–600 |year=2004 |last1=Jin |first1=Menglin |bibcode=2004BAMS...85..587J |s2cid=8868968 |doi-access=free }} Studies have been conducted on the urban heat island effect via satellite imagery.{{cite journal |url=http://www.asprs.org/a/publications/pers/2003journal/may/2003_may_555-566.pdf |title=Fractal Analysis of Satellite-Detected Urban Heat Island Effect |first1=Qihao |last1=Weng |date=May 2003 |pages=555–66 |journal=Photogrammetric Engineering & Remote Sensing |volume=69 |issue=5 |access-date=14 January 2011 |doi=10.14358/PERS.69.5.555 |archive-date=3 March 2016 |archive-url=https://web.archive.org/web/20160303231227/http://www.asprs.org/a/publications/pers/2003journal/may/2003_may_555-566.pdf |url-status=live }} By using the fractal technique, Weng, Q. et al. characterized the spatial pattern of urban heat island.{{Cite journal |last1=Weng |first1=Qihao |last2=Lu |first2=Dengsheng |last3=Schubring |first3=Jacquelyn |date=2004-02-29 |title=Estimation of land surface temperature–vegetation abundance relationship for urban heat island studies |url=https://www.sciencedirect.com/science/article/pii/S0034425703003390 |journal=Remote Sensing of Environment |language=en |volume=89 |issue=4 |pages=467–483 |doi=10.1016/j.rse.2003.11.005 |bibcode=2004RSEnv..89..467W |s2cid=2502717 |issn=0034-4257}} Use of advanced very high resolution infrared satellite imagery can be used, in the absence of cloudiness, to detect density discontinuities (weather fronts) such as cold fronts at ground level.{{cite web|url=http://www.wpc.ncep.noaa.gov/sfc/UASfcManualVersion1.pdf|title=Unified Surface Analysis Manual|author=David M. Roth|publisher=Hydrometeorological Prediction Center|date=14 December 2006|access-date=14 January 2011|page=19|author-link=David M. Roth|archive-date=29 September 2006|archive-url=https://web.archive.org/web/20060929004553/http://www.hpc.ncep.noaa.gov/sfc/UASfcManualVersion1.pdf|url-status=live}} Using the Dvorak technique, infrared satellite imagery can be used to determine the temperature difference between the eye and the cloud top temperature of the central dense overcast of mature tropical cyclones to estimate their maximum sustained winds and their minimum central pressures.{{cite web|author=Chris Landsea|date=8 June 2010|url=http://www.aoml.noaa.gov/hrd/tcfaq/H1.html|title=Subject: H1) What is the Dvorak technique and how is it used?|publisher=Atlantic Oceanographic and Meteorological Laboratory|access-date=14 January 2011|author-link=Chris Landsea|archive-date=25 January 2014|archive-url=https://web.archive.org/web/20140125190925/http://www.aoml.noaa.gov/hrd/tcfaq/H1.html|url-status=live}}

Along Track Scanning Radiometers aboard weather satellites are able to detect wildfires, which show up at night as pixels with a greater temperature than {{convert|308|K|C F}}.{{cite press release |title=Greece Suffers More Fires In 2007 Than In Last Decade, Satellites Reveal |publisher=European Space Agency |date=29 August 2007 |url=http://www.esa.int/Our_Activities/Observing_the_Earth/Envisat/Greece_suffers_more_fires_in_2007_than_in_last_decade_satellites_reveal |access-date=26 April 2015 |archive-date=21 February 2021 |archive-url=https://web.archive.org/web/20210221062604/http://www.esa.int/Applications/Observing_the_Earth/Envisat/Greece_suffers_more_fires_in_2007_than_in_last_decade_satellites_reveal |url-status=live }} The Moderate-Resolution Imaging Spectroradiometer aboard the Terra satellite can detect thermal hot spots associated with wildfires, volcanoes, and industrial hot spots.{{cite journal |doi=10.1016/S0034-4257(02)00030-5 |title=Automated volcanic eruption detection using MODIS |journal=Remote Sensing of Environment |volume=82 |issue=1 |pages=135–55 |year=2002 |last1=Wright |first1=Robert |last2=Flynn |first2=Luke |last3=Garbeil |first3=Harold |last4=Harris |first4=Andrew |last5=Pilger |first5=Eric |bibcode=2002RSEnv..82..135W |url=http://www.higp.hawaii.edu/~wright/rse82.pdf |citeseerx=10.1.1.524.19 |access-date=5 January 2018 |archive-date=9 August 2017 |archive-url=https://web.archive.org/web/20170809054442/https://www.higp.hawaii.edu/~wright/rse82.pdf |url-status=live }}

The Atmospheric Infrared Sounder on the Aqua satellite, launched in 2002, uses infrared detection to measure near-surface temperature.Harvey, Chelsea (18 April 2019). [https://www.scientificamerican.com/article/its-a-match-satellite-and-ground-measurements-agree-on-warming/ "It's A Match: Satellite and Ground Measurements Agree on Warming"] {{Webarchive|url=https://web.archive.org/web/20191215140410/https://www.scientificamerican.com/article/its-a-match-satellite-and-ground-measurements-agree-on-warming/ |date=15 December 2019 }}, Scientific American. Retrieved 8 January 2019.

Stratospheric temperature measurements are made from the Stratospheric Sounding Unit (SSU) instruments, which are three-channel infrared (IR) radiometers.Lilong Zhao et al. (2016). "[https://www.mdpi.com/2072-4292/8/1/13/htm Use of SSU/MSU Satellite Observations to Validate Upper Atmospheric Temperature Trends in CMIP5 Simulations] {{Webarchive|url=https://web.archive.org/web/20200112184008/https://www.mdpi.com/2072-4292/8/1/13/htm |date=12 January 2020 }}", Remote Sens. 8(1), 13; https://doi.org/10.3390/rs8010013 {{Webarchive|url=https://web.archive.org/web/20210221062607/https://www.mdpi.com/2072-4292/8/1/13 |date=21 February 2021 }}. Retrieved 12 January 2019 Since this measures infrared emission from carbon dioxide, the atmospheric opacity is higher and hence the temperature is measured at a higher altitude (stratosphere) than microwave measurements.

Since 1979 the Stratospheric sounding units (SSUs) on the NOAA operational satellites have provided near global stratospheric temperature data above the lower stratosphere.

The SSU is a far-infrared spectrometer employing a pressure modulation technique to make measurement in three channels in the 15 μm carbon dioxide absorption band. The three channels use the same frequency but different carbon dioxide cell pressure, the corresponding weighting functions peaks at 29 km for channel 1, 37 km for channel 2 and 45 km for channel 3.http://www.ncdc.noaa.gov/oa/pod-guide/ncdc/docs/podug/html/c4/sec4-2.htm{{full citation needed|date=April 2015}}{{Dead link|date=January 2020 |bot=InternetArchiveBot |fix-attempted=yes }}{{Clarify|reason=|date=May 2020}}

The process of deriving trends from SSUs measurement has proved particularly difficult because of satellite drift, inter-calibration between different satellites with scant overlap and gas leaks in the instrument carbon dioxide pressure cells. Furthermore since the radiances measured by SSUs are due to emission by carbon dioxide the weighting functions move to higher altitudes as the carbon dioxide concentration in the stratosphere increase.

Mid to upper stratosphere temperatures shows a strong negative trend interspersed by transient volcanic warming after the explosive volcanic eruptions of El Chichón and Mount Pinatubo, little temperature trend has been observed since 1995.

The greatest cooling occurred in the tropical stratosphere consistent with enhanced Brewer-Dobson circulation under greenhouse gas concentrations increase.{{cite journal |doi=10.1175/JCLI-D-11-00350.1 |title=Construction of Stratospheric Temperature Data Records from Stratospheric Sounding Units |journal=Journal of Climate |volume=25 |issue=8 |pages=2931–46 |year=2012 |last1=Wang |first1=Likun |last2=Zou |first2=Cheng-Zhi |last3=Qian |first3=Haifeng |bibcode=2012JCli...25.2931W |url=https://zenodo.org/record/1234597 |access-date=12 January 2020 |archive-date=11 January 2020 |archive-url=https://web.archive.org/web/20200111143852/https://zenodo.org/record/1234597 |url-status=live |doi-access=free }}{{Primary source inline|date=May 2020}}

Lower stratospheric cooling is mainly caused by the effects of ozone depletion with a possible contribution from increased stratospheric water vapor and greenhouse gases increase.{{cite journal |doi=10.1256/qj.02.186 |title=A comparison of model-simulated trends in stratospheric temperatures |journal=Quarterly Journal of the Royal Meteorological Society |volume=129 |issue=590 |pages=1565–55 |year=2003 |last1=Shine |first1=K. P. |author-link1=Keith Shine |last2=Bourqui |first2=M. S. |last3=Forster |first3=P. M. de F. |last4=Hare |first4=S. H. E. |last5=Langematz |first5=U. |last6=Braesicke |first6=P. |last7=Grewe |first7=V. |last8=Ponater |first8=M. |last9=Schnadt |first9=C. |last10=Smith |first10=C. A. |last11=Haigh |first11=J. D. |last12=Austin |first12=J. |last13=Butchart |first13=N. |last14=Shindell |first14=D. T. |last15=Randel |first15=W. J. |last16=Nagashima |first16=T. |last17=Portmann |first17=R. W. |last18=Solomon |first18=S. |last19=Seidel |first19=D. J. |last20=Lanzante |first20=J. |last21=Klein |first21=S. |last22=Ramaswamy |first22=V. |last23=Schwarzkopf |first23=M. D. |bibcode=2003QJRMS.129.1565S |s2cid=14359017 }}{{cite web|url=http://www.grida.no/climate/ipcc_tar/wg1/fig8-20.htm|title=United Nations Environment Programme|website=grida.no|access-date=9 April 2018|archive-date=3 June 2016|archive-url=https://web.archive.org/web/20160603110616/http://www.grida.no/climate/ipcc_tar/wg1/fig8-20.htm|url-status=live}} There has been a decline in stratospheric temperatures, interspersed by warmings related to volcanic eruptions. Global Warming theory suggests that the stratosphere should cool while the troposphere warms.{{cite journal |last=Clough |first=S.A. |author2=M. J. Iacono |year=1995 |title=Line-by-line calculation of atmospheric fluxes and cooling rates 2. Application to carbon dioxide, ozone, methane, nitrous oxide and the halocarbons |journal=Journal of Geophysical Research |volume=100 |issue=D8 |pages=16519–16535 |doi=10.1029/95JD01386 |url=http://www.agu.org/pubs/crossref/1995/95JD01386.shtml |bibcode=1995JGR...10016519C |access-date=15 February 2010 |archive-date=10 April 2011 |archive-url=https://web.archive.org/web/20110410033725/http://www.agu.org/pubs/crossref/1995/95JD01386.shtml |url-status=live }}

File:STAR TTS SSU Trend.png The long term cooling in the lower stratosphere occurred in two downward steps in temperature both after the transient warming related to explosive volcanic eruptions of El Chichón and Mount Pinatubo, this behavior of the global stratospheric temperature has been attributed to global ozone concentration variation in the two years following volcanic eruptions.{{cite journal |doi=10.1175/2008JCLI2482.1 |title=Understanding Recent Stratospheric Climate Change |journal=Journal of Climate |volume=22 |issue=8 |pages=1934 |year=2009 |last1=Thompson |first1=David W. J. |last2=Solomon |first2=Susan |bibcode=2009JCli...22.1934T |url=http://www.atmos.colostate.edu/ao/ThompsonPapers/ThompsonSolomon_JClimate2009.pdf |citeseerx=10.1.1.624.8499 |s2cid=3103526 |access-date=12 January 2020 |archive-date=9 July 2009 |archive-url=https://web.archive.org/web/20090709153247/http://www.atmos.colostate.edu/ao/ThompsonPapers/ThompsonSolomon_JClimate2009.pdf |url-status=live }}

Since 1996 the trend is slightly positive{{cite journal |last=Liu |first=Quanhua |author2=Fuzhong Weng |year=2009 |title=Recent Stratospheric Temperature Observed from Satellite Measurements |journal=Scientific Online Letters on the Atmosphere |volume=5 |pages=53–56 |doi=10.2151/sola.2009-014 |bibcode=2009SOLA....5...53L |doi-access=free }} due to ozone recovery juxtaposed to a cooling trend of 0.1K/decade that is consistent with the predicted impact of increased greenhouse gases.

The table below shows the stratospheric temperature trend from the SSU measurements in the three different bands, where negative trend indicated cooling.

{{clear}}

{{main|Microwave Sounding Unit temperature measurements}}

Image:Weighting Function.png.]]

From 1979 to 2005 the microwave sounding units (MSUs) and since 1998 the Advanced Microwave Sounding Units on NOAA polar orbiting weather satellites have measured the intensity of upwelling microwave radiation from atmospheric oxygen. The intensity is proportional to the temperature of broad vertical layers of the atmosphere. Upwelling radiance is measured at different frequencies; these different frequency bands sample a different weighted range of the atmosphere.[http://www.ssmi.com/msu/img/msu_weighting_functions.png Remote Sensing Systems] {{webarchive |url=https://web.archive.org/web/20130403061135/http://www.ssmi.com/msu/img/msu_weighting_functions.png |date=3 April 2013 }}

Figure 3 (right) shows the atmospheric levels sampled by different wavelength reconstructions from the satellite measurements, where TLS, TTS, and TTT represent three different wavelengths.

A different technique is used by the Aura spacecraft, the Microwave Limb Sounder, which measure microwave emission horizontally, rather than aiming at the nadir.M. J. Schwartz et al., [https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2007JD008783 Validation of the Aura Microwave Limb Sounder temperature and geopotential height measurements] {{Webarchive|url=https://web.archive.org/web/20200807002615/https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2007JD008783 |date=7 August 2020 }}, JGR: Atmospheres, Vol. 113, No. D15, 16 August 2008. https://doi.org/10.1029/2007JD008783 {{Webarchive|url=https://web.archive.org/web/20210221062606/https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2007JD008783 |date=21 February 2021 }}. Retrieved 9 January 2020.

Temperature measurements are also made by GPS radio occultation.Remote Sensing Systems, [http://www.remss.com/measurements/upper-air-temperature/ Upper Air Temperature] {{Webarchive|url=https://web.archive.org/web/20200105114524/http://www.remss.com/measurements/upper-air-temperature/ |date=5 January 2020 }}. Retrieved 12 January 2020. This technique measures the refraction of the radio waves transmitted by GPS satellites as they propagate in the Earth's atmosphere, thus allowing vertical temperature and moisture profiles to be measured.

Planetary science missions also make temperature measurements on other planets and moons of the Solar System, using both infrared techniques (typical of orbiter and flyby missions of planets with solid surfaces) and microwave techniques (more often used for planets with atmospheres). Infrared temperature measurement instruments used in planetary missions include surface temperature measurements taken by the Thermal Emission Spectrometer (TES) instrument on Mars Global Surveyor and the Diviner instrument on the Lunar Reconnaissance Orbiter;National Oceanic and Atmospheric Administration, [https://sos.noaa.gov/datasets/moon-surface-temperature/ Moon: Surface Temperature] {{Webarchive|url=https://web.archive.org/web/20200807070939/https://sos.noaa.gov/datasets/moon-surface-temperature/ |date=7 August 2020 }}, retrieved 9 January 2020. and atmospheric temperature measurements taken by the composite infrared spectrometer instrument on the NASA Cassini spacecraft.NASA/JPL/GSFC/Univ. Oxford (19 May 2011). [https://solarsystem.nasa.gov/resources/15314/taking-the-temperature-of-a-saturn-storm/ Taking the Temperature of a Saturn Storm] {{Webarchive|url=https://web.archive.org/web/20210221062606/https://solarsystem.nasa.gov/resources/15314/taking-the-temperature-of-a-saturn-storm/ |date=21 February 2021 }}, retrieved 10 January 2020.

Microwave atmospheric temperature measurement instruments include the Microwave Radiometer on the Juno mission to Jupiter.

• Atmospheric sounding
• Instrumental temperature record
• Sea surface temperature
• Temperature record
• Outgoing longwave radiation

{{Reflist}}

• [http://hadobs.metoffice.com/hadat/images/update_images/tropical_upper_air.png A graph comparing of the surface, balloon and satellite records] [https://web.archive.org/web/20070928025821/http://www.metoffice.gov.uk/research/hadleycentre/CR_data/Monthly/upper_air_temps.gif (2007 archive)]
• [https://web.archive.org/web/20070203081058/http://www.climatescience.gov/Library/sap/sap1-1/finalreport/default.htm Temperature Trends in the Lower Atmosphere: Steps for Understanding and Reconciling Differences] CCSP Synthesis and Assessment Product 1.1
• [https://web.archive.org/web/20060222024828/http://www.ghcc.msfc.nasa.gov/overview/microwave.html What Microwaves Teach Us About the Atmosphere]
• [https://web.archive.org/web/20070323005914/http://www.ghcc.msfc.nasa.gov/MSU/msusci.html Globally Averaged Atmospheric Temperatures]

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