Editing Satellite temperature measurement

{{Short description|Measurements of atmospheric, land surface or sea temperature by satellites.}}
{{Use dmy dates|date=March 2020}}
{{multiple image|align=right|direction=vertical|width=200|image1=Satellite Temperatures.png|caption1=Comparison of ground-based measurements of near-surface temperature (blue) and satellite based records of mid-tropospheric temperature (red: [[UAH satellite temperature dataset|UAH]]; green: [[Remote Sensing Systems|RSS]]) from 1979 to 2010. Trends plotted 1982-2010.|image2=RSS_troposphere_stratosphere_trend.png|caption2=Atmospheric temperature trends from 1979-2016 based on satellite measurements; troposphere above, stratosphere below.}}
{{broader|Temperature measurement}}

'''Satellite temperature measurements''' are [[Remote sensing#Data processing|inferences]] of the [[temperature]] of the [[atmosphere]] at various altitudes as well as sea and land surface temperatures obtained from [[radiometric]] measurements by [[satellites]]. These measurements can be used to locate [[weather fronts]], monitor the [[El Niño-Southern Oscillation]], determine the strength of [[tropical cyclones]], study [[urban heat island]]s and monitor the global climate. [[Wildfires]], [[volcano]]s, and industrial hot spots can also be found via thermal imaging from weather satellites.

[[Weather satellite]]s do not measure temperature directly. They measure [[radiance]]s in various [[wavelength]] bands. Since 1978 [[microwave sounding unit]]s (MSUs) on [[National Oceanic and Atmospheric Administration]] [[polar orbit]]ing satellites have measured the intensity of upwelling microwave radiation from atmospheric [[oxygen]], which is related to the temperature of broad vertical layers of the atmosphere. Measurements of [[infrared]] radiation pertaining to sea surface temperature have been collected since 1967.

Satellite datasets show that over the past four decades the [[troposphere]] has warmed and the [[stratosphere]] has cooled. Both of these trends are consistent with the influence of increasing atmospheric concentrations of [[greenhouse gases]].

==Principles== 
[[Satellite]]s measure radiances in various wavelength bands, which must then be mathematically inverted to obtain indirect inferences of temperature.<ref name="NRC2000">{{cite book |chapter=Atmospheric Soundings |title=Issues in the Integration of Research and Operational Satellite Systems for Climate Research: Part I. Science and Design |author=National Research Council (U.S.). Committee on Earth Studies |year=2000 |publisher=National Academy Press |location=Washington, D.C. |isbn=978-0-309-51527-6 |pages=17–24 |chapter-url=http://books.nap.edu/openbook.php?record_id=9963&page=17 |doi=10.17226/9963 |access-date=17 May 2007 |archive-date=7 June 2011 |archive-url=https://web.archive.org/web/20110607114059/http://books.nap.edu/openbook.php?record_id=9963&page=17 |url-status=live }}</ref><ref name="Uddstrom1988">{{cite journal |doi=10.1175/1520-0450(1988)027<0515:ROAPFS>2.0.CO;2 |year=1988 |volume=27 |issue=5 |pages=515–49 |title=Retrieval of Atmospheric Profiles from Satellite Radiance Data by Typical Shape Function Maximum a Posteriori Simultaneous Retrieval Estimators |journal=Journal of Applied Meteorology |last1=Uddstrom |first1=Michael J. |bibcode=1988JApMe..27..515U |doi-access=free }}</ref> The resulting temperature profiles depend on details of the methods that are used to obtain temperatures from radiances. As a result, different groups that have analyzed the satellite data have produced differing temperature datasets.

The satellite time series is not homogeneous. It is constructed from a series of satellites with similar but not identical sensors. The sensors also deteriorate over time, and corrections are necessary for orbital drift and decay.<ref>{{cite journal |last1=Po-Chedley |first1=S. |last2=Thorsen |first2=T. J. |last3=Fu |first3=Q. |date=2015 |title=Removing Diurnal Cycle Contamination in Satellite-Derived Tropospheric Temperatures: Understanding Tropical Tropospheric Trend Discrepancies |journal=Journal of Climate |volume=28 |issue=6 |pages=2274–2290 | doi=10.1175/jcli-d-13-00767.1|bibcode=2015JCli...28.2274P |s2cid=43153422 |doi-access=free }}</ref><ref>{{citation|doi=10.1175/JCLI-D-15-0744.1|title=Sensitivity of Satellite-Derived Tropospheric Temperature Trends to the Diurnal Cycle Adjustment|year=2016|last1=Mears|first1=Carl A.|last2=Wentz|first2=Frank J.|journal=Journal of Climate|volume=29|issue=10|pages=3629–3646|bibcode=2016JCli...29.3629M|s2cid=131718796 }}</ref><ref>{{citation|doi=10.1175/2008JTECHA1176.1|title=Construction of the Remote Sensing Systems V3.2 Atmospheric Temperature Records from the MSU and AMSU Microwave Sounders|year=2009|last1=Mears|first1=Carl A.|last2=Wentz|first2=Frank J.|journal=Journal of Atmospheric and Oceanic Technology|volume=26|issue=6|pages=1040–1056|bibcode=2009JAtOT..26.1040M|doi-access=free}}</ref> Particularly large differences between reconstructed temperature series occur at the few times when there is little temporal overlap between successive satellites, making intercalibration difficult.{{citation needed|date=April 2015}}<ref>[https://moyhu.blogspot.co.uk/2017/07/new-rss-tlt-v4-comparisons.html New RSS TLT V4 - comparisons] {{Webarchive|url=https://web.archive.org/web/20170705195051/https://moyhu.blogspot.co.uk/2017/07/new-rss-tlt-v4-comparisons.html |date=5 July 2017 }} Moyhu 4 July 2017</ref><!-- this ref only says "One consequence is that with satellites there is a big problem with the inevitable changeovers" so not ideal but is better than nothing. hence leaving the CN tag in-->

==Infrared measurements==
===Surface measurements===
{{see also|Sea surface temperature#Weather satellites}}
{{multiple image
| align     = right
| direction = vertical
| width     = 200
| 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.<ref>{{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}}</ref>

| image2    = AMSRE SSTAn M.ogv
| alt2      = 
| caption2  = Sea surface temperature anomalies for a given month compared to the long-term average temperature of that month from 1985 through 1997.<ref>{{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}}</ref>
}}

[[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), [[AATSR|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.<ref name="Schwartz2008" />

Weather satellites have been available to infer [[sea surface temperature]] (SST) information since 1967, with the first global composites occurring during 1970.<ref>{{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 }}</ref> Since 1982,<ref>{{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}}</ref> [[satellite]]s have been increasingly utilized to measure SST and have allowed its [[Spatial variability|spatial]] and [[time|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|El Niño-Southern Oscillation]] since the 1970s.<ref>{{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}}</ref>

Over land the retrieval of temperature from radiances is harder, because of inhomogeneities in the surface.<ref>{{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 }}</ref> Studies have been conducted on the [[urban heat island]] effect via satellite imagery.<ref>{{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 }}</ref> By using the fractal technique, [[Qihao Weng|Weng, Q]]. et al. characterized the spatial pattern of urban heat island.<ref>{{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|url-access=subscription }}</ref> Use of [[Advanced very-high-resolution radiometer|advanced very high resolution infrared satellite imagery]] can be used, in the absence of cloudiness, to detect [[density]] discontinuities ([[weather front]]s) such as [[cold front]]s at ground level.<ref>{{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}}</ref> Using the [[Dvorak technique]], infrared satellite imagery can be used to determine the temperature difference between the [[eye (cyclone)|eye]] and the [[cloud]] top temperature of the [[central dense overcast]] of mature tropical cyclones to estimate their [[maximum sustained wind]]s and their minimum central [[Atmospheric pressure|pressures]].<ref>{{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}}</ref>

[[AATSR|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}}.<ref>{{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 }}</ref> The [[Moderate Resolution Imaging Spectroradiometer|Moderate-Resolution Imaging Spectroradiometer]] aboard the [[Terra (satellite)|Terra satellite]] can detect thermal hot spots associated with wildfires, volcanoes, and industrial hot spots.<ref>{{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 }}</ref>

The [[Atmospheric Infrared Sounder]] on the [[Aqua satellite]], launched in 2002, uses infrared detection to measure near-surface temperature.<ref name="Harvey_2019">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.</ref>

===Stratosphere measurements===

Stratospheric temperature measurements are made from the Stratospheric Sounding Unit (SSU) instruments, which are three-channel infrared (IR) radiometers.<ref>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</ref> 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|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&nbsp;km for channel 1, 37&nbsp;km for channel 2 and 45&nbsp;km for channel 3.<ref>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 }}</ref>{{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.<ref name="Wang 2011">{{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 }}</ref>{{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.<ref name="Shine 2003">{{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 }}</ref><ref>{{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}}</ref> There has been a decline in stratospheric temperatures, interspersed by warmings related to volcanic eruptions. [[Global warming|Global Warming]] theory suggests that the [[stratosphere]] should cool while the [[troposphere]] warms.<ref name="Clough 1995" >{{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 |url-access=subscription }}</ref>
[[File:STAR TTS SSU Trend.png|thumb|Top of the stratosphere (TTS) 1979–2006 temperature trend.]] 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.<ref name="Thompson 2009">{{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 }}</ref>
Since 1996 the trend is slightly positive<ref name="Liu 2009">{{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 }}</ref> due to ozone recovery juxtaposed to a cooling trend of 0.1K/decade that is consistent with the predicted impact of increased greenhouse gases.<ref name="Thompson 2009"/>

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

{| class="wikitable"
|-
! Channel !! Start !! End Date 
! STAR v3.0 
Global Trend<br>(K/decade)<ref name="star">{{cite web |url=http://www.star.nesdis.noaa.gov/smcd/emb/mscat/mscatmain.htm |title=Microwave Sounding Calibration and Trend |author=National Environmental Satellite, Data, and Information Service |access-date=2012-02-13 |publisher=[[National Oceanic and Atmospheric Administration]] |date=December 2010 |archive-date=17 December 2009 |archive-url=https://web.archive.org/web/20091217112205/http://www.star.nesdis.noaa.gov/smcd/emb/mscat/mscatmain.htm |url-status=live }}</ref>
|-
! scope="row" | TMS
| 1978-11 || 2017-01 || −0.583
|-
! scope="row" | TUS
| 1978-11 || 2017-01 || −0.649
|-
! scope="row" | TTS
| 1979-07 || 2017-01 || −0.728
|}

{{clear}}

==Microwave (tropospheric and stratospheric) measurements==

===Microwave Sounding Unit (MSU) measurements===
{{main|Microwave Sounding Unit temperature measurements}}
[[Image:Weighting Function.png|thumb|MSU weighting functions based upon the [[U.S. Standard Atmosphere]].]]
From 1979 to 2005 the [[microwave sounding unit]]s (MSUs) and since 1998 the [[Advanced Microwave Sounding Unit]]s on NOAA polar orbiting [[weather satellite]]s 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.<ref>[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 }}</ref>

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.

===Other microwave measurements===

A different technique is used by the [[Aura (satellite)|Aura]] spacecraft, the [[Microwave limb sounder|Microwave Limb Sounder]], which measure microwave emission horizontally, rather than aiming at the nadir.<ref name="Schwartz2008">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.</ref>

Temperature measurements are also made by [[GPS radio occultation]].<ref name= "upper air temperature">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.</ref> This technique measures the [[refraction]] of the [[radio wave]]s transmitted by [[GPS satellites]] as they [[radio propagation|propagate]] in the Earth's atmosphere, thus allowing vertical temperature and moisture profiles to be measured.

==Temperature measurements on other planets==

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]];<ref>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.</ref> and atmospheric temperature measurements taken by the composite infrared spectrometer instrument on the NASA [[Cassini–Huygens|''Cassini'' spacecraft]].<ref>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.</ref>

Microwave atmospheric temperature measurement instruments include the [[Microwave Radiometer (Juno)|Microwave Radiometer]] on the ''[[Juno (spacecraft)|Juno]]'' mission to Jupiter.

==See also==
* [[Atmospheric sounding]]
* [[Instrumental temperature record]]
* [[Sea surface temperature]]
* [[Temperature record]]
* [[Outgoing longwave radiation]]

==References==
{{Reflist}}

==External links==
*[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]

{{Global warming}}

{{DEFAULTSORT:Satellite Temperature Measurements}}
[[Category:Satellite meteorology]]
[[Category:Articles containing video clips]]
[[Category:Temperature]]