The Total Carbon Column Observing Network (TCCON) is a global network of instruments that measure the amount of
carbon dioxide
Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
,
methane
Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Ea ...
,
carbon monoxide
Carbon monoxide (chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simple ...
,
nitrous oxide
Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or nos, is a chemical compound, an oxide of nitrogen with the formula . At room temperature, it is a colourless non-flammable gas, and has ...
and other
trace gas
Trace gases are gases that are present in small amounts within an environment such as a planet's atmosphere. Trace gases in Earth's atmosphere are gases other than nitrogen (78.1%), oxygen (20.9%), and argon (0.934%) which, in combination, make u ...
es in the
Earth's atmosphere
The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing fo ...
. The TCCON ( ) began in 2004 with the installation of the first instrument in
Park Falls, Wisconsin
Park Falls is a city in Price County, Wisconsin, United States. The population was 2,462 at the 2010 census. Located in the woods of north central Wisconsin, primarily the Chequamegon National Forest, Park Falls is a small community divided by t ...
, USA, and has since grown to 23 operational instruments worldwide, with 7 former sites.
The TCCON is designed to investigate several things, including the flow (or
flux) of carbon between the atmosphere, land, and ocean (the so-called
carbon budget
A carbon budget is "the maximum amount of cumulative net global anthropogenic carbon dioxide () emissions that would result in limiting global warming to a given level with a given probability, taking into account the effect of other anthropogen ...
or
carbon cycle
The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and Earth's atmosphere, atmosphere of the Earth. Carbon is the main component of biological compounds as well as ...
). This is achieved by measuring the atmospheric mass of carbon (the
airborne fraction). The TCCON measurements have improved the scientific community's understanding of the
carbon cycle
The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and Earth's atmosphere, atmosphere of the Earth. Carbon is the main component of biological compounds as well as ...
,
[Yang, Z., R. A. Washenfelder, G. Keppel-Aleks, N. Y. Krakauer, J. T. Randerson, P. P. Tans, C. Sweeney, and P. O. Wennberg (2007), New constraints on Northern Hemisphere growing season net flux, Geophysical Research Letters, 34(12), 1-6, . Available from: http://www.agu.org/pubs/crossref/2007/2007GL029742.shtml][Chevallier, F. et al. (2011), Global CO 2 fluxes inferred from surface air-sample measurements and from TCCON retrievals of the CO2 total column, Geophysical Research Letters, 38(24), 1-5, . Available from: http://www.agu.org/pubs/crossref/201...GL049899.shtml] and urban
greenhouse gas emissions
Greenhouse gas emissions from human activities strengthen the greenhouse effect, contributing to climate change. Most is carbon dioxide from burning fossil fuels: coal, oil, and natural gas. The largest emitters include coal in China and ...
.
[Verifying Greenhouse Gas Emissions: Methods to Support International Climate Agreements, http://www.nap.edu/catalog/12883.html]
The TCCON supports several satellite instruments by providing an independent measurement to compare (or validate) the satellite measurements of the atmosphere over the TCCON site locations.
[ ][Boland, S. et al. (2009), The Need for Atmospheric Carbon Dioxide Measurements from Space : Contributions from a Rapid Reflight of the Orbiting Carbon Observatory, http://www.nasa.gov/pdf/363474main_OCO_Reflight.pdf] The TCCON provides the primary measurement validation dataset for the
Orbiting Carbon Observatory (OCO-2) mission,
[NASA.gov](_blank)
/ref> and has been used to validate other space-based measurements of carbon dioxide
Space-based measurements of carbon dioxide () are used to help answer questions about Earth's carbon cycle. There are a variety of active and planned instruments for measuring carbon dioxide in Earth's atmosphere from space. The first satellite ...
.
History
The TCCON was established partly because of modeling errors between mixing efficiency between the PBL and the free troposphere
The troposphere is the first and lowest layer of the atmosphere of the Earth, and contains 75% of the total mass of the planetary atmosphere, 99% of the total mass of water vapour and aerosols, and is where most weather phenomena occur. From ...
. Because TCCON measurements are of the entire column of atmosphere above a site (PBL and free troposphere are simultaneously measured) the measurements are an improvement over the traditional in situ
''In situ'' (; often not italicized in English) is a Latin phrase that translates literally to "on site" or "in position." It can mean "locally", "on site", "on the premises", or "in place" to describe where an event takes place and is used in ...
near surface measurements in this regard. TCCON has improved the CO2 mass gradient measurements between the northern and southern hemispheres.
The first annual TCCON meeting was in San Francisco, California
San Francisco (; Spanish for " Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the fourth most populous in California and 17th ...
in 2005. Every year a meeting is held in a location that rotates between North America, the Western Pacific, and Europe hosted by a participating institution. In 2015 the meeting was held at the University of Toronto
The University of Toronto (UToronto or U of T) is a public research university in Toronto, Ontario, Canada, located on the grounds that surround Queen's Park. It was founded by royal charter in 1827 as King's College, the first institution ...
.[TCCON Webpage, https://tccon-wiki.caltech.edu/Sites, accessed February 6, 2016]
Measurement technique
The main instrument at each TCCON site is a Bruker
Bruker Corporation is an American manufacturer of scientific instruments for molecular and materials research, as well as for industrial and applied analysis. It is headquartered in Billerica, Massachusetts, and is the publicly traded parent compa ...
IFS 125HR (HR for high resolution, ~0.02 cm−1) or occasionally 120HR Fourier transform spectrometer
Fourier-transform spectroscopy is a measurement technique whereby spectra are collected based on measurements of the coherence of a radiative source, using time-domain or space-domain measurements of the radiation, electromagnetic or not. It can ...
. Sunlight is directed into the spectrometer by solar tracking mirrors and other optics. The spectrometers measure the absorption of direct sunlight by atmospheric trace gases primarily in the near infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
region. This remote sensing
Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object, in contrast to in situ or on-site observation. The term is applied especially to acquiring information about Earth ...
technique produces a precise and accurate measurement of the total column abundance of the trace gas
Trace gases are gases that are present in small amounts within an environment such as a planet's atmosphere. Trace gases in Earth's atmosphere are gases other than nitrogen (78.1%), oxygen (20.9%), and argon (0.934%) which, in combination, make u ...
. The main limitation to this technique is that measurements can not be recorded when it is not sunny (i.e. there are no measurements available at nighttime or when there is heavy cloud cover).[Wunch, D., G. C. Toon, J.-F. L. Blavier, R. A. Washenfelder, J. Notholt, B. J. Connor, D. W. T. Griffith, V. Sherlock, and P. O. Wennberg (2011), The total carbon column observing network, Philosophical Transactions of the Royal Society - Series A: Mathematical, Physical and Engineering Sciences, 369(1943), 2087-2112, . Available from: http://rsta.royalsocietypublishing.o.../2087.full.pdf]
Participating sites and Institutions
Current TCCON sites are located in the United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
, China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
, Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
, Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
, Poland
Poland, officially the Republic of Poland, is a country in Central Europe. It is divided into 16 administrative provinces called voivodeships, covering an area of . Poland has a population of over 38 million and is the fifth-most populous ...
, France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
, Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
, Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
, New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
, South Korea
South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korea, Korean Peninsula and sharing a Korean Demilitarized Zone, land border with North Korea. Its western border is formed ...
, Réunion
Réunion (; french: La Réunion, ; previously ''Île Bourbon''; rcf, label= Reunionese Creole, La Rényon) is an island in the Indian Ocean that is an overseas department and region of France. It is located approximately east of the island ...
, and Ascension Island. A former site was in Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
. Sites can change when an instrument needs to be moved to a new location.
TCCON members collaborate from a variety of different institutions. In North America some of these include Caltech
The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasional ...
, JPL, Los Alamos National Laboratory
Los Alamos National Laboratory (often shortened as Los Alamos and LANL) is one of the sixteen research and development laboratories of the United States Department of Energy (DOE), located a short distance northwest of Santa Fe, New Mexico, ...
, NASA Ames
The Ames Research Center (ARC), also known as NASA Ames, is a major NASA research center at Moffett Federal Airfield in California's Silicon Valley. It was founded in 1939 as the second National Advisory Committee for Aeronautics (NACA) laborat ...
, and the University of Toronto
The University of Toronto (UToronto or U of T) is a public research university in Toronto, Ontario, Canada, located on the grounds that surround Queen's Park. It was founded by royal charter in 1827 as King's College, the first institution ...
. In Europe some of these include Karlsruhe Institute of Technology
The Karlsruhe Institute of Technology (KIT; german: Karlsruher Institut für Technologie) is a public research university in Karlsruhe, Germany. The institute is a national research center of the Helmholtz Association.
KIT was created in 2009 w ...
, Max Planck Institute for Biogeochemistry, University of Bremen
The University of Bremen (German: ''Universität Bremen'') is a public university in Bremen, Germany, with approximately 23,500 people from 115 countries. It is one of 11 institutions which were successful in the category "Institutional Strategi ...
, Agencia Estatal de Meteorología, Royal Belgian Institute for Space Aeronomy
Royal may refer to:
People
* Royal (name), a list of people with either the surname or given name
* A member of a royal family
Places United States
* Royal, Arkansas, an unincorporated community
* Royal, Illinois, a village
* Royal, Iowa, a ci ...
, Finnish Meteorological Institute
The Finnish Meteorological Institute (FMI; fi, Ilmatieteen laitos; sv, Meteorologiska institutet) is the government agency responsible for gathering and reporting weather data and forecasts in Finland. It is a part of the Ministry of Transport ...
, and Pierre and Marie Curie University
Pierre and Marie Curie University (french: link=no, Université Pierre-et-Marie-Curie, UPMC), also known as Paris 6, was a public university, public research university in Paris, France, from 1971 to 2017. The university was located on the Jussi ...
. In the western Pacific some of these include University of Wollongong
The University of Wollongong (abbreviated as UOW) is an Australian public research university located in the coastal city of Wollongong, New South Wales, approximately 80 kilometres south of Sydney. As of 2017, the university had an enrolment of ...
, National Institute of Water and Atmospheric Research
The National Institute of Water and Atmospheric Research or NIWA ( mi, Taihoro Nukurangi), is a Crown Research Institute of New Zealand. Established in 1992, NIWA conducts research across a broad range of disciplines in the environmental scien ...
, National Institute for Environmental Studies
The National Institute for Environmental Studies (''NIES'':国立環境研究所, Kokuritsu-Kankyō kenkyūsho) was established in 1974 as a focal point for environmental research in Japan. In 2001 it became an Independent Administrative Institut ...
, JAXA
The is the Japanese national air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satellites into orb ...
, and National Institute of Meteorological Research of the Republic of Korea.
New sites are admitted into the network when site investigators demonstrate required hardware, and data processing ability. Uniformity is maintained across the network by using the same FTS model and the same retrieval software. GGG is the software of the TCCON. It includes the I2S (interferogram to spectrum) FFT
A fast Fourier transform (FFT) is an algorithm that computes the discrete Fourier transform (DFT) of a sequence, or its inverse (IDFT). Fourier analysis converts a signal from its original domain (often time or space) to a representation in the ...
, and GFIT spectral fitting subroutines. GFIT is also the fitting algorithm that was used for ATMOS which flew on the Space Shuttle
The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program na ...
, and is used for spectral fitting of spectra obtained by a balloon borne spectrometer.
Map
Highlights of Data Use
Data from each site is processed by the investigators that head that particular site. Atmospheric abundances of gases are uploaded and saved in uniform formats and data are hosted at Caltech
The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasional ...
with the Caltech Library and are available from http://tccondata.org. Data are made publicly available provided the data license is followed.
Data have been used for a variety of analyses. Some of these include
* Emission estimates of methane and carbon monoxide were made for the South Coast Air Basin The South Coast Air Basin—SCAB (or SoCAB) is one of several regional air basin areas designated by the state of California, for the purpose of air quality management and air pollution control in Southern California. The SCAB district was created ...
containing Los Angeles
Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the world' ...
using TCCON measurements and the CARB inventory.[Wunch, D., P. O. Wennberg, G. C. Toon, G. Keppel-Aleks, and Y. G. Yavin (2009), Emissions of greenhouse gases from a North American megacity, Geophys. Res. Lett., 36, L15810, doi:10.1029/2009GL039825.]
* Characterization of biosphere fluxes in the Southern Hemisphere
* Evaluation of the seasonal exchange of CO2 between the biosphere and the atmosphere
* Numerous satellite validation projects [Wunch, D., et al.: A method for evaluating bias in global measurements of CO2 total columns from space, Atmos. Chem. Phys., 11, 12317-12337, doi:10.5194/acp-11-12317-2011, 2011.]
* Validation projects involving comparison of CO2 and CH4 measured by TCCON with that measured by lower-resolution instruments
* Covariation between surface temperature and CO2 in boreal regions
* Distinguishing between which of two power plants (~2000 MW each) plumes of polluted air came from in conjunction with a Pandora NO2 spectrometer[Rodica Lindenmaier, Manvendra K. Dubey, Bradley G. Henderson, Zachary T. Butterfield, Jay R. Herman, Thom Rahn, and Sang-Hyun Lee. Multiscale observations of CO2, 13CO2, and pollutants at Four Corners for emission verification and attribution. PNAS 2014 111 (23) 8386-8391; published ahead of print May 19, 2014, doi:10.1073/pnas.1321883111]
Satellite support
The satellite missions supported by the TCCON include the Greenhouse Gases Observing Satellite (GOSAT),[Crisp, D. et al.: The ACOS XCO2 retrieval algorithm, Part 2: Global XCO2 data characterization, Atmos. Meas. Tech. Discuss., 5, 1-60, , 2012, http://www.atmos-meas-tech-discuss.net/5/1/2012/amtd-5-1-2012.html][Butz, A. et al. (2011), Toward accurate CO2 and CH4 observations from GOSAT, Geophysical Research Letters, 38(14), 2-7, , http://www.agu.org/pubs/crossref/2011/2011GL047888.shtml][Morino, I. et al. (2011), Preliminary validation of column-averaged volume mixing ratios of carbon dioxide and methane retrieved from GOSAT short-wavelength infrared spectra, Atmospheric Measurement Techniques, 4(6), 1061-1076, , http://www.atmos-meas-tech.net/4/1061/2011/] SCIAMACHY
SCIAMACHY (SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY; Greek: σκιάμάχη: analogously: "Fighting shadows") was one of ten instruments aboard of ESA's ENVIronmental SATellite, ENVISAT. It was a satellite spectrome ...
,[Buchwitz, M. et al. (2006), Atmospheric carbon gases retrieved from SCIAMACHY by WFM-DOAS: version 0.5 CO and CH4 and impact of calibration improvements on CO2 retrieval, Atmospheric Chemistry and Physics, 6(9), 2727-2751, , http://www.atmos-chem-phys.net/6/2727/2006/] and the Orbiting Carbon Observatory-2 (OCO-2).
See also
* The TCCON home page: https://tccon-wiki.caltech.edu
* Orbiting Carbon Observatory 2
Orbiting Carbon Observatory-2 (OCO-2) is an American environmental science satellite which launched on 2 July 2014. A NASA mission, it is a replacement for the Orbiting Carbon Observatory which was lost in a launch failure in 2009. It is the secon ...
* Greenhouse Gases Observing Satellite
The Greenhouse Gases Observing Satellite (GOSAT''), also known as , is an Earth observation satellite and the world's first satellite dedicated to greenhouse gas monitoring. It measures the densities of carbon dioxide and methane from 56,000 loca ...
* Founding member Paul Wennberg
Paul O. Wennberg is the R. Stanton Avery Professor of Atmospheric Chemistry and Environmental Science and Engineering at the California Institute of Technology (Caltech). He is the director of the Ronald and Maxine Linde Center for Global Environm ...
References
External links
*{{Commons category-inline, TCCON
Atmospheric sciences