Paul Wennberg | |
---|---|
Nationality | American |
Alma mater | Oberlin College, Harvard University |
Known for | atmospheric science, carbon cycle |
Spouse | Cheryl Margaret Wold |
Awards | MacArthur Fellow |
Scientific career | |
Fields | atmospheric scientist |
Institutions | California Institute of Technology |
Doctoral advisor | James G. Anderson |
Website | www |
Paul O. Wennberg is the R. Stanton Avery Professor of Atmospheric Chemistry and Environmental Science and Engineering at the California Institute of Technology (Caltech). [1] Until 2023, he was the director of the Ronald and Maxine Linde Center for Global Environmental Science. [2] He served as the first chair of the Total Carbon Column Observing Network [3] and a founding member of the Orbiting Carbon Observatory project, which created NASA's first spacecraft for analysis of carbon dioxide in the atmosphere. [4] He was previously the principal investigator for the Mars Atmospheric Trace Molecule Occultation Spectrometer (MATMOS) to investigate trace gases in Mars's atmosphere. [5]
Wennberg's research focuses on the atmospheric chemistry of planets, including air quality, photochemistry, and the carbon cycle. [2] He designs and builds remote-sensing and in-situ scientific instruments which are used in field investigations supported by the National Science Foundation and NASA. [5] His scientific instruments have made it possible to measure radicals in the atmosphere at concentrations that could not previously be detected. He measures atmospheric trace gases, making it possible to accurately describe the exchange of carbon dioxide and other gases between the atmosphere and the land and ocean. [6] His research has substantially advanced understanding of the atmospheric chemistry of the troposphere and the stratosphere. [7]
Paul Wennberg grew up in Waterbury Center, Vermont. He received a B.A. from Oberlin College in 1985, and a Ph.D. from Harvard University in 1994. [8] At Harvard, he worked with James G. Anderson, professor of atmospheric chemistry. [9] His doctoral thesis was In Situ Measurements of Stratospheric Hydroxyl and Hydroperoxyl Radicals. [10]
Wennberg joined Caltech in 1998. He was an associate professor of atmospheric chemistry and environmental engineering science from 1998 to 2001, becoming a full professor in 2001. In 2004, he was appointed as the R. Stanton Avery Professor of Atmospheric Chemistry and Environmental Science and Engineering. [2] Wennberg has been associated with the Ronald and Maxine Linde Center for Global Environmental Science at Caltech since it was established in 2008. [11] He served as the director from 2008 to 2011, acting director from 2012 to 2014 and director from 2014 onwards. [2]
While still at Harvard, Wennberg developed advanced airborne sensors to measure radicals in the atmosphere, in particular the odd-hydrogen radicals OH and HO2. [12] The laser-induced fluorescence instrument that he developed was placed in the nose of a NASA ER-2 aircraft to measure radicals during flight. [13] [14] It has been used to measure radicals in both the troposphere and the stratosphere. [13]
Wennberg's sensor was used in several NASA missions, beginning with the SPADE mission in 1993. [13] SPADE obtained the first simultaneous in situ measurements of OH, HO2, NO, NO2, ClO, and BrO from the lower stratosphere. The data were used to calculate ozone loss rates and showed that HOx dominated stratospheric ozone loss, a result that had not been previously observable. [15] NASA's ASHOE/MAESA mission (1994) took measurements of HOx from latitudes of -70°S to 70°N, reaching nearly from the south pole to the north pole. The STRAT mission (1995–1996) was the first to record measurements of HOx in the upper troposphere, and demonstrated that the concentration of HOx considerably exceeded expected levels. [16] The POLARIS mission in 1997 obtained measurements all the way to 90° N latitude, the North pole. [14] As of 2004, Wennberg's instrument was modified for in situ measurements of water vapour and its Isotopologue HDO, and became the basis of the Harvard "Hoxotope". [17] [13]
Using these tools, he overturned the long-held belief that lower stratospheric ozone is destroyed principally by nitrogen oxides; Wennberg showed that odd-hydrogen catalysis represents a quantitatively more important process. By contrast to the stratosphere, a significant fraction of tropospheric ozone results from the presence of nitric oxide delivered to the atmosphere by aircraft and surface hydrocarbon burning. Ozone in the stratosphere acts as a protective shield against ultraviolet radiation, but ozone in the troposphere significantly reduces air quality. By developing methods for measuring radical gases in situ and interpreting these results within a theoretical framework, Wennberg has advanced our understanding of atmospheric chemistry. [7]
Since his move to Caltech, Wennberg has been deeply involved in two inter-related long-term instrumentation and data-collection projects: the Orbiting Carbon Observatory, and its ground-based counterpart, the Total Carbon Column Observing Network. [10] Goals include better understanding of the carbon cycle, validation of data from space-based instruments, and establishing a standard for ground-based in situ networked data collection. [18]
In 2002, [10] Wennberg was elected chair of the Total Carbon Column Observing Network (TCCON). [3] In 2004, the first TCCON site was established. [19] The Total Carbon Column Observing Network is a group of about 20 ground-based sites worldwide that host Fourier transform spectrometers. The spectrometers examine near-infrared (NIR) solar absorption spectra and measure atmospheric column abundances of CO2, CH4, CO, N2O and other molecules in terrestrial ecosystems. [20] Data enables researchers to identify and study local carbon "sources" and "sinks", and by pooling data across the system, to better understand mechanisms of carbon exchange involving the atmosphere, the land, and the ocean. [19] Data from the sites is used to understand carbon dynamics and to validate data from space-based measurements of atmospheric CO2 and CH4. Both terrestrial and atmospheric data are used to study carbon transfer within the atmosphere. [20] [18] Methane emissions from the Aliso Canyon gas leak were detected by TCCON within a day of the start of the leak. [21] "TCCON has pioneered a key element of the ground segment measurements required to provide the evidence base for policy making for the next 100 years." [19]
Wennberg is a founding member of the Orbiting Carbon Observatory and its successor, the Orbiting Carbon Observatory-2. The first satellite failed to separate from the Orbital Taurus XL rocket used as its launch vehicle on February 24, 2009, and was destroyed during reentry. The second satellite, a near duplicate, was launched successfully by NASA on July 2, 2014, using a ULA Delta II 7320-10C rocket. [6] [4] [22] Spectrometers on the satellite can map the distribution of CO2 particles across the planet by measuring the average amount of CO2 above specific locations. [6]
Wennberg was the principal investigator for the development of the Mars Atmospheric Trace Molecule Occultation Spectrometer (MATMOS), a collaboration between Caltech and the Canadian Space Agency with NASA support. MATMOS was to have been flown on the ExoMars Trace Gas Orbiter and take spectra of the sunlight through Mars' atmosphere as the spacecraft goes through its orbital sunrise and sunset but the US contribution to the mission was cancelled.
Wennberg received a Presidential Early Career Award for Scientists and Engineers (PECASE) in 1999 from President Bill Clinton. [23] He was named a MacArthur Foundation Fellow in 2002. [7] [24] Wennberg is a member of the US National Academy of Sciences and a Fellow of the American Geophysical Union and the American Academy of Arts and Sciences.
Satellite temperature measurements are 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 islands and monitor the global climate. Wildfires, volcanos, and industrial hot spots can also be found via thermal imaging from weather satellites.
Envisat is a large Earth-observing satellite which has been inactive since 2012. It is still in orbit and considered space debris. Operated by the European Space Agency (ESA), it was the world's largest civilian Earth observation satellite.
Ground-level ozone (O3), also known as surface-level ozone and tropospheric ozone, is a trace gas in the troposphere (the lowest level of the Earth's atmosphere), with an average concentration of 20–30 parts per billion by volume (ppbv), with close to 100 ppbv in polluted areas. Ozone is also an important constituent of the stratosphere, where the ozone layer (2 to 8 parts per million ozone) exists which is located between 10 and 50 kilometers above the Earth's surface. The troposphere extends from the ground up to a variable height of approximately 14 kilometers above sea level. Ozone is least concentrated in the ground layer (or planetary boundary layer) of the troposphere. Ground-level or tropospheric ozone is created by chemical reactions between NOx gases (oxides of nitrogen produced by combustion) and volatile organic compounds (VOCs). The combination of these chemicals in the presence of sunlight form ozone. Its concentration increases as height above sea level increases, with a maximum concentration at the tropopause. About 90% of total ozone in the atmosphere is in the stratosphere, and 10% is in the troposphere. Although tropospheric ozone is less concentrated than stratospheric ozone, it is of concern because of its health effects. Ozone in the troposphere is considered a greenhouse gas, and as such contribute to global warming. as reported in IPCC reports. Actually, tropospheric ozone is considered the third most important greenhouse gas after CO2 and CH4, as indicated by estimates of its radiative forcing.
MOPITT is an ongoing astronomical instrument aboard NASA's Terra satellite that measures global tropospheric carbon monoxide levels. It is part of NASA's Earth Observing System (EOS), and combined with the other payload remote sensors on the Terra satellite, the spacecraft monitors the Earth's environment and climate changes. Following its construction in Canada, MOPITT was launched into Earth's orbit in 1999 and utilizes gas correlation spectroscopy to measure the presence of different gases in the troposphere. The fundamental operations occur in its optical system composed of two optical tables holding the bulk of the apparatus. Results from the MOPITT enable scientists to better understand carbon monoxide's effects on a global scale, and various studies have been conducted based on MOPITT's measurements.
SCISAT-1 is a Canadian satellite designed to make observations of the Earth's atmosphere. Its main instruments are an optical Fourier transform infrared spectrometer, the ACE-FTS Instrument, and an ultraviolet spectrophotometer, MAESTRO. These devices record spectra of the Sun, as sunlight passes through the Earth's atmosphere, making analyses of the chemical elements of the atmosphere possible.
The Upper Atmosphere Research Satellite (UARS) was a NASA-operated orbital observatory whose mission was to study the Earth's atmosphere, particularly the protective ozone layer. The 5,900-kilogram (13,000 lb) satellite was deployed from Space Shuttle Discovery during the STS-48 mission on 15 September 1991. It entered Earth orbit at an operational altitude of 600 kilometers (370 mi), with an orbital inclination of 57 degrees.
The Orbiting Carbon Observatory (OCO) was a failed NASA satellite mission intended to provide global space-based observations of atmospheric carbon dioxide. The original spacecraft was lost in a launch failure on 24 February 2009, when the payload fairing of the Taurus rocket which was carrying it failed to separate during ascent. The added mass of the fairing prevented the satellite from reaching orbit. It subsequently re-entered the atmosphere and crashed into the Indian Ocean near Antarctica. The replacement satellite, Orbiting Carbon Observatory-2, was launched 2 July 2014 aboard a Delta II rocket. The Orbiting Carbon Observatory-3, a stand-alone payload built from the spare OCO-2 flight instrument, was installed on the International Space Station's Kibō Exposed Facility in May 2019.
Over the last two centuries many environmental chemical observations have been made from a variety of ground-based, airborne, and orbital platforms and deposited in databases. Many of these databases are publicly available. All of the instruments mentioned in this article give online public access to their data. These observations are critical in developing our understanding of the Earth's atmosphere and issues such as climate change, ozone depletion and air quality. Some of the external links provide repositories of many of these datasets in one place. For example, the Cambridge Atmospheric Chemical Database, is a large database in a uniform ASCII format. Each observation is augmented with the meteorological conditions such as the temperature, potential temperature, geopotential height, and equivalent PV latitude.
The ozone monitoring instrument (OMI) is a nadir-viewing visual and ultraviolet spectrometer aboard the NASA Aura spacecraft, which is part of the satellite constellation A-Train. In this group of satellites Aura flies in formation about 15 minutes behind Aqua satellite, both of which orbit the Earth in a polar Sun-synchronous pattern, and which provides nearly global coverage in one day. Aura satellite was launched on July 15, 2004, and OMI has collected data since August 9, 2004.
The atmospheric infrared sounder (AIRS) is one of six instruments flying on board NASA's Aqua satellite, launched on May 4, 2002. The instrument is designed to support climate research and improve weather forecasting.
The Solar Backscatter Ultraviolet Radiometer, or SBUV/2, is a series of operational remote sensors on NOAA weather satellites in Sun-synchronous orbits which have been providing global measurements of stratospheric total ozone, as well as ozone profiles, since March 1985. The SBUV/2 instruments were developed from the SBUV experiment flown on the Nimbus-7 spacecraft which improved on the design of the original BUV instrument on Nimbus-4. These are nadir viewing radiometric instruments operating at mid to near UV wavelengths. SBUV/2 data sets overlap with data from SBUV and TOMS instruments on the Nimbus-7 spacecraft. These extensive data sets measure the density and vertical distribution of ozone in the Earth's atmosphere from six to 30 miles.
The Stratospheric Aerosol and Gas Experiment (SAGE) is a series of remote sensing satellite instruments used to study the chemical composition of Earth's atmosphere. Specifically, SAGE has been used to study the Earth's ozone layer and aerosols at the troposphere through the stratosphere. The SAGE instruments use solar occultation measurement technique to determine chemical concentrations in the atmosphere. Solar occultation measurement technique measures sunlight through the atmosphere and ratios that measurement with a sunlight measurement without atmospheric attenuation. This is achieved by observing sunrises and sunsets during a satellite orbit. Physically, the SAGE instruments measure ultraviolet/visible energy and this is converted via algorithms to determine chemical concentrations. SAGE data has been used to study the atmospheres aerosols, ozone, water vapor, and other trace gases.
Greenhouse gas monitoring is the direct measurement of greenhouse gas emissions and levels. There are several different methods of measuring carbon dioxide concentrations in the atmosphere, including infrared analyzing and manometry. Methane and nitrous oxide are measured by other instruments. Greenhouse gases are measured from space such as by the Orbiting Carbon Observatory and networks of ground stations such as the Integrated Carbon Observation System.
ADEOS I was an Earth observation satellite launched by NASDA in 1996. The mission's Japanese name, Midori means "green". The mission ended in July 1997 after the satellite sustained structural damage to the solar panel. Its successor, ADEOS II, was launched in 2002. Like the first mission, it ended after less than a year, also following solar panel malfunctions.
SAGE III on ISS is the fourth generation of a series of NASA Earth-observing instruments, known as the Stratospheric Aerosol and Gas Experiment. The first SAGE III instrument was launched on a Russian Meteor-3M satellite. The recently revised SAGE III was mounted to the International Space Station where it uses the unique vantage point of ISS to make long-term measurements of ozone, aerosols, water vapor, and other gases in Earth's atmosphere.
The Total Carbon Column Observing Network (TCCON) is a global network of instruments that measure the amount of carbon dioxide, methane, carbon monoxide, nitrous oxide and other trace gases in the Earth's atmosphere. The TCCON began in 2004 with the installation of the first instrument in Park Falls, Wisconsin, USA, and has since grown to 23 operational instruments worldwide, with 7 former sites.
Meteor-3M No.1 was the first and only of the Meteor-3M series polar-orbiting weather satellites. It was launched on 10 December 2001 at 17:18:57 UTC from the Baikonur Cosmodrome in Kazakhstan. The satellite is in a Sun-synchronous orbit with an ascending node time of about 9AM.
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 mission designed to measure CO2 was the Interferometric Monitor for Greenhouse Gases (IMG) on board the ADEOS I satellite in 1996. This mission lasted less than a year. Since then, additional space-based measurements have begun, including those from two high-precision satellites. Different instrument designs may reflect different primary missions.
SPRITE was a proposed Saturn atmospheric probe mission concept of the NASA. SPRITE is a design for an atmospheric entry probe that would travel to Saturn from Earth on its own cruise stage, then enter the atmosphere of Saturn, and descend taking measurements in situ.
Nadir and Occultation for MArs Discovery (NOMAD) is a 3-channel spectrometer on board the ExoMars Trace Gas Orbiter (TGO) launched to Mars orbit on 14 March 2016.