Paul Wennberg

{{Infobox scientist | name = Paul Wennberg | native_name = | native_name_lang = | image = | imagesize = | alt = | caption = | birth_date =  | birth_place = | death_date =  | death_place = | death_cause = | resting_place = | resting_place_coordinates =  | other_names = | residence = | citizenship = | fields = atmospheric scientist | workplaces = California Institute of Technology | patrons = | alma_mater = Oberlin College, Harvard University | thesis_title =  | thesis_url =  | thesis_year =  | doctoral_advisor = James G. Anderson | academic_advisors = | doctoral_students = Rebecca Washenfelder | notable_students = | known_for = atmospheric science, carbon cycle | influences = | influenced = | awards = MacArthur Fellow | author_abbrev_bot = | author_abbrev_zoo = | spouse = Cheryl Margaret Wold | partner =  | children = | signature =  | signature_alt = | website = {{URL|www.gps.caltech.edu/content/paul-o-wennberg}} | footnotes = }} '''Paul O. Wennberg''' is the R. Stanton Avery Professor of Atmospheric Chemistry and Environmental Science and Engineering at the California Institute of Technology (Caltech).<ref name="CaltechBio">{{cite web|title=Paul O. Wennberg|url=https://www.gps.caltech.edu/content/paul-o-wennberg|website=Caltech|access-date=10 May 2016|archive-url=https://web.archive.org/web/20180824210403/http://www.gps.caltech.edu/content/paul-o-wennberg|archive-date=24 August 2018}}</ref> Until 2023, he was the director of the Ronald and Maxine Linde Center for Global Environmental Science.<ref name="ESE">{{cite web|title=Paul O. Wennberg|url=http://www.ese.caltech.edu/people/3250/profile|website=Environmental Science and Engineering|access-date=10 May 2016}}</ref> He served as the first chair of the Total Carbon Column Observing Network<ref name="Griffith">{{cite journal|last1=Griffith|first1=D.|journal=Light, Energy and the Environment, OSA Technical Digest|date=2014|title=Near Infrared remote sensing of atmospheric composition from the ground and space: the Total Carbon Column Observing Network (TCCON), GOSAT and OCO-2|article-number=ETh4A.2|doi=10.1364/E2.2014.ETh4A.2|isbn=978-1-55752-756-1|url=https://www.osapublishing.org/abstract.cfm?uri=E2-2014-ETh4A.2|access-date=12 May 2016}}</ref> and a founding member of the Orbiting Carbon Observatory project, which created NASA's first spacecraft for analysis of carbon dioxide in the atmosphere.<ref name="Crisp"/> He was previously the principal investigator for the Mars Atmospheric Trace Molecule Occultation Spectrometer (MATMOS) to investigate trace gases in Mars's atmosphere.<ref name="Oliwenstein">{{cite news|last1=Oliwenstein|first1=Lori|title=Caltech, Canadian Space Agency Awarded NASA Project to Develop Spectrometer Headed to Mars|url=https://www.caltech.edu/news/caltech-canadian-space-agency-awarded-nasa-project-develop-spectrometer-headed-mars-1638|access-date=12 May 2016|work=Caltech News|date=2010}}</ref>

Wennberg's research focuses on the atmospheric chemistry of planets, including air quality, photochemistry, and the carbon cycle.<ref name="ESE"/> 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.<ref name="Oliwenstein"/> 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.<ref name="Morin"/> His research has substantially advanced understanding of the atmospheric chemistry of the troposphere and the stratosphere.<ref name = "Fellows02"/>

==Education== 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.<ref name="Short">{{cite web|last1=Wennberg|first1=Paul|title=Paul Wennberg / Caltech|url=http://web.gps.caltech.edu/~wennberg/a-short-biography.html|website=Caltech|access-date=10 May 2016}}</ref> At Harvard, he worked with James G. Anderson, professor of atmospheric chemistry.<ref name="Group">{{cite web|title=Anderson Research Group|url=http://www.arp.harvard.edu/our-team|website=Harvard College|access-date=10 May 2016}}</ref> His doctoral thesis was ''In Situ Measurements of Stratospheric Hydroxyl and Hydroperoxyl Radicals''.<ref name="CV">{{cite web|title=Paul O. Wennberg (C.V.)|url=http://web.gps.caltech.edu/~wennberg/Cv_wennberg.pdf|website=Caltech|access-date=12 May 2016}}</ref>

==Career== 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.<ref name="ESE"/> Wennberg has been associated with the Ronald and Maxine Linde Center for Global Environmental Science at Caltech since it was established in 2008.<ref name="Conservancy">{{cite web|title=Linde + Robinson Laboratory at Caltech|url=https://www.laconservancy.org/locations/linde-robinson-laboratory-caltech|website=Los Angeles Conservancy|access-date=10 May 2016}}</ref> He served as the director from 2008 to 2011, acting director from 2012 to 2014 and director from 2014 onwards.<ref name="ESE"/>

==Research== While still at Harvard, Wennberg developed advanced airborne sensors to measure radicals in the atmosphere, in particular the odd-hydrogen radicals OH and HO2.<ref name="Wennberg1994">{{cite journal |doi=10.1063/1.1144835 |title=Aircraft-borne, laser-induced fluorescence instrument for the in situ detection of hydroxyl and hydroperoxyl radicals |journal=Review of Scientific Instruments |volume=65 |issue=6 |pages=1858–1876 |year=1994 |last1=Wennberg |first1=P. O. |last2=Cohen |first2=R. C. |last3=Hazen |first3=N. L. |last4=Lapson |first4=L. B. |last5=Allen |first5=N. T. |last6=Hanisco |first6=T. F. |last7=Oliver |first7=J. F. |last8=Lanham |first8=N. W. |last9=Demusz |first9=J. N. |last10=Anderson |first10=J. G. |bibcode=1994RScI...65.1858W |url=https://authors.library.caltech.edu/7575/1/WENrsi94.pdf }}</ref> The laser-induced fluorescence instrument that he developed was placed in the nose of a NASA ER-2 aircraft to measure radicals during flight.<ref name="North"/><ref name="Anderson">{{cite web|title=HOx Research Group|url=http://ent.arp.harvard.edu/sci/atmobs/hox/index.html|website=Anderson Group|access-date=12 May 2016|archive-url=https://web.archive.org/web/20160629115306/http://ent.arp.harvard.edu/sci/atmobs/hox/index.html|archive-date=29 June 2016}}</ref> It has been used to measure radicals in both the troposphere and the stratosphere.<ref name="North">{{cite book|last1=North|first1=Gerald R.|last2=Pyle|first2=John A.|last3=Zhang|first3=Fuqing|title=Encyclopedia of atmospheric sciences|date=2014|publisher=Elsevier Academic Press|isbn=978-0-12-382225-3|pages=393–394|url=https://books.google.com/books?id=8lpzAwAAQBAJ&pg=PA393|access-date=11 May 2016}}</ref>

Wennberg's sensor was used in several NASA missions, beginning with the SPADE mission in 1993.<ref name="North"/> 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.<ref name="Removal1994">{{cite journal |doi=10.1126/science.266.5184.398 |pmid=17816682 |title=Removal of Stratospheric O3 by Radicals: In Situ Measurements of OH, HO2, NO, NO2, ClO, and BrO |journal=Science |volume=266 |issue=5184 |pages=398–404 |year=1994 |last1=Wennberg |first1=P. O. |last2=Cohen |first2=R. C. |last3=Stimpfle |first3=R. M. |last4=Koplow |first4=J. P. |last5=Anderson |first5=J. G. |last6=Salawitch |first6=R. J. |last7=Fahey |first7=D. W. |last8=Woodbridge |first8=E. L. |last9=Keim |first9=E. R. |last10=Gao |first10=R. S. |last11=Webster |first11=C. R. |last12=May |first12=R. D. |last13=Toohey |first13=D. W. |last14=Avallone |first14=L. M. |last15=Proffitt |first15=M. H. |last16=Loewenstein |first16=M. |last17=Podolske |first17=J. R. |last18=Chan |first18=K. R. |last19=Wofsy |first19=S. C. |bibcode=1994Sci...266..398W |s2cid=2520718 }}</ref> 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.<ref name="Wennberg1998">{{cite journal |doi=10.1126/science.279.5347.49 |pmid=9417019 |title=Hydrogen Radicals, Nitrogen Radicals, and the Production of O3 in the Upper Troposphere |journal=Science |volume=279 |issue=5347 |pages=49–53 |year=1998 |last1=Wennberg |first1=P. O. |last2=Hanisco |first2=T. F. |last3=Jaegle |first3=L. |last4=Jacob |first4=D. J. |last5=Hintsa |first5=E. J. |last6=Lanzendorf |first6=E. J. |last7=Anderson |first7=J. G. |last8=Gao |first8=R. |last9=Keim |first9=E. R. |last10=Donnelly |first10=S. G. |author11=Negro LAD |last12=Fahey |first12=D. W. |last13=McKeen |first13=S. A. |last14=Salawitch |first14=R. J. |last15=Webster |first15=C. R. |last16=May |first16=R. D. |last17=Herman |first17=R. L. |last18=Proffitt |first18=M. H. |last19=Margitan |first19=J. J. |last20=Atlas |first20=E. L. |last21=Schauffler |first21=S. M. |last22=Flocke |first22=F. |last23=McElroy |first23=C. T. |last24=Bui |first24=T. P. |bibcode=1998Sci...279...49W }}</ref> The POLARIS mission in 1997 obtained measurements all the way to 90° N latitude, the North pole.<ref name="Anderson"/> 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".<ref name="Clair">{{cite journal |doi=10.1063/1.2940221 |pmid=18601418 |title=A new photolysis laser-induced fluorescence instrument for the detection of H2O and HDO in the lower stratosphere |journal=Review of Scientific Instruments |volume=79 |issue=6 |pages=064101–064101–14 |year=2008 |last1=St. Clair |first1=J. M. |last2=Hanisco |first2=T. F. |last3=Weinstock |first3=E. M. |last4=Moyer |first4=E. J. |last5=Sayres |first5=D. S. |last6=Keutsch |first6=F. N. |last7=Kroll |first7=J. H. |last8=Demusz |first8=J. N. |last9=Allen |first9=N. T. |last10=Smith |first10=J. B. |last11=Spackman |first11=J. R. |last12=Anderson |first12=J. G. |bibcode=2008RScI...79f4101S |url=https://authors.library.caltech.edu/11231/1/CLArsi08.pdf }}</ref><ref name="North"/>

{{quote|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.<ref name = "Fellows02"/>}}

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.<ref name="CV"/> 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.<ref name="Wunch2011"/>

In 2002,<ref name="CV"/> Wennberg was elected chair of the Total Carbon Column Observing Network (TCCON).<ref name="Griffith"/> In 2004, the first TCCON site was established.<ref name="Stoller-Conrad">{{cite journal|last1=Stoller-Conrad|first1=Jessica|title=Integrating Carbon from the Ground Up: TCCON Turns Ten|journal=The Earth Observer|date=2014|volume=26|issue=4|pages=13–15|url=http://eospso.gsfc.nasa.gov/sites/default/files/eo_pdfs/JulyAug_2014_color508.pdf|access-date=12 May 2016}}</ref> 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.<ref name="NASA"/> 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.<ref name="Stoller-Conrad"/> 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.<ref name="NASA">{{cite web|title=Carbon cycle and ecosystems funded research|url=http://cce.nasa.gov/cgi-bin/cce/cce_profile.pl?project_group_id=3173|website=National Aeronautics and Space Administration|access-date=12 May 2016}}</ref><ref name="Wunch2011">{{cite journal |doi=10.1098/rsta.2010.0240 |pmid=21502178 |title=The Total Carbon Column Observing Network |journal=Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences |volume=369 |issue=1943 |pages=2087–2112 |year=2011 |last1=Wunch |first1=D. |last2=Toon |first2=G. C. |last3=Blavier |first3=J.-F. L. |last4=Washenfelder |first4=R. A. |last5=Notholt |first5=J. |last6=Connor |first6=B. J. |last7=Griffith |first7=D. W. T. |last8=Sherlock |first8=V. |last9=Wennberg |first9=P. O. |bibcode=2011RSPTA.369.2087W |doi-access=free }}</ref> Methane emissions from the Aliso Canyon gas leak were detected by TCCON within a day of the start of the leak.<ref name="Fesenmaier">{{cite news|last1=Fesenmaier|first1=Kimm|title=Aliso Canyon, Methane, and Global Climate: A Conversation with Paul Wennberg|url=http://www.scienceandtechnologyresearchnews.com/aliso-canyon-methane-global-climate-conversation-paul-wennberg/|access-date=12 May 2016|work=Science and Technology Research News|date=April 18, 2016}}</ref> "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."<ref name="Stoller-Conrad"/>

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.<ref name="Morin">{{cite news|last1=Morin|first1=Monte|title=NASA makes second attempt to launch CO2-measuring satellite|url=http://www.latimes.com/science/sciencenow/la-sci-sn-oco-launch-20140626-story.html|access-date=10 May 2016|work=Los Angeles Times|date=June 30, 2014}}</ref><ref name="Crisp">{{cite journal |doi=10.1016/j.asr.2003.08.062 |title=The Orbiting Carbon Observatory (OCO) mission |journal=Advances in Space Research |volume=34 |issue=4 |pages=700–709 |year=2004 |last1=Crisp |first1=D. |last2=Atlas |first2=R.M |last3=Breon |first3=F.-M |last4=Brown |first4=L.R |last5=Burrows |first5=J.P |last6=Ciais |first6=P. |last7=Connor |first7=B.J |last8=Doney |first8=S.C |last9=Fung |first9=I.Y |last10=Jacob |first10=D.J |last11=Miller |first11=C.E |last12=O'Brien |first12=D. |last13=Pawson |first13=S. |last14=Randerson |first14=J.T |last15=Rayner |first15=P. |last16=Salawitch |first16=R.J |last17=Sander |first17=S.P |last18=Sen |first18=B. |last19=Stephens |first19=G.L |last20=Tans |first20=P.P |last21=Toon |first21=G.C |last22=Wennberg |first22=P.O |last23=Wofsy |first23=S.C |last24=Yung |first24=Y.L |last25=Kuang |first25=Z. |last26=Chudasama |first26=B. |last27=Sprague |first27=G. |last28=Weiss |first28=B. |last29=Pollock |first29=R. |last30=Kenyon |first30=D. |display-authors=29 |bibcode=2004AdSpR..34..700C |s2cid=16804121 |url=http://www.escholarship.org/uc/item/0jj7t8mg }}</ref><ref name="Frankenberg">{{cite journal |doi=10.5194/amt-8-301-2015 |title=The Orbiting Carbon Observatory (OCO-2): Spectrometer performance evaluation using pre-launch direct sun measurements |journal=Atmospheric Measurement Techniques |volume=8 |issue=1 |pages=301–313 |year=2015 |last1=Frankenberg |first1=C. |last2=Pollock |first2=R. |last3=Lee |first3=R. A. M. |last4=Rosenberg |first4=R. |last5=Blavier |first5=J.-F. |last6=Crisp |first6=D. |last7=O'Dell |first7=C. W. |last8=Osterman |first8=G. B. |last9=Roehl |first9=C. |last10=Wennberg |first10=P. O. |last11=Wunch |first11=D. |bibcode=2015AMT.....8..301F |doi-access=free }}</ref> Spectrometers on the satellite can map the distribution of CO2 particles across the planet by measuring the average amount of CO2 above specific locations.<ref name="Morin"/>

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.

==Awards and honors== Wennberg received a Presidential Early Career Award for Scientists and Engineers (PECASE) in 1999 from President Bill Clinton.<ref name="WhiteHouse1999">{{cite web|title=President names outstanding young U.S. scientists|url=http://homes.cs.washington.edu/~diorio/Awards/Pecase99/WhiteHouse.html|website=The White House|date=February 10, 1999}}</ref> He was named a MacArthur Foundation Fellow in 2002.<ref name = "Fellows02">{{cite web|url = https://www.macfound.org/fellows/701/|title = MacArthur Fellows September 2002|author = The John D. and Catherine T. MacArthur Foundation|access-date = 2007-06-02}}</ref><ref name="Maugh">{{cite news|last1=Maugh II|first1=Thomas H.|title=Eight Californians Win MacArthur Fellowships|url=https://www.latimes.com/archives/la-xpm-2002-sep-25-sci-macarthur25-story.html|access-date=12 May 2016|work=Los Angeles Times|date=September 25, 2002}}</ref> 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.

==References== {{Reflist}}

{{DEFAULTSORT:Wennberg, Paul}} Category:Living people Category:Harvard University alumni Category:MacArthur Fellows Category:California Institute of Technology faculty Category:Atmospheric chemists Category:Year of birth missing (living people) Category:20th-century American chemists Category:21st-century American chemists Category:Oberlin College alumni Category:People from Waterbury, Vermont Category:Scientists from Vermont Category:Recipients of the Presidential Early Career Award for Scientists and Engineers