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William J. Massman Jr



240 West Prospect Road
Fort Collins, CO 80526
Contact William J. Massman Jr

Current Research

I conduct research to quantify atmospheric-biospheric interactions, including the use of eddy covariance technology to study the exchange of trace gases (carbon dioxide, water, ozone) between the atmosphere and the earth's surface (vegetation, soil, and snow). I also research issues involving the physical processes governing CO2 transport in soils and snowpacks and the impact of fire on soil physical properties and microbial populations.

Research Interests

Develop a better understanding of an ongoing spruce beetle epidemic can have on carbon and water cycles at a high elevation subalpine forest.Develop physically-based computer models to improve predictions of and insights into the long-term impacts on soils that extreme heating during a prescribed burn or wildfires can cause.

Past Research

My research focuses on some of the long-term impacts that relatively short-lived, but extreme, events or environmental conditions can have on vegetation and soils. Such events alter ecosystem benefits and resources, such as the potential for carbon sequestration, stream flow amounts and timing, and soil water availability, for decades to centuries. Quantifying these impacts on water and carbon is critical for long-term resource planning and sustainability.

Why This Research is Important

** Theory and practice of eddy covariance(1) A perspective on thirty years of the Webb, Pearman and Leuning density corrections ,(2) The canopy horizontal array turbulence study (CHATS) ** Carbon cycling and climate Climate control of terrestrial carbon exchange across biomes and continents **Fire and soils Advancing investigation and modeling of first-order fire effects on soils ** Beetle impacts on high elevation siteEvapotranspiration response of a high elevation Rocky Mountain (Wyoming, USA) forest to a bark beetle epidemic


  • University of Wisconsin, Madison, Ph.D., Meteorology, 1978
  • University of Wisconsin, Madison, M.S., Meteorology, 1973
  • University of Wisconsin, Madison, M.S., Physics, 1970
  • University of Missouri, Columbia, B.S., Physics, 1969
  • Professional Organizations

    • American Geophysical Union, Member ( 1988 to present )
    • American Meteorological Society, Member ( 1978 to present )
    • European Geophysical Union, Member ( 2008 )
    • Journal of Geophysical Research: Atmospheres, Associate Editor ( 2005 to 2008 )
    • Association of Fire Ecology, Member ( 2007 )
    • American Meteorological Society, Member ( 2002 to 2005 )
      Committee on Agricultural and Forest Meteorology
    • Air and Waste Management Association, Member ( 1994 )
    • American Society of Agronomy, Member ( 1992 to 1993 )
    • American Meteorological Society, Member ( 1987 to 1989 )
      Committee on Mountain Meteorology


    American Meteorological Society Outstanding Achievement in Biometeorology, 2016
    For innovative and rigorous theoretical advances that have improved the biomicrometeorological measurement and modeling of mass and energy exchange between plants and the atmosphere
    American Meteorological Society 32nd Conference on Agricultural and Forest Meteorology, 2016
    Special Session Honoring the Contributions of Dr. William J. Massman to Biometeorology
    Agricultural and Forest Meteorology Outstanding Contribution in Reviewing, 2014
    In recognition of the contributions made to the quality of the journal
    UN WMO Norbert Gerbier-MUMM International Award 2012, 2012
    For the publication "Climate control of terrestrial carbon exchange across biomes and continents" Environmental Research Letters 5 034007.
    Rocky Mountain Research Station Best Scientific Publication of the Year 2010, 2011
    Advancing investigation and modeling of first-order fire effects on soils, fire Ecology 6:36-54
    Distinguished Visiting Scientist Commonwealth Scientific and Industrial Research Organization, CSIRO, 2010
    CSIRO is Australia's national science agency and one of the largest and most diverse research agencies in the world. This award is made annually and is competitive across all scientific disciplines within CSIRO.
    USDA Certificate of Merit, 2007
    For careful and diligent efforts to remove the obsolescent tower at the GLEES research site
    USDA Certificate of Merit, 2004
    For significant efforts to continue fire ecology research on soils and to initiate new studies in the National Fire Plan Ecology Research Project in FY04
    USDA Certificate of Appreciation, 1995
    For significant contribution to the understanding and quantification of ozone deposition and its interaction with the plant surface
    USDA Certificate of Appreciation, 1995
    For contributions to the 1993 RPA assessment update
    Senior Postdoctoral Fellowship, 1985
    National Research Council
    Scholastic Achievement, 1969
    Phi Beta Kappa
    National Mathematics Honor Society, 1969
    Phi Mu Epsilon

    Featured Publications


    Chen, Xuelong; Massman , William J. , Jr; Su, Zhongbo, 2019. A column canopy‐air turbulent diffusion method for different canopy structures
    Frank, John M.; Massman , William J. , Jr; Ewers, Brent E.; Williams, David G., 2019. Bayesian analyses of 17 winters of water vapor fluxes show bark beetles reduce sublimation
    Chu, Housen; Baldocchi, Dennis D.; Poindexter, Cristina; Abraha, Michael; Desai, Ankur R.; Bohrer, Gil; Arain, M. Altaf; Griffis, Timothy; Blanken, Peter D.; O'Halloran, Thomas L.; Thomas, R. Quinn; Zhang, Quan; Burns, Sean P.; Frank, John M.; Christian, Dold; Brown, Shannon; Black, T. Andrew; Gough, Christopher M.; Law, Beverly E.; Lee, Xuhui; Chen, Jiquan; Reed, David E.; Massman , William J. , Jr; Clark, Kenneth; Hatfield, Jerry; Prueger, John; Bracho, Rosvel; Baker, John M.; Martin, Timothy A., 2018. Temporal dynamics of aerodynamic canopy height derived from eddy covariance momentum flux data across North American flux networks
    Massman , William J. , Jr; Forthofer, Jason M.; Finney, Mark A., 2017. An improved canopy wind model for predicting wind adjustment factors and wildland fire behavior
    Frank, John M.; Massman , William J. , Jr; Swiatek, Edward; Zimmerman, Herb A.; Ewers, Brent E., 2016. All sonic anemometers need to correct for transducer and structural shadowing in their velocity measurements
    Smits, Kathleen M.; Kirby, Elizabeth; Massman , William J. , Jr; Baggett, Scott, 2016. Experimental and modeling study of forest fire effect on soil thermal conductivity
    Kelleners, Thijs J.; Koonce, Jeremy; Shillito, Rose; Dijkema, Jelle; Berli, Markus; Young, Michael H.; Frank, John M.; Massman , William J. , Jr, 2016. Numerical modeling of coupled water flow and heat transport in soil and snow
    Chen, Fei; Zhang, Guo; Barlage, Michael; Zhang, Ying; Hicke, Jeffrey A.; Meddens, Arjan; Zhou, Guangsheng; Massman , William J. , Jr; Frank, John M., 2015. An observational and modeling study of impacts of bark beetle-caused tree mortality on surface energy and hydrological cycles
    Speckman, Heather N.; Frank, John M.; Bradford, John B.; Miles, Brianna L.; Massman , William J. , Jr; Parton, William J.; Ryan, Michael G., 2015. Forest ecosystem respiration estimated from eddy covariance and chamber measurements under high turbulence and substantial tree mortality from bark beetles
    Frank, John M.; Massman , William J. , Jr; Ewers, Brent E.; Huckaby, Laurie Kay Stroh; Negron, Jose, 2014. Ecosystem CO2/H2O fluxes are explained by hydraulically limited gas exchange during tree mortality from spruce bark beetles
    Schlaepfer, Daniel R.; Ewers, Brent E.; Shuman, Bryan N.; Williams, David G.; Frank, John M.; Massman , William J. , Jr; Lauenroth, William K., 2014. Terrestrial water fluxes dominated by transpiration: Comment
    Kochendorfer, John; Meyers, Tilden P.; Frank, John M.; Massman , William J. , Jr; Heuer, Mark W., 2013. Reply to comment by Mauder on "How well can we measure the vertical wind speed? Implications for fluxes of energy and mass"
    Rafkin, S.; Banfield, D.; Dissly, R.; Silver, J.; Stanton, A.; Wilkinson, E.; Massman , William J. , Jr; Ham, J., 2012. An instrument to measure turbulent eddy fluxes in the atmosphere of Mars
    Kochendorfer, John; Meyers, Tilden P.; Frank, John M.; Massman , William J. , Jr; Heuer, Mark W., 2012. How well can we measure the vertical wind speed? Implications for fluxes of energy and mass
    Leuning, Ray; van Gorsela, Eva; Massman , William J. , Jr; Isaac, Peter R., 2012. Reflections on the surface energy imbalance problem
    Gu, Lianhong; Massman , William J. , Jr; Leuning, Ray; Pallardy, Stephen G.; Meyers, Tilden; Hanson, Paul J.; Riggs, Jeffery S.; Hosman, Kevin P.; Yang, Bai, 2012. The fundamental equation of eddy covariance and its application in flux measurements
    Patton, Edward G.; Horst, Thomas W.; Sullivan, Peter P.; Lenschow, Donald H.; Oncley, Steven P.; Brown, William O. J.; Burns, Sean P.; Guenther, Alex B.; Held, Andreas; Karl, Thomas; Mayor, Shane D.; Rizzo, Luciana V.; Spuler, Scott M.; Sun, Jielun; Turnipsee, Andrew A.; Allwine, Eugene J.; Edburg, Steven L.; Lamb, Brian K.; Avissar, Roni; Calhoun, Ronald J.; Kleissl, Jan; Massman , William J. , Jr; U, Kyaw Tha Paw; Weil, Jeffrey C., 2011. The canopy horizontal array turbulence study
    Nobles, M. M.; Massman , William J. , Jr; Mbila, M.; Butters, G., 2010. Mineralogical and micromorphological modifications in soil affected by slash pile burn
    Massman , William J. , Jr; Nobles, M. M.; Butters, G.; Mooney, S. J., 2010. Transport of CO2 and other combustion products in soils during slash-pile burns [Presentation]
    Bowling, D. R.; Massman , William J. , Jr; Schaeffer, S. M.; Burns, S. P.; Monson, R. K.; Williams, M. W., 2009. Biological and physical influences on the carbon isotope content of CO2 in a subalpine forest snowpack, Niwot Ridge, Colorado
    Wilson, J. D.; Massman , William J. , Jr; Swaters, G. E., 2009. Dynamic response of the thermometric net radiometer
    Patton, Edward G.; Horst, Thomas W.; Lenschow, Donald H.; Sullivan, Peter P.; Oncley, Steven; Burns, Sean; Guenther, Alex; Held, Andreas; Karl, Thomas; Mayor, Shane; Rizzo, Luciana; Spuler, Scott; Sun, Jielun; Turnipseed, Andrew; Allwine, Eugene; Edburg, Steven; Lamb, Brian; Avissar, Roni; Holder, Heidi E.; Calhoun, Ron; Kleissl, Jan; Massman , William J. , Jr; U, Kyaw Tha Paw; Weil, Jeffrey C., 2008. The Canopy Horizontal Array Turbulence Study (CHATS)
    Oncley, Steven P.; Massman , William J. , Jr; Patton, Edward G., 2008. Turbulent pressure fluctuations measured during CHATS
    Buker, P.; Emberson, L.D.; Ashmore, M. R.; Cambridge, H. M.; Jacobs, C. M.; Massman , William J. , Jr; Muller, J.; Nikolov, N.; Novak, K.; Oksanen, E.; Schaub, M.; de la Torre, D., 2007. Comparison of different stomatal conductance algorithms for ozone flux modelling
    Esquilin, Aida E. Jimenez; Stromberger, Mary E.; Massman , William J. , Jr; Frank, John M.; Shepperd, Wayne D., 2007. Microbial community structure and activity in a Colorado Rocky Mountain forest soil scarred by slash pile burning
    Musselman, Robert (Bob) C.; Lefohn, Allen S.; Massman , William J. , Jr; Heath, Robert L., 2006. A critical review and analysis of the use of exposure- and flux-based ozone indices for predicting vegetation effects
    Buker, P.; Emberson, L. D.; Ashmore, M. R.; Gerosa, G.; Jacobs, C.; Massman , William J. , Jr; Muller, J.; Nikolov, N.; Novak, K.; Oksanen, E.; De La Torre, D.; Tuovinen, J. -P., 2006. Comparison of different stomatal conductance algorithms for ozone flux modelling [Proceedings]
    Liu, Heping; Randerson, James T.; Lindfors, Jamie; Massman , William J. , Jr; Foken, Thomas, 2006. Consequences of incomplete surface energy balance closure for CO2 fluxes from open-path CO2/H2O infrared gas analyzers
    Wieser, G.; Matyssek, R.; Musselman, Robert (Bob) C.; Lefohn, A. S.; Massman , William J. , Jr, 2006. Glossary: Definitions of relevancy for the 'flux concept' in ozone risk assessment
    Massman , William J. , Jr; Frank, J. M.; Jimenez Esquilin, A. E.; Stromberger, M. E.; Shepperd, W. D., 2006. Long term consequences of a controlled slash burn and slash mastication to soil moisture and CO2 at a southern Colorado site
    Emberson, L. D.; Massman , William J. , Jr; Buker, P.; Soja, G.; Van De Sand, I.; Mills, G.; Jacobs, C., 2006. The development, evaluation, and application of O3 flux and flux-response models for additional agricultural crops
    Musselman, Robert (Bob) C.; Massman , William J. , Jr; Frank, John M.; Korfmacher, John L., 2005. The temporal dynamics of carbon dioxide under snow in a high elevation Rocky Mountain subalpine forest and meadow
    Takle, Eugene S.; Massman , William J. , Jr; Brandle, James R.; Schmidt, R. A.; Zhou, Xinhua; Litvina, Irina V.; Garcia, Rick; Doyle, Geoffrey; Rice, Charles W., 2004. Influence of high-frequency ambient pressure pumping on carbon dioxide efflux from soil
    Takle, Eugene S.; Brandle, James R.; Schmidt, R. A.; Garcia, Rick; Litvina, Irina V.; Massman , William J. , Jr; Zhou, Xinhua; Doyle, Geoffrey; Rice, Charles W., 2003. High-frequency pressure variations in the vicinity of a surface CO2 flux chamber
    Massman , William J. , Jr; Frank, John M.; Shepperd, W. D.; Platten, M. J., 2003. In situ soil temperature and heat flux measurements during controlled surface burns at a southern Colorado forest site
    Massman , William J. , Jr; Frank, J. M.; Massman, S. M.; Shepperd, W. D., 2003. Performance of high temperature heat flux plates and soil moisture probes during controlled surface fires
    Massman , William J. , Jr; Finnigan, J.; Billesbach, D.; Miller, S.; Black, A.; Amiro, B.; Law, B.; Lee, X.; Mahrt, L.; Dahlman, R.; Foken, T., 2003. Summary and synthesis of recommendations of the AmeriFlux Workshop on standardization of flux analysis and diagnostics; Corvallis, Oregon; August 2002
    Takle, E. S.; Brandle, J. R.; Schmidt, R. A.; Garcia, R.; Litvina, I. V.; Doyle, G.; Zhou, X.; Hou, Q.; Rice, C. W.; Massman , William J. , Jr, 2000. Pressure pumping of carbon dioxide from soil
    Massman , William J. , Jr; Sommerfeld, R. A.; Mosier, A. R.; Zeller, K. F.; Hehn, T.J .; Rochelle, S. G., 1997. A model investigation of turbulence-driven pressure-pumping effects on the rate of diffusion of CO2, N2O, and CH4 through layered snowpacks
    Sommerfeld, Richard A.; Massman , William J. , Jr; Musselman, Robert (Bob) C., 1996. Diffusional flux of CO2 through snow: Spatial and temporal variability among alpine-subalpine sites
    Massman , William J. , Jr; Sommerfeld, Richard; Zeller, Karl; Hehn, Ted; Hudnell, Laura; Rochelle, Shannon, 1995. CO2 flux through a Wyoming seasonal snowpack: Diffusional and pressure pumping effects
    Musselman, Robert (Bob) C.; Wooldridge, Gene L.; Massman , William J. , Jr; Sommerfeld, Richard A., 1995. Wind and ecosystem response at the GLEES
    An analysis of seventeen years of eddy covariance data using a Bayesian statistical model based on the two-source energy and canopy snow mass balance showed a decrease in sublimation in a subalpine forest following a spruce beetle outbreak.
    Snow sublimation is a major component of the annual water budget across the Front Range where recent bark beetle outbreaks have dramatically changed the forest canopy structure. A seventeen year study at the Glacier Lakes Ecosystem Experiments Site (GLEES) in Wyoming revealed that sublimation decreased following a spruce beetle outbreak due to reduced canopy intercepted snowfall.
    As prescribed fires become more popular among land managers, there's an increasing need to analyze the relationship between fire and soil. As wildfires and prescribed fires burn through forests, they consequentially alter the soil compositions. RMRS scientists have developed a new model to better simulate soil heating and evaporation rates.
    The eddy covariance technique is used worldwide to measure the exchange of energy and mass between ecosystems and the atmosphere. Data from these flux sites are combined across continental and global networks and used to calibrate climate models and to inform water and carbon policy. Yet, at a vast majority of these sites, there is surface energy imbalance, bringing into question the accuracy of these measurements.
    In the Rocky Mountains, bark beetles have become a major agent of change. Over the past two decades, the spruce beetle has disrupted forests in British Columbia, Canada, Alaska and the western United States. Rocky Mountain Research Station scientists conducted a study at the Glacier Lakes Ecosystem Experiments Site (GLEES), a high-elevation watershed research site located in the Snowy Range of southeast Wyoming, to determine how a spruce beetle epidemic causes ecosystems to use less carbon and water.
    High Soil Temperature Data Archive - From Prescribed Fires and Wildfires across the Western US.
    Increasing use of prescribed fire by land managers and increasing likelihood of wildfires due to climate change creates a need to improve tools modelling extreme heating of soils during fires. Rocky Mountain Research scientist William Massman addressed this issue by developing and testing of a novel numerical model of soil evaporation and transport of heat, soil moisture, and water vapor under extreme conditions produced by wildfires.
    Sonic anemometry is fundamental to all eddy-covariance studies of surface energy and ecosystem carbon and water balance. Recent studies have shown some anemometers underestimate vertical wind.