Current Research

Dr. Riggan is investigating the spatial patterns and rates of spread and energy release of large fires and effects on large-fire behavior of fire-altered winds, fuel loading and condition, and aerially delivered fire retardant and suppressants. He and his team are developing and applying airborne remote-sensing systems for the quantitative measurement of wildland fires and developing applications for making fire intelligence readily available to and interpretable by incident management teams during ongoing large fires. He is also co-principal investigator on an interagency study that is developing applications of fire observations by new satellite-based sensors, including the Visible Infrared Imaging Radiometer Suite (VIIRS), and is principal investigator for a bilateral research program and interagency working group on fire and environmental change in tropical ecosystems.

Research Interests

fire remote sensing, fire behavior, global consequences of wildland fire in tropical ecosystems

Past Research

Dr. Riggan has conducted research on remote measurement of wildfire properties; the biogeochemistry, primary production, plant community development, and effects of fire in Mediterranean ecosystems of California; and the global consequences of wildland fire in tropical ecosystems. He has been Principal Investigator and leader of the Forest Service/IBAMA Working Group on Fire and Environmental Change in Tropical Ecosystems and led eight airborne remote sensing campaigns in Brazil from 1992 through 2000 that made the first synoptic, quanitiative measurements of large wildland fires. He also managed interagency teams studying watershed-scale fires and fire effects on biogeochemistry and the atmosphere in 1984/85 in California and under sponsorship of the Defense Nuclear Agency in California and Canada in 1986 and 1987. Since 2000 he has led development of the FireMapper thermal-imaging radiometer and its application to measurement and monitoring of large wildland fires and forest drought stress and mortality in mixed conifer forest.

Why This Research is Important

Wildland fires continue to threaten life, property, natural resources, and ecosystems in the western United States. They are an important global source of greenhouse gas emissions to the atmosphere and can adversely affect air quality in both rural and urban settings for weeks at a time. Management of fires and their impacts requires strategic information, such as long-term changes in fire frequency and behavior or structural changes in ecosystems from burning, and tactical fire intelligence, such as current fire locations, intensity, and rates and direction of spread. Dr. Riggan's research has provided the remote sensing tools and systems to measure the physical properties of large wildland fires, and is providing the first synoptic and high-resolution measurements of fire behavior. His work with the Government of Brazil is estimating the rates and impacts of burning in tropical savanna and forests and seeking solutions to mitigate fire emissions of greenhouse gases and air pollutants with potentially regional or global consequences on climate change and human and ecosystem health.

Education

• University of Washington, College of Forest Resources, Doctor Of Philosophy Forest nutrition: measurement and simulation of growth and yield and nitrogen cycling in Douglas-fir forest 1979
• San Diego State University, B.S. Chemistry (with emphasis on analytical chemistry) and systems ecology 1973

Professional Experience

Awards & Recognition

Publications

• Schag, Gavin M.; Stow, Douglas A.; Riggan, Philip J.; Tissell, Robert G.; Coen, Janice L. 2021. Examining landscape-scale fuel and terrain controls of wildfire spread rates using repetitive airborne thermal infrared (ATIR) imagery.
• Grulke, Nancy ; Maxfield, Jason ; Riggan, Phillip ; Schrader-Patton, Charlie . 2020. Pre-emptive detection of mature pine drought stress using multispectral aerial imagery.
• Stow, Douglas ; Riggan, Philip ; Schag, Gavin ; Brewer, William ; Tissell, Robert ; Coen, Janice ; Storey, Emanuel . 2019. Assessing uncertainty and demonstrating potential for estimating fire rate of spread at landscape scales based on time sequential airborne thermal infrared imaging.
• Hudak, Andrew T.; Freeborn, Patrick H.; Lewis, Sarah A.; Hood, Sharon M.; Smith, Helen Y.; Hardy, Colin C.; Kremens, Robert J.; Butler, Bret W.; Teske, Casey; Tissell, Robert G.; Queen, Lloyd P.; Nordgren, Bryce L.; Bright, Benjamin C.; Morgan, Penelope; Riggan, Philip J.; Macholz, Lee; Lentile, Leigh B.; Riddering, James P.; Mathews, Edward E. 2018. The Cooney Ridge Fire Experiment: An early operation to relate pre-, active, and post-fire field and remotely sensed measurements.
• Uyeda, Kellie A.; Stow, Douglas A.; Roberts, Dar A.; Riggan, Philip J. 2017. Combining ground-based measurements and MODIS-based spectral vegetation indices to track biomass accumulation in post-fire chaparral.
• Lippitt, Christopher D.; Stow, Douglas A.; Riggan, Philip J. 2016. Application of the remote-sensing communication model to a time-sensitive wildfire remote-sensing system.
• Uyeda, Kellie A.; Stow, Douglas A.; O'Leary, John F.; Tague, Christina; Riggan, Philip J. 2016. Chaparral growth-ring analysis as an indicator of stand biomass development.
• Rachels, Diane H.; Stow, Douglas A.; O'Leary, John F.; Johnson, Harry D.; Riggan, Philip J. 2016. Chaparral recovery following a major fire with variable burn conditions.
• Uyeda, Kellie A.; Stow, Douglas A.; O'Leary, John F.; Schmidt, Ian T.; Riggan, Philip J. 2016. Spatial variation of fuel loading within varying aged stands of chaparral.
• Schmidt, Ian T.; O'Leary, John F.; Stow, Douglas A.; Uyeda, Kellie A.; Riggan, Philip. 2016. Use of ultra-high spatial resolution aerial imagery in the estimation of chaparral wildfire fuel loads.
• Uyeda, Kellie A.; Stow, Douglas A.; Riggan, Philip J. 2015. Tracking MODIS NDVI time series to estimate fuel accumulation.
• Stow, Douglas A.; Riggan, Philip J.; Storey, Emanual A.; Coulter, Lloyd L. 2014. Measuring fire spread rates from repeat pass airborne thermal infrared imagery.
• Coen, Janice L.; Riggan, Philip J. 2014. Simulation and thermal imaging of the 2006 Esperanza Wildfire in southern California: application of a coupled weather-wildland fire model.
• Coen, Janice L.; Cameron, Marques; Michalakes, John; Patton, Edward G.; Riggan, Philip J.; Yedinak, Kara M. 2012. WRF-Fire: coupled weather-wildland fire modeling with the weather research and forecasting model.
• Coen, J.L.; Riggan, Philip. 2011. A landscape-scale wildland fire study using coupled weather-wildland fire model and airborne remote sensing.
• Coleman, Tom W.; Grulke, Nancy E.; Daly, Miles; Godinez, Cesar; Schilling, Susan L.; Riggan, Philip J.; Seybold, Steven J. 2011. Coast live oak, Quercus agrifolia, susceptibility and response to goldspotted oak borer, Agrilus auroguttatus, injury in southern California.
• Riggan, Philip; Wolden, Lynn; Tissell, Bob; Weise, David; Coen, J. 2011. Remote sensing fire and fuels in southern California.
• Grulke, N.E.; Minnich, R.A.; Paine, T.; Riggan, P. 2010. Air pollution increases forest susceptibility to wildfires: a case study for the San Bernardino Mountains in southern California.
• Bytnerowicz, A.; Cayan, D.; Riggan, P.; Schilling, S.; Dawson, P.; Tyree, M.; Wolden, L.; Tissell, R.; Preisler, H. 2010. Analysis of the effects of combustion emissions and Santa Ana winds on ambient ozone during the October 2007 southern California wildfires.
• Riggan, P.J.; Tissell, R.G.; Lockwood, R.N. 2010. Remote measurement of the 1992 Tapera prescribed fire at the Reserva Ecologica do IBGE.
• Grulke, N.E.; Minnich, R.A.; Paine, T.D.; Seybold, S.J.; Chavez, D.J.; Fenn, M.E.; Riggan, P.J.; Dunn, A. 2009. Air pollution increases forest susceptibility to wildfires: A case study in the San Bernardino Mountains in southern California.
• Riggan, Philip J.; Tissell, Robert G. 2009. Airborne remote sensing of wildland fires.
• Riggan, P.; Hoffman, J.; Brass, J. 2009. Estimating fire properties by remote sensing.
• Lucatelli Dória de Araújo, Geraldo José, Jr..; Raposo Pereira, João Antônio; Vieira da Silva, Tânia Maria; Mafra, Helvécio; Brass, James A.; Lockwood, Robert N.; Higgins, Robert G.; Riggan, Philip J. 2008. Utilização Do Sensor Airdas (Airborne Infrared Disaster Assessment System) no monitoramento de desflorestamentos no norte do estado do mato grosso - Brasil.
• Meixner, T.; Fenn, Mark E.; Wohlgemuth, P.; Oxford, M.; Riggan, P. 2006. N saturation symptoms in chaparral catchments are not reversed by prescribed fire.
• Hoffman, James W.; Coulter, Lloyd L.; Riggan, Philip J. 2005. Rapid turn-around mapping of wildfires and disasters with airborne infrared imagery fro the new FireMapper 2.0 and Oilmapper systems.
• Riggan, P.J.; Tissell, R.G.; Lockwood, R.N.; Brass, J.A.; Pereira, J.A.R.; Miranda, H.S.; Miranda, A.C.; Campos, T.; Higgins, R. 2004. Remote measurement of energy and carbon flux from wildfires in Brazil.
• Radke, L.F.; Ward, D.E.; Riggan, P.J. 2001. A prescription for controlling the air pollution resulting from the use of prescribed biomass fire: clouds.
• Radke, L.F.; Clark, T.L.; Coen, J.L.; Walther, C.A.; Lockwood, R.N.; Riggan, P.J.; Brass, J.A.; Higgins, R.G. 2000. The wildfire experiment (WIFE): observations with airborne remote sensors.
• Miranda, A. C.; Miranda, H. S.; Lloyd, J.; Grace, J.; Francey, R. J.; Mcintyre, J. A.; Meir, P.; Riggan, P.; Lockwood, R.; Brass, J. 1997. Fluxes of carbon, water and energy over Brazilian cerrado: an analysis using eddy covariance and stable isotopes.
• Brass, James A.; Guild, Liane S.; Riggan, Philip J.; Ambrosia, Vincent G.; Lockwood, Robert N.; Joao, A. Pereira, Higgins. 1996. Characterizing Brazilian fire and estimating areas burned by using the Airborne Infrared Disaster Assessment System.
• Brass, James A.; Ambrosia, Vincent G.; Riggan, Philip J.; Sebesta, Paul D. 1996. Consequences of fire on aquatic nitrate and phosphate dynamics in Yellowstone National Park.
• Poth, Mark; Anderson, Iris Cofman; Miranda, Heloisa Sinatora; Miranda, Antonia Carlos; Riggan, Philip J. 1995. The magnitude and persistence of soil NO, N20, CH4, and C02 fluxes from burned tropical savanna in Brazil.
• Clarke, Keith C.; Brass, James A.; Riggan, Phillip J. 1994. A cellular automaton model of wildfire propagation and extinction.
• Riggan, P.J.; Lockwood, R.N.; Jacks, P.M.; Colver, C.G.; Weirich, F.; DeBano, L.F.; Brass, J.A. 1994. Effects of fire severity on nitrate mobilization in watersheds subject to chronic atmospheric deposition.
• Riggan, Philip J.; Franklin, Scott E.; Brass, James A.; Brooks, Fred E. 1994. Perspectives on fire management in Mediterranean ecosystems of southern California.
• Riggan, Philip J.; Brass, James A.; Lockwood, Robert N. 1993. Assessing fire emissions from tropical savanna and forests of central Brazil.
• Radke, Lawrence F.; Hegg, Dean A.; Hobbs, Peter V.; Nance, J.David; Lyons, Jamie H.; Laursen, Krista K.; Weiss, Raymond E.; Riggan, Phillip J.; Ward, Darold E. 1991. Particulate and trace gas emissions from large biomass fire in North America.
• Hegg, Dean A.; Radke, Lawrence F.; Hobbs, Peter V.; Rasmussen, Rei A.; Riggan, Philip J. 1990. Emissions of some trace gases from biomass fires.
• Hegg, Dean A.; Radke, Lawrence F.; Hobbs, Peter V.; Riggan, Philip J. 1988. Ammonia emissions from biomass burning.
• Anderson, Iris C.; Levine, Joel S.; Poth, Mark A.; Riggan, Philip J. 1988. Enhanced biogenic emissions of nitric oxide and nitrous oxide following surface biomass burning.
• Riggan, Philip J.; Goode, Suzanne; Jacks, Paula M.; Lockwood, Robert N. 1988. Interaction of fire and community development in chaparral of southern California.
• Cofer, Wesley R., III.; Levine, Joel S.; Sebacher, Daniel I.; Winstead, Edward L.; Riggan, Philip J.; Brass, James A.; Ambrosia, Vincent G. 1988. Particulate emissions from a mid-latitude prescribed chaparral fire.
• Cofer, Wesley R., III.; Levine, Joel S.; Riggan, Philip J.; Sebacher, Daniel I.; Winstead, Edward L.; Edwin F., Shaw, Jr..; Brass, James A.; Ambrosia, Vincent. G. 1988. Trace gas emissions from a mid-latitude prescribed chaparral fire.
• Hegg, Dean A.; Radke, Lawrence F.; Hobbs, Peter V.; Brock, Charles A.; Riggan, Phillip J. 1987. Nitrogen and sulfur emissions from the burning of forest products near large urban areas.
• Riggan, Philip J.; Franklin, Scott; Brass, James A. 1986. Fire and chaparral management at the chaparral/urban interface.
• Riggan, Philip J.; Lockwood, Robert N.; Lopez, Ernest N. 1985. Deposition and processing of airborne nitrogen pollutants in mediterranean-type ecosystems of southern California.
• Dougherty, Ron; Riggan, Philip J. 1982. Operational use of prescribed fire in southern California chaparral.

Research Highlights

Highlight	Title	Year
PSW-2011-23	Measuring Prescribed Burns in Tropical Savannas A remote-sensing based model has been developed that produces heat flux estimates that are highly consistent with in situ fire plume measurement ...	2011
PNW-2020-122	Remote Sensing Tools Preemptively Detect Drought-Stressed Pines with 80% Accuracy Large swaths of dead trees across a landscape pose an extreme fire hazard, as seen in the southern Sierra Nevada range of California. Researcher ...	2020
PSW-2014-100	Research Explains Deadly and Unexpected Fire Behavior of the 2006 Esperanza Fire in Southern California Simulations and thermal imaging of a wind-driven chaparral wildfire show the importance of fire-induced winds in the direction and velocity of f ...	2014
PSW-2013-089	Satellite-based Earth Observations Aid Fire Fighting and Fire Forecasting The Forest Service's Pacific Southwest Research Station, in association with multiple partners, has developed methods based on new sources of sa ...	2013