Gabriel Katul | Duke University (original) (raw)

Gabriel G. Katul received his B.E. degree in 1988 at the American University of Beirut (Beirut, Lebanon), his M.S. degree in 1990 at Oregon State University (Corvallis, OR) and his Ph.D degree in 1993 at the University of California in Davis (Davis, CA). He currently holds a distinguished Professorship in Hydrology and Micrometeorology at the Department of Civil and Environmental Engineering at Duke University (Durham, NC). He was a visiting fellow at University of Virginia (USA) in 1997, the Commonwealth Science and Industrial Research Organization (Australia) in 2002, the University of Helsinki (Finland) in 2009, the FulBright-Italy Distinguished Fellow at Politecnico di Torino (Italy) in 2010, the École polytechnique fédérale de Lausanne (Switzerland) in 2013, Nagoya University (Japan) in 2014, University of Helsinki (Finland) in 2017, the Karlsruher Institute for Technology (Germany) in 2017, Princeton University (USA) in 2020, and CzechGlobe (Brno - Czech Republic) in 2023. He received several honorary awards, including the inspirational teaching award by the students of the School of the Environment at Duke University (in 1994 and 1996), an honorary certificate by La Seccion de Agrofisica de la Sociedad Cubana de Fisica in Habana (in 1998), the Macelwane medal and became thereafter a fellow of the American Geophysical Union (in 2002), the editor’s citation for excellence in refereeing from the American Geophysical Union (in 2008), the Hydrologic Science Award from the American Geophysical Union (in 2012), the John Dalton medal from the European Geosciences Union (in 2018), and the Outstanding Achievements in Biometeorology Award from the American Meteorological Society (in 2021) and later became an elected fellow of the American Meteorological Society (in 2024). Katul was elected to the National Academy of Engineering (in 2023) for his contributions in eco-hydrology and environmental fluid mechanics. He served as the Secretary General for the Hydrologic Science Section at the American Geophysical Union (2006-2008). His research focuses on micro-meteorology and near-surface hydrology with emphasis on heat, momentum, carbon dioxide, water vapor, ozone, particulate matter (including aerosols, pollen, and seeds) and water transport in the soil-plant-atmosphere system as well as their implications to a plethora of hydrological, ecological, atmospheric and climate change related problems.

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Papers by Gabriel Katul

Research paper thumbnail of Are the effects of large scale flow conditions really lost through the turbulent cascade

Geophysical research …, Jan 1, 2003

Research paper thumbnail of Wind-induced Leaf Transpiration

Wind-induced Leaf Transpiration

Research paper thumbnail of Interaction effects of CO2 and nutrient supplies on carbon cycling and sequestration in a pine forest

Under elevated CO2, the enhancement in the amount of carbon (C) sequestered in woody biomass of f... more Under elevated CO2, the enhancement in the amount of carbon (C) sequestered in woody biomass of forests is controlled by availability of other resources that influence growth, such as nutrients and water. At the Duke Forest FACE site, a large growth response of woody tissue in a loblolly pine forest was transient, settling after three years at a marginal gain.

Research paper thumbnail of Detto, M., A. Molini, G. Katul, P. Stoy, S. Palmroth, and D. Baldocchi (2012), Causality and Persistence in Ecological Systems: A Nonparametric Spectral Granger Causality Approach, The American Naturalist

Causality and Persistence in Ecological Systems: A Nonparametric Spectral Granger Causality Appro... more Causality and Persistence in Ecological Systems: A Nonparametric Spectral Granger Causality Approach,

Research paper thumbnail of Water cycling in a Bornean tropical rain forest under current and projected precipitation scenarios

Research paper thumbnail of Flume experiments on wind induced flow in static water bodies in the presence of protruding vegetation

Advances in Water Resources, 2015

Research paper thumbnail of Existence of k⁻¹ power-law scaling in the equilibrium regions of wall-bounded turbulence explained by Heisenberg's eddy viscosity

Physical review. E, Statistical, nonlinear, and soft matter physics, 2012

The existence of a "-1" power-law scaling at low wavenumbers in the longitudinal veloci... more The existence of a "-1" power-law scaling at low wavenumbers in the longitudinal velocity spectrum of wall-bounded turbulence was explained by multiple mechanisms; however, experimental support has not been uniform across laboratory studies. This letter shows that Heisenberg's eddy viscosity approach can provide a theoretical framework that bridges these multiple mechanisms and explains the elusiveness of the "-1" power law in some experiments. Novel theoretical outcomes are conjectured about the role of intermittency and very-large scale motions in modifying the k⁻¹ scaling.

Research paper thumbnail of Variability in net ecosystem exchange from hourly to inter-annual time scales at adjacent pine and hardwood forests: a wavelet analysis

Tree physiology, 2005

Orthonormal wavelet transformation (OWT) is a computationally efficient technique for quantifying... more Orthonormal wavelet transformation (OWT) is a computationally efficient technique for quantifying underlying frequencies in nonstationary and gap-infested time series, such as eddy-covariance-measured net ecosystem exchange of CO2 (NEE). We employed OWT to analyze the frequency characteristics of synchronously measured and modeled NEE at adjacent pine (PP) and hardwood (HW) ecosystems. Wavelet cospectral analysis showed that NEE at PP was more correlated to light and vapor pressure deficit at the daily time scale, and NEE at HW was more correlated to leaf area index (LAI) and temperature, especially soil temperature, at seasonal time scales. Models were required to disentangle the impacts of environmental drivers on the components of NEE, ecosystem carbon assimilation (Ac) and ecosystem respiration (RE). Sensitivity analyses revealed that using air temperature rather than soil temperature in RE models improved the modeled wavelet spectral frequency response on time scales longer tha...

Research paper thumbnail of Sensible and latent heat flux predictions using conditional sampling methods

Research paper thumbnail of Predicting Scalar Source-Sink and Flux Distributions Within a Forest Canopy Using a 2-D Lagrangian Stochastic Dispersion Model

Research paper thumbnail of The application of a scanning, water Raman-lidar as a probe of the atmospheric boundary layer

IEEE Transactions on Geoscience and Remote Sensing, 1993

A scanning water Raman-lidar, designed and constructed to study surface-atmosphere processes with... more A scanning water Raman-lidar, designed and constructed to study surface-atmosphere processes with high spatial and temporal resolution is described. It is shown that the lidar is able to measure the absolute water content and then calculate evaporative fluxes and other atmospheric parameters quickly over relatively large areas. This capability provides new opportunities for the study of microscale atmospheric processes. Examples

Research paper thumbnail of Onset of water stress, hysteresis in plant conductance, and hydraulic lift: Scaling soil water dynamics from millimeters to meters

Water Resources Research, 2008

Research paper thumbnail of Wind Induced Turbulence in Static Water without and with the Presence of Protruded Flexible Oscillating Vegetation

Research paper thumbnail of Wind shear induced wave-turbulence interaction in quiescent water in presence of flexible protruding obstacles

Research paper thumbnail of Surface heterogeneity and its signature in higher-order scalar similarity relationships

Agricultural and Forest Meteorology, 2008

Over the past three decades, a number of field experiments have suggested that land-cover heterog... more Over the past three decades, a number of field experiments have suggested that land-cover heterogeneity (LCH) impacts Monin and Obukhov (M–O) scaling, when applied to second-order statistics of temperature (T), water vapor (q), and CO2 (c) fluctuations. To further explore how LCH modifies M–O scaling for second-order statistics, 2 years of atmospheric surface layer (ASL) measurements, conducted above a Mediterranean

Research paper thumbnail of MEETING GLOBAL POLICY COMMITMENTS Carbon Sequestration and Southern Pine Forests

Research paper thumbnail of Soil water depletion by oak trees and the influence of root water uptake on the moisture content spatial statistics

Water Resources Research, 1997

The space-time statistical structure of soil water uptake by oak trees was investigated in a 3.1-... more The space-time statistical structure of soil water uptake by oak trees was investigated in a 3.1-m-diameter closed top chamber using a three-dimensional measurement grid of soil moisture and pressure, and measurements of tree transpiration. Using the time domain reflectometry (TDR) measured moisture content, resistance block measured soil water pressure, and a compact constant head permeameter measured saturated hydraulic conductivity, the

Research paper thumbnail of Vertical variability and effect of stability on turbulence characteristics down to the floor of a pine forest

Tellus Series B-chemical and Physical Meteorology, 2007

Among the fundamental problems in canopy turbulence, particularly near the forest floor, remain t... more Among the fundamental problems in canopy turbulence, particularly near the forest floor, remain the local diabatic effects and linkages between turbulent length scales and the canopy morphology. To progress on these problems, mean and higher order turbulence statistics are collected in a uniform pine forest across a wide range of atmospheric stability conditions using five 3-D anemometers in the subcanopy.

Research paper thumbnail of Soil Moisture Feedbacks on Convection Triggers: The Role of Soil-Plant Hydrodynamics

Journal of Hydrometeorology, 2009

The linkages between soil moisture dynamics and convection triggers, defined here as the first cr... more The linkages between soil moisture dynamics and convection triggers, defined here as the first crossing between the boundary layer height (hBL) and lifting condensation level (hLCL), are complicated by a large number of interacting processes occurring over a wide range of space and time scales. To progress on this problem, a soil-plant hydrodynamics model was coupled to a simplified ABL

Research paper thumbnail of A Stochastic-Dynamical Approach to Snow Accumulation-Melting in a Changing Climate

High elevation snow-melt runoff represents one of the main sources of freshwater in many differen... more High elevation snow-melt runoff represents one of the main sources of freshwater in many different regions of the world, e.g. Western North America, where as much as 75% of water supplies are delivered from snowmelt. This resource is sensitive to climatic fluctuations, as changes in the precipitation regime have been proven to affect both the total runoff volume and the

Research paper thumbnail of Are the effects of large scale flow conditions really lost through the turbulent cascade

Geophysical research …, Jan 1, 2003

Research paper thumbnail of Wind-induced Leaf Transpiration

Wind-induced Leaf Transpiration

Research paper thumbnail of Interaction effects of CO2 and nutrient supplies on carbon cycling and sequestration in a pine forest

Under elevated CO2, the enhancement in the amount of carbon (C) sequestered in woody biomass of f... more Under elevated CO2, the enhancement in the amount of carbon (C) sequestered in woody biomass of forests is controlled by availability of other resources that influence growth, such as nutrients and water. At the Duke Forest FACE site, a large growth response of woody tissue in a loblolly pine forest was transient, settling after three years at a marginal gain.

Research paper thumbnail of Detto, M., A. Molini, G. Katul, P. Stoy, S. Palmroth, and D. Baldocchi (2012), Causality and Persistence in Ecological Systems: A Nonparametric Spectral Granger Causality Approach, The American Naturalist

Causality and Persistence in Ecological Systems: A Nonparametric Spectral Granger Causality Appro... more Causality and Persistence in Ecological Systems: A Nonparametric Spectral Granger Causality Approach,

Research paper thumbnail of Water cycling in a Bornean tropical rain forest under current and projected precipitation scenarios

Research paper thumbnail of Flume experiments on wind induced flow in static water bodies in the presence of protruding vegetation

Advances in Water Resources, 2015

Research paper thumbnail of Existence of k⁻¹ power-law scaling in the equilibrium regions of wall-bounded turbulence explained by Heisenberg's eddy viscosity

Physical review. E, Statistical, nonlinear, and soft matter physics, 2012

The existence of a "-1" power-law scaling at low wavenumbers in the longitudinal veloci... more The existence of a "-1" power-law scaling at low wavenumbers in the longitudinal velocity spectrum of wall-bounded turbulence was explained by multiple mechanisms; however, experimental support has not been uniform across laboratory studies. This letter shows that Heisenberg's eddy viscosity approach can provide a theoretical framework that bridges these multiple mechanisms and explains the elusiveness of the "-1" power law in some experiments. Novel theoretical outcomes are conjectured about the role of intermittency and very-large scale motions in modifying the k⁻¹ scaling.

Research paper thumbnail of Variability in net ecosystem exchange from hourly to inter-annual time scales at adjacent pine and hardwood forests: a wavelet analysis

Tree physiology, 2005

Orthonormal wavelet transformation (OWT) is a computationally efficient technique for quantifying... more Orthonormal wavelet transformation (OWT) is a computationally efficient technique for quantifying underlying frequencies in nonstationary and gap-infested time series, such as eddy-covariance-measured net ecosystem exchange of CO2 (NEE). We employed OWT to analyze the frequency characteristics of synchronously measured and modeled NEE at adjacent pine (PP) and hardwood (HW) ecosystems. Wavelet cospectral analysis showed that NEE at PP was more correlated to light and vapor pressure deficit at the daily time scale, and NEE at HW was more correlated to leaf area index (LAI) and temperature, especially soil temperature, at seasonal time scales. Models were required to disentangle the impacts of environmental drivers on the components of NEE, ecosystem carbon assimilation (Ac) and ecosystem respiration (RE). Sensitivity analyses revealed that using air temperature rather than soil temperature in RE models improved the modeled wavelet spectral frequency response on time scales longer tha...

Research paper thumbnail of Sensible and latent heat flux predictions using conditional sampling methods

Research paper thumbnail of Predicting Scalar Source-Sink and Flux Distributions Within a Forest Canopy Using a 2-D Lagrangian Stochastic Dispersion Model

Research paper thumbnail of The application of a scanning, water Raman-lidar as a probe of the atmospheric boundary layer

IEEE Transactions on Geoscience and Remote Sensing, 1993

A scanning water Raman-lidar, designed and constructed to study surface-atmosphere processes with... more A scanning water Raman-lidar, designed and constructed to study surface-atmosphere processes with high spatial and temporal resolution is described. It is shown that the lidar is able to measure the absolute water content and then calculate evaporative fluxes and other atmospheric parameters quickly over relatively large areas. This capability provides new opportunities for the study of microscale atmospheric processes. Examples

Research paper thumbnail of Onset of water stress, hysteresis in plant conductance, and hydraulic lift: Scaling soil water dynamics from millimeters to meters

Water Resources Research, 2008

Research paper thumbnail of Wind Induced Turbulence in Static Water without and with the Presence of Protruded Flexible Oscillating Vegetation

Research paper thumbnail of Wind shear induced wave-turbulence interaction in quiescent water in presence of flexible protruding obstacles

Research paper thumbnail of Surface heterogeneity and its signature in higher-order scalar similarity relationships

Agricultural and Forest Meteorology, 2008

Over the past three decades, a number of field experiments have suggested that land-cover heterog... more Over the past three decades, a number of field experiments have suggested that land-cover heterogeneity (LCH) impacts Monin and Obukhov (M–O) scaling, when applied to second-order statistics of temperature (T), water vapor (q), and CO2 (c) fluctuations. To further explore how LCH modifies M–O scaling for second-order statistics, 2 years of atmospheric surface layer (ASL) measurements, conducted above a Mediterranean

Research paper thumbnail of MEETING GLOBAL POLICY COMMITMENTS Carbon Sequestration and Southern Pine Forests

Research paper thumbnail of Soil water depletion by oak trees and the influence of root water uptake on the moisture content spatial statistics

Water Resources Research, 1997

The space-time statistical structure of soil water uptake by oak trees was investigated in a 3.1-... more The space-time statistical structure of soil water uptake by oak trees was investigated in a 3.1-m-diameter closed top chamber using a three-dimensional measurement grid of soil moisture and pressure, and measurements of tree transpiration. Using the time domain reflectometry (TDR) measured moisture content, resistance block measured soil water pressure, and a compact constant head permeameter measured saturated hydraulic conductivity, the

Research paper thumbnail of Vertical variability and effect of stability on turbulence characteristics down to the floor of a pine forest

Tellus Series B-chemical and Physical Meteorology, 2007

Among the fundamental problems in canopy turbulence, particularly near the forest floor, remain t... more Among the fundamental problems in canopy turbulence, particularly near the forest floor, remain the local diabatic effects and linkages between turbulent length scales and the canopy morphology. To progress on these problems, mean and higher order turbulence statistics are collected in a uniform pine forest across a wide range of atmospheric stability conditions using five 3-D anemometers in the subcanopy.

Research paper thumbnail of Soil Moisture Feedbacks on Convection Triggers: The Role of Soil-Plant Hydrodynamics

Journal of Hydrometeorology, 2009

The linkages between soil moisture dynamics and convection triggers, defined here as the first cr... more The linkages between soil moisture dynamics and convection triggers, defined here as the first crossing between the boundary layer height (hBL) and lifting condensation level (hLCL), are complicated by a large number of interacting processes occurring over a wide range of space and time scales. To progress on this problem, a soil-plant hydrodynamics model was coupled to a simplified ABL

Research paper thumbnail of A Stochastic-Dynamical Approach to Snow Accumulation-Melting in a Changing Climate

High elevation snow-melt runoff represents one of the main sources of freshwater in many differen... more High elevation snow-melt runoff represents one of the main sources of freshwater in many different regions of the world, e.g. Western North America, where as much as 75% of water supplies are delivered from snowmelt. This resource is sensitive to climatic fluctuations, as changes in the precipitation regime have been proven to affect both the total runoff volume and the