A5025865785- Plant Water Relations and Carbon Dynamics
- Atmospheric and Environmental Gas Dynamics
- Climate variability and models
- Remote Sensing in Agriculture
- Plant responses to elevated CO2
- Meteorological Phenomena and Simulations
- Soil Carbon and Nitrogen Dynamics
- Climate change impacts on agriculture
- Atmospheric Ozone and Climate
- Soil and Unsaturated Flow
- Tree-ring climate responses
- Ecology and Vegetation Dynamics Studies
- Urban Heat Island Mitigation
- Irrigation Practices and Water Management
- Remote Sensing and Land Use
- Rice Cultivation and Yield Improvement
- Bioenergy crop production and management
- Computer Graphics and Visualization Techniques
- Environmental and Agricultural Sciences
- Water-Energy-Food Nexus Studies
- Spectroscopy and Chemometric Analyses
- Soil Geostatistics and Mapping
- Land Use and Ecosystem Services
- Greenhouse Technology and Climate Control
- 3D Shape Modeling and Analysis
The Ohio State University
2019-2024
Jet Propulsion Laboratory
2012-2019
Carbon Cycle and Ecosystems
2019
University of California, Los Angeles
2014-2017
California Institute of Technology
2012-2015
Max Planck Institute for Biogeochemistry
2010-2013
Max Planck Society
2011-2012
University of Illinois Urbana-Champaign
2010
Duke University
2005-2006
University of Virginia
2002-2006
INTRODUCTION Reliable estimation of gross primary production (GPP) from landscape to global scales is pivotal a wide range ecological research areas, such as carbon-climate feedbacks, and agricultural applications, crop yield drought monitoring. However, measuring GPP at these remains major challenge. Solar-induced chlorophyll fluorescence (SIF) signal emitted directly the core photosynthetic machinery. SIF integrates complex plant physiological functions in vivo reflect dynamics real time....
Abstract. Terrestrial biosphere models typically abstract the immense diversity of vegetation forms and functioning into a relatively small set predefined semi-empirical plant functional types (PFTs). There is growing evidence, however, from field ecology community as well modelling studies that current PFT schemes may not adequately represent observed variations in traits their effect on ecosystem functioning. In this paper, we introduce Jena Diversity-Dynamic Global Vegetation Model...
Estimating transpiration and water flow in trees remains a major challenge for quantifying exchange between the biosphere atmosphere. We develop finite element tree crown hydrodynamics (FETCH) model that uses porous media equations an explicit three‐dimensional branching fractal tree‐crown system. It also incorporates first‐order canopy‐air turbulence closure to generate external forcing of use FETCH conduct sensitivity analysis transpirational dynamics changes canopy structure via two...
Abstract Recent studies have utilized coarse spatial and temporal resolution remotely sensed solar‐induced fluorescence (SIF) for modeling terrestrial gross primary productivity (GPP) at regional scales. Although these demonstrated the potential of SIF, there been concerns about ecophysiological basis relationship between SIF GPP in different environmental conditions. Launched 2014, Orbiting Carbon Observatory‐2 (OCO‐2) has enabled fine‐scale (1.3 by 2.5 km) retrievals that are comparable...
Vegetation acclimation to changing climate, in particular elevated atmospheric concentrations of carbon dioxide (CO 2 ), has been observed include modifications the biochemical and ecophysiological functioning leaves structural components canopy. These responses have potential significantly modify plant uptake surface energy partitioning, attributed with large‐scale changes hydrology over recent decades. While aggregated effects vegetation can be pronounced, they often result from subtle...
To meet emerging bioenergy demands, significant areas of the large-scale agricultural landscape Midwestern United States could be converted to second generation crops such as miscanthus and switchgrass. The high biomass productivity in a longer growing season linked tightly water use highlight potential for impact on hydrologic cycle region. This issue is further exacerbated by uncertainty response vegetation under elevated CO 2 temperature. We mechanistic multilayer canopy-root-soil model (...
The hypothesis that reducing chlorophyll content (Chl) can increase canopy photosynthesis in soybeans was tested using an advanced model of photosynthesis. relationship among leaf Chl, optical properties, and photosynthetic biochemical capacity measured 67 soybean (Glycine max) accessions showing large variation Chl. These relationships were integrated into a biophysical canopy-scale to simulate the intercanopy light environment carbon assimilation canopies with wild type, Chl-deficient...
Spanning 15% of the global ice-free terrestrial surface, agricultural lands provide an immense and near-term opportunity to address climate change, food, water security challenges. Through computationally informed breeding canopy structural traits away from those modern cultivars, we show that solutions exist increase productivity use efficiency, while increasing land-surface reflectivity offset greenhouse gas warming. Plants have evolved maximize capture radiation in upper leaves, thus...
Abstract. Canopy and aerodynamic conductances (gC gA) are two of the key land surface biophysical variables that control response schemes in climate models. Their representation is crucial for predicting transpiration (λET) evaporation (λEE) flux components terrestrial latent heat (λE), which has important implications global change water resource management. By physical integration radiometric temperature (TR) into an integrated framework Penman–Monteith Shuttleworth–Wallace models, we...
Abstract Thermal infrared sensing of evapotranspiration ( E ) through surface energy balance (SEB) models is challenging due to uncertainties in determining the aerodynamic conductance g A and inequalities between radiometric T R temperatures 0 ). We evaluated a novel analytical model, Surface Temperature Initiated Closure (STIC1.2), that physically integrates observations into combined Penman‐Monteith Shuttleworth‐Wallace (PM‐SW) framework for directly estimating , overcoming associated...
The goal of this study is to understand the interaction between belowground and aboveground ecohydrologic dynamics as facilitated by hydraulic redistribution. We analyze partitioning moisture energy tall understory vegetation, soil evaporation. Both competitive facilitative dependencies are examined using a shared resource model where serves common reservoir for different vegetation species. state altered addition withdrawal roots in conjunction with soil‐moisture transport. Vertical...
Abstract Here we demonstrate a novel method to physically integrate radiometric surface temperature ( T R ) into the Penman‐Monteith (PM) formulation for estimating terrestrial sensible and latent heat fluxes H λE in framework of modified Surface Temperature Initiated Closure (STIC). It combines data with standard energy balance closure models deriving hybrid scheme that does not require parameterization (or stomatal) aerodynamic conductances g S B ). STIC is formed by simultaneous solution...
Abstract Because of the possibility getting right answers for wrong reasons, predictive performance a complex systems model is not by itself reliable indicator hypothesis quality purposes scientific learning about processes. The structurally adequate should be an emergent property its functional performance. In this context, any Pareto trade‐off between measures versus indicates process‐level error in model; trade‐off, if it exists, that model's predictions are reasons. This paper...
Feedbacks between atmospheric processes like precipitation and land surface fluxes including evapotranspiration are difficult to observe, but critical for understanding the role of in Earth System. To quantify global surface-atmosphere feedbacks we use results a process network (PN) applied 251 eddy covariance sites from LaThuile database train neural across terrestrial surface. There is strong land–atmosphere coupling latent (LE) sensible heat flux (H) (P) during summer months temperate...
Soil heat flux (SHF) is a key component of the surface energy balance and driver soil physiochemical biological processes. Accurate estimation challenging due to variations in composition, overlying vegetation density phenology, highly variable environmental forcings. Existing SHF process-based data-driven methods have focused on midday landscape scale estimates that correspond satellite acquisitions, despite high variability displays at diurnal scales throughout growing season. Recently...
The ability to accurately predict land‐atmosphere exchange of mass, energy, and momentum over the coming century requires consideration plant biochemical, ecophysiological, structural acclimation modifications ambient environment. Amongst most important environmental changes experienced by terrestrial vegetation last has been increase in carbon dioxide (CO 2 ) concentrations, with a projected doubling CO from preindustrial levels middle this century. This change atmospheric composition...
[2] Surface and subsurface moisture dynamics are strongly influenced by the ability of vegetation to take up redistribute soil using hydraulic redistribution (HR). These in turn affect biogeochemical cycling through controls on decomposition mineralization rates ion transport. The goal this study is explore coupling between HR biogeochemistry a numerical model. We examine organic matter analyze whether differences induced influence long-term storage carbon movement nitrate ( NO 3−) ammonium...
Stomatal conductance (gs) is a key leaf-level function controlling water, carbon, and energy exchange between vegetation the surrounding environment. Conventionally, semi-empirical models have been used to model gs, but these require re-parameterization as ecosystems undergo phenological changes over growing season. In contrast, machine learning (ML) offer potential path overcome this problem are less interpretable than process-based models. This study explores ML an approach develop...
Soil heat flux (SHF) is a key component of the surface energy balance and driver soil physiochemical biological processes. Despite its importance accurate estimation hindered due to variations in composition, overlying vegetation density phenology, highly variable environmental forcings. These factors have challenged development robust models SHF, with modeling studies focused on mid-day conditions corresponding satellite overpass times, missing significant variability that occurs throughout...
Abstract. Dynamic Global Vegetation Models (DGVMs) typically abstract the immense diversity of vegetation forms and functioning into a relatively small set predefined semi-empirical Plant Functional Types (PFTs). There is growing evidence, however, from field ecology community as well modelling studies that current PFT schemes may not adequately represent observed variations in plant functional traits their effect on ecosystem functioning. In this paper, we introduce Jena Diversity DGVM...
Abstract Diagnosing and predicting evaporation through satellite‐based surface energy balance (SEB) land models (LSMs) faces challenges due to the non‐linear responses of aerodynamic ( g a ) stomatal conductance cs concurrent soil atmospheric drought. Despite soaring popularity refine formulation in LSMs by integrating soil‐plant hydraulics, SEB often overlook utility . This oversight is attributed overriding emphasis on reducing uncertainties lack coordination between these two modeling...