A5029655426- Methane Hydrates and Related Phenomena
- Soil Moisture and Remote Sensing
- Seismic Waves and Analysis
- Soil Carbon and Nitrogen Dynamics
- Atmospheric and Environmental Gas Dynamics
- Climate change and permafrost
- Plant Water Relations and Carbon Dynamics
- Peatlands and Wetlands Ecology
- Geophysics and Gravity Measurements
- Ionosphere and magnetosphere dynamics
- Climate variability and models
- Cryospheric studies and observations
- Geology and Paleoclimatology Research
- Fire effects on ecosystems
- Rangeland and Wildlife Management
- Soil and Water Nutrient Dynamics
- Atmospheric chemistry and aerosols
- Microbial Community Ecology and Physiology
- Soil and Unsaturated Flow
- Meteorological Phenomena and Simulations
- Isotope Analysis in Ecology
- Hydrocarbon exploration and reservoir analysis
- Plant responses to elevated CO2
- Soil Geostatistics and Mapping
- Forest ecology and management
Lawrence Berkeley National Laboratory
2016-2025
University of California, Berkeley
2016-2025
Ecosystem Sciences
2016-2025
University of Nebraska–Lincoln
2015-2024
Berkeley College
2014-2022
NASA Earth Science
2003-2020
Environmental Energy & Engineering
2015
University of Zurich
2014
Oregon State University
2013
Max Planck Institute for Biogeochemistry
2013
Several states and countries have adopted targets for deep reductions in greenhouse gas emissions by 2050, but there has been little physically realistic modeling of the energy economic transformations required. We analyzed infrastructure technology path required to meet California's goal an 80% reduction below 1990 levels, using detailed stocks, resource constraints, electricity system operability. found that technically feasible levels efficiency decarbonized supply alone are not...
Warming the top meter increased soil CO 2 production by 37%, with 40% of response coming from soils more than 15 centimeters deep.
Abstract Soil carbon (C) is a critical component of Earth system models (ESMs), and its diverse representations are major source the large spread across in terrestrial C sink from third to fifth assessment reports Intergovernmental Panel on Climate Change (IPCC). Improving soil projections high priority for modeling future IPCC other assessments. To achieve this goal, we suggest that (1) model structures should reflect real‐world processes, (2) parameters be calibrated match outputs with...
Abstract. Soils are a crucial component of the Earth system; they comprise large portion terrestrial carbon stocks, mediate supply and demand nutrients, influence overall response ecosystems to perturbations. In this paper, we develop new soil biogeochemistry model for Community Land Model, version 4 (CLM4). The includes vertical dimension (C) nitrogen (N) pools transformations, more realistic treatment mineral N pools, flexible dynamics decomposing carbon, radiocarbon (14C) tracer. We...
Estimating carbon (C) balance in erosional and depositional landscapes is complicated by the effects of soil redistribution on both net primary productivity (NPP) decomposition. Recent studies are contradictory as to whether erosion does or not constitute a C sink. Here we clarify conceptual basis for how can Specifically, criterion an sink that dynamic replacement eroded C, reduced decomposition rates sites, must together more than compensate losses. This fact met many settings, thus...
Summary Soil minerals are known to influence the biological stability of soil organic matter (SOM). Our study aimed relate properties mineral matrix its ability protect C against decomposition in acid soils. We used amount hydroxyl ions released after exposure NaF solution establish a reactivity gradient spanning 12 subsoil horizons collected from 10 different locations. The represent six orders and diverse geological parent materials. Phyllosilicates were characterized by X‐ray diffraction...
Microbial communities and their associated enzyme activities affect the amount chemical quality of carbon (C) in soils. Increasing nitrogen (N) deposition, particularly N-rich tropical forests, is likely to change composition behavior microbial feed back on ecosystem structure function. This study presents a novel assessment mechanistic links between responses N deposition shifts soil organic matter (SOM) quantity. We used phospholipid fatty acid (PLFA) analysis assays soils assess community...
The life cycle greenhouse gas (GHG) emissions induced by increased biofuel consumption are highly uncertain: individual estimates vary from each other and has a wide intrinsic error band. Using reduced-form model, we estimated that the bounding range for indirect land-use change (ILUC) US corn ethanol expansion was 10 to 340 g CO2 MJ−1. Considering various probability distributions model parameters, broadest 95% central interval, i.e., between 2.5 97.5%ile values, ranged 21 142 CO2e ILUC...
Abstract Soil is the largest terrestrial reservoir of organic carbon and central for climate change mitigation carbon-climate feedbacks. Chemical physical associations soil with minerals play a critical role in storage, but amount global capacity storage this form remain unquantified. Here, we produce spatially-resolved estimates mineral-associated stocks carbon-storage by analyzing 1144 globally-distributed profiles. We show that current total 899 Pg C to depth 1 m non-permafrost mineral...
Abstract. Terrestrial net CH4 surface fluxes often represent the difference between much larger gross production and consumption depend on multiple physical, biological, chemical mechanisms that are poorly understood represented in regional- global-scale biogeochemical models. To characterize uncertainties, study feedbacks climate, to guide future model development experimentation, we developed tested a new biogeochemistry (CLM4Me) integrated land component (Community Land Model; CLM4) of...
Numerous studies have demonstrated that fertilization with nutrients such as nitrogen, phosphorus, and potassium increases plant productivity in both natural managed ecosystems, demonstrating primary is nutrient limited most terrestrial ecosystems. In contrast, it has been heterotrophic microbial communities soil are primarily by organic carbon or energy. While this concept of contrasting limitations, is, limitation, based on strong evidence we review paper, often ignored discussions...
Large datasets of greenhouse gas and energy surface-atmosphere fluxes measured with the eddy-covariance technique (e.g., FLUXNET2015, AmeriFlux BASE) are widely used to benchmark models remote-sensing products. This study addresses one major challenges facing model-data integration: To what spatial extent do flux measurements taken at individual sites reflect model- or satellite-based grid cells? We evaluate footprints—the temporally dynamic source areas that contribute fluxes—and...
Accurately simulating gross primary productivity (GPP) in terrestrial ecosystem models is critical because errors simulated GPP propagate through the model to introduce additional biomass and other fluxes. We evaluated simulated, daily average from 26 against estimated at 39 eddy covariance flux tower sites across United States Canada. None of this study match within observed uncertainty. On average, overestimate winter, spring, fall, underestimate summer. Models overpredicted under dry...
Abstract The Intergovernmental Panel on Climate Change (IPCC) Special Report Global Warming of 1.5°C points to the need for carbon neutrality by mid‐century. Achieving this in United States only 30 years will be challenging, and practical pathways detailing technologies, infrastructure, costs, tradeoffs involved are needed. Modeling entire U.S. energy industrial system with new analysis tools that capture synergies not represented sector‐specific or integrated assessment models, we created...
Abstract. We present one of the first estimates global distribution CO2 surface fluxes using total column measurements retrieved by SRON-KIT RemoTeC algorithm from Greenhouse gases Observing SATellite (GOSAT). derive optimized June 2009 to December 2010. estimate use as baselines for comparing GOSAT data-derived fluxes. Assimilating only data, we can reproduce observed time series at and TCCON sites in tropics northern extra-tropics. In contrast, southern extra-tropics XCO2 leads enhanced...
Biochar may contribute to climate change mitigation at negative cost by sequestering photosynthetically fixed carbon in soil while increasing crop yields. The magnitude of biochar's potential this regard will depend on yield benefits, which have not been well-characterized across different soils and biochars. Using data from 84 studies, we employ meta-analytical, missing data, semiparametric statistical methods explain heterogeneity responses soils, biochars, agricultural management factors,...