Walter C. Oechel
A5087838453- Climate change and permafrost
- Atmospheric and Environmental Gas Dynamics
- Cryospheric studies and observations
- Peatlands and Wetlands Ecology
- Plant Water Relations and Carbon Dynamics
- Geology and Paleoclimatology Research
- Methane Hydrates and Related Phenomena
- Climate variability and models
- Plant responses to elevated CO2
- Fire effects on ecosystems
- Arctic and Antarctic ice dynamics
- Lichen and fungal ecology
- Soil Carbon and Nitrogen Dynamics
- Rangeland and Wildlife Management
- Ecology and Vegetation Dynamics Studies
- Remote Sensing in Agriculture
- Geological Studies and Exploration
- Indigenous Studies and Ecology
- Bryophyte Studies and Records
- Atmospheric chemistry and aerosols
- Species Distribution and Climate Change
- Polar Research and Ecology
- Smart Materials for Construction
- Coastal wetland ecosystem dynamics
- Meteorological Phenomena and Simulations
San Diego State University
2016-2025
University of Exeter
2017-2024
University of California, Davis
2002-2024
National Research Council
2022
Institute for Agricultural and Forest Systems in the Mediterranean
2022
NOAA National Marine Fisheries Service Southwest Fisheries Science Center
2022
NOAA National Marine Fisheries Service
2022
NOAA Earth System Research Laboratory
2022
National Agriculture and Food Research Organization
2022
Hokkaido Agricultural Research Center
2022
FLUXNET is a global network of micrometeorological flux measurement sites that measure the exchanges carbon dioxide, water vapor, and energy between biosphere atmosphere. At present over 140 are operating on long-term continuous basis. Vegetation under study includes temperate conifer broadleaved (deciduous evergreen) forests, tropical boreal crops, grasslands, chaparral, wetlands, tundra. Sites exist five continents their latitudinal distribution ranges from 70°N to 30°S. has several...
The Moderate Resolution Spectroradiometer (MODIS) sensor has provided near real-time estimates of gross primary production (GPP) since March 2000. We compare four years (2000 to 2003) satellite-based calculations GPP with tower eddy CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> flux-based across diverse land cover types and climate regimes. examine the potential error contributions from meteorology, leaf area index (LAI)/fPAR,...
Field‐chamber measurements of soil respiration from 17 different forest and shrubland sites in Europe North America were summarized analyzed with the goal to develop a model describing seasonal, interannual spatial variability as affected by water availability, temperature, site properties. The analysis was performed at daily monthly time step. With step, relative content upper layer expressed fraction field capacity good predictor all sites. Among variables tested, those related...
Journal Article Global Change and the Carbon Balance of Arctic Ecosystems: Carbon/nutrient interactions should act as major constraints on changes in global terrestrial carbon cycling Get access Gaius R. Shaver, Shaver Search for other works by this author on: Oxford Academic Google Scholar W. D. Billings, Billings F. Stuart Chapin, III, III Anne E. Giblin, Giblin Knute J. Nadelhoffer, Nadelhoffer C. Oechel, Oechel B. Rastetter BioScience, Volume 42, Issue 6, June 1992, Pages 433–441,...
Abstract Continuous and direct measurements of ecosystem carbon dioxide water vapour fluxes can improve our ability to close regional global hydrological budgets. On this behalf, an international multidisciplinary group scientists (micrometeorologists, ecophysiologists biogeochemists) assembled at La Thuile, Italy convene a workshop on ‘Strategies for Monitoring Modelling CO 2 Water Vapour Fluxes over Terrestrial Ecosystems’. Over the course week talks discussions focused on: (i) results...
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...
Significance Arctic ecosystems are major global sources of methane. We report that emissions during the cold season (September to May) contribute ≥50% annual methane from Alaskan tundra, based on fluxes obtained eddy covariance sites and regional calculated aircraft data. The largest were observed at driest site (<5% inundation). Emissions in linked extended “zero curtain” period, where soil temperatures poised near 0 °C, indicating total very sensitive climate related factors, such as...
Abstract. Although Arctic tundra has been estimated to cover only 8% of the global land surface, large and potentially labile carbon pools currently stored in soils have potential for emissions (C) under a warming climate. These as radiatively active greenhouse gases form both CO2 CH4 could amplify warming. Given sensitivity these ecosystems climate change expectation that will experience appreciable over next century, it is important assess whether responses C exchange regions are likely...
Carbon flux models based on light use efficiency (LUE), such as the MOD17 algorithm, have proved difficult to parameterize because of uncertainties in LUE term, which is usually estimated from meteorological variables available only at large spatial scales. In search simpler entirely remote‐sensing data, we examined direct relationships between enhanced vegetation index (EVI) and gross primary productivity (GPP) measured nine eddy covariance tower sites across North America. When data winter...
Journal Article Predicting Ecosystem Responses to Elevated CO2 Concentrations: What has been learned from laboratory experiments on plant physiology and field observations? Get access H. A. Mooney, Mooney Search for other works by this author on: Oxford Academic Google Scholar B. G. Drake, Drake R. J. Luxmoore, Luxmoore W. C. Oechel, Oechel L. F. Pitelka BioScience, Volume 41, Issue 2, February 1991, Pages 96–104, https://doi.org/10.2307/1311562 Published: 01 1991
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...
Small greenhouses were used in the arctic to maintain Erioporum vaginatum—dominated tussock tundra for 10 wk at ambient CO 2 (340 μL/L), elevated (510 or 680 and 4°C above temperature (680 μL/L, + 4°). These treatments represent present levels of atmospheric temperature, those predicted next century. Within 3 wk, plants maintained exhibited a physiological adjustment their photosynthetic rate so that grown had similar rates respective growth concentrations. The reduction capacity did not...
Abstract Operational monitoring of global terrestrial gross primary production (GPP) and net (NPP) is now underway using imagery from the satellite‐borne Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Evaluation MODIS GPP NPP products will require site‐level studies across a range biomes, with close attention to numerous scaling issues that must be addressed link ground measurements satellite‐based carbon flux estimates. Here, we report results study aimed at evaluating...
Our current understanding of terrestrial carbon processes is represented in various models used to integrate and scale measurements CO 2 exchange from remote sensing other spatiotemporal data. Yet assessments are rarely conducted determine how well simulate across vegetation types environmental conditions. Using standardized data the North American Carbon Program we compare observed simulated monthly 44 eddy covariance flux towers America 22 biosphere models. The analysis period spans ∼220...