A5031295206- Atmospheric and Environmental Gas Dynamics
- Climate variability and models
- Plant Water Relations and Carbon Dynamics
- Climate change and permafrost
- Plant responses to elevated CO2
- Cryospheric studies and observations
- Methane Hydrates and Related Phenomena
- Climate Change Policy and Economics
- Geology and Paleoclimatology Research
- Soil Carbon and Nitrogen Dynamics
- Geological Studies and Exploration
- Atmospheric chemistry and aerosols
- Peatlands and Wetlands Ecology
- Environmental Impact and Sustainability
- Global Energy and Sustainability Research
- Fire effects on ecosystems
- Hydrology and Watershed Management Studies
- Economic and Environmental Valuation
- Conservation, Biodiversity, and Resource Management
- Biofuel production and bioconversion
- Tree-ring climate responses
- Forest ecology and management
- Bioenergy crop production and management
- Geophysics and Gravity Measurements
- Climate change impacts on agriculture
Marine Biological Laboratory
2012-2023
Multi Base (China)
2016-2018
Woodwell Climate Research Center
2013
Massachusetts Institute of Technology
2009-2010
Lehigh University
2009-2010
Pennsylvania State University
2009-2010
Engineering Systems (United States)
2009-2010
University of New Hampshire
1991
Amazon (United States)
1991
University of Montana
1987
Summary Seventeen global models of terrestrial biogeochemistry were compared with respect to annual and seasonal fluxes net primary productivity (NPP) for the land biosphere. The comparison, sponsored by IGBP‐GAIM/DIS/GCTE, used standardized input variables wherever possible was carried out through two international workshops over Internet. differed widely in complexity original purpose, but could be grouped three major categories: satellite‐based that use data from NOAA/AVHRR sensor as...
There are pressing reasons for developing a better understanding of net primary production (NPP) in the world's forests. These ecosystems play large role carbon budget, and their dynamics, which likely to be responding global changes climate atmospheric composition, have major economic implications impacts on biodiversity. Although there is long history forest NPP studies ecological literature, current ecosystem-level remains limited. Forest cannot directly measured; it must approached by...
We use a mechanistically based ecosystem simulation model to describe and analyze the spatial temporal patterns of terrestrial net primary productivity (NPP) in South America. The Terrestrial Ecosystem Model (TEM) is designed predict major carbon nitrogen fluxes pool sizes ecosystems at continental global scales. Information from intensively studies field sites used combination with continental-scale information on climate, soils, vegetation estimate NPP each 5888 non-wetland, 0.5° latitude...
The concurrent effects of increasing atmospheric CO 2 concentration, climate variability, and cropland establishment abandonment on terrestrial carbon storage between 1920 1992 were assessed using a standard simulation protocol with four process‐based biosphere models. Over the long‐term(1920–1992), simulations yielded time history uptake that is consistent (within uncertainty) long‐term analysis based ice core data. Up to 1958, three analyses indicated net release from ecosystems atmosphere...
Information on net primary production in tropical forests is needed for the development of realistic global carbon budgets, projecting how these ecosystems will be affected by climatic and atmospheric changes, evaluating eddy covariance measurements forest flux. However, a review database commonly used to address issues shows that it has serious flaws. In this paper we synthesize data literature NPP old-growth produce consistent set forests. Studies biome have addressed only few components,...
A global biofuels program will lead to intense pressures on land supply and can increase greenhouse gas emissions from land-use changes. Using linked economic terrestrial biogeochemistry models, we examined direct indirect effects of possible changes an expanded cellulosic bioenergy over the 21st century. Our model predicts that use be responsible for substantially more carbon loss (up twice as much) than use; however, because predicted increases in fertilizer use, nitrous oxide important...
The effects of increasing carbon dioxide (CO2) and climate on net storage in terrestrial ecosystems the conterminous United States for period 1895-1993 were modeled with new, detailed historical information. For 1980-1993, results from an ensemble three models agree within 25%, simulating a land sink CO2 0.08 gigaton per year. best estimates total inventory data are about times larger, suggesting that processes such as regrowth abandoned agricultural or forests harvested before 1980 have...
Summary Rising atmospheric CO 2 and temperatures are probably altering ecosystem carbon cycling, causing both positive negative feedbacks to climate. Below‐ground processes play a key role in the global (C) cycle because they regulate storage of large quantities C, potentially very sensitive direct indirect effects elevated temperature. Soil organic matter pools, roots associated rhizosphere organisms all have distinct responses environmental change drivers, although availability C...
We develop and use a new version of the Terrestrial Ecosystem Model (TEM) to study how rates methane (CH 4 ) emissions consumption in high‐latitude soils Northern Hemisphere have changed over past century response observed changes region's climate. estimate that net CH (emissions minus consumption) from these increased by an average 0.08 Tg yr −1 during twentieth century. Our annual emission rate at end for region is 51 . Russia, Canada, Alaska are major regional sources atmosphere,...
Abstract The impact of carbon–nitrogen dynamics in terrestrial ecosystems on the interaction between carbon cycle and climate is studied using an earth system model intermediate complexity, MIT Integrated Global Systems Model (IGSM). Numerical simulations were carried out with two versions IGSM’s Terrestrial Ecosystems Model, one without dynamics. Simulations show that consideration interactions not only limits effect CO2 fertilization but also changes sign feedback cycle. In absence...
The magnitude, spatial, and temporal patterns of the terrestrial carbon sink underlying mechanisms remain uncertain need to be investigated.China is important in determining global balance terms both emission uptake.Of particular importance climate-change policy management ability evaluate relative contributions multiple environmental factors net source China's ecosystems.Here effects (climate, atmospheric CO 2 , ozone pollution, nitrogen deposition, fertilizer application, land cover/land...
Abstract This paper summarizes the results of an intercomparison project with Earth System Models Intermediate Complexity (EMICs) undertaken in support Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5). The focus is long-term climate projections designed to 1) quantify change commitment different radiative forcing trajectories and 2) explore extent which reversible human time scales. All simulations follow four representative concentration pathways (RCPs) their...
[1] Studies indicate that, historically, terrestrial ecosystems of the northern high-latitude region may have been responsible for up to 60% global net land-based sink atmospheric CO2. However, these regions recently experienced remarkable modification major driving forces carbon cycle, including surface air temperature warming that is significantly greater than average and associated increases in frequency severity disturbances. Whether Arctic tundra boreal forest will continue sequester...
Abstract. Both historical and idealized climate model experiments are performed with a variety of Earth system models intermediate complexity (EMICs) as part community contribution to the Intergovernmental Panel on Climate Change Fifth Assessment Report. Historical simulations start at 850 CE continue through 2005. The standard include changes in forcing from solar luminosity, Earth's orbital configuration, CO2, additional greenhouse gases, land use, sulphate volcanic aerosols. In spite very...
The extent and consequences of global land-cover land-use change are increasingly apparent. One consequence not so apparent is the altered structure plants belowground. This paper examines such belowground changes, emphasizing interaction root distributions with other factors their treatment in models. Shifts woody herbaceous vegetation deforestation, afforestation, plant encroachment typically alter depth distribution roots, influencing soil nutrients, water balance, net primary...
Abstract The Massachusetts Institute of Technology (MIT) Integrated Global System Model is used to make probabilistic projections climate change from 1861 2100. Since the model’s first were published in 2003, substantial improvements have been made model, and improved estimates probability distributions uncertain input parameters become available. new are considerably warmer than 2003 projections; for example, median surface warming 2091–2100 5.1°C compared 2.4°C earlier study. Many changes...
We use a new version of the Terrestrial Ecosystem Model (TEM), which has been parameterized to control for reactive soil organic carbon (SOC) across climatic gradients, evaluate sensitivity SOC 1?C warming in both empirical and process-based analyses. In analyses we steady state estimates TEM derive SOC-response equations that depend on temperature volumetric moisture, extrapolate them terrestrial biosphere at 0.50 spatial resolution. For contemporary climate atmospheric C02, mean annual...
Abstract We determined stocks of C and N for soils under undisturbed vegetation across the Brazilian Amazon Basin based on 1162 soil profiles RADAMBRASIL survey a digitized map. Mean basin density was 10.3 kg m −2 . Forty‐seven petagrams 4.4 Pg were contained in top 1 soil. Forty‐five percent total (21 C) 41% (1.8 N) 20 cm ≈ 5 000 000‐km 2 area. C/N ratio to depth 10.7. Because these data represent sites with forest absence significant disturbances, they valuable baseline evaluating effects...
Abstract The boreal forest contains large reserves of carbon. Across this region, wildfires influence the temporal and spatial dynamics carbon storage. In study, we estimate fire emissions changes in storage for North America over 21st century. We use a gridded data set developed with multivariate adaptive regression spline approach to determine how area burned varies each year changing climatic fuel moisture conditions. apply process‐based Terrestrial Ecosystem Model evaluate role future on...
We ran the terrestrial ecosystem model (TEM) for globe at 0.5° resolution atmospheric CO 2 concentrations of 340 and 680 parts per million by volume (ppmv) to evaluate global regional responses net primary production (NPP) carbon storage elevated their sensitivity changes in vegetation nitrogen concentration. At ppmv, TEM estimated NPP 49.0 10 15 g (Pg) C yr −1 total 1701.8 Pg C; estimate does not include content inert soil organic matter. For reference simulation which doubled was...