Download or read book Using a Regional Cluster of AmeriFlux Sites in Central California to Advance Our Knowledge on Decadal Scale Ecosystem Atmosphere Carbon Dioxide Exchange written by and published by . This book was released on 2015 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Continuous eddy convariance measurements of carbon dioxide, water vapor and heat were measured continuously between an oak savanna and an annual grassland in California over a 4 year period. These systems serve as representative sites for biomes in Mediterranean climates and experience much seasonal and inter-annual variability in temperature and precipitation. These sites hence serve as natural laboratories for how whole ecosystem will respond to warmer and drier conditions. The savanna proved to be a moderate sink of carbon, taking up about 150 gC m-2y-1 compared to the annual grassland, which tended to be carbon neutral and often a source during drier years. But this carbon sink by the savanna came at a cost. This ecosystem used about 100 mm more water per year than the grassland. And because the savanna was darker and rougher its air temperature was about 0.5 C warmer. In addition to our flux measurements, we collected vast amounts of ancillary data to interpret the site and fluxes, making this site a key site for model validation and parameterization. Datasets consist of terrestrial and airborne lidar for determining canopy structure, ground penetrating radar data on root distribution, phenology cameras monitoring leaf area index and its seasonality, predawn water potential, soil moisture, stem diameter and physiological capacity of photosynthesis.

Download or read book Modeling Regional Carbon Dioxide Flux Over California Using the WRF ACASA Coupled Model written by and published by . This book was released on 2016 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many processes and interactions in the atmosphere and the biosphere influence the rate of carbon dioxide exchange between these two systems. However, it is difficult to estimate the carbon dioxide flux over regions with diverse ecosystems and complex terrains, such as California. Traditional carbon dioxide measurements are sparse and limited to specific ecosystems. Therefore, accurately estimating carbon dioxide flux on a regional scale remains a major challenge. In this study, we couple the weather Research and Forecasting Model (WRF) with the Advanced Canopy- Atmosphere-Soil Algorithm (ACASA), a high complexity land surface model. Although WRF is a state-of- the-art regional atmospheric model with high spatial and temporal resolutions, the land surface schemes available in WRF lack the capability to simulate carbon dioxide. ACASA is a complex multilayer land surface model with interactive canopy physiology and full surface hydrological processes. It allows microenvironmental variables such as air and surface temperatures, wind speed, humidity, and carbon dioxide concentration to vary vertically. Carbon dioxide, sensible heat, water vapor, and momentum fluxes between the atmosphere and land surface are estimated in the ACASA model through turbulence equations with a third order closure scheme. It therefore permits counter-gradient transports that low-order turbulence closure models are unable to simulate. A new CO2 tracer module is introduced into the model framework to allow the atmospheric carbon dioxide concentration to vary according to terrestrial responses. In addition to the carbon dioxide simulation, the coupled WRF-ACASA model is also used to investigate the interactions of neighboring ecosystems in their response to atmospheric carbon dioxide concentration. The model simulations with and without the CO2 tracer for WRF-ACASA are compared with surface observations from the AmeriFlux network.

Download or read book Integrating Remote Sensing Field Observations and Models to Understand Disturbance and Climate Effects on the Carbon Balance of the West Coast U S written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: GOAL: To develop and apply an approach to quantify and understand the regional carbon balance of the west coast states for the North American Carbon Program. OBJECTIVE: As an element of NACP research, the proposed investigation is a two pronged approach that derives and evaluates a regional carbon (C) budget for Oregon, Washington, and California. Objectives are (1) Use multiple data sources, including AmeriFlux data, inventories, and multispectral remote sensing data to investigate trends in carbon storage and exchanges of CO2 and water with variation in climate and disturbance history; (2) Develop and apply regional modeling that relies on these multiple data sources to reduce uncertainty in spatial estimates of carbon storage and NEP, and relative contributions of terrestrial ecosystems and anthropogenic emissions to atmospheric CO2 in the region; (3) Model terrestrial carbon processes across the region, using the Biome-BGC terrestrial ecosystem model, and an atmospheric inverse modeling approach to estimate variation in rate and timing of terrestrial uptake and feedbacks to the atmosphere in response to climate and disturbance. APPROACH: In performing the regional analysis, the research plan for the bottom-up approach uses a nested hierarchy of observations that include AmeriFlux data (i.e., net ecosystem exchange (NEE) from eddy covariance and associated biometric data), intermediate intensity inventories from an extended plot array partially developed from the PI's previous research, Forest Service FIA and CVS inventory data, time since disturbance, disturbance type, and cover type from Landsat developed in this study, and productivity estimates from MODIS algorithms. The BIOME-BGC model is used to integrate information from these sources and quantify C balance across the region. The inverse modeling approach assimilates flux data from AmeriFlux sites, high precision CO2 concentration data from AmeriFlux towers and four new calibrated CO2 sites, reanalysis meteorology and various remote sensing products to generate statewide estimates of biosphere carbon exchange from the atmospheric point of view.

Download or read book Magmatic Carbon Dioxide Emissions at Mammoth Mountain California written by Christopher D. Farrar and published by . This book was released on 1999 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book AmeriFlux CA NS2 UCI 1930 Burn Site written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the AmeriFlux version of the carbon flux data for the site CA-NS2 UCI-1930 burn site. Site Description - The UCI-1930 site is located in a continental boreal forest, dominated by black spruce trees, within the BOREAS northern study area in central Manitoba, Canada. The site is a member of a chronological series of sites that are representative secondary succession growth stages after large stand replacement fires. Black spruce trees undergo a slow growth process enabling the accurate determination of the chronosequence of stand age disturbance. Additionally, boreal forests make up approximately 25% of forest ecosystems on earth. With both of these in mind, the UCI sites provide an excellent location to study the CO2 exchange between the atmosphere and boreal forest ecosystems as a function of sequential wildfires.

Download or read book Spatiotemporal Dynamics of Carbon Dioxide and Methane Fluxes from Agricultural and Restored Wetlands in the California Delta written by Jaclyn Hatala and published by . This book was released on 2013 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Sacramento-San Joaquin Delta in California was drained for agriculture and human settlement over a century ago, resulting in extreme rates of soil subsidence and release of CO2 to the atmosphere from peat oxidation. Because of this century-long ecosystem carbon imbalance where heterotrophic respiration exceeded net primary productivity, most of the land surface in the Delta is now up to 8 meters below sea level. To potentially reverse this trend of chronic carbon loss from Delta ecosystems, land managers have begun converting drained lands back to flooded ecosystems, but at the cost of increased production of CH4, a much more potent greenhouse gas than CO2. To evaluate the impacts of inundation on the biosphere-atmophere exchange of CO2 and CH4 in the Delta, I first measured and analyzed net fluxes of CO2 and CH4 for two continuous years with the eddy covariance technique in a drained peatland pasture and a recently re-flooded rice paddy. This analysis demonstrated that the drained pasture was a consistent large source of CO2 and small source of CH4, whereas the rice paddy was a mild sink for CO2 and a mild source of CH4. However more importantly, this first analysis revealed nuanced complexities for measuring and interpreting patterns in CO2 and CH4 fluxes through time and space. CO2 and CH4 fluxes are inextricably linked in flooded ecosystems, as plant carbon serves as the primary substrate for the production of CH4 and wetland plants also provide the primary transport pathway of CH4 flux to the atmosphere. At the spatially homogeneous rice paddy during the summer growing season, I investigated rapid temporal coupling between CO2 and CH4 fluxes. Through wavelet Granger-causality analysis, I demonstrated that daily fluctuations in growing season gross ecosystem productivity (photosynthesis) exert a stronger control than temperature on the diurnal pattern in CH4 flux from rice. At a spatially heterogeneous restored wetland site, I analyzed the spatial coupling between net CO2 and CH4 fluxes by characterizing two-dimensional patterns of emergent vegetation within eddy covariance flux footprints. I combined net CO2 and CH4 fluxes from three eddy flux towers with high-resolution remote sensing imagery classified for emergent vegetation and an analytical 2-D flux footprint model to assess the impact of vegetation fractal pattern and abundance on the measured flux. Both emergent vegetation abundance and fractal complexity are important metrics for constraining variability within CO2 and CH4 flux in this complex landscape. Scaling between carbon flux measurements at individual sites and regional scales depends on the connection to remote sensing metrics that can be broadly applied. In the final chapter of this dissertation, I analyzed a long term dataset of hyperspectral ground reflectance measurements collected within the flux tower footprints of three structurally similar yet functionally diverse ecosystems: an annual grassland, a degraded pepperweed pasture, and a rice paddy. The normalized difference vegetation index (NDVI) was highly correlated with landscape-scale photosynthesis across all sites, however this work also revealed new potential spectral indices with high correlation to both net and partitioned CO2 fluxes. This analysis within this dissertation serves as a framework for considering the impacts of temporal and spatial heterogeneity on measured landscape-scale fluxes of CO2 and CH4. Scaling measurements through time and space is especially critical for interpreting fluxes of trace gases with a high degree of temporal heterogeneity, like CH4 and N2O, from landscapes that have a high degree of spatial heterogeneity, like wetlands. This work articulates a strong mechanistic connection between CO2 and CH4 fluxes in wetland ecosystems, and provides important management considerations for implementing and monitoring inundated land-use conversion as an effective carbon management strategy in the California Delta.

Download or read book Phenology of Ecosystem Processes written by Asko Noormets and published by Springer Science & Business Media. This book was released on 2009-06-19 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt: Terrestrial carbon balance is uncertain at the regional and global scale. A significant source of variability in mid-latitude ecosystems is related to the timing and duration of phenological phases. Spring phenology, in particular, has disproportionate effects on the annual carbon balance. However, the traditional phenological indices that are based on leaf-out and flowering times of select indicator species are not universally amenable for predicting the temporal dynamics of ecosystem carbon and water exchange. Phenology of Ecosystem Processes evaluates current applications of traditional phenology in carbon and H2O cycle research, as well as the potential to identify phenological signals in ecosystem processes themselves. The book summarizes recent progress in the understanding of the seasonal dynamics of ecosystem carbon and H2O fluxes, the novel use of various methods (stable isotopes, time-series, forward and inverse modeling), and the implications for remote sensing and global carbon cycle modeling. Each chapter includes a literature review, in order to present the state-of-the-science in the field and enhance the book’s usability as an educational aid, as well as a case study to exemplify the use and applicability of various methods. Chapters that apply a specific methodology summarize the successes and challenges of particular methods for quantifying the seasonal changes in ecosystem carbon, water and energy fluxes. The book will benefit global change researchers, modelers, and advanced students.

Download or read book Effects of Manipulated Atmospheric Carbon Dioxide Concentrations on Carbon Dioxide and Water Vapor Fluxes in Southern California Chaparral written by Yufu Cheng and published by . This book was released on 2003 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research took two different approaches to measuring carbon and water vapor flux at the plot level (2 x 2 meter and 1 x 1 meter plots) to help understand and predict ecosystem responses to elevated CO2 concentrations and concomitant environmental changes. The first measurement approach utilized a CO2-controlled, ambient lit, temperature controlled (CO 2LT) null-balance chamber system run in a chaparral ecosystem in southern California, with six different CO2 concentrations ranging from 250 to 750 PPM CO2 concentrations with 100 ppm difference between treatments. The second measurement approach used a free air CO2 enrichment (FACE) system operated at 550 PPM CO2 concentration. These manipulations allowed the study of responses of naturally-growing chaparral to varying levels of CO2, under both chamber and open air conditions. There was a statistically significant CO2 effect on annual NEE (net ecosystem exchange) during the period of this study, 1997 to 2000. The effects of elevated CO2 on CO2 and water vapor flux showed strong seasonal patterns. Elevated CO2 delayed the development of water stress, enhanced leaf-level photosynthesis, and decreased transpiration and conductance rates. These effects were observed regardless of water availability. Ecosystem CO2 sink strength and plant water status were significantly enhanced by elevated CO2 when water availability was restricted. Comparing the FACE treatment and the FACE control, the ecosystem was either a stronger sink or a weaker source to the atmosphere throughout the dry seasons, but there was no statistically significant difference during the wet seasons. Annual average leaf transpiration decreased with the increasing of the atmospheric CO2 concentration. Although leaf level water-use efficiency (WUE) increased with the growth CO2 concentration increase, annual evapotranspiration (ET) during these four years also increased with the increase of the atmospheric CO2 concentrations. These results indicate that chaparral or other similar ecosystems, under future elevated CO2concentrations, might be even more water stressed than they are under current conditions.

Download or read book Where Do Fossil Fuel Carbon Dioxide Emissions from California Go An Analysis Based on Radiocarbon Observations and an Atmospheric Transport Model written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Characterizing flow patterns and mixing of fossil fuel-derived CO2 is important for effectively using atmospheric measurements to constrain emissions inventories. Here we used measurements and a model of atmospheric radiocarbon (14C) to investigate the distribution and fluxes of atmospheric fossil fuel CO2 across the state of California. We sampled 14C in annual C3 grasses at 128 sites and used these measurements to test a regional model that simulated anthropogenic and ecosystem CO2 fluxes, transport in the atmosphere, and the resulting 14C of annual grasses ([Delta]{sub g}). Average measured [Delta]{sub g} in Los Angeles, San Francisco, the Central Valley, and the North Coast were 27.7 ± 20.0, 44.0 ± 10.9, 48.7 ± 1.9, and 59.9 ± 2.5{per_thousand}, respectively, during the 2004-2005 growing season. Model predictions reproduced regional patterns reasonably well, with estimates of 27.6 ± 2.4, 39.4 ± 3.9, 46.8 ± 3.0, and 59.3 ± 0.2{per_thousand} for these same regions and corresponding to fossil fuel CO2 mixing ratios (Cf) of 13.7, 6.1, 4.8, and 0.3 ppm. [Delta]{sub g} spatial heterogeneity in Los Angeles and San Francisco was higher in the measurements than in the predictions, probably from insufficient spatial resolution in the fossil fuel inventories (e.g., freeways are not explicitly included) and transport (e.g., within valleys). We used the model to predict monthly and annual transport patterns of fossil fuel-derived CO2 within and out of California. Fossil fuel CO2 emitted in Los Angeles and San Francisco was predicted to move into the Central Valley, raising Cf above that expected from local emissions alone. Annually, about 21, 39, 35, and 5% of fossil fuel emissions leave the California airspace to the north, east, south, and west, respectively, with large seasonal variations in the proportions. Positive correlations between westward fluxes and Santa Ana wind conditions were observed. The southward fluxes over the Pacific Ocean were maintained in a relatively coherent flow within the marine boundary layer, while the eastward fluxes were more vertically dispersed. Our results indicate that state and continental scale atmospheric inversions need to consider areas where concentration measurements are sparse (e.g., over the ocean to the south and west of California), transport within and across the marine boundary layer, and terrestrial boundary layer dynamics. Measurements of [Delta]{sub g} can be very useful in constraining these estimates.

Download or read book AmeriFlux CA NS1 UCI 1850 Burn Site written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the AmeriFlux version of the carbon flux data for the site CA-NS1 UCI-1850 burn site. Site Description - The UCI-1850 site is located in a continental boreal forest, dominated by black spruce trees, within the BOREAS northern study area in central Manitoba, Canada. The site is a member of a chronological series of sites that are representative secondary succession growth stages after large stand replacement fires. Black spruce trees undergo a slow growth process enabling the accurate determination of the chronosequence of stand age disturbance. Additionally, boreal forests make up approximately 25% of forest ecosystems on earth. With both of these in mind, the UCI sites provide an excellent location to study the CO2 exchange between the atmosphere and boreal forest ecosystems as a function of sequential wildfires.

Download or read book AmeriFlux CA NS4 UCI 1964 Burn Site Wet written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the AmeriFlux version of the carbon flux data for the site CA-NS4 UCI-1964 burn site wet. Site Description - The UCI-1964 wet site is located in a continental boreal forest, dominated by black spruce trees, within the BOREAS northern study area in central Manitoba, Canada. The site is a member of a chronological series of sites that are representative secondary succession growth stages after large stand replacement fires. Black spruce trees undergo a slow growth process enabling the accurate determination of the chronosequence of stand age disturbance. Additionally, boreal forests make up approximately 25% of forest ecosystems on earth. With both of these in mind, the UCI sites provide an excellent location to study the CO2 exchange between the atmosphere and boreal forest ecosystems as a function of sequential wildfires.

Download or read book Measurements of Landscape scale Fluxes of Carbon Dioxide at Two AmeriFlux Sites Using a New Vertical Profiling Technique written by Kristen Jean Schulz and published by . This book was released on 2003 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measuring the Effects of Disturbance Climate on the CO2 Energy Exchange of Ponderosa Pine Forests in the Pacific Northwest written by and published by . This book was released on 2007 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal is to quantify and understand the influence of climate and disturbance on ecosystem processes and thus net carbon uptake by forests. The objective is to combine tower and ground-based observations to quantify the effects of disturbance on processes controlling carbon storage and CO2 and energy exchange in varying climatic conditions. Specific objectives are: (1) Investigate the effects of logging and fire on carbon storage and carbon dioxide and energy exchange in chronosequences of ponderosa pine, using consistent methodology; (2) Determine key environmental factors controlling carbon storage and carbon dioxide and energy exchange in these forests through a combination of measurements and process modeling; and (3) Assess spatial variation of the concentrations and transport in complex terrain. The eddy covariance method is used for measurements of CO2, water vapor, and energy exchanges in a chronosequence of ponderosa pine forests (burned in 2002 wildfire, 10 year-old stand, 90 year-old mature stand). The mature stand has been an AmeriFlux site since 2000 (following previous flux sites in young and old stands initiated in 1996). In addition to the eddy covariance measurements, a large suite of biological processes and ecosystem properties are determined for the purpose of developing independent forest carbon budgets and NEP estimates; these include photosynthesis, stand respiration, soil CO2 fluxes, annual litterfall, foliar chemistry, and bole increment, and soil organic matter among other parameters. The measurements are being integrated and evaluated with two ecosystem models (BIOME-BGC and SPA). Such analyses are needed to assess regional terrestrial ecosystem carbon budgets. The results will contribute scientific understanding of carbon processes, and will provide comprehensive data sets for forest managers and those preparing national carbon inventories to use in assessments of carbon sequestration in relation to interannual climate variation and disturbance. Frameworks and methodologies developed by the PI will contribute to AmeriFlux Network facility functions for data acquisition, exchange and modeling of results in a broad spectrum of carbon cycle research.

Download or read book Carbonyl Sulfide Exchange Between Soils and the Atmosphere Observations and Modeling written by Wu Sun and published by . This book was released on 2017 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbonyl sulfide (COS) is a trace gas participating in key processes of the terrestrial carbon cycle. Despite its low mixing ratio in the troposphere (400-550 pmol mol-1), the amplitude of seasonal variability of COS greatly exceeds that of CO2 and is in phase with the gross photosynthesis of the terrestrial biosphere. Over the recent decade, COS has emerged as a promising tracer for quantifying terrestrial gross primary productivity (GPP) independently from respiration across the ecosystem to the global scales, because of the parallel uptake of COS and CO2 through leaf stomata. While leaf uptake of COS dominates surface COS flux on land in the absence of industrial and biomass burning emissions, soil COS flux is another smaller but significant component. Neglecting the soil component in ecosystem COS budget may bias GPP estimates derived from COS measurements. Soil may also vary from a sink to a source of COS depending on temperature and microbial sulfur metabolism. Due to the presence of potential interference from soil COS activities, using COS as a photosynthetic tracer requires soil COS flux to be separated from the net ecosystem COS exchange. This dissertation is dedicated to the mechanistic understanding of the soil-atmosphere exchange of COS using process-oriented modeling and field observations. A reactive transport model for soil COS processes is constructed to simulate soil-atmosphere COS flux from environmental variables. This model takes into account the dual-phase diffusive transport and the microbial sources and sinks of COS in the soil column. COS uptake and production rates are parameterized with enzyme kinetics and thermodynamics, consistent with lab incubation data. Leaf litter layer is explicitly resolved to account for litter COS uptake, whenever a litter layer is present. The model is evaluated against published field data of COS flux and demonstrates good skill in predicting both soil uptake and emission of COS. Model simulations further confirm that COS flux dependence on soil moisture is a result of two rivaling controls--the diffusive limitation on COS supply and the water limitation on microbial activity. Field observations on soil COS exchange have been conducted at an oak woodland in southern California and a boreal pine forest in southern Finland using automated soil chambers and mid-infrared quantum cascade laser spectrometer. Soils at both sites show consistent uptake behavior related to soil moisture and respiration. At the semi-arid oak woodland in California, microbial COS uptake is strongly limited by water availability in the dry season. The intact leaf litter layer contributes a significant portion to the overall soil COS uptake. Litter COS uptake increases with moisture content and shows a strong pulse immediately after the rain event, indicating a rapid reactivation of litter microbial activity following alleviated water stress. In the Finnish pine forest, soil COS uptake is limited by the diffusional supply of COS to soil microbes, according to the negative correlation with soil moisture. The contrasting responses of soil COS uptake to moisture in semi-arid and humid ecosystems reflect the coupling of diffusion and microbial uptake controls on COS flux. At both sites, soil COS uptake correlates well with respiration and the COS : CO2 flux ratio varies with temperature. The temperature dependence of COS : CO2 flux ratio may be a common feature of soils and indicate underlying shifts in active microbial groups. This dissertation advances knowledge of the physical and biological drivers of soil-atmosphere exchange of COS. Anticipated applications of the findings will be to better constrain global soil COS flux and derive COS-based estimates of GPP, which will be useful in understanding the responses of photosynthesis to climate variability.

Download or read book Final Technical Report written by and published by . This book was released on 2016 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Investigate the effects of disturbance and climate variables on processes controlling carbon and water processes at AmeriFlux cluster sites in semi-arid and mesic forests in Oregon. The observations were made at three existing and productive AmeriFlux research sites that represent climate and disturbance gradients as a natural experiment of the influence of climatic and hydrologic variability on carbon sequestration and resulting atmospheric CO2 feedback that includes anomalies during the warm/ dry phase of the Pacific Decadal Oscillation.

Download or read book Regional Scale Land atmosphere Carbon Dioxide Exchange Data Design and Inversion Within a Receptor Oriented Modeling Framework written by Daniel Michael Matross and published by . This book was released on 2006 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a model-data fusion study to derive regional-scale (∼104 km2) CO2 flux estimates for summer 2004 in the northeast United States and southern Quebec, using an end-to-end treatment that goes from strategizing observations to assimilating extensive data into a receptor-oriented modeling framework. Surface fluxes are specified using the Vegetation Photosynthesis and Respiration Model (VPRM), a simple, readily optimized biosphere model driven by satellite data, AmeriFlux eddy covariance measurements, and meteorological fields. The surface flux model is coupled to a Lagrangian atmospheric adjoint model, the Stochastic Time-Inverted Lagrangian Transport Model (STILT), which links point observations to upwind sources with high spatio-temporal resolution. Concentration data for assimilation comes from the CO2 Budget and Regional Airborne Maine (COBRA-Maine) airborne campaign---which is described fully---and the NOAA-ESRL tall tower at Argyle, ME, as well as an ad-hoc regional network of surface observation stations. The variety of independent constraints provided by each input demonstrates the need for large amounts of data, shows the importance of both spatial and temporal coverage, and emphasizes the complementarity of tower and airborne observations. Although the dataset is dense and regionally representative, the surface source function is relatively insensitive to Bayesian optimization, providing an important counterexample to the current working paradigm of CO2 data assimilation studies. Errors in transport and tracer boundary conditions and in representation of the atmospheric boundary layer contribute to variance at the surface which is large enough to limit the effectiveness of atmospheric data assimilation for constraining surface fluxes.

Download or read book Estimating Carbon Flux Phenology with Satellite Derived Land Surface Phenology and Climate Drivers for Different Biomes written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon Flux Phenology (CFP) can affect the interannual variation in Net Ecosystem Exchange (NEE) of carbon between terrestrial ecosystems and the atmosphere. In this paper, we proposed a methodology to estimate CFP metrics with satellite-derived Land Surface Phenology (LSP) metrics and climate drivers for 4 biomes (i.e., deciduous broadleaf forest, evergreen needleleaf forest, grasslands and croplands), using 159 site-years of NEE and climate data from 32 AmeriFlux sites and MODIS vegetation index time-series data. LSP metrics combined with optimal climate drivers can explain the variability in Start of Carbon Uptake (SCU) by more than 70% and End of Carbon Uptake (ECU) by more than 60%. The Root Mean Square Error (RMSE) of the estimations was within 8.5 days for both SCU and ECU. The estimation performance for this methodology was primarily dependent on the optimal combination of the LSP retrieval methods, the explanatory climate drivers, the biome types, and the specific CFP metric. In conclusion, this methodology has a potential for allowing extrapolation of CFP metrics for biomes with a distinct and detectable seasonal cycle over large areas, based on synoptic multi-temporal optical satellite data and climate data.