Download or read book Investigating Covariances in and for Carbon Dioxide Surface Flux Inversions written by Daniel Robert Wesloh and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current CO2 flux inversion systems use matrix representations of the spatial correlations and do not include correlations between the parts of the daily cycle. We set up a framework to test these assumptions and compare stochastic and deterministic representations of the posterior CO2 flux uncertainty. Producing deterministic posterior uncertainty matrices at reduced resolution with the same transport error as the full inversion produced uncertainty estimates that were lower than expected, and became lower still with coarsening resolution. Stochastic estimates of the posterior CO2 flux uncertainty provide similar information to the deterministic estimates at full resolution in the ideal case, and become more variable as the number of ensemble members used to construct the stochastic estimate decreases. We then investigate the temporal biogenic CO2 flux error correlations using the difference between eddy covariance and terrestrial carbon cycle estimates of the CO2 flux, construct a family of temporal correlation functions to describe these data, and recommend a member of that family for inversions. The new temporal correlation function performs as well as two correlation functions used in previous regional inversions at matching previously-published estimates of the uncertainties in the hourly CO2 fluxes at the site level and in the annual fluxes at the continental-average level at the same time. However, neither the new nor the existing correlations were able to match previously-published estimates of the uncertainty in the monthly flux at the continental-average scale. The investigation indicates that much of the room for improving the prior mean flux estimates from terrestrial carbon cycle models lies in improving the daily cycle, either within an inversion or in the terrestrial carbon cycle models. We integrate the new correlations into a pseudo-data experiment to see whether the new correlations perform better than previously-used correlations from the literature in a best case scenario. The new correlations recover the ``true'' continental-average CO2 flux better than the correlations from previous inversions in the ideal case. The new CO2 flux error temporal correlation functions merit further investigation for suitability for real-data inversions.

Download or read book Investigating Land air Carbon Fluxes Using a Lagrangian Model and Satellite Retrieved Carbon Dioxide written by Alan James Hewitt and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The existing generation of satellite instruments (such as SCIAMACHY and AIRS) has allowed the retrieval of atmospheric mixing ratios of carbon dioxide. The feasibility of using these and later satellites (OCO-like or GOSAT) to investigate carbon fluxes between the terrestrial biosphere and the atmosphere, either alone or complemented by the high precision but low density network of surface measurement sites has been investigated. A methodology to investigate regional scale carbon budgets, based on the UK Met Office Lagrangian trajectory model NAME (Numerical Atmospheric-dispersion Modelling Environment), has been developed and demonstrated. A forward modelling methodology was developed, where top-down surface flux information from CarbonTracker was combined with the background CO2 mixing ratio to obtain an atmospheric concentration. Synthetic testing of the initialisation method demonstrated that a strong correlation coefficient (R2? 0:9) between the forward modelled and satellite observed atmospheric CO2 fields can be achieved. Forward modelled CO2 concentrations using CarbonTracker fluxes were demonstrated to be moderately correlated with the SCIAMACHY-retrieved CO2 field(R2 varies by month, from 0.4 to 0.8). An inverse modelling methodology was developed, where the change in carbon mass between the satellite-retrieved CO2 columns and the background concentration was combined with the surface residence time from the NAME model. Synthetic testing of the inversion method has shown that the a posteriori flux covariance scaled linearly to the satellite-retrieved error covariance and inversely to the NAME residence time of the ecosystem. On the regional scale, this method could improve on the carbon flux estimates from CarbonTracker and an equivalent Eulerian method using GOSAT. This thesis also presents the first carbon fluxes inverted from satellite retrieved CO2 columns, which captured the seasonality of the carbon fluxes of the vegetation and negligible ocean fluxes.

Download or read book Toward Improved Regional Estimates of Carbon Dioxide Sources and Sinks Through Coupled Carbon atmospheric Data Assimilation written by Hans Weiteng Chen and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurate estimates of regional carbon dioxide (CO2) sources and sinks are necessary to further our understanding of the carbon cycle and improve predictions of future climate change. CO2 surface fluxes can be constrained using atmospheric CO2 observations combined with atmospheric transport models through so-called top-down or inverse methods. At regional scales, however, inverse estimates of CO2 fluxes have been shown to be sensitive to errors in model representation of atmospheric transport. How to account for such atmospheric transport errors in inversions is currently not well understood.This dissertation examines the impact of atmospheric transport errors on simulated atmospheric CO2 mole fractions and inferred CO2 fluxes at subcontinental scales and hourly to monthly time scales. We first investigate how much space for improvement there is in two contemporary CO2 analysis datasets by comparing CO2 mole fractions from the analyses with airborne in situ measurements of CO2 from the Atmospheric Carbon and Transport - America field campaigns in summer 2016 and winter 2017. The analyses show an overall good agreement with observations except for large biases in near-surface CO2 mole fractions in the Mid-Atlantic region of the United States during summer, which suggests that CO2 fluxes can be further optimized in this region. Next, we quantify how transport errors due to uncertainties in meteorological initial conditions propagate to errors in atmospheric CO2 mole fractions through ensemble sensitivity experiments in a regional mesoscale model. Transport errors in CO2 are found to be of comparable magnitude and share similar spatiotemporal characteristics as errors due to uncertainties in CO2 fluxes on sub-monthly time scales. Finally, we present the development of a coupled carbon--atmospheric data assimilation system for regional CO2 flux inversion. This data assimilation system uses the ensemble Kalman Filter to optimize both meteorological variables and CO2 mole fractions and fluxes. Coupling the atmospheric and carbon states allows us to investigate the role of atmospheric transport errors in the CO2 flux optimization. The data assimilation system is tested in a series of perfect model experiments with synthetic observations to examine how well the CO2 flux inversion performs when different types of errors are introduced.

Download or read book Carbon Dioxide and the Greenhouse Effect written by United States. Congress. House. Committee on Science and Technology. Subcommittee on Investigations and Oversight and published by . This book was released on 1984 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of the Influence of Temperature Inversions and Turbulence on Land atmosphere Interactions for Rolling Terrain written by Olabosipo O. Osibanjo and published by . This book was released on 2016 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of this work are to calculate surface fluxes for rolling terrain using observational data collected during one week in September 2014 from a monitoring site in Echo, Oregon and to investigate the log law in the ABL. The site is located in the Columbia Basin with rolling terrain, irrigated farmland, and over 100 wind turbines. The 10 m tower was placed in a small valley depression to isolate nighttime temperature inversions. This thesis presents observations of momentum, sensible heat, moisture, and CO2 fluxes from data collected at a sampling frequency of 10Hz at four heights. Results show a strong correlation between temperature inversions and CO2 flux. The log layer could not be achieved as the value of the estimated von Karman constant (~ 0.62) is not close to that of the accepted value of 0.41. The impact of the irrigated farmland near the measurement site was observed in the latent heat flux, where the advection of moisture was evident in the tower moisture gradient. A strong relationship was also observed between fluxes of sensible heat, latent heat, CO2, and atmospheric stability. The average nighttime CO2 concentration observed was ~ 407 ppm, and daytime ~ 388 ppm compared to the 2013 global average CO2 concentration of 395 ppm. The maximum CO2 concentration (~ 485 ppm) was observed on the strongest temperature inversion night. There are few uncertainties in the measurements. The manufacturer for the eddy covariance instruments (EC 150) quotes uncertainty of ± 0.1°C for temperature between - 0°C-40°C. Error bars were generated on the estimated surface sensible heat flux using the standard deviation and mean values. Under the most stable atmospheric conditions, uncertainty (assumed to be the variability in the flux estimates) was close to the minimum (~ ± 5W m−2).

Download or read book Simulating the Measurement of Surface Carbon Dioxide Flux in Studying the Chamber Headspcae Problem written by Rebecca M. Newman and published by . This book was released on 2003 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Reducing the Uncertainty of North American Carbon Flux Estimates Using an Extended Atmospheric Carbon Dioxide Measurement Network written by Martha Peirce Butler and published by . This book was released on 2010 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: We evaluate North American carbon fluxes using a monthly global Bayesian synthesis inversion that includes well-calibrated carbon dioxide concentrations measured at continental flux towers. We employ the NASA Parameterized Chemistry Tracer Model (PCTM) for atmospheric transport and a modified version of the inversion used by the Atmospheric Tracer Transport Model Intercomparison Project (TransCom) with sub-continental resolution and annual variability of transport. We sub-sample carbon dioxide time series at four North American flux tower sites for mid-day hours to ensure sampling of a deep, well-mixed atmospheric boundary layer. The addition of these flux tower sites to a global network reduces North America mean annual flux uncertainty for 2001-2003 by 15% to 0.4 Pg yr−1 compared to a network without the tower sites. North American flux is estimated to be a net sink of 1.3 Pg C yr−1, within the uncertainty bounds of the result without the towers. Uncertainty reduction is found to be local to the regions within North America where the flux towers are located. Including the towers reduces covariances between regions within North America. We estimated potential future uncertainty reduction with simulated observations at North American sites that are now or planned to be instrumented for suitable carbon dioxide measurements. We also tested a micrometeorological adjustment to surface carbon dioxide measurements to approximate mid-continental-boundary-layer measurements. This adjustment can be calculated during mid-day hours using atmospheric measurements commonly available at flux tower sites. The atmospheric transport models used in global atmospheric inversions often do not have sufficient spatial or temporal resolution to capture small-scale variability in the continental boundary layer. We find that using mid-day hours of observations at continental sites, either with or without the micrometeorological adjustment, allows inclusion of continental sites in global atmospheric inversions. Increased continental observation density is necessary for estimating carbon fluxes with finer resolution in space and time.

Download or read book Global CO2 Flux Inferred From Atmospheric Observations and Its Response to Climate Variabilities written by Feng Deng and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Carbon Management Technologies written by Subhas Sikdar and published by CRC Press. This book was released on 2020-03-19 with total page 471 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Carbon Management Technologies comprises 43 chapters contributed by experts from all over the world. Volume 1 of the book, containing 23 chapters, discusses the status of technologies capable of yielding substantial reduction of carbon dioxide emissions from major combustion sources. Such technologies include renewable energy sources that can replace fossil fuels and technologies to capture CO2 after fossil fuel combustion or directly from the atmosphere, with subsequent permanent long-term storage. The introductory chapter emphasizes the gravity of the issues related to greenhouse gas emissionglobal temperature correlation, the state of the art of key technologies and the necessary emission reductions needed to meet international warming targets. Section 1 deals with global challenges associated with key fossil fuel mitigation technologies, including removing CO2 from the atmosphere, and emission measurements. Section 2 presents technological choices for coal, petroleum, and natural gas for the purpose of reducing carbon footprints associated with the utilization of such fuels. Section 3 deals with promising contributions of alternatives to fossil fuels, such as hydropower, nuclear, solar photovoltaics, and wind. Chapter 19 of this book is freely available as a downloadable Open Access PDF at http://www.taylorfrancis.com under a Creative Commons Attribution-Non Commercial-No Derivatives (CC-BY-NC-ND) 4.0 license.

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 An Investigation of Sea Surface Carbon Dioxide and Its Distribution in the North Atlantic Using a Neutral Network Technique written by Maciej Telszewski and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Atmospheric Inversion of the Global Surface Carbon Flux with Consideration of the Spatial Distributions of US Crop Production and Consumption written by Jonathan Winston Fung and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Turbulent CO 1tn2 H 1tn2O and Energy Fluxes Above a Mediterranean Oak and a Mountainous Spruce Forrest Investigated by Eddy Covariance Measurements written by Kai Morgenstern and published by Cuvillier Verlag. This book was released on 2001 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Carbon Dioxide Flux Divergence Near the Earth s Surface written by Larry Lorin Stowe and published by . This book was released on 1966 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Energy Water and Carbon Dioxide Fluxes at the Earth s Surface written by Meghan F. Cronin and published by Frontiers Media SA. This book was released on 2022-10-03 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Summary Report written by Climate Monitoring and Diagnostics Laboratory (U.S.) and published by . This book was released on 2004 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: