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Modeling Regional Carbon Dioxide Flux Over California Using The Wrf Acasa Coupled Model
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Book Synopsis Modeling Regional Carbon Dioxide Flux Over California Using the WRF-ACASA Coupled Model by :
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.
Book Synopsis Toward Improved Regional Estimates of Carbon Dioxide Sources and Sinks Through Coupled Carbon--atmospheric Data Assimilation by : Hans Weiteng Chen
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.
Book Synopsis Temporal and Spatial Modeling of Urban Carbon Dioxide Fluxes Using a Data Based Approach by : Olaf Menzer
Download or read book Temporal and Spatial Modeling of Urban Carbon Dioxide Fluxes Using a Data Based Approach written by Olaf Menzer and published by . This book was released on 2015 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: The spatial variation in the flux magnitude when modeling annual sums of FC was up to a factor of two depending on major land use types in different wind directions, including residential and recreational areas. Gross primary production had the largest magnitude of all separated urban FC components both on a monthly and on a diurnal temporal scale during the growing season, and was also the most seasonally dynamic flux (compared to vehicular traffic emissions, natural gas emissions from space heating as well as water heating and cooking, and ecosystem respiration). The modeled biogenic and anthropogenic fluxes were significantly related to source area weighted fractions of green cover and impervious cover, respectively. Finally, I calculated the first estimates of net CO2 exchange from urban trees in residential areas directly based on eddy covariance measurements and scaled them up to the larger metropolitan area throughout the growing seasons of 2007 and 2008. The modeling studies in this work provide estimates of CO2 release and CO2 uptake from urban trees and turfgrass lawns in a suburban neighborhood at half-hourly, daily, monthly and annual levels. New insights on the controlling factors of these biogenic fluxes can lead to improvements in capturing the function of urban greenspace in carbon and climate models at metropolitan, regional, and global scales.
Book Synopsis Modeling the Influence of Carbon Dioxide on the Global and Regional Climate by : Wilfrid Bach
Download or read book Modeling the Influence of Carbon Dioxide on the Global and Regional Climate written by Wilfrid Bach and published by . This book was released on 1985 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A 2xCo2 Climate Change Simulation Over California Using a Integrated Regional Atmospheric-hydrologic Model by : Liqin Tan
Download or read book A 2xCo2 Climate Change Simulation Over California Using a Integrated Regional Atmospheric-hydrologic Model written by Liqin Tan and published by . This book was released on 1997 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Spatiotemporal Dynamics of Carbon Dioxide and Methane Fluxes from Agricultural and Restored Wetlands in the California Delta by : Jaclyn Hatala
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.
Book Synopsis Final Report on "Modeling Diurnal Variations of California Land Biosphere CO2 Fluxes." by :
Download or read book Final Report on "Modeling Diurnal Variations of California Land Biosphere CO2 Fluxes." written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In Mediterranean climates, the season of water availability (winter) is out of phase with the season of light availability and atmospheric demand for moisture (summer). Multi-year half-hourly observations of sap flow velocities in 26 evergreen trees in a small watershed in Northern California show that different species of evergreen trees have different seasonalities of transpiration: Douglas-firs respond immediately to the first winter rain, while Pacific madrones have peak transpiration in the dry summer. Using these observations, we have derived species-specific parameterization of normalized sap flow velocities in terms of insolation, vapor pressure deficit and near-surface soil moisture. A simple 1-D boundary layer model showed that afternoon temperatures may be higher by 1 degree Celsius in an area with Douglas-firs than with Pacific madrones. The results point to the need to develop a new representation of subsurface moisture, in particular pools beneath the organic soil mantle and the vadose zone. Our ongoing and future work includes coupling our new parameterization of transpiration with new representation of sub-surface moisture in saprolite and weathered bedrock. The results will be implemented in a regional climate model to explore vegetation-climate feedbacks, especially in the dry season.
Book Synopsis Using a Regional Cluster of AmeriFlux Sites in Central California to Advance Our Knowledge on Decadal-Scale Ecosystem-Atmosphere Carbon Dioxide Exchange by :
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.
Book Synopsis Computational Science and Its Applications - ICCSA 2011 by : Beniamino Murgante
Download or read book Computational Science and Its Applications - ICCSA 2011 written by Beniamino Murgante and published by Springer Science & Business Media. This book was released on 2011-06-15 with total page 796 pages. Available in PDF, EPUB and Kindle. Book excerpt: The five-volume set LNCS 6782 - 6786 constitutes the refereed proceedings of the International Conference on Computational Science and Its Applications, ICCSA 2011, held in Santander, Spain, in June 2011. The five volumes contain papers presenting a wealth of original research results in the field of computational science, from foundational issues in computer science and mathematics to advanced applications in virtually all sciences making use of computational techniques. The topics of the fully refereed papers are structured according to the five major conference themes: geographical analysis, urban modeling, spatial statistics; cities, technologies and planning; computational geometry and applications; computer aided modeling, simulation, and analysis; and mobile communications.
Book Synopsis Investigating Land-air Carbon Fluxes Using a Lagrangian Model and Satellite Retrieved Carbon Dioxide by : Alan James Hewitt
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.
Book Synopsis Regional Carbon Balance by : Panagiotis Kountouris
Download or read book Regional Carbon Balance written by Panagiotis Kountouris and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Long term observations of atmospheric greenhouse gas measuring stations improve our understanding of greenhouse gas sources and sinks. These dry mole fraction measurements can be linked to surface fluxes by atmospheric transport inversions. In the framework of ICOS (Integrated Carbon Observation System), more observing stations are to be deployed within the European domain. A quantitative network design study is required to perform this optimization and to assess potential observing networks. A regional inverse modeling framework was set up that derives biosphere-atmosphere exchange fluxes at regional scales using CO2 measurements from tall towers, and ground stations. The modeling framework consists of the following components: the global transport model TM3, the regional Stochastic Time-Inverted Lagrangian Transport model (STILT), the Vegetation Photosynthesis and Respiration Model (VPRM), gridded emissions from fossil fuel burning, ocean-atmosphere exchange fluxes, and a Bayesian inversion scheme. This thesis first studies the flux error structure, and explains how these uncertainties are distributed spatially and temporally. Fluxes from three biosphere models were used and compared against flux observations from 53 Eddy covariance flux towers and from an aircraft campaign. Spatial and temporal autocorrelations of the daily model-data flux residuals were approximated by an exponentially decay error model. This flux error information is implemented in the inversion system. A synthetic experiment was performed using two different biosphere models, one to produce the a-priori flux field, and the other to provide fluxes that served as a "known truth". This experiment allows to quantitatively assess the system's ability to correct fluxes at different spatial and temporal scales. A network design study is conducted, using different network configurations for ICOS current and future stations, evaluating the uncertainty reduction on the terrestrial fluxes.
Book Synopsis An Evaluation of the Variable-resolution CESM for Modeling California's Climate by :
Download or read book An Evaluation of the Variable-resolution CESM for Modeling California's Climate written by and published by . This book was released on 2016 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper, the recently developed variable-resolution option within the Community Earth System Model (VR-CESM) is assessed for long-term regional climate modeling of California at 0.25° (~ 28 km) and 0.125° (~ 14 km) horizontal resolutions. The mean climatology of near-surface temperature and precipitation is analyzed and contrasted with reanalysis, gridded observational data sets, and a traditional regional climate model (RCM)--the Weather Research and Forecasting (WRF) model. Statistical metrics for model evaluation and tests for differential significance have been extensively applied. VR-CESM tended to produce a warmer summer (by about 1-3°C) and overestimated overall winter precipitation (about 25%-35%) compared to reference data sets when sea surface temperatures were prescribed. Increasing resolution from 0.25° to 0.125° did not produce a statistically significant improvement in the model results. By comparison, the analogous WRF climatology (constrained laterally and at the sea surface by ERA-Interim reanalysis) was ~1-3°C colder than the reference data sets, underestimated precipitation by ~20%-30% at 27 km resolution, and overestimated precipitation by ~ 65-85% at 9 km. Overall, VR-CESM produced comparable statistical biases to WRF in key climatological quantities. Moreover, this assessment highlights the value of variable-resolution global climate models (VRGCMs) in capturing fine-scale atmospheric processes, projecting future regional climate, and addressing the computational expense of uniform-resolution global climate models.
Book Synopsis Long-term Greenhouse Gas Emissions Mitigation in California and the Associated Regional Air Quality and Public Health Impacts by : Tianyang Wang
Download or read book Long-term Greenhouse Gas Emissions Mitigation in California and the Associated Regional Air Quality and Public Health Impacts written by Tianyang Wang and published by . This book was released on 2019 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation we investigate the roadmap for California to achieve deep greenhouse gas (GHG) emissions reductions by 2050 and the resulting regional air quality and public health impacts, form the strategy feasibility and selections that achieves different levels of ambitious climate target, to the benefits and trade-offs of different technology pathways with respect to air quality and public health consequences, as well as the relative contributions of emissions from different origins to regional air quality and public health. We first develop a roadmap for California to achieve net-zero GHG emissions in 2050 using detailed modeling of energy system transformation, cross-sectorial connectivity, and technology applicability. GHG mitigation strategies also reduce co-emitted criteria pollutants in California. By utilizing the Weather Research and Forecasting Model with Chemistry (WRF-Chem) and the Environmental Benefit Mapping and Analysis Program (BenMAP), we find that achieving net-zero GHG emissions can reduce 14,066 (95% Confidence Interval: 10,855 - 17,226) air pollution-related mortality in 2050, 35% of which are in disadvantaged communities. The monetized health co-benefit can offset most of the GHG abatement costs (i.e., 26 -116 billion dollars). These co-benefits are mainly contributed by ambient fine particulate matter (PM2.5) concentration reductions, while ambient ozone (O3) concentration in California is not likely to drop when local emissions reduce. The net-zero target also requires bioenergy with carbon capture and sequestration (BECCS) technology to offset some GHG emissions. BECCS technology, whereas supporting the net-zero target, would emit air pollutants through biomass combustion and reduce health co-benefits by 3 billion dollars, suggesting a potential trade-off between climate benefits and health co-benefits of ambitious climate policies. We then analyze the air quality and health impacts of different GHG mitigation pathways. By adopting an integrated approach that combines energy and emission technology modeling, high-resolution chemical transport simulation, and health impact assessment, we find that achievement of the 80% GHG reduction target would always bring substantial air quality and health co-benefits. But more importantly, the level of co-benefits are highly related to the selected technology pathway largely because of California's relatively clean energy structure. Compared with the business-as-usual levels, a decarbonization pathway that focuses on electrification and clean renewable energy is estimated to reduce concentrations of PM2.5 by 18-37% in four major metropolitan areas of California and subsequently avoid 10,196 (95% CI: 8,169-12,202) premature deaths. In contrast, a pathway focusing more on combustible renewable fuels only results in a quarter of such air quality and health benefits. Similar to what we found before, both GHG mitigation pathways may not reduce ambient O3 concentrations in California. Our findings could also assist the development of optimized technology pathway to simultaneously reduce GHG emissions and improve human health in California. Lastly, we conduct a detailed analysis to understand the relative contributions of local and non-local emission sources to ambient PM2.5 and O3 and evaluate the mortality burden in California associated with these two pollutants. We attribute the ambient PM2.5 and O3 concentrations in California to four emission groups: (1) California in-state anthropogenic emissions; (2) anthropogenic emissions from the western United States, excluding California; (3) natural emissions from the western United States; and (4) all emissions from outside of the western United States. Our health impact analyses find that PM2.5 and O3 are associated with 27,445 [95% Confidence Interval (CI): 19,277 - 35,885] and 13,822 (95% CI: 6,106-23,659) mortalities in California in 2012, respectively. Our estimates of O3-assocoated mortality are much higher than previously reported, mainly because we estimate 6,354 (95% CI 2,224 - 10,268) O3-associated cardiovascular mortality based on new epidemiological evidence. Approximately 67% of PM2.5-associated mortality in California is attributable to PM2.5 from in-state anthropogenic emissions. In contrast, 75% of the ambient O3 in California is contributed by distant emissions outside western United States, leading to 92% of O3-associated mortality, while in-state emissions were found to contribute to a much lesser extent to O3-associated mortality [i.e., 771 (95% CI 389-1,146) in ozone season]. The different patterns of PM2.5 and O3 we found also help explain our previous findings that GHG mitigation efforts in California mainly reduce local PM2.5 pollution.
Book Synopsis Quantifying Carbon-Climate Processes at the Regional Scale Using Atmospheric Carbonyl Sulfide by :
Download or read book Quantifying Carbon-Climate Processes at the Regional Scale Using Atmospheric Carbonyl Sulfide written by and published by . This book was released on 2013 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric carbonyl sulfide (COS) analysis has the potentially transformative capability for partitioning the regional carbon flux into respiration and photosynthesis components. This emerging approach is based on the observation that continental atmospheric CO2 gradients are dominated by net ecosystem fluxes while continental atmospheric COS gradients are dominated by photosynthesis-related plant uptake. Regional flux partitioning represents a critical knowledge gap due to a lack of robust methods for regional-scale flux partitioning and large uncertainties in forecasting carbon-climate feedbacks. Our completed project characterized the relationship between COS and CO2 surface fluxes using a novel measurement and modeling system in a winter wheat field at the U.S. Department of Energy?s Atmospheric and Radiation Measurement program Central Facility (DOE-ARM CF). The scope of this project included canopy flux measurements, soil flux measurements, regional atmospheric modeling, and analysis of COS and CO2 airborne observations at SGP. Three critical discoveries emerged from this investigation: (1) the new measurement system provided the first field evidence of a robust relationship between COS leaf fluxes and GPP; (2) a previously unknown seasonal soil source of COS was observed and characterized; (3) the regional atmospheric analysis of airborne measurements provided the first COS-based constraints on GPP parameterizations used in earth systems models. Dissemination of these results includes three publications [Billesbach et al., In Press; Campbell et al., In Preparation; Seibt et al., In Review], three presentations at the AGU Fall Meeting (2012), and four invited presentations to department seminars. We have leveraged this foundational project to continue our work on understanding carbon cycle processes at large scales through one funded project (DOE Lab Fee, 2012-2015) and one proposal that is under review (DOE/NASA/USDA/NOAA, 2014-2016).
Book Synopsis Detection and Attribution of Regional Climate Change by :
Download or read book Detection and Attribution of Regional Climate Change written by and published by . This book was released on 2007 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: We developed a high resolution global coupled modeling capability to perform breakthrough studies of the regional climate change. The atmospheric component in our simulation uses a 1{sup o} latitude x 1.25{sup o} longitude grid which is the finest resolution ever used for the NCAR coupled climate model CCSM3. Substantial testing and slight retuning was required to get an acceptable control simulation. The major accomplishment is the validation of this new high resolution configuration of CCSM3. There are major improvements in our simulation of the surface wind stress and sea ice thickness distribution in the Arctic. Surface wind stress and ocean circulation in the Antarctic Circumpolar Current are also improved. Our results demonstrate that the FV version of the CCSM coupled model is a state of the art climate model whose simulation capabilities are in the class of those used for IPCC assessments. We have also provided 1000 years of model data to Scripps Institution of Oceanography to estimate the natural variability of stream flow in California. In the future, our global model simulations will provide boundary data to high-resolution mesoscale model that will be used at LLNL. The mesoscale model would dynamically downscale the GCM climate to regional scale on climate time scales.
Book Synopsis Where Do Fossil Fuel Carbon Dioxide Emissions from California Go? An Analysis Based on Radiocarbon Observations and an Atmospheric Transport Model by :
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.
Book Synopsis Planning Support Systems for Sustainable Urban Development by : Stan Geertman
Download or read book Planning Support Systems for Sustainable Urban Development written by Stan Geertman and published by Springer Science & Business Media. This book was released on 2013-06-20 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book collects a selection of the best articles presented at the CUPUM (Computers in Urban Planning and Urban Management) conference, held in the second week of July 2013 in Utrecht, the Netherlands. The articles included were selected by external reviewers using a double blind process.
