scholarly journals Remote sensing and ecosystem modeling to simulate terrestrial carbon fluxes

2019 ◽  
pp. 87
Author(s):  
Sergio Sánchez-Ruiz
Keyword(s):  
Remote Sensing ◽  
Carbon Cycle ◽  
Spatial Scale ◽  
Forest Ecosystems ◽  
Carbon Fluxes ◽  
Daily Basis ◽  
Ecosystem Models ◽  
Validation Process ◽  
Data Source ◽  
Peninsular Spain

<p>The main goal of this thesis is the establishment of a framework to analyze the forest ecosystems in peninsular Spain in terms of their role in the carbon cycle. In particular, the carbon fluxes that they exchange with atmosphere are modeled to evaluate their potential as carbon sinks and biomass reservoirs. The assessment of gross and net carbon fluxes is performed at 1-km spatial scale and on a daily basis using two different ecosystem models, Monteith and BIOME-BGC, respectively. These models are driven by a combination of satellite and ground data, part of the latter being also employed as a complementary data source and in the validation process.</p>

Historical vegetation dynamics and the carbon cycle: current requirements and future challenges for quantifying carbon fluxes in Australian terrestrial ecosystems

2002 ◽  
Vol 50 (4) ◽  
pp. 533 ◽  
Author(s):  
Rodney J. Keenan
Keyword(s):  
Remote Sensing ◽  
Carbon Cycle ◽  
Kyoto Protocol ◽  
Terrestrial Ecosystems ◽  
Carbon Fluxes ◽  
Carbon Dynamics ◽  
International Climate Agreements ◽  
Future Challenges ◽  
The Impact ◽  
Atmospheric Concentrations

Concern about the potentially dangerous effects of increased atmospheric concentrations of CO2 and other greenhouse gases on global climate has resulted in international agreement to stabilise atmospheric concentrations of these gases. Terrestrial vegetation plays a significant role in the global carbon cycle and management actions that increase carbon stocks in vegetation and soils could potentially offset CO2 emissions from use of fossil fuels. Inclusion of such actions in international climate agreements has been controversial. The Kyoto Protocol allowed for a limited set of vegetation 'sink' activities to be accounted toward greenhouse-gas mitigation targets in the first commitment period and rules regarding implementation of these activities have recently been agreed. Inclusion of carbon in vegetation sinks in the Kyoto Protocol has focused policy attention on the need for better understanding and monitoring of carbon dynamics in terrestrial ecosystems. Recent investment in remote sensing, modelling and accounting systems has improved capacity to assess and report on carbon fluxes in vegetation, particularly those associated with recent land-cover change from forest to non-forest and vice versa. Quantitative understanding of carbon dynamics across the broader vegetation estate remains limited. Future challenges for a comprehensive assessment of carbon cycling in vegetation include quantification of the effects of changes in vegetation structure from historical changes in fire and grazing regimes, the impact of human and natural wildfire and the area and growth of regrowth forest created by past clearing and timber harvesting. Different reporting processes will require separation of the effects of human-induced versus natural processes. These will require greater investment in vegetation monitoring systems that efficiently integrate remote sensing and field measurements.

scholarly journals Using remote sensing to assess tsunami-induced impacts on coastal forest ecosystems at the Andaman Sea coast of Thailand

2010 ◽  
Vol 10 (4) ◽  
pp. 729-745 ◽  
Author(s):  
H. Roemer ◽  
G. Kaiser ◽  
H. Sterr ◽  
R. Ludwig
Keyword(s):  
Remote Sensing ◽  
Forest Ecosystems ◽  
Ground Truth ◽  
Andaman Sea ◽  
Coastal Forest ◽  
Coastal Forests ◽  
Change Detection Algorithms ◽  
Damage Maps ◽  
2004 Tsunami ◽  
Sea Coast

Abstract. The December 2004 tsunami strongly impacted coastal ecosystems along the Andaman Sea coast of Thailand. In this paper tsunami-induced damage of five different coastal forest ecosystems at the Phang-Nga province coast is analysed with a remote sensing driven approach based on multi-date IKONOS imagery. Two change detection algorithms, change vector analysis (CVA) and direct multi-date classification (DMC), are applied and compared regarding their applicability to assess tsunami impacts. The analysis shows that DMC outperforms CVA in terms of accuracy (Kappa values for DMC ranging between 0.947 and 0.950 and between 0.610–0.730 for CVA respectively) and the degree of detail of the created change classes. Results from DMC show that mangroves were the worst damaged among the five forests, with a 55% of directly damaged forest in the study area, followed by casuarina forest and coconut plantation. Additionally this study points out the uncertainties in both methods which are mainly due to a lack of ground truth information for the time between the two acquisition dates of satellite images. The created damage maps help to better understand the way the tsunami impacted coastal forests and give basic information for estimating tsunami sensitivity of coastal forests.

scholarly journals Historical and idealized climate model experiments: an intercomparison of Earth system models of intermediate complexity

2013 ◽  
Vol 9 (3) ◽  
pp. 1111-1140 ◽  
Author(s):  
M. Eby ◽  
A. J. Weaver ◽  
K. Alexander ◽  
K. Zickfeld ◽  
A. Abe-Ouchi ◽  
...  
Keyword(s):  
Land Use ◽  
Carbon Cycle ◽  
Air Temperature ◽  
Climate Model ◽  
Surface Air Temperature ◽  
Carbon Fluxes ◽  
Carbon Uptake ◽  
Earth System ◽  
Model Experiments ◽  
Earth System Models

Abstract. Both historical and idealized climate model experiments are performed with a variety of Earth system models of intermediate complexity (EMICs) as part of a community contribution to the Intergovernmental Panel on Climate Change Fifth Assessment Report. Historical simulations start at 850 CE and continue through to 2005. The standard simulations include changes in forcing from solar luminosity, Earth's orbital configuration, CO2, additional greenhouse gases, land use, and sulphate and volcanic aerosols. In spite of very different modelled pre-industrial global surface air temperatures, overall 20th century trends in surface air temperature and carbon uptake are reasonably well simulated when compared to observed trends. Land carbon fluxes show much more variation between models than ocean carbon fluxes, and recent land fluxes appear to be slightly underestimated. It is possible that recent modelled climate trends or climate–carbon feedbacks are overestimated resulting in too much land carbon loss or that carbon uptake due to CO2 and/or nitrogen fertilization is underestimated. Several one thousand year long, idealized, 2 × and 4 × CO2 experiments are used to quantify standard model characteristics, including transient and equilibrium climate sensitivities, and climate–carbon feedbacks. The values from EMICs generally fall within the range given by general circulation models. Seven additional historical simulations, each including a single specified forcing, are used to assess the contributions of different climate forcings to the overall climate and carbon cycle response. The response of surface air temperature is the linear sum of the individual forcings, while the carbon cycle response shows a non-linear interaction between land-use change and CO2 forcings for some models. Finally, the preindustrial portions of the last millennium simulations are used to assess historical model carbon-climate feedbacks. Given the specified forcing, there is a tendency for the EMICs to underestimate the drop in surface air temperature and CO2 between the Medieval Climate Anomaly and the Little Ice Age estimated from palaeoclimate reconstructions. This in turn could be a result of unforced variability within the climate system, uncertainty in the reconstructions of temperature and CO2, errors in the reconstructions of forcing used to drive the models, or the incomplete representation of certain processes within the models. Given the forcing datasets used in this study, the models calculate significant land-use emissions over the pre-industrial period. This implies that land-use emissions might need to be taken into account, when making estimates of climate–carbon feedbacks from palaeoclimate reconstructions.

Study on the Wetland Change in Northeast China Based on RS and GIS Technology

2011 ◽  
Vol 356-360 ◽  
pp. 2886-2891
Author(s):  
Han Wen Cui ◽  
Qi Gang Jiang
Keyword(s):  
Remote Sensing ◽  
Current Distribution ◽  
Constructed Wetland ◽  
Human Activities ◽  
Northeast China ◽  
Transition Matrix ◽  
Gis Technology ◽  
Wetland Area ◽  
Rs And Gis ◽  
Data Source

Based on the RS and GIS technology, the remote sensing imageries MSS in 1975, ETM in 2000 and CBERS-2 in 2007 have been used as main data source in this paper. Wetland current distribution, spatiotemporal change principle and transition matrix have been analyzed in order to realize the wetland change situation in Northeast China during the 30 years. The results show that the wetland area in Northeast China, on the whole, is decreased first and then increased. The dramatic change happened in mire and constructed wetland. Mire is decreased first and then increased, but the whole is still decreased. While, constructed wetland is increased continuously. Constructed wetland increased owing to the transition from mire and non-wetland. The level of the transition from mire to constructed wetland is lower. In Northeast China, human activities have a great impact on wetland change than nature factors.

scholarly journals A global CO<sub>2</sub> flux dataset (2015–2019) inferred from OCO-2 retrievals using the Tan-Tracker inversion system

2021 ◽  
Author(s):  
Zhe Jin ◽  
Xiangjun Tian ◽  
Rui Han ◽  
Yu Fu ◽  
Xin Li ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Carbon Cycle ◽  
Carbon Flux ◽  
Carbon Budget ◽  
Terrestrial Ecosystem ◽  
Carbon Fluxes ◽  
Global Carbon Cycle ◽  
Ocean Carbon ◽  
Global Carbon ◽  
Regional Fluxes

Abstract. Accurate assessment of the various sources and sinks of carbon dioxide (CO2), especially terrestrial ecosystem and ocean fluxes with high uncertainties, is important for understanding of the global carbon cycle, supporting the formulation of climate policies, and projecting future climate change. Satellite retrievals of the column-averaged dry air mole fractions of CO2 (XCO2) are being widely used to improve carbon flux estimation due to their broad spatial coverage. However, there is no consensus on the robust estimates of regional fluxes. In this study, we present a global and regional resolved terrestrial ecosystem carbon flux (NEE) and ocean carbon flux dataset for 2015–2019. The dataset was generated using the Tan-Tracker inversion system by assimilating Observing Carbon Observatory 2 (OCO-2) column CO2 retrievals. The posterior NEE and ocean carbon fluxes were comprehensively validated by comparing posterior simulated CO2 concentrations with OCO-2 independent retrievals and Total Carbon Column Observing Network (TCCON) measurements. The validation showed that posterior carbon fluxes significantly improved the modelling of atmospheric CO2 concentrations, with global mean biases of 0.33 ppm against OCO-2 retrievals and 0.12 ppm against TCCON measurements. We described the characteristics of the dataset at global, regional, and Tibetan Plateau scales in terms of the carbon budget, annual and seasonal variations, and spatial distribution. The posterior 5-year annual mean global atmospheric CO2 growth rate was 5.35 PgC yr−1, which was within the uncertainty of the Global Carbon Budget 2020 estimate (5.49 PgC yr−1). The posterior annual mean NEE and ocean carbon fluxes were −4.07 and −3.33 PgC yr−1, respectively. Regional fluxes were analysed based on TransCom partitioning. All 11 land regions acted as carbon sinks, except for Tropical South America, which was almost neutral. The strongest carbon sinks were located in Boreal Asia, followed by Temperate Asia and North Africa. The entire Tibetan Plateau ecosystem was estimated as a carbon sink, taking up −49.52 TgC yr−1 on average, with the strongest sink occurring in eastern alpine meadows. These results indicate that our dataset captures surface carbon fluxes well and provides insight into the global carbon cycle. The dataset can be accessed at https://doi.org/10.11888/Meteoro.tpdc.271317 (Jin et al., 2021).

scholarly journals Problématique du bilan de carbone dans les écosystèmes forestiers: exemple d'une jeune hêtraie de plaine | Problematics of the Carbon Net-Balance Within the Forest Ecosystems: a Juvenile Beech Forest in the Lowlands

2000 ◽  
Vol 151 (9) ◽  
pp. 317-324
Author(s):  
André Granier ◽  
Claire Damesin ◽  
Daniel Epron ◽  
Valérie Le Dantec
Keyword(s):  
Biomass Production ◽  
Forest Ecosystems ◽  
Photosynthetic Activity ◽  
Carbon Fluxes ◽  
Beech Forest ◽  
High Variability ◽  
Daily Cycles

The results of an investigation carried through within the ‹Euroflux›-programme in eastern France assessing the carbon fluxes above the canopy of the forest are presented. The photosynthetic activity within the annual and daily cycles are discussed. The high variability of the carbon netbalance and the variation of the total respiration make further research into the understanding of the correlation between the carbon net-balance and the biomass production necessary.

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