Papers by Georgii Alexandrov
Chapter 5 5.2.1.4.2 29:8 confirm this statement, is it "confirms this statement," instead? please... more Chapter 5 5.2.1.4.2 29:8 confirm this statement, is it "confirms this statement," instead? please double check, it refers to "A set" Chapter 5 Cross-Chapter Box 5.1 30:21 at the leaf, canopy to ecosystem scales By at the leaf, canopy and ecosystem scales Chapter 5 Cross-Chapter Box 5.1 30:34 ecosystems-scale water savings By ecosystem-scale water savings Chapter 5
Global Change Biology, 2022
The dynamics of soil organic carbon (SOC) play a critical role in modulating global warming. Howe... more The dynamics of soil organic carbon (SOC) play a critical role in modulating global warming. However, the long‐term spatiotemporal changes of SOC at large scale, and the impacts of driving forces remain unclear. In this study, we investigated the dynamics of SOC in different soil layers across China through the1980s to 2010s using a machine learning approach and quantified the impacts of the key factors based on factorial simulation experiments.Our results showed that the latest (2000–2014) SOC stock in the first meter soil (SOC100) was 80.68 ± 3.49 Pg C, of which 42.6% was stored in the top 20 cm, sequestrating carbon with a rate of 30.80 ± 12.37 g C m−2 yr−1since the 1980s. Our experiments focusing on the recent two periods (2000s and 2010s) revealed that climate change exerted the largest relative contributions to SOC dynamics in both layers and warming or drying can result in SOC loss. However, the influence of climate change weakened with soil depth, while the opposite for vegetation growth. Relationships between SOC and forest canopy height further confirmed this strengthened impact of vegetation with soil depth and highlighted the carbon sink function of deep soil in mature forest. Moreover, our estimates suggested that SOC dynamics in 71% of topsoil were controlled by climate change and its coupled influence with environmental variation (CE). Meanwhile, CE and the combined influence of climate change and vegetation growth dominated the SOC dynamics in 82.05% of the first meter soil. Additionally, the national cropland topsoil organic carbon increased with a rate of 23.6 ± 7.6 g C m−2 yr−1since the 1980s, and the widely applied nitrogenous fertilizer was a key stimulus. Overall, our study extended the knowledge about the dynamics of SOC and deepened our understanding about the impacts of the primary factors.
This is a pre-release of the source code of an impeded drainage model for simulating peatland gro... more This is a pre-release of the source code of an impeded drainage model for simulating peatland growth and expansion.
Scientific workflows in the field of biosphere modelling include assessment of the state of the a... more Scientific workflows in the field of biosphere modelling include assessment of the state of the art in modelling global biogeochemical cycles. The process of assessment consists of the following steps: collecting model outputs, performing model inter-comparison study, writing summary for policymakers, formulating an agenda for further research. Here, we present a web-based service that automates the entire process.
Engineering, 2021
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Geoscience Letters, 2018
Compared with the conventional fossil fuel, bioenergy has obvious advantages due to its renewabil... more Compared with the conventional fossil fuel, bioenergy has obvious advantages due to its renewability and large quantity, and thus plays a crucial role in helping defend the energy security. However, the bioenergy development may potentially cause serious environmental alterations, which remain unclear. The study summarizes the environmental impacts of bioenergy production based on the compilation and published data. Our analysis shows that more and more attention is being paid to the environmental protection as the development of bioenergy, and among the influencing terms of bioenergy production, water issues (i.e., water quantity and quality) gain the greatest concern, whereas the least attention has been given to soil erosion. Although we recognize that the bioenergy production can indeed exert negative effects on the environment in terms of water quantity and quality, greenhouse gas emissions, biodiversity and soil organic carbon, and soil erosion, the adverse impacts varied greatly depending on biomass types, land locations, and management practices. Identifying the reasonable cultivation locations, appropriate bioenergy crop types, and optimal management practices can be beneficial to environment and sustainable development of bioenergy. In this field, Chinese bioenergy production has lagged behind and does not match its rising energy consumption, but it has a great potential of and demand for biomass-based energy especially under its urbanization, in spite of the negative environmental impacts. Therefore, this article is expected to serve as a reference and guideline on what has been done in the bioenergy-oriented countries that might stimulate development of more effective and environmentally sound guidelines for promoting bioenergy production in China and other developing countries as well.
The spread of cloud computing services gives community modelling a reasonable opportunity to beco... more The spread of cloud computing services gives community modelling a reasonable opportunity to become a reality in scientific research. However, even if models will be deployed in clouds, and model codes will be open for re-use, there will be little progress in community modelling in the lack of consensus standards for model documentation. This paper is to discuss a conceptual framework for developing such standards. The proposed conceptual framework is based on the idea that a new model is often a modification of an old one, and hence, the similarities between the models of the same environmental process could be expressed in terms of object-oriented programming (i.e., as either inheritance or polymorphism). The advantages of such conceptual framework are illustrated with an ensemble of so-called production efficiency models (PEMs) which are used for modelling primary production of terrestrial ecosystems.
Heterotrophic respiration, an important item in ecosystem carbon balance, is the process which is... more Heterotrophic respiration, an important item in ecosystem carbon balance, is the process which is addressed in the global carbon cycle models and Earth system models. The seasonal cycle of the heterotrophic respiration is determined by seasonal changes in climatic conditions and in the storage of litter (i.e., in the amount of organic substrate available as a food source for organisms composing the heterotrophic community). The model component presented in this paper is focussing at effects produced by seasonal depletion in litter storage. The seasonal changes in litter storage are modelled by ordinary differential equations, which are solved analytically to make model spin-up runs unnecessary. The steady seasonal cycle is calculated by using solutions of the differential equations expressed in functional form.
This editorial provides a subject index from published articles, active researchers, and publishe... more This editorial provides a subject index from published articles, active researchers, and published papers in the field of carbon balance and management.
Environmental Modelling & Software, 2011
ABSTRACT The intention of this paper it to open up debate within the environmental modelling and ... more ABSTRACT The intention of this paper it to open up debate within the environmental modelling and software (EMS) community on how best to respond to the increasing desire to evaluate the success of EMS projects in terms of outcomes rather than outputs. Outcomes ...
Environmental Modelling & Software, 2011
Science in China (series C), 2002
Net biome production (NBP) is considered as the most appropriate concept for analyzing long-term ... more Net biome production (NBP) is considered as the most appropriate concept for analyzing long-term and large-scale changes of the carbon cycle induced by land use. We have estimated NBP potential of Japanese managed forests, based on their age structure, to be 16 Mt C/a. Fifty-nine percent of this sink is located in the warm-temperate broadleaf forest zone and the remaining 39% is located in the cool-temperate broadleaf forest zone. This potential of NBP could be achieved under a long rotation period (70 a) and may serve as a target for sink enhancement efforts with the potential to uptake up to 4% of current fossil fuel emissions.
Despite the common expectation that climate change may make Siberia a warm heaven, this would not... more Despite the common expectation that climate change may make Siberia a warm heaven, this would not be good for local people. Surprisingly the people of Siberia do rely on the winter cold. Warming may be a serious challenge here. Climate change threatens Siberian forests, lakes and permafrost. In the region where landscapes are unstable this implies the risks of losing the traditional means of subsistence, at least for a while. Social adaptation to climate change is becoming an urgent issue, as the first signs of warming are becoming noticeable to local people. This article reports an attempt to explore the gaps between the state-of-the-art and desired progress in environmental modelling with respect to the integrated assessment of the climate change impacts on Siberia.
This letter details the collective views of a number of independent researchers on the technical ... more This letter details the collective views of a number of independent researchers on the technical assessment and evaluation of environmental models and software. The purpose is to stimulate debate and initiate action that leads to an improved quality of model development and evaluation, so increasing the capacity for models to have positive outcomes from their use.
The components of terrestrial carbon sink are estimated by means of models. Many different models... more The components of terrestrial carbon sink are estimated by means of models. Many different models are possible for any given component, and no criterion exists to pick one model over another (Cramer and Field, 1999). Instead, the models form an ensemble, which is assumed to be a consistent estimator of the terrestrial carbon sink and its components -- that is, to be converging to the quantities being estimated as the number of models grows. Is this assumption close to reality? Are confidence intervals shrinking? To answer this question we need regular checks of model consistency based on well-agreed methodology. A biosphere model is a geographical extension of an ecosystem model, and so modeling ecosystems at global scale we are facing the same problem as at the local scale -- structural uncertainty. The structural uncertainty includes competing conceptual frameworks, lack of agreement on model structure, ambiguous definitions of system boundaries, inadequate description of signific...
Atmospheric CO2 concentration can be decreased not only by reducing fossil fuel burning but also ... more Atmospheric CO2 concentration can be decreased not only by reducing fossil fuel burning but also by increasing the terrestrial ecosystems that serve as sinks for CO2. The Kyoto Protocol allows countries that are burdened with emission reduction commitments to use carbon sequestration by terrestrial sinks. However, opinions differ widely on how the inclusion of terrestrial carbon sinks in the legally binding framework (Article 3.3) will affect the demand for emission reduction during the commitment period. We approach this issue by combining a simulation model of the carbon stock change with that of land-use change. The result of the simulation shows that the Annex I countries in total may potentially claim for a net carbon offset as high as 0.2GtC per year by carrying out ARD (Afforestation, Reforestation and Deforestation) activities. In order to come up with an effective long-term climate regime, political decisions are necessary to realize an appropriate balance between the sink ...
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Papers by Georgii Alexandrov