Soil organic carbon(SOC)depletion caused by changes in land use is one of the main causes of rising atmospheric carbon dioxide(CO_(2))levels.As such,pedometric approaches are essential for understanding SOC dynamics i...Soil organic carbon(SOC)depletion caused by changes in land use is one of the main causes of rising atmospheric carbon dioxide(CO_(2))levels.As such,pedometric approaches are essential for understanding SOC dynamics in forest restoration,which is crucial for mitigating climate change and sustaining ecosystem services.This review summarizes methodologies and advancements in pedometric approaches,focusing on their application in predicting SOC changes across various environments.It highlights the integration of pedometric methods involving spatiotemporal and vertical modeling tools,such as spatially explicit models and geospatial models,to improve soil carbon(C)stock estimates.These methods utilize advanced statistical techniques and remote sensing technologies to model soil properties and predict soil C dynamics across different spatiotemporal scales.The Century model,noted for its effectiveness in simulating long-term SOC drivers under various restoration scenarios,provides critical insights into sustainable forest management.This review evaluates potential solutions for understanding how C evolves over time and under different forest management practices,including afforestation and selective logging.In addition,the review identifies knowledge gaps,such as the need for improved models to predict soil C stocks under diverse environmental conditions accurately.Addressing these gaps through enhanced pedometric models and evaluation efforts is crucial for informing effective soil management strategies and supporting global climate change mitigation initiatives through forest restoration.Integrating pedometric approaches with spatial modeling tools provides a robust framework for guiding forest restoration decision-making and enhancing ecosystem resilience against climate change.展开更多
Harmonic analysis of satellite altimetry data based on a global regular grid is affected by the grid spatial tessellation and placement of the grids.With the increase of latitude,the traditional lat/lon grid deforms g...Harmonic analysis of satellite altimetry data based on a global regular grid is affected by the grid spatial tessellation and placement of the grids.With the increase of latitude,the traditional lat/lon grid deforms greatly,resulting in uneven distribution of satellite altimeter data with latitude,which affects the extraction of tidal information.Alternatively,Hexagonal grids have been proved to be advantageous due to their isotropic,uniform neighbourhood,equal-area and more.Considering the merits above,the purpose of this paper is to use the global equal-area hexagonal grid to conduct a harmonic analysis of satellite altimeter data.First,the Icosahedron Snyder Equal Area projection method is used to construct a global equal-area hexagonal grid,Then the time series data of 19.8 years of Jason series satellite altimeter data are obtained.Finally,the harmonic constants of eight constituents(the M2,S2,N2,K2,K1,O1,P1,Q1)are extracted by harmonic analysis.By analysing the results,we conclude that the harmonic constants extracted from the global equal-area hexagonal grid have considerable accuracy and are consistent with the tidal characteristics of the eight components.Meanwhile,the accuracy of harmonic constants extracted from equal-area hexagonal grids is better than that of lat/lon grids.展开更多
由跟网型变换器(grid-following voltage source converter,GFL-VSC)及构网型变换器(grid-forming voltage source converter,GFM-VSC)构成的混联系统中,复杂的暂态交互作用使系统的安全稳定运行面临挑战,明确变换器间的动态耦合机理及...由跟网型变换器(grid-following voltage source converter,GFL-VSC)及构网型变换器(grid-forming voltage source converter,GFM-VSC)构成的混联系统中,复杂的暂态交互作用使系统的安全稳定运行面临挑战,明确变换器间的动态耦合机理及其对系统暂态稳定性的影响至关重要。GFM-VSC中设置的电流限幅环节会导致其暂态运行方式发生切换,进一步增加了GFM-VSC与GFL-VSC之间的耦合机理的复杂性。为揭示GFM-VSC发生暂态模式切换时与GFL-VSC之间的动态耦合机理及该耦合对GFM-VSC故障恢复过程的作用机制,首先,建立考虑GFM-VSC限幅环节的混联系统暂态耦合模型;基于此模型,分析故障期间及故障切除后,GFL-VSC的参数对GFM-VSC工作模式切换的影响机理;随后,针对不同程度的电网电压跌落故障,分析故障切除后GFM-VSC的工作模式切换过程,得到混联系统中GFM-VSC在故障切除后可切换回正常工作模式的临界条件;最后,构建混联系统的仿真模型,验证理论分析的正确性。展开更多
基金the National Research Foundation of South Africa(No.PMDS230608115010)the University of Fort Hare Postgraduate Office for their financial support awarded to Vuyo Qasha。
文摘Soil organic carbon(SOC)depletion caused by changes in land use is one of the main causes of rising atmospheric carbon dioxide(CO_(2))levels.As such,pedometric approaches are essential for understanding SOC dynamics in forest restoration,which is crucial for mitigating climate change and sustaining ecosystem services.This review summarizes methodologies and advancements in pedometric approaches,focusing on their application in predicting SOC changes across various environments.It highlights the integration of pedometric methods involving spatiotemporal and vertical modeling tools,such as spatially explicit models and geospatial models,to improve soil carbon(C)stock estimates.These methods utilize advanced statistical techniques and remote sensing technologies to model soil properties and predict soil C dynamics across different spatiotemporal scales.The Century model,noted for its effectiveness in simulating long-term SOC drivers under various restoration scenarios,provides critical insights into sustainable forest management.This review evaluates potential solutions for understanding how C evolves over time and under different forest management practices,including afforestation and selective logging.In addition,the review identifies knowledge gaps,such as the need for improved models to predict soil C stocks under diverse environmental conditions accurately.Addressing these gaps through enhanced pedometric models and evaluation efforts is crucial for informing effective soil management strategies and supporting global climate change mitigation initiatives through forest restoration.Integrating pedometric approaches with spatial modeling tools provides a robust framework for guiding forest restoration decision-making and enhancing ecosystem resilience against climate change.
基金supported by the National Natural Science Foundation of China[42076203].
文摘Harmonic analysis of satellite altimetry data based on a global regular grid is affected by the grid spatial tessellation and placement of the grids.With the increase of latitude,the traditional lat/lon grid deforms greatly,resulting in uneven distribution of satellite altimeter data with latitude,which affects the extraction of tidal information.Alternatively,Hexagonal grids have been proved to be advantageous due to their isotropic,uniform neighbourhood,equal-area and more.Considering the merits above,the purpose of this paper is to use the global equal-area hexagonal grid to conduct a harmonic analysis of satellite altimeter data.First,the Icosahedron Snyder Equal Area projection method is used to construct a global equal-area hexagonal grid,Then the time series data of 19.8 years of Jason series satellite altimeter data are obtained.Finally,the harmonic constants of eight constituents(the M2,S2,N2,K2,K1,O1,P1,Q1)are extracted by harmonic analysis.By analysing the results,we conclude that the harmonic constants extracted from the global equal-area hexagonal grid have considerable accuracy and are consistent with the tidal characteristics of the eight components.Meanwhile,the accuracy of harmonic constants extracted from equal-area hexagonal grids is better than that of lat/lon grids.
文摘由跟网型变换器(grid-following voltage source converter,GFL-VSC)及构网型变换器(grid-forming voltage source converter,GFM-VSC)构成的混联系统中,复杂的暂态交互作用使系统的安全稳定运行面临挑战,明确变换器间的动态耦合机理及其对系统暂态稳定性的影响至关重要。GFM-VSC中设置的电流限幅环节会导致其暂态运行方式发生切换,进一步增加了GFM-VSC与GFL-VSC之间的耦合机理的复杂性。为揭示GFM-VSC发生暂态模式切换时与GFL-VSC之间的动态耦合机理及该耦合对GFM-VSC故障恢复过程的作用机制,首先,建立考虑GFM-VSC限幅环节的混联系统暂态耦合模型;基于此模型,分析故障期间及故障切除后,GFL-VSC的参数对GFM-VSC工作模式切换的影响机理;随后,针对不同程度的电网电压跌落故障,分析故障切除后GFM-VSC的工作模式切换过程,得到混联系统中GFM-VSC在故障切除后可切换回正常工作模式的临界条件;最后,构建混联系统的仿真模型,验证理论分析的正确性。
