Vegetation plays an important role in the dry deposition of particles with significant spatial variability,but the magnitude remains unclear at the global scale.With the aid of satellite products,this study estimated ...Vegetation plays an important role in the dry deposition of particles with significant spatial variability,but the magnitude remains unclear at the global scale.With the aid of satellite products,this study estimated the vegetation-related dry deposition of fine particulate matter(PM_(2.5)).Methodologically,dry deposition was first calculated using an empirical algorithm.Then,deposition on the leaf surface was estimated to evaluate the influence of vegetation.Our results showed that the mean deposition velocity(V_(d))of global PM_(2.5)was 0.91×10^(-3)μg·m^(-2)·s^(-1),with high velocities observed in sparsely vegetated regions because of the high friction velocity.Under the combined effect of the PM_(2.5)mass concentration and deposition velocity,the global mean dry deposition reached 0.47 g·m-^(2)·yr^(-1).Global vegetation absorbed 0.26 g·m-^(2)·yr^(-1)from PM_(2.5)pollution sources,contributing 54.98%of the total dry deposition.Spatially,vegetation-related dry deposition was high in the Amazon,Central Africa and East China due to dense vegetation coverage or serious pollution.Temporally,the increasing trends were mainly in Central Africa and India because of worsening air pollution.The results of this study helped to clarify the impact of vegetation on air pollution,which supported related land management and planning for air quality improvement.展开更多
New requirements have been proposed for GIS practice teaching in colleges and universities in response to the developmental changes of national and industrial sectors during the social transition.Meanwhile,the underly...New requirements have been proposed for GIS practice teaching in colleges and universities in response to the developmental changes of national and industrial sectors during the social transition.Meanwhile,the underlying core characteristics of GIS should remain unchanged in GIS teaching to ensure they serve as the inherent attributes distinguishing GIS from other disciplines.Therefore,the clarification of the dialectical relationship between “changing” and “unchanging” in GIS practice teaching becomes the primary issue to address in relevant teaching reform.To address this issue,the present study systematically analyzes the structural contradictions in GIS practice teaching in the social transition period,and then closely examines the dialectical relationship between “changing” and “unchanging” from the key aspects of educational philosophy,teaching content,teaching methodology,and teaching assessment.Next,using the course of “GIS Practice Design” at the Central South University as an example,the present study describes this university’s reform and inheritance in GIS practice teaching,aiming to provide reference for GIS practice teaching in other universities or majors.展开更多
基金National Natural Science Foundation of China,No.42071378Natural Science Foundation of Hunan Province,No.2020JJ3045Foundation of Natural Science of Guangdong,No.2019BT02H594。
文摘Vegetation plays an important role in the dry deposition of particles with significant spatial variability,but the magnitude remains unclear at the global scale.With the aid of satellite products,this study estimated the vegetation-related dry deposition of fine particulate matter(PM_(2.5)).Methodologically,dry deposition was first calculated using an empirical algorithm.Then,deposition on the leaf surface was estimated to evaluate the influence of vegetation.Our results showed that the mean deposition velocity(V_(d))of global PM_(2.5)was 0.91×10^(-3)μg·m^(-2)·s^(-1),with high velocities observed in sparsely vegetated regions because of the high friction velocity.Under the combined effect of the PM_(2.5)mass concentration and deposition velocity,the global mean dry deposition reached 0.47 g·m-^(2)·yr^(-1).Global vegetation absorbed 0.26 g·m-^(2)·yr^(-1)from PM_(2.5)pollution sources,contributing 54.98%of the total dry deposition.Spatially,vegetation-related dry deposition was high in the Amazon,Central Africa and East China due to dense vegetation coverage or serious pollution.Temporally,the increasing trends were mainly in Central Africa and India because of worsening air pollution.The results of this study helped to clarify the impact of vegetation on air pollution,which supported related land management and planning for air quality improvement.
基金Teaching Reform Project of Central South University(No.2022jy001-2)Higher Education Teaching Reform Project of Hunan Province(No.HNJG-2022-0025)。
文摘New requirements have been proposed for GIS practice teaching in colleges and universities in response to the developmental changes of national and industrial sectors during the social transition.Meanwhile,the underlying core characteristics of GIS should remain unchanged in GIS teaching to ensure they serve as the inherent attributes distinguishing GIS from other disciplines.Therefore,the clarification of the dialectical relationship between “changing” and “unchanging” in GIS practice teaching becomes the primary issue to address in relevant teaching reform.To address this issue,the present study systematically analyzes the structural contradictions in GIS practice teaching in the social transition period,and then closely examines the dialectical relationship between “changing” and “unchanging” from the key aspects of educational philosophy,teaching content,teaching methodology,and teaching assessment.Next,using the course of “GIS Practice Design” at the Central South University as an example,the present study describes this university’s reform and inheritance in GIS practice teaching,aiming to provide reference for GIS practice teaching in other universities or majors.
