The coastal seawater of Mediterranean of Alexandria receives large amount of discharged waters containing industrial wastes, sewage, and agricultural and domestic drainage. Fluoride and some parameters were(chemical a...The coastal seawater of Mediterranean of Alexandria receives large amount of discharged waters containing industrial wastes, sewage, and agricultural and domestic drainage. Fluoride and some parameters were(chemical and physical) determined. The data gave indication that the content and the amount of the discharged water largely affect the chemical composition of the coastal water. Stepwise regression analysis was highly significant and the model was very fruitful, where the observed and calculated values were mostly concordant. This may indicated that there was a relation between fluoride content in coastal seawater and its content in the discharged water.展开更多
Remote sensing-based methods of aboveground biomass(AGB)estimation in forest ecosystems have gained increased attention,and substantial research has been conducted in the past three decades.This paper provides a surve...Remote sensing-based methods of aboveground biomass(AGB)estimation in forest ecosystems have gained increased attention,and substantial research has been conducted in the past three decades.This paper provides a survey of current biomass estimation methods using remote sensing data and discusses four critical issues–collection of field-based biomass reference data,extraction and selection of suitable variables from remote sensing data,identification of proper algorithms to develop biomass estimation models,and uncertainty analysis to refine the estimation procedure.Additionally,we discuss the impacts of scales on biomass estimation performance and describe a general biomass estimation procedure.Although optical sensor and radar data have been primary sources for AGB estimation,data saturation is an important factor resulting in estimation uncertainty.LIght Detection and Ranging(lidar)can remove data saturation,but limited availability of lidar data prevents its extensive application.This literature survey has indicated the limitations of using single-sensor data for biomass estimation and the importance of integrating multi-sensor/scale remote sensing data to produce accurate estimates over large areas.More research is needed to extract a vertical vegetation structure(e.g.canopy height)from interferometry synthetic aperture radar(InSAR)or optical stereo images to incorporate it into horizontal structures(e.g.canopy cover)in biomass estimation modeling.展开更多
文摘The coastal seawater of Mediterranean of Alexandria receives large amount of discharged waters containing industrial wastes, sewage, and agricultural and domestic drainage. Fluoride and some parameters were(chemical and physical) determined. The data gave indication that the content and the amount of the discharged water largely affect the chemical composition of the coastal water. Stepwise regression analysis was highly significant and the model was very fruitful, where the observed and calculated values were mostly concordant. This may indicated that there was a relation between fluoride content in coastal seawater and its content in the discharged water.
基金a grant from Research Center of Agricultural and Forestry Carbon Sinks and Ecological Environmental Remediation,Zhejiang A&F University.
文摘Remote sensing-based methods of aboveground biomass(AGB)estimation in forest ecosystems have gained increased attention,and substantial research has been conducted in the past three decades.This paper provides a survey of current biomass estimation methods using remote sensing data and discusses four critical issues–collection of field-based biomass reference data,extraction and selection of suitable variables from remote sensing data,identification of proper algorithms to develop biomass estimation models,and uncertainty analysis to refine the estimation procedure.Additionally,we discuss the impacts of scales on biomass estimation performance and describe a general biomass estimation procedure.Although optical sensor and radar data have been primary sources for AGB estimation,data saturation is an important factor resulting in estimation uncertainty.LIght Detection and Ranging(lidar)can remove data saturation,but limited availability of lidar data prevents its extensive application.This literature survey has indicated the limitations of using single-sensor data for biomass estimation and the importance of integrating multi-sensor/scale remote sensing data to produce accurate estimates over large areas.More research is needed to extract a vertical vegetation structure(e.g.canopy height)from interferometry synthetic aperture radar(InSAR)or optical stereo images to incorporate it into horizontal structures(e.g.canopy cover)in biomass estimation modeling.
