Effective waste management is a major challenge for Small Island Developing States (SIDS) like Maldives due to limited land availability. Maldives exemplifies these issues as one of the most geographically dispersed c...Effective waste management is a major challenge for Small Island Developing States (SIDS) like Maldives due to limited land availability. Maldives exemplifies these issues as one of the most geographically dispersed countries, with a population unevenly distributed across numerous islands varying greatly in size and population density. This study provides an in-depth analysis of the unique waste management practices across different regions of Maldives in relation to its natural and socioeconomic context. Data shows Maldives has one of the highest population density and per capita waste generation among SIDS, despite its small land area and medium GDP per capita. Large disparities exist between the densely populated capital Male’ with only 5.8 km2 area generating 63% of waste and the ~194 scattered outer islands with ad hoc waste management practices. Given Male’s dense population and high calorific waste, incineration could generate up to ~30 GW/a energy and even increase Maldives’ renewable energy supply by 200%. In contrast, decentralized anaerobic digestion presents an optimal solution for outer islands to reduce waste volume while providing over 40%–100% energy supply for daily cooking in local families. This timely study delivers valuable insights into designing context-specific waste-to-energy systems and integrated waste policies tailored to Maldives’ distinct regions. The framework presented can also guide other SIDS facing similar challenges as Maldives in establishing sustainable, ecologically sound waste management strategies.展开更多
In this work, it is investigated the Urban Heat Island (UHI) using conservative thermodynamic variables observed by surface weather stations on the Metropolitan Area of Porto (Oporto) in Portugal, under adiabatic cond...In this work, it is investigated the Urban Heat Island (UHI) using conservative thermodynamic variables observed by surface weather stations on the Metropolitan Area of Porto (Oporto) in Portugal, under adiabatic conditions at the surface. These conditions are usually present and associated with the development of a mixture layer into the diurnal Convective Boundary Layer (CBL), which residual layer in the late afternoon defines the initial state for the development of the nocturnal UHI. Both the spatial structure and temporal variation of potential temperature and specific humidity were considered, along the hours and days of the year, from a statistical point of view, resulting in hourly climatology. Details of the hourly evolution of the meteorological variables on the Oporto surface are presented and discussed. Results show a seasonal variation of the potential temperature up to 17°C throughout the year, which is associated with horizontal thermal gradients that can control and trigger mesoscale circulations such as sea-land, urban and valley-mountain breezes.展开更多
Complementarities between wind and wave energies have many signifcant advantages that are unavailable with the sole deployment of either.Using all available wind speed,signifcant wave height,and wave period buoy obser...Complementarities between wind and wave energies have many signifcant advantages that are unavailable with the sole deployment of either.Using all available wind speed,signifcant wave height,and wave period buoy observations over a 10-year period(i.e.,2009–2019),colocated wind and wave energy resources are estimated.Although buoy records are imper-fect,results show that the inner Caribbean Sea(CS)under the infuence of the Caribbean low-level jet has the highest wind energy resource at~1500 W/m^(2),followed by the outer CS at~600 W/m^(2) and Atlantic Ocean(AO)at~550–600 W/m^(2) at a 100 m height.Wave energy was most abundant in the AO at 14 kW/m,followed by the inner CS at 13 kW/m and outer CS at 5 kW/m.The average and dominant wave energies can reach a maximum of 10 and 14 kW/m,respectively.Asymmetry between wind and wave energy resources is observed in the AO,where wave energy is higher than the low wind speed/energy would suggest.Swell is responsible for this discrepancy;thus,it must be considered not only for wave energy extraction but also for wind turbine fatigue,stability,and power extraction efciency.展开更多
MacArthur and Wilson's equilibrium theory is one of the most influential theories in ecology.Although evolution on islands is to be important to island biodiversity,speciation has not been well integrated into isl...MacArthur and Wilson's equilibrium theory is one of the most influential theories in ecology.Although evolution on islands is to be important to island biodiversity,speciation has not been well integrated into island biogeography models.By incorporating speciation and factors influencing it into the MacArthur-Wilson model,we propose a generalized model unifying ecological and evolutionary processes and island features.Intra-island speciation may play an important role in both island species richness and endemism,and the contribution of speciation to local species diversity may eventually be greater than that of immigration under certain conditions.Those conditions are related to the per species speciation rate,per species extinction rate,and island features,and they are independent of immigration rate.The model predicts that large islands will have a high,though not the highest,proportional endemism when other parameters are fixed.Based on the generalized model,changes in species richness and endemism on an oceanic island over time were predicted to be similar to empirical observations.Our model provides an ideal starting point for re-evaluating the role of speciation and re-analyzing available data on island species diversity,especially those biased by the MacArthur-Wilson model.展开更多
文摘Effective waste management is a major challenge for Small Island Developing States (SIDS) like Maldives due to limited land availability. Maldives exemplifies these issues as one of the most geographically dispersed countries, with a population unevenly distributed across numerous islands varying greatly in size and population density. This study provides an in-depth analysis of the unique waste management practices across different regions of Maldives in relation to its natural and socioeconomic context. Data shows Maldives has one of the highest population density and per capita waste generation among SIDS, despite its small land area and medium GDP per capita. Large disparities exist between the densely populated capital Male’ with only 5.8 km2 area generating 63% of waste and the ~194 scattered outer islands with ad hoc waste management practices. Given Male’s dense population and high calorific waste, incineration could generate up to ~30 GW/a energy and even increase Maldives’ renewable energy supply by 200%. In contrast, decentralized anaerobic digestion presents an optimal solution for outer islands to reduce waste volume while providing over 40%–100% energy supply for daily cooking in local families. This timely study delivers valuable insights into designing context-specific waste-to-energy systems and integrated waste policies tailored to Maldives’ distinct regions. The framework presented can also guide other SIDS facing similar challenges as Maldives in establishing sustainable, ecologically sound waste management strategies.
文摘In this work, it is investigated the Urban Heat Island (UHI) using conservative thermodynamic variables observed by surface weather stations on the Metropolitan Area of Porto (Oporto) in Portugal, under adiabatic conditions at the surface. These conditions are usually present and associated with the development of a mixture layer into the diurnal Convective Boundary Layer (CBL), which residual layer in the late afternoon defines the initial state for the development of the nocturnal UHI. Both the spatial structure and temporal variation of potential temperature and specific humidity were considered, along the hours and days of the year, from a statistical point of view, resulting in hourly climatology. Details of the hourly evolution of the meteorological variables on the Oporto surface are presented and discussed. Results show a seasonal variation of the potential temperature up to 17°C throughout the year, which is associated with horizontal thermal gradients that can control and trigger mesoscale circulations such as sea-land, urban and valley-mountain breezes.
文摘Complementarities between wind and wave energies have many signifcant advantages that are unavailable with the sole deployment of either.Using all available wind speed,signifcant wave height,and wave period buoy observations over a 10-year period(i.e.,2009–2019),colocated wind and wave energy resources are estimated.Although buoy records are imper-fect,results show that the inner Caribbean Sea(CS)under the infuence of the Caribbean low-level jet has the highest wind energy resource at~1500 W/m^(2),followed by the outer CS at~600 W/m^(2) and Atlantic Ocean(AO)at~550–600 W/m^(2) at a 100 m height.Wave energy was most abundant in the AO at 14 kW/m,followed by the inner CS at 13 kW/m and outer CS at 5 kW/m.The average and dominant wave energies can reach a maximum of 10 and 14 kW/m,respectively.Asymmetry between wind and wave energy resources is observed in the AO,where wave energy is higher than the low wind speed/energy would suggest.Swell is responsible for this discrepancy;thus,it must be considered not only for wave energy extraction but also for wind turbine fatigue,stability,and power extraction efciency.
基金supported by the National Natural Science Foundation of China (Grant No. 30870361)the National High Technology Research and Development Program of China (Grant No. 2007AA09Z432)the "211 Project" of East China Normal University
文摘MacArthur and Wilson's equilibrium theory is one of the most influential theories in ecology.Although evolution on islands is to be important to island biodiversity,speciation has not been well integrated into island biogeography models.By incorporating speciation and factors influencing it into the MacArthur-Wilson model,we propose a generalized model unifying ecological and evolutionary processes and island features.Intra-island speciation may play an important role in both island species richness and endemism,and the contribution of speciation to local species diversity may eventually be greater than that of immigration under certain conditions.Those conditions are related to the per species speciation rate,per species extinction rate,and island features,and they are independent of immigration rate.The model predicts that large islands will have a high,though not the highest,proportional endemism when other parameters are fixed.Based on the generalized model,changes in species richness and endemism on an oceanic island over time were predicted to be similar to empirical observations.Our model provides an ideal starting point for re-evaluating the role of speciation and re-analyzing available data on island species diversity,especially those biased by the MacArthur-Wilson model.
