Community park is one of the most important landscape spaces for urban people to live outdoors,and people’s perception of environmental microclimate is a direct factor affecting the use frequency and experience of co...Community park is one of the most important landscape spaces for urban people to live outdoors,and people’s perception of environmental microclimate is a direct factor affecting the use frequency and experience of community parks.In this paper,Shijingshan Sculpture Park of Beijing was taken as experimental object.Using the method of fi eld measurement,9-d winter test for 3 months was conducted in three kinds of landscape architecture spaces,including waterfront plaza,open green space and square under the forest.Via regression analysis method,the measured air temperature(Ta),relative humidity of air(RH),particulate matter(PM2.5)were analyzed.It is found that winter sunshine is main infl uence factor of garden microclimate,and there is a negative correlation between local temperature and humidity;local temperature and humidity can regulate the local PM2.5 concentration,and temperature shows negative correlation with PM2.5 concentration,while humidity shows positive correlation with PM2.5 concentration.Meanwhile,via comparative analysis of temperature,humidity and PM2.5 concentration in different types of garden spaces,the infl uence of different space forms,planting forms and materials on thermal environment of underlying surface and PM2.5 concentration was summarized,and design strategy was optimized,to be as benefi cial reference of reconstruction design of community parks.展开更多
To reveal the characteristics of evapotranspiration and environmental control factors of typical underlying surfaces(alpine wetland and alpine meadow)on the Qinghai-Tibetan Plateau,a comprehensive study was performed ...To reveal the characteristics of evapotranspiration and environmental control factors of typical underlying surfaces(alpine wetland and alpine meadow)on the Qinghai-Tibetan Plateau,a comprehensive study was performed via in situ observations and remote sensing data in the growing season and non-growing season.Evapotranspiration was positively correlated with precipitation,the decoupling coefficient,and the enhanced vegetation index,but was energy-limited and mainly controlled by the vapor pressure deficit and solar radiation at an annual scale and growing season scale,respectively.Compared with the non-growing season,monthly evapotranspiration,equilibrium evaporation,and decoupling coefficient were greater in the growing season due to lower vegetation resistance and considerable precipitation.However,these factors were restricted in the alpine meadow.The decoupling factor was more sensitive to changes of conductance in the alpine wetland.This study is of great significance for understanding hydro-meteorological processes on the Qinghai-Tibetan Plateau.展开更多
In response to the water shortage in Wanzhou North Station(WNS),the authors investigated the stormwater quality characteristics with different underlying surfaces of WNS and carried out stormwater reuse analysis in co...In response to the water shortage in Wanzhou North Station(WNS),the authors investigated the stormwater quality characteristics with different underlying surfaces of WNS and carried out stormwater reuse analysis in conjunction with the InfoWorks ICM model.The results show that during heavy,torrential,and moderate rainfall,the road stormwater runoff has the highest concentrations of pollutants,with an average EMC(event mean concentration)value of 206 mg/L for COD.For the square runoff,the average EMC values of COD,SS,TN,and TP are 108 mg/L,395 mg/L,2.113 mg/L,and 0.128 mg/L,in comparison,the average EMC values of the corresponding indexes for the roof runoff are 65 mg/L,212 mg/L,1.449 mg/L,and 0.086 mg/L,respectively,demonstrating their potential for reuse.The R2(coefficient of determination)of SS and COD in both roof and square runoff are greater than 0.85,with a good correlation,indicating that SS removal is the key to stormwater purification.InfoWorks ICM analysis shows that the recyclable volume of rainwater from WNS in 2018 is 29,410 m3,accounting for 61.8%of the total annual rainfall.This study is expected to provide an ideal reference for the stormwater management of public buildings in mountainous areas.展开更多
The regulation and spatial differences of urban runoffs are of great concern in contemporary hydrological research.However,owing to a shortage of basic data sources and restrictions on urban hydrological simulation fu...The regulation and spatial differences of urban runoffs are of great concern in contemporary hydrological research.However,owing to a shortage of basic data sources and restrictions on urban hydrological simulation functions,simulating and investigating the regulation mechanism behind rainfall-runoff processes remain significantly challenging.In this study,the Time Variant Gain Model(TVGM),a hydrological nonlinear system model,was extrapolated to the hydrodynamic model of an urban drainage network system by integrating it with the widely used Stormwater Management Model(SWMM)to adequately simulate urban runoff events while considering various underlying surfaces and runoff routing modes,such as surface,drainage network and river runoff,in urban regions(i.e.,TVGM-SWMM).Moreover,runoff events were characterized using the following four runoff regime metrics:runoff coefficient,capture ratio of annual runoff volume,standardized flood timescale,and the ratio of occurrence time differences between flow and rainfall peak to event duration(peak flow delay time).The characteristics and spatial differences of urban runoff regulations were investigated,and the key impact factors and their relative contributions were identified using multivariate statistical analyses.Four communities were selected as our study areas,consisting of communities from Beijing,Shenzhen,Wuhan,and Chongqing.Our results showed that the TVGM-SWMM performed considerably better than SWMM alone.The comprehensive simulation accuracy of 60%of the events(12/20)improved by 4-86%,with the bias improving the most,followed by the efficiency coefficient.Barring the runoff coefficient,significant spatial differences were identified at the patch scale for the runoff regime metrics,with differences of 0.43,0.22,and 0.16(p<0.05).The key impact factors were the pipe length(r=0.51)in the drainage network system and the forest area ratios(r=0.56),sponge measures(r=0.52),grassland(r=0.48),and impervious surface(r=0.46)in the underlying surfaces.The contributions of the drainage network system and the underlying surfaces were 4.27%and 37.83%,respectively.Regulation in the Beijing community,dominated by grassland regulation,delayed and reduced the peak flow and total runoff volume.In the Shenzhen community,sharp and thin runoff events were mainly generated by impervious surfaces and were not adequately regulated.Forest regulation was the dominant regulation type in the Wuhan community,which reduced the total runoff volume and delayed the peak flow.Waterbody regulation was the primary regulation type in the Chongqing community,which reduced the total runoff volume and peak flow.This study aims to introduce a comprehensive theoretical and technical assessment of the hydrological effects of urbanization and the performance of sponge city construction and provide a reference for urban hydrological model improvements in China.展开更多
Based on observation data from urban observation stations in Nanjing and Suzhou at two heights in the roughness sublayer above the canopy and observation data at three heights in the SORPES station at the Xianlin Camp...Based on observation data from urban observation stations in Nanjing and Suzhou at two heights in the roughness sublayer above the canopy and observation data at three heights in the SORPES station at the Xianlin Campus of Nanjing University in a suburban area,the of land-atmosphere turbulent flux exchange and the energy balance over complex underlying surfaces were analyzed.The results indicated that in the roughness sublayer above the canopy,the nearsurface momentum flux,sensible heat flux,and latent heat flux increase with height,and the observation value of the surface albedo increases with height.However,the observation value of the net radiation decreases with height,thus resulting in a change in the urban surface energy budget with height.At the SORPES station in the Xianlin Campus of Nanjing University located in a hilly area,the momentum flux,sensible heat flux,and latent heat flux of the ground observation field significantly differed from those of the two heights on the tower,while the two heights on the tower were extremely close.These results indicate that the flux observation over the complex underlying surface exhibits adequate local only when it is conducted at a higher altitude above the ground.The turbulent flux observation results at a lower altitude in urban areas are underestimated,while the turbulent flux observation results near the surface produce a large deviation over the underlying hilly complex.展开更多
基金National Natural Science Foundation of China(51708004)North University of Technology YuYou Talent Training Program(215051360020XN160/009)+1 种基金Beijing Natural Science Foundation(8202017)2018 Beijing Municipal University Academic Human Resources Development—Youth Talent Support Program(PXM2018_014212_000043).
文摘Community park is one of the most important landscape spaces for urban people to live outdoors,and people’s perception of environmental microclimate is a direct factor affecting the use frequency and experience of community parks.In this paper,Shijingshan Sculpture Park of Beijing was taken as experimental object.Using the method of fi eld measurement,9-d winter test for 3 months was conducted in three kinds of landscape architecture spaces,including waterfront plaza,open green space and square under the forest.Via regression analysis method,the measured air temperature(Ta),relative humidity of air(RH),particulate matter(PM2.5)were analyzed.It is found that winter sunshine is main infl uence factor of garden microclimate,and there is a negative correlation between local temperature and humidity;local temperature and humidity can regulate the local PM2.5 concentration,and temperature shows negative correlation with PM2.5 concentration,while humidity shows positive correlation with PM2.5 concentration.Meanwhile,via comparative analysis of temperature,humidity and PM2.5 concentration in different types of garden spaces,the infl uence of different space forms,planting forms and materials on thermal environment of underlying surface and PM2.5 concentration was summarized,and design strategy was optimized,to be as benefi cial reference of reconstruction design of community parks.
基金This work is financially supported by the National Natural Science Foundation of China(Grant Nos.42005075 and 41530529),the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(No.2019QZKK0605)the State Key Laboratory of Cryospheric Science(Grant Nos.SKLCS-ZZ-2020 and SKLCS-ZZ-2021)+1 种基金Foundation for Excellent Youth Scholars of"Northwest Institute of Eco-Environment and Resources",CAS(Grant No.FEYS2019020)The authors declare no competing interest in this paper.Our cordial gratitude should be extended to anonymous reviewers and the Editors for their professional and pertinent comments on this manuscript.
文摘To reveal the characteristics of evapotranspiration and environmental control factors of typical underlying surfaces(alpine wetland and alpine meadow)on the Qinghai-Tibetan Plateau,a comprehensive study was performed via in situ observations and remote sensing data in the growing season and non-growing season.Evapotranspiration was positively correlated with precipitation,the decoupling coefficient,and the enhanced vegetation index,but was energy-limited and mainly controlled by the vapor pressure deficit and solar radiation at an annual scale and growing season scale,respectively.Compared with the non-growing season,monthly evapotranspiration,equilibrium evaporation,and decoupling coefficient were greater in the growing season due to lower vegetation resistance and considerable precipitation.However,these factors were restricted in the alpine meadow.The decoupling factor was more sensitive to changes of conductance in the alpine wetland.This study is of great significance for understanding hydro-meteorological processes on the Qinghai-Tibetan Plateau.
基金the financial support provided by the National Natural Science Foundation of Chongqing(cstc2020jcyj-msxmX1000).
文摘In response to the water shortage in Wanzhou North Station(WNS),the authors investigated the stormwater quality characteristics with different underlying surfaces of WNS and carried out stormwater reuse analysis in conjunction with the InfoWorks ICM model.The results show that during heavy,torrential,and moderate rainfall,the road stormwater runoff has the highest concentrations of pollutants,with an average EMC(event mean concentration)value of 206 mg/L for COD.For the square runoff,the average EMC values of COD,SS,TN,and TP are 108 mg/L,395 mg/L,2.113 mg/L,and 0.128 mg/L,in comparison,the average EMC values of the corresponding indexes for the roof runoff are 65 mg/L,212 mg/L,1.449 mg/L,and 0.086 mg/L,respectively,demonstrating their potential for reuse.The R2(coefficient of determination)of SS and COD in both roof and square runoff are greater than 0.85,with a good correlation,indicating that SS removal is the key to stormwater purification.InfoWorks ICM analysis shows that the recyclable volume of rainwater from WNS in 2018 is 29,410 m3,accounting for 61.8%of the total annual rainfall.This study is expected to provide an ideal reference for the stormwater management of public buildings in mountainous areas.
基金supported by the Subproject of Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA23040301)the National Natural Science Foundation of China(Grant No.42071041)。
文摘The regulation and spatial differences of urban runoffs are of great concern in contemporary hydrological research.However,owing to a shortage of basic data sources and restrictions on urban hydrological simulation functions,simulating and investigating the regulation mechanism behind rainfall-runoff processes remain significantly challenging.In this study,the Time Variant Gain Model(TVGM),a hydrological nonlinear system model,was extrapolated to the hydrodynamic model of an urban drainage network system by integrating it with the widely used Stormwater Management Model(SWMM)to adequately simulate urban runoff events while considering various underlying surfaces and runoff routing modes,such as surface,drainage network and river runoff,in urban regions(i.e.,TVGM-SWMM).Moreover,runoff events were characterized using the following four runoff regime metrics:runoff coefficient,capture ratio of annual runoff volume,standardized flood timescale,and the ratio of occurrence time differences between flow and rainfall peak to event duration(peak flow delay time).The characteristics and spatial differences of urban runoff regulations were investigated,and the key impact factors and their relative contributions were identified using multivariate statistical analyses.Four communities were selected as our study areas,consisting of communities from Beijing,Shenzhen,Wuhan,and Chongqing.Our results showed that the TVGM-SWMM performed considerably better than SWMM alone.The comprehensive simulation accuracy of 60%of the events(12/20)improved by 4-86%,with the bias improving the most,followed by the efficiency coefficient.Barring the runoff coefficient,significant spatial differences were identified at the patch scale for the runoff regime metrics,with differences of 0.43,0.22,and 0.16(p<0.05).The key impact factors were the pipe length(r=0.51)in the drainage network system and the forest area ratios(r=0.56),sponge measures(r=0.52),grassland(r=0.48),and impervious surface(r=0.46)in the underlying surfaces.The contributions of the drainage network system and the underlying surfaces were 4.27%and 37.83%,respectively.Regulation in the Beijing community,dominated by grassland regulation,delayed and reduced the peak flow and total runoff volume.In the Shenzhen community,sharp and thin runoff events were mainly generated by impervious surfaces and were not adequately regulated.Forest regulation was the dominant regulation type in the Wuhan community,which reduced the total runoff volume and delayed the peak flow.Waterbody regulation was the primary regulation type in the Chongqing community,which reduced the total runoff volume and peak flow.This study aims to introduce a comprehensive theoretical and technical assessment of the hydrological effects of urbanization and the performance of sponge city construction and provide a reference for urban hydrological model improvements in China.
基金supported by the National Key R&D Program of China(Grant No.2016YFC0200500)the Youth Project of National Natural Science Foundation of China(Grant No.41805007)。
文摘Based on observation data from urban observation stations in Nanjing and Suzhou at two heights in the roughness sublayer above the canopy and observation data at three heights in the SORPES station at the Xianlin Campus of Nanjing University in a suburban area,the of land-atmosphere turbulent flux exchange and the energy balance over complex underlying surfaces were analyzed.The results indicated that in the roughness sublayer above the canopy,the nearsurface momentum flux,sensible heat flux,and latent heat flux increase with height,and the observation value of the surface albedo increases with height.However,the observation value of the net radiation decreases with height,thus resulting in a change in the urban surface energy budget with height.At the SORPES station in the Xianlin Campus of Nanjing University located in a hilly area,the momentum flux,sensible heat flux,and latent heat flux of the ground observation field significantly differed from those of the two heights on the tower,while the two heights on the tower were extremely close.These results indicate that the flux observation over the complex underlying surface exhibits adequate local only when it is conducted at a higher altitude above the ground.The turbulent flux observation results at a lower altitude in urban areas are underestimated,while the turbulent flux observation results near the surface produce a large deviation over the underlying hilly complex.
