Based on the consecutive measurement (1995-1997) of meteorology and microclimate of artificial Pinus forest in Mount Dinghu, we calculated the potential evapotranspiration by using four different methods to discuss th...Based on the consecutive measurement (1995-1997) of meteorology and microclimate of artificial Pinus forest in Mount Dinghu, we calculated the potential evapotranspiration by using four different methods to discuss the method which is fit for forest ecosystem. The results are given as follows.1) In terms of the enviromental conditions of forest ecosystem, we redefined some parameters in Penman equation and used it to calculate the potential evapotranspiration of artificial Pinus forest ecosystem in Mount Dinghu.Preliminary result is that Penman equation is worth spreading for calculating the potential evapotranspiration of forest ecosystem,compared with several other methods.2) The annual average potential evapotranspiration of the artificial Pinus forest in Mount Dinghu is 937.55 mm,according to Penman equation. It is 50% of the rainfall in the corresponding period. The highest mean monthly potential evapotranspiration is July and the lowest mean monthly potential evapotranspiration is January. This is completely consistent with the variations of temperature.展开更多
Net primary productivity (NPP) and evapotranspiration (ET) are two key variables in the carbon and water cycles of terrestrial ecosystems. In this study, to test a newly developed NPP algorithm designed for H J-1 ...Net primary productivity (NPP) and evapotranspiration (ET) are two key variables in the carbon and water cycles of terrestrial ecosystems. In this study, to test a newly developed NPP algorithm designed for H J-1 A/B data and to evaluate the usage of HJ-1 A/B data in the quantitative assessment of environments, NPP and ET in Jinggangshan city, Jiangxi province, are calculated using H J-1 A/B data. The results illustrate the following: (1) The NPP and ET in Jinggangshan city in 2olo both show obvious seasonal variation, with the highest values in summer and the lowest values in winter, and relatively higher values were observed in autumn than in spring. (2) The spatial pattern indicates that the annual NPP is high in the southern area in Jinggangshan city and low in the northern area. Additionally, high NPP is distributed in forests located in areas with high elevation, and low NPP is found in croplands at low elevations. ET has no significant north-south difference, with high values in the southeast and northwest and low values in the southwest, and high ET is distributed in forests at low elevations in contrast to low ET in forests in high-elevation areas and in cropland and shrub grassland in low-elevation areas. (3) Compared to the MODIS product, the range of H J-1 NPP is larger, and the spatial pattern is more coincident with the topography. The range of H J-1 ET is smaller than that of the MODIS product, and ET is underestimated to some extent but can reflect the effect of topography. This study suggests that the algorithm can be used to estimate NPP and ET in a subtropical monsoon climate if remotely sensed images with high spatial resolution are available.展开更多
Enviromnental pollution is serious social concern. The inflow of heavy metals in the ecological food chain and their subsequent bio-magnification in human bodies is cascading its harmful effects. The metabolism of pla...Enviromnental pollution is serious social concern. The inflow of heavy metals in the ecological food chain and their subsequent bio-magnification in human bodies is cascading its harmful effects. The metabolism of plants is being hampered by these heavy metals. In the present studies, effect of heavy metal especially cadmium has been studied on stomatal diffusive resistance (SDR), transpiration rate, leaf surface humidity and leaf temperature of soybean plants growing in hydroponic cultures. Cadmium treatment decelerates the rate of transpiration. The inhibition of transpiration associated with increased SDR leads to dehydration of leaf surface, thereby, increasing temperature of leaves in comparison to control plants. In the present study, temperature difference between stressed and non-stressed plant leaves was as high as 3℃ Moreover, any such rise in leaf temperature due to uptake and induced toxicity of heavy metals can possibly be a good bio-indicator having wide applications in thermal remote sensing and geospatial monitoring of metal polluted soils.展开更多
The carbon and water cycle,an important biophysical process of terrestrial ecosystems,is changed by anthropogenic revegetation in arid and semiarid areas.However,there is still a lack of understanding of the mechanism...The carbon and water cycle,an important biophysical process of terrestrial ecosystems,is changed by anthropogenic revegetation in arid and semiarid areas.However,there is still a lack of understanding of the mechanisms of carbon and water coupling in intrinsic ecosystems in the context of human activities.Based on the CO,and H,O flux measurements of the desert steppe with the planted shrub Caragana liouana,this study explored the carbon and water flux coupling of the ecosystem by analyzing the variations in gross primary productivity(GPP),evapotranspiration(ET)and water use efficiency(WUE)and discussing the driving mechanisms of biological factors.The seasonal variation in climate factors induced a periodic variation pattern of biophysical traits and carbon and water fluxes.The GPP and ET fluctuated in seasons,but the WUE was relatively stable in the growing season.The GP,ET and WUE were significantly driven by global radiation(R,),temperature(T,and T),water vapor pressure deficit,leaf area index and plant water stress index(PWSI).However,R,temperature and PWSI were the most important factors regulating WUE.R,and temperature directly affected WUE with a positive effect but indirectly inhibited WUE by rising PWSl.Plant water stress inhibited photosynthesis and transpiration of the planted shrub community in the desert steppe.When the plant water stress exceeded a threshold(PWSI>0.54),the WUE would decrease since the GPP responded more quickly to the plant water stress than ET.Our findings suggest that policies related to large-scale carbon sequestration initiatives under afforestation must first fully consider the status of water consumption and WUE.展开更多
文摘Based on the consecutive measurement (1995-1997) of meteorology and microclimate of artificial Pinus forest in Mount Dinghu, we calculated the potential evapotranspiration by using four different methods to discuss the method which is fit for forest ecosystem. The results are given as follows.1) In terms of the enviromental conditions of forest ecosystem, we redefined some parameters in Penman equation and used it to calculate the potential evapotranspiration of artificial Pinus forest ecosystem in Mount Dinghu.Preliminary result is that Penman equation is worth spreading for calculating the potential evapotranspiration of forest ecosystem,compared with several other methods.2) The annual average potential evapotranspiration of the artificial Pinus forest in Mount Dinghu is 937.55 mm,according to Penman equation. It is 50% of the rainfall in the corresponding period. The highest mean monthly potential evapotranspiration is July and the lowest mean monthly potential evapotranspiration is January. This is completely consistent with the variations of temperature.
基金funded by the National Natural Science Foundation of China (Grant no. 40971221)the National High Technology Research and Development Program of China (863 Program) (Grant no. 2012AA12A304)
文摘Net primary productivity (NPP) and evapotranspiration (ET) are two key variables in the carbon and water cycles of terrestrial ecosystems. In this study, to test a newly developed NPP algorithm designed for H J-1 A/B data and to evaluate the usage of HJ-1 A/B data in the quantitative assessment of environments, NPP and ET in Jinggangshan city, Jiangxi province, are calculated using H J-1 A/B data. The results illustrate the following: (1) The NPP and ET in Jinggangshan city in 2olo both show obvious seasonal variation, with the highest values in summer and the lowest values in winter, and relatively higher values were observed in autumn than in spring. (2) The spatial pattern indicates that the annual NPP is high in the southern area in Jinggangshan city and low in the northern area. Additionally, high NPP is distributed in forests located in areas with high elevation, and low NPP is found in croplands at low elevations. ET has no significant north-south difference, with high values in the southeast and northwest and low values in the southwest, and high ET is distributed in forests at low elevations in contrast to low ET in forests in high-elevation areas and in cropland and shrub grassland in low-elevation areas. (3) Compared to the MODIS product, the range of H J-1 NPP is larger, and the spatial pattern is more coincident with the topography. The range of H J-1 ET is smaller than that of the MODIS product, and ET is underestimated to some extent but can reflect the effect of topography. This study suggests that the algorithm can be used to estimate NPP and ET in a subtropical monsoon climate if remotely sensed images with high spatial resolution are available.
文摘Enviromnental pollution is serious social concern. The inflow of heavy metals in the ecological food chain and their subsequent bio-magnification in human bodies is cascading its harmful effects. The metabolism of plants is being hampered by these heavy metals. In the present studies, effect of heavy metal especially cadmium has been studied on stomatal diffusive resistance (SDR), transpiration rate, leaf surface humidity and leaf temperature of soybean plants growing in hydroponic cultures. Cadmium treatment decelerates the rate of transpiration. The inhibition of transpiration associated with increased SDR leads to dehydration of leaf surface, thereby, increasing temperature of leaves in comparison to control plants. In the present study, temperature difference between stressed and non-stressed plant leaves was as high as 3℃ Moreover, any such rise in leaf temperature due to uptake and induced toxicity of heavy metals can possibly be a good bio-indicator having wide applications in thermal remote sensing and geospatial monitoring of metal polluted soils.
基金the National Natural Science Foundation of China(41967027)the Natural Science Foundation of Ningxia Province(2022AAC02011)+2 种基金the Excellent Talents Support Program of Ningxia Province(RQoo12)the Key Research and Development Program of Ningxia Province(2021BEG02010)the Special Plan for Local Sci-Tech Development Guided by the Central Government of China.
文摘The carbon and water cycle,an important biophysical process of terrestrial ecosystems,is changed by anthropogenic revegetation in arid and semiarid areas.However,there is still a lack of understanding of the mechanisms of carbon and water coupling in intrinsic ecosystems in the context of human activities.Based on the CO,and H,O flux measurements of the desert steppe with the planted shrub Caragana liouana,this study explored the carbon and water flux coupling of the ecosystem by analyzing the variations in gross primary productivity(GPP),evapotranspiration(ET)and water use efficiency(WUE)and discussing the driving mechanisms of biological factors.The seasonal variation in climate factors induced a periodic variation pattern of biophysical traits and carbon and water fluxes.The GPP and ET fluctuated in seasons,but the WUE was relatively stable in the growing season.The GP,ET and WUE were significantly driven by global radiation(R,),temperature(T,and T),water vapor pressure deficit,leaf area index and plant water stress index(PWSI).However,R,temperature and PWSI were the most important factors regulating WUE.R,and temperature directly affected WUE with a positive effect but indirectly inhibited WUE by rising PWSl.Plant water stress inhibited photosynthesis and transpiration of the planted shrub community in the desert steppe.When the plant water stress exceeded a threshold(PWSI>0.54),the WUE would decrease since the GPP responded more quickly to the plant water stress than ET.Our findings suggest that policies related to large-scale carbon sequestration initiatives under afforestation must first fully consider the status of water consumption and WUE.