Understanding the distribution and dynamics of glaciers is of great significance to the management and allocation of regional water resources and socio-economic development in arid regions of Northwest China.In this s...Understanding the distribution and dynamics of glaciers is of great significance to the management and allocation of regional water resources and socio-economic development in arid regions of Northwest China.In this study,based on 36 Landsat images,we extracted the glacier boundaries in the Manas River Basin,Northwest China from 2000 to 2020 using eCognition combined with band operation,GIS(geographic information system)spatial overlay techniques,and manual visual interpretation.We further analyzed the distribution and variation characteristics of glacier area,and simulated glacial runoff using a distributed degree-day model to explore the regulation of runoff recharge.The results showed that glacier area in the Manas River Basin as a whole showed a downward trend over the past 21 a,with a decrease of 10.86%and an average change rate of–0.54%/a.With the increase in glacier scale,the number of smaller glaciers decreased exponentially,and the number and area of larger glaciers were relatively stable.Glacier area showed a normal distribution trend of increasing first and then decreasing with elevation.About 97.92%of glaciers were distributed at 3700–4800 m,and 48.11%of glaciers were observed on the northern and northeastern slopes.The retreat rate of glaciers was the fastest(68.82%)at elevations below 3800 m.There was a clear rise in elevation at the end of glaciers.Glaciers at different slope directions showed a rapid melting trend from the western slope to the southern slope then to the northern slope.Glacial runoff in the basin showed a fluctuating upward trend in the past 21 a,with an increase rate of 0.03×10^(8) m^(3)/a.The average annual glacial runoff was 4.80×10^(8) m^(3),of which 33.31%was distributed in the ablation season(June–September).The average annual contribution rate of glacial meltwater to river runoff was 35.40%,and glacial runoff accounted for 45.37%of the total runoff during the ablation season.In addition,precipitation and glacial runoff had complementary regulation patterns for river runoff.The findings can provide a scientific basis for water resource management in the Manas River Basin and other similar arid inland river basins.展开更多
The variation of land surface temperature(LST)has a vital impact on the energy balance of the land surface process and the ecosystem stability.Based on MDO11C3,we mainly used regression analysis,GIS spatial analysis,c...The variation of land surface temperature(LST)has a vital impact on the energy balance of the land surface process and the ecosystem stability.Based on MDO11C3,we mainly used regression analysis,GIS spatial analysis,correlation analysis,and center-of-gravity model,to analyze the LST variation and its spatiotemporal differentiation in China from 2001 to 2020.Furthermore,we employed the Geodetector to identify the dominant factors contributing to LST variation in 38 eco-geographic zones of China and investigate the underlying causes of its pattern.The results indicate the following:(1)From 2001 to 2020,the LST climate average in China is 9.6℃,with a general pattern of higher temperatures in the southeast and northwest regions,lower temperatures in the northeast and Qinghai-Tibet Plateau,and higher temperatures in plains compared to lower temperatures in mountainous areas.Generally,LST has a significant negative correlation with elevation,with a correlation coefficient of–0.66.China’s First Ladder has the most pronounced negative correlation,with a correlation coefficient of–0.76 and the lapse rate of LST is 0.57℃/100 m.(2)The change rate of LST in China during the study is 0.21℃/10 a,and the warming area accounts for 78%,demonstrating the overall spatial pattern a“multi-core warming and axial cooling”.(3)LST’s variation exhibits prominent seasonal characteristics in the whole country.The spatial distribution of average value in winter and summer differs significantly from other seasons and shows more noticeable fluctuations.The centroid trajectory of the seasonal warming/cooling area is close to a loop shape and displays corresponding seasonal reverse movement.Cooling areas exhibit more substantial centroid movement,indicating greater regional variation and seasonal variability.(4)China’s LST variation is driven by both natural influences and human activities,of which natural factors contribute more,with sunshine duration and altitude being key factors.The boundary trend between the two dominant type areas is highly consistent with the“Heihe-Tengchong Line”.The eastern region is mostly dominated by human activity in conjunction with terrain factors,while the western region is predominantly influenced by natural factors,which enhance/weaken the change range of LST through mutual coupling with climate,terrain,vegetation,and other factors.This study offers valuable scientific references for addressing climate change,analyzing surface environmental patterns,and protecting the ecological environment.展开更多
Research on the spatio-temporal correlation between the intensity of human activities and the temperature of earth surfaces is of great significance in many aspects,including fully understanding the causes and mechani...Research on the spatio-temporal correlation between the intensity of human activities and the temperature of earth surfaces is of great significance in many aspects,including fully understanding the causes and mechanisms of climate change,actively adapting to climate change,pursuing rational development,and protecting the ecological environment.Taking the north slope of Tianshan Mountains,located in the arid area of northwestern China and extremely sensitive to climate change,as the research area,this study retrieves the surface temperature of the mountain based on MODIS data,while characterizing the intensity of human activities thereby data on the night light,population distribution and land use.The evolution characteristics of human activity intensity and surface temperature in the study area from 2000 to 2018 were analyzed,and the spatio-temporal correlation between them was further explored.It is found that:(1)The average human activity intensity(0.11)in the research area has kept relatively low since this century,and the overall trend has been slowly rising in a stepwise manner(0.0024·a-1);in addition,the increase in human activity intensity has lagged behind that in construction land and population by 1-2 years.(2)The annual average surface temperature in the area is 7.18℃with a pronounced growth.The rate of change(0.02℃·a-1)is about 2.33 times that of the world.The striking boost in spring(0.068℃·a-1)contributes the most to the overall warming trend.Spatially,the surface temperature is low in the south and high in the north,due to the prominent influence of the underlying surface characteristics,such as elevation and vegetation coverage.(3)The intensity of human activity and the surface temperature are remarkably positively correlated in the human activity areas there,showing a strong distribution in the east section and a weak one in the west section.The expression of its spatial differentiation and correlation is comprehensively affected by such factors as scopes of human activities,manifestations,and land-use changes.Vegetation-related human interventions,such as agriculture and forestry planting,urban greening,and afforestation,can effectively reduce the surface warming caused by human activities.This study not only puts forward new ideas to finely portray the intensity of human activities but also offers a scientific reference for regional human-land coordination and overall development.展开更多
The mass elevation effect(MEE)is a thermal effect,in which heating produced by long wave radiation on a mountain surface generates atmospheric uplift,which has a profound impact on the hydrothermal conditions and natu...The mass elevation effect(MEE)is a thermal effect,in which heating produced by long wave radiation on a mountain surface generates atmospheric uplift,which has a profound impact on the hydrothermal conditions and natural geographical processes in mountainous areas.Based on multi-source remote sensing data and field observations,a spatial downscaling inversion of temperature in the Tianshan Mountains in China was conducted,and the MEE was estimated and a spatio-temporal analysis was conducted.The Geo Detector model(GDM)and a geographically weighted regression(GWR)model were applied to explore the spatial and temporal heterogeneity of the study area.Four key results can be obtained.(1)The temperature pattern is complex and diverse,and the overall temperature presented a pattern of high in the south and east,but low in the north and west.There were clear zonal features of temperature that were negatively correlated with altitude,and the temperature difference between the internal and external areas of the mountains.(2)The warming effect of mountains was prominent,and the temperature at the same altitude increased in steps from west to east and north to south.Geomorphological units,such as large valleys and intermontane basins,weakened the latitudinal zonality and altitudinal dependence of temperature at the same altitude,with the warming effect of mountains in the southern Tianshan Mountains.(3)The dominant factors affecting the overall pattern of the MEE were topography and location,among which the difference between the internal and external areas of the mountains,and the absolute elevation played a prominent role.The interaction between factors had a greater influence on the spatial differentiation of mountain effects than single factors,and there was a strong interaction between terrain and climate,precipitation,nthe normalized difference vegetation index(NDVI),and other factors.(4)There was a spatial heterogeneity in the direction and intensity of the spatial variation of the MEE.Absolute elevation was significantly positively correlated with the change of MEE,while precipitation and the NDVI were dominated by negative feedback.In general,topography had the largest effect on the macroscopic control of MEE,and coupled with precipitation,the underlying surface,and other factors to form a unique mountain circulation system and climate characteristics,which in turn enhanced the spatial and temporal heterogeneity of the MEE.The results of this study will be useful in the further analysis of the causes of MEE and its ecological effects.展开更多
基金supported by the National Natural Science Foundation of China(52169005)the Support Plan for Innovation and Development of Key Industries in southern Xinjiang,China(2022DB024)the Corps Science and Technology Innovation Talents Program Project of China(2023CB008-08).
文摘Understanding the distribution and dynamics of glaciers is of great significance to the management and allocation of regional water resources and socio-economic development in arid regions of Northwest China.In this study,based on 36 Landsat images,we extracted the glacier boundaries in the Manas River Basin,Northwest China from 2000 to 2020 using eCognition combined with band operation,GIS(geographic information system)spatial overlay techniques,and manual visual interpretation.We further analyzed the distribution and variation characteristics of glacier area,and simulated glacial runoff using a distributed degree-day model to explore the regulation of runoff recharge.The results showed that glacier area in the Manas River Basin as a whole showed a downward trend over the past 21 a,with a decrease of 10.86%and an average change rate of–0.54%/a.With the increase in glacier scale,the number of smaller glaciers decreased exponentially,and the number and area of larger glaciers were relatively stable.Glacier area showed a normal distribution trend of increasing first and then decreasing with elevation.About 97.92%of glaciers were distributed at 3700–4800 m,and 48.11%of glaciers were observed on the northern and northeastern slopes.The retreat rate of glaciers was the fastest(68.82%)at elevations below 3800 m.There was a clear rise in elevation at the end of glaciers.Glaciers at different slope directions showed a rapid melting trend from the western slope to the southern slope then to the northern slope.Glacial runoff in the basin showed a fluctuating upward trend in the past 21 a,with an increase rate of 0.03×10^(8) m^(3)/a.The average annual glacial runoff was 4.80×10^(8) m^(3),of which 33.31%was distributed in the ablation season(June–September).The average annual contribution rate of glacial meltwater to river runoff was 35.40%,and glacial runoff accounted for 45.37%of the total runoff during the ablation season.In addition,precipitation and glacial runoff had complementary regulation patterns for river runoff.The findings can provide a scientific basis for water resource management in the Manas River Basin and other similar arid inland river basins.
基金National Natural Science Foundation of China,No.41461086,No.41761108。
文摘The variation of land surface temperature(LST)has a vital impact on the energy balance of the land surface process and the ecosystem stability.Based on MDO11C3,we mainly used regression analysis,GIS spatial analysis,correlation analysis,and center-of-gravity model,to analyze the LST variation and its spatiotemporal differentiation in China from 2001 to 2020.Furthermore,we employed the Geodetector to identify the dominant factors contributing to LST variation in 38 eco-geographic zones of China and investigate the underlying causes of its pattern.The results indicate the following:(1)From 2001 to 2020,the LST climate average in China is 9.6℃,with a general pattern of higher temperatures in the southeast and northwest regions,lower temperatures in the northeast and Qinghai-Tibet Plateau,and higher temperatures in plains compared to lower temperatures in mountainous areas.Generally,LST has a significant negative correlation with elevation,with a correlation coefficient of–0.66.China’s First Ladder has the most pronounced negative correlation,with a correlation coefficient of–0.76 and the lapse rate of LST is 0.57℃/100 m.(2)The change rate of LST in China during the study is 0.21℃/10 a,and the warming area accounts for 78%,demonstrating the overall spatial pattern a“multi-core warming and axial cooling”.(3)LST’s variation exhibits prominent seasonal characteristics in the whole country.The spatial distribution of average value in winter and summer differs significantly from other seasons and shows more noticeable fluctuations.The centroid trajectory of the seasonal warming/cooling area is close to a loop shape and displays corresponding seasonal reverse movement.Cooling areas exhibit more substantial centroid movement,indicating greater regional variation and seasonal variability.(4)China’s LST variation is driven by both natural influences and human activities,of which natural factors contribute more,with sunshine duration and altitude being key factors.The boundary trend between the two dominant type areas is highly consistent with the“Heihe-Tengchong Line”.The eastern region is mostly dominated by human activity in conjunction with terrain factors,while the western region is predominantly influenced by natural factors,which enhance/weaken the change range of LST through mutual coupling with climate,terrain,vegetation,and other factors.This study offers valuable scientific references for addressing climate change,analyzing surface environmental patterns,and protecting the ecological environment.
基金National Natural Science Foundation of China(41461086)National Natural Science Foundation of China(41761108)。
文摘Research on the spatio-temporal correlation between the intensity of human activities and the temperature of earth surfaces is of great significance in many aspects,including fully understanding the causes and mechanisms of climate change,actively adapting to climate change,pursuing rational development,and protecting the ecological environment.Taking the north slope of Tianshan Mountains,located in the arid area of northwestern China and extremely sensitive to climate change,as the research area,this study retrieves the surface temperature of the mountain based on MODIS data,while characterizing the intensity of human activities thereby data on the night light,population distribution and land use.The evolution characteristics of human activity intensity and surface temperature in the study area from 2000 to 2018 were analyzed,and the spatio-temporal correlation between them was further explored.It is found that:(1)The average human activity intensity(0.11)in the research area has kept relatively low since this century,and the overall trend has been slowly rising in a stepwise manner(0.0024·a-1);in addition,the increase in human activity intensity has lagged behind that in construction land and population by 1-2 years.(2)The annual average surface temperature in the area is 7.18℃with a pronounced growth.The rate of change(0.02℃·a-1)is about 2.33 times that of the world.The striking boost in spring(0.068℃·a-1)contributes the most to the overall warming trend.Spatially,the surface temperature is low in the south and high in the north,due to the prominent influence of the underlying surface characteristics,such as elevation and vegetation coverage.(3)The intensity of human activity and the surface temperature are remarkably positively correlated in the human activity areas there,showing a strong distribution in the east section and a weak one in the west section.The expression of its spatial differentiation and correlation is comprehensively affected by such factors as scopes of human activities,manifestations,and land-use changes.Vegetation-related human interventions,such as agriculture and forestry planting,urban greening,and afforestation,can effectively reduce the surface warming caused by human activities.This study not only puts forward new ideas to finely portray the intensity of human activities but also offers a scientific reference for regional human-land coordination and overall development.
基金National Natural Science Foundation of China,No.41761108。
文摘The mass elevation effect(MEE)is a thermal effect,in which heating produced by long wave radiation on a mountain surface generates atmospheric uplift,which has a profound impact on the hydrothermal conditions and natural geographical processes in mountainous areas.Based on multi-source remote sensing data and field observations,a spatial downscaling inversion of temperature in the Tianshan Mountains in China was conducted,and the MEE was estimated and a spatio-temporal analysis was conducted.The Geo Detector model(GDM)and a geographically weighted regression(GWR)model were applied to explore the spatial and temporal heterogeneity of the study area.Four key results can be obtained.(1)The temperature pattern is complex and diverse,and the overall temperature presented a pattern of high in the south and east,but low in the north and west.There were clear zonal features of temperature that were negatively correlated with altitude,and the temperature difference between the internal and external areas of the mountains.(2)The warming effect of mountains was prominent,and the temperature at the same altitude increased in steps from west to east and north to south.Geomorphological units,such as large valleys and intermontane basins,weakened the latitudinal zonality and altitudinal dependence of temperature at the same altitude,with the warming effect of mountains in the southern Tianshan Mountains.(3)The dominant factors affecting the overall pattern of the MEE were topography and location,among which the difference between the internal and external areas of the mountains,and the absolute elevation played a prominent role.The interaction between factors had a greater influence on the spatial differentiation of mountain effects than single factors,and there was a strong interaction between terrain and climate,precipitation,nthe normalized difference vegetation index(NDVI),and other factors.(4)There was a spatial heterogeneity in the direction and intensity of the spatial variation of the MEE.Absolute elevation was significantly positively correlated with the change of MEE,while precipitation and the NDVI were dominated by negative feedback.In general,topography had the largest effect on the macroscopic control of MEE,and coupled with precipitation,the underlying surface,and other factors to form a unique mountain circulation system and climate characteristics,which in turn enhanced the spatial and temporal heterogeneity of the MEE.The results of this study will be useful in the further analysis of the causes of MEE and its ecological effects.
