This work sets out to simulate landscape model of Mu Us Desert in Inner Mongolia Autonomous Region of China at different spatial resolution using remote sensing images and distinguished landscape heterogeneity among d...This work sets out to simulate landscape model of Mu Us Desert in Inner Mongolia Autonomous Region of China at different spatial resolution using remote sensing images and distinguished landscape heterogeneity among different spatial resolutions. Landscape models were created from classification image of SPOT satellite data with 20m resolution and NOAA data with 1 km resolution. This study created landscape models of different scales by resampling the SPOT classified image using majority rule. The pixel resolution was increased from the finest scale of 20m by 20m up to 1000m by 1000m that was the coarsest spatial resolution. The Shannon diversity index was used to compare landscape models between different scales. At the finer scale the verify small patches such as deciduous forest, shrub and reedswamp with high vegetation coverage set on matrices with low vegetation cover (moving sand dune and sparse grassland) were verified. Broadening of scale resulted to the loss of small patches and at 1000m resolution, matrix classes were dominant. At 1km resolution of NOAA data, the matrix classes which greatly related to the topography of Mu Us Desert were detected. Diversity index decreased during scale broadening and the difference between SPOT 1km scale model and AVHRR data was not significant. The results showed that SPOT 20m model is good for the use of ecotone oriented revegetation planning, and NOAA 1km model is good for the seasonal and annual monitoring of each landscape unit, and revegetation planning at the regional level.展开更多
This research aims to analyse the spatio-temporal changes of vegetation cover in coastal regions of Char Fasson and Galachipa Upazila, Bangladesh for a period of 30 years (1994-2024) based on Landsat satellite imagery...This research aims to analyse the spatio-temporal changes of vegetation cover in coastal regions of Char Fasson and Galachipa Upazila, Bangladesh for a period of 30 years (1994-2024) based on Landsat satellite imagery and NDVI. Through the evaluation of NDVI this paper classifies vegetation as no water/bare vegetation, slightly densed vegetation, moderately densed vegetation, and highly densed vegetation. The findings reveal significant fluctuations in vegetation cover: from 1994 to 2004, there has been an increase in vegetation density implying that afforestation has created more moderate and highly densed vegetation out of density vegetation. However, between 2004 and 2014, vegetation cover decreased because some cyclones, like Sidr and Aila, affected the coastal forest of Bangladesh. Other attempts to afforestation supported improved coverage from vegetation between 2014 and 2024. These findings provide clear evidence of the sustainable benefits of coastal afforestation in the reduction of coastal erosion and storm surges that affect vegetation and coasts. Knowledge gained in this research is highly useful to the environmental planners on recommendations for sustainable land uses and preservation to build up ecological stability in Bangladesh weak coastal areas.展开更多
Soil erosion occurred in orchards has often attracted extensive attentions from the society with environmental considerations,as orchard is one of major methods of agricultural production in China.In the hilly red soi...Soil erosion occurred in orchards has often attracted extensive attentions from the society with environmental considerations,as orchard is one of major methods of agricultural production in China.In the hilly red soil region of China,many orchards are established on slope lands with a lack of grass covers,leading to severe soil losses.In order to mitigate this common environmental problem and evaluate the efficiency of erosion-control approaches,four treatments were set in field plots in this study,including terraced peach orchard with Arachis pintoi cv.Amarillo as mulch and Paspalum natatu and Digitariasmutsii as hedgerows(TTM),terraced peach orchard without conservation measures(TTW),sloping peach orchard with A.pintoi as mulch and P.natatu and Digitariasmutsii as hedgerows(STM),and sloping peach orchard without conservation measures(STW).The surface runoff,sediment yields and the contents of soil nutrients and organic carbon were monitored in the four treatments and the comprehensive eco-service benefits were further evaluated.The results indicate that available phosphorus(AP),available potassium(AK),total nitrogen(TN) and organic matter(OM) in the soils of the TTM treatments and STM were significantly higher than those of the treatments TTW and STW,suggesting positive effects of the vegetation covers on the soil nutrients.Mean annual surface runoff and coefficient ranged from 0.86 to 34.79 m^3,and 0.007 to 0.282,respectively;the treatment TTM exhibited the best water conservation benefits and the treatment STW was the worst.Soil erosion modulus of the plots were 0-28.76t/hm^2 per year in average,and the treatments TTM and STM reduced significantly soil loss in comparison of the treatments TTW and STW;(d) total organic carbon in the vegetation covers ranged from 130.23 to 195.93 kg per year,and that for TTM and STM treatment significantly higher than TTW and STW treatment;comprehensive eco-service values of the orchards were evaluated considering all the factors including water conservation,soil fertility conservation,CO_2 fixation and O_2 supply,ranging from 563.35 $/y to 765.51 $/y.As expected,the treatments TTM and STM had significantly greater eco-service values than the treatments TTW and STW.In summary,we concluded that terraced orchard with A.pintoi as live mulch plus Paspalum natatu and Digitariasmutsii as hedgerows is a highly sustainable land use practice for the slope lands in red soil hilly region of China.展开更多
The continuous retrieval of clear-sky land surface temperature(LST)holds paramount importance in monitoring vegetation temperature and assessing water stress conditions.Nonetheless,the extensive cloud cover results in...The continuous retrieval of clear-sky land surface temperature(LST)holds paramount importance in monitoring vegetation temperature and assessing water stress conditions.Nonetheless,the extensive cloud cover results in a widespread lack of LST data,posing challenges in accurately forecasting LST in regions characterized by diverse vegetation types and complex terrains.Therefore,this paper proposes a synthetic aperture radar(SAR)-and digital elevation model(DEM)-integrated LST reconstruction model(SDX-LST)to generate realistic and high-spatial-resolution(30 m)clear-sky LST data.To assess the practicality and robustness of the SDX-LST model,this paper selects the study areas of Loess Plateau(LP),Qinghai-Tibet Plateau,Northeast China Plain,Nanling Mountains,and North China Plain in China,Desert Rock,Nevada in America,spanning a wide range of longitude and latitude and having obvious differences in topography,landforms,and vegetation.The analysis of the reconstruction results in different spatial location distributions,vegetation cover types,and multidate and time distributions throughout the year indicate that the SDX-LST model achieves excellent performance and high stability(with a mean absolute error lower than 2K).The SDX-LST predictions demonstrate a commendable level of consistency with the ERA5-hourly product and in situ data.We conclude that the integration of SAR and DEM within the SDX-LST model enables precise predictions of LST for various vegetation types and intricate terrains.The study quantitatively analyzes the effects of SAR and DEM on LST and introduces novel insights for exploring SAR-based reconstruction of LST.展开更多
文摘This work sets out to simulate landscape model of Mu Us Desert in Inner Mongolia Autonomous Region of China at different spatial resolution using remote sensing images and distinguished landscape heterogeneity among different spatial resolutions. Landscape models were created from classification image of SPOT satellite data with 20m resolution and NOAA data with 1 km resolution. This study created landscape models of different scales by resampling the SPOT classified image using majority rule. The pixel resolution was increased from the finest scale of 20m by 20m up to 1000m by 1000m that was the coarsest spatial resolution. The Shannon diversity index was used to compare landscape models between different scales. At the finer scale the verify small patches such as deciduous forest, shrub and reedswamp with high vegetation coverage set on matrices with low vegetation cover (moving sand dune and sparse grassland) were verified. Broadening of scale resulted to the loss of small patches and at 1000m resolution, matrix classes were dominant. At 1km resolution of NOAA data, the matrix classes which greatly related to the topography of Mu Us Desert were detected. Diversity index decreased during scale broadening and the difference between SPOT 1km scale model and AVHRR data was not significant. The results showed that SPOT 20m model is good for the use of ecotone oriented revegetation planning, and NOAA 1km model is good for the seasonal and annual monitoring of each landscape unit, and revegetation planning at the regional level.
文摘This research aims to analyse the spatio-temporal changes of vegetation cover in coastal regions of Char Fasson and Galachipa Upazila, Bangladesh for a period of 30 years (1994-2024) based on Landsat satellite imagery and NDVI. Through the evaluation of NDVI this paper classifies vegetation as no water/bare vegetation, slightly densed vegetation, moderately densed vegetation, and highly densed vegetation. The findings reveal significant fluctuations in vegetation cover: from 1994 to 2004, there has been an increase in vegetation density implying that afforestation has created more moderate and highly densed vegetation out of density vegetation. However, between 2004 and 2014, vegetation cover decreased because some cyclones, like Sidr and Aila, affected the coastal forest of Bangladesh. Other attempts to afforestation supported improved coverage from vegetation between 2014 and 2024. These findings provide clear evidence of the sustainable benefits of coastal afforestation in the reduction of coastal erosion and storm surges that affect vegetation and coasts. Knowledge gained in this research is highly useful to the environmental planners on recommendations for sustainable land uses and preservation to build up ecological stability in Bangladesh weak coastal areas.
文摘Soil erosion occurred in orchards has often attracted extensive attentions from the society with environmental considerations,as orchard is one of major methods of agricultural production in China.In the hilly red soil region of China,many orchards are established on slope lands with a lack of grass covers,leading to severe soil losses.In order to mitigate this common environmental problem and evaluate the efficiency of erosion-control approaches,four treatments were set in field plots in this study,including terraced peach orchard with Arachis pintoi cv.Amarillo as mulch and Paspalum natatu and Digitariasmutsii as hedgerows(TTM),terraced peach orchard without conservation measures(TTW),sloping peach orchard with A.pintoi as mulch and P.natatu and Digitariasmutsii as hedgerows(STM),and sloping peach orchard without conservation measures(STW).The surface runoff,sediment yields and the contents of soil nutrients and organic carbon were monitored in the four treatments and the comprehensive eco-service benefits were further evaluated.The results indicate that available phosphorus(AP),available potassium(AK),total nitrogen(TN) and organic matter(OM) in the soils of the TTM treatments and STM were significantly higher than those of the treatments TTW and STW,suggesting positive effects of the vegetation covers on the soil nutrients.Mean annual surface runoff and coefficient ranged from 0.86 to 34.79 m^3,and 0.007 to 0.282,respectively;the treatment TTM exhibited the best water conservation benefits and the treatment STW was the worst.Soil erosion modulus of the plots were 0-28.76t/hm^2 per year in average,and the treatments TTM and STM reduced significantly soil loss in comparison of the treatments TTW and STW;(d) total organic carbon in the vegetation covers ranged from 130.23 to 195.93 kg per year,and that for TTM and STM treatment significantly higher than TTW and STW treatment;comprehensive eco-service values of the orchards were evaluated considering all the factors including water conservation,soil fertility conservation,CO_2 fixation and O_2 supply,ranging from 563.35 $/y to 765.51 $/y.As expected,the treatments TTM and STM had significantly greater eco-service values than the treatments TTW and STW.In summary,we concluded that terraced orchard with A.pintoi as live mulch plus Paspalum natatu and Digitariasmutsii as hedgerows is a highly sustainable land use practice for the slope lands in red soil hilly region of China.
基金supported by the National Key Research and Development Program of China(2023Y-FD2000100)the Natural Science Foundation of China(42171303).
文摘The continuous retrieval of clear-sky land surface temperature(LST)holds paramount importance in monitoring vegetation temperature and assessing water stress conditions.Nonetheless,the extensive cloud cover results in a widespread lack of LST data,posing challenges in accurately forecasting LST in regions characterized by diverse vegetation types and complex terrains.Therefore,this paper proposes a synthetic aperture radar(SAR)-and digital elevation model(DEM)-integrated LST reconstruction model(SDX-LST)to generate realistic and high-spatial-resolution(30 m)clear-sky LST data.To assess the practicality and robustness of the SDX-LST model,this paper selects the study areas of Loess Plateau(LP),Qinghai-Tibet Plateau,Northeast China Plain,Nanling Mountains,and North China Plain in China,Desert Rock,Nevada in America,spanning a wide range of longitude and latitude and having obvious differences in topography,landforms,and vegetation.The analysis of the reconstruction results in different spatial location distributions,vegetation cover types,and multidate and time distributions throughout the year indicate that the SDX-LST model achieves excellent performance and high stability(with a mean absolute error lower than 2K).The SDX-LST predictions demonstrate a commendable level of consistency with the ERA5-hourly product and in situ data.We conclude that the integration of SAR and DEM within the SDX-LST model enables precise predictions of LST for various vegetation types and intricate terrains.The study quantitatively analyzes the effects of SAR and DEM on LST and introduces novel insights for exploring SAR-based reconstruction of LST.
