This paper gives internal characterizations of some sequence covering compact images and compact covering compact images of paracompact locally compact spaces, which improve some results on compact images of locally...This paper gives internal characterizations of some sequence covering compact images and compact covering compact images of paracompact locally compact spaces, which improve some results on compact images of locally compact metric spaces.展开更多
Human well-being and livelihoods depend on natural ecosystem services(ESs).Following the increment of population,ESs have been deteriorated over time.Ultimately,land use/land cover(LULC)changes have a profound impact ...Human well-being and livelihoods depend on natural ecosystem services(ESs).Following the increment of population,ESs have been deteriorated over time.Ultimately,land use/land cover(LULC)changes have a profound impact on the change of ecosystem.The primary goal of this study is to determine the impacts of LULC changes on ecosystem service values(ESVs)in the upper Gilgel Abbay watershed,Ethiopia.Changes in LULC types were studied using three Landsat images representing 1986,2003,and 2021.The Landsat images were classified using a supervised image classification technique in Earth Resources Data Analysis System(ERDAS)Imagine 2014.We classified ESs in this study into four categories(including provisioning,regulating,supporting,and cultural services)based on global ES classification scheme.The adjusted ESV coefficient benefit approach was employed to measure the impacts of LULC changes on ESVs.Five LULC types were identified in this study,including cultivated land,forest,shrubland,grassland,and water body.The result revealed that the area of cultivated land accounted for 64.50%,71.50%,and 61.50%of the total area in 1986,2003,and 2021,respectively.The percentage of the total area covered by forest was 9.50%,5.90%,and 14.80%in 1986,2003,and 2021,respectively.Result revealed that the total ESV decreased from 7.42×10^(7) to 6.44×10^(7) USD between 1986 and 2003.This is due to the expansion of cultivated land at the expense of forest and shrubland.However,the total ESV increased from 6.44×10^(7) to 7.76×10^(7) USD during 2003-2021,because of the increment of forest and shrubland.The expansion of cultivated land and the reductions of forest and shrubland reduced most individual ESs during 1986-2003.Nevertheless,the increase in forest and shrubland at the expense of cultivated land enhanced many ESs during 2003-2021.Therefore,the findings suggest that appropriate land use practices should be scaled-up to sustainably maintain ESs.展开更多
Land cover changes significantly affect mangrove forests,driven by both anthropogenic activities and natural processes.The Banlaem mangrove in Nakhon Si Thammarat,Thailand,supports numerous mangrove plantation project...Land cover changes significantly affect mangrove forests,driven by both anthropogenic activities and natural processes.The Banlaem mangrove in Nakhon Si Thammarat,Thailand,supports numerous mangrove plantation projects but lacks comprehensive assessments and monitoring related to land cover changes.This study aimed to(1)investigate land cover changes in the Banlaem mangrove from 1995 to 2023,and(2)generate a predictive model for future land cover changes.For land cover assessment,satellite imagery from multiple sources,including Sentinel-2(Level 2A)and Landsat(Collection 2 Level 2),was utilized to examine and classify changes in mangrove cover within the Banlaem mangrove forest from 1995 to 2023,using supervised classification with the maximum likelihood algorithm.Various regression models were analysed to develop a predictive model based on area size and time.The mangrove area in the Banlaem mangrove forest steadily grew throughout the study period,with the total area increasing from 56.16 ha in 1995 to 527.55 ha in 2023.This study represents the first analysis of changes in the Banlaem mangrove cover.Throughout the tested models,they reveal an unclear pattern of mangrove expansion,yet they indicate a high rate of expansion in the Banlaem mangrove forest.In addition,these results are expected to encourage greater community involvement in the monitoring and management of the Banlaem mangrove.We recommend establishing a community monitoring network to engage local residents in tracking changes in mangrove cover,supported by training and resources.展开更多
Snow cover in mountainous areas is characterized by high reflectivity,strong spatial heterogeneity,rapid changes,and susceptibility to cloud interference.However,due to the limitations of a single sensor,it is challen...Snow cover in mountainous areas is characterized by high reflectivity,strong spatial heterogeneity,rapid changes,and susceptibility to cloud interference.However,due to the limitations of a single sensor,it is challenging to obtain high-resolution satellite remote sensing data for monitoring the dynamic changes of snow cover within a day.This study focuses on two typical data fusion methods for polar-orbiting satellites(Sentinel-3 SLSTR)and geostationary satellites(Himawari-9 AHI),and explores the snow cover detection accuracy of a multitemporal cloud-gap snow cover identification model(Loose data fusion)and the ESTARFM(Spatiotemporal data fusion).Taking the Qilian Mountains as the research area,the accuracy of two data fusion results was verified using the snow cover extracted from Landsat-8 SR products.The results showed that both data fusion models could effectively capture the spatiotemporal variations of snow cover,but the ESTARFM demonstrated superior performance.It not only obtained fusion images at any target time,but also extracted snow cover that was closer to the spatial distribution of real satellite images.Therefore,the ESTARFM was utilized to fuse images for hourly reconstruction of the snow cover on February 14–15,2023.It was found that the maximum snow cover area of this snowfall reached 83.84%of the Qilian Mountains area,and the melting rate of the snow was extremely rapid,with a change of up to 4.30%per hour of the study area.This study offers reliable high spatiotemporal resolution satellite remote sensing data for monitoring snow cover changes in mountainous areas,contributing to more accurate and timely assessments.展开更多
Watersheds play a fundamental role in the hydrological cycle because of their contributions to the water regulation of essential tributaries for ecosystems.However,the balance between soil and climatological component...Watersheds play a fundamental role in the hydrological cycle because of their contributions to the water regulation of essential tributaries for ecosystems.However,the balance between soil and climatological components of these watersheds has been altered by human activities,which directly impacts them through changes in land use.In Colombia,the lack of control over land-use in watersheds has affected the water regulation services of important tributaries,such as the Onzaga River,whose waters are mainly used for agricultural activities.For this reason,this study aims to evaluate how changes in land use in the basin affected the capacity of water regulation.For this,a statistical correlation analysis was conducted between the Water Regulation Index(WRI)and vegetation cover areas from 1985 to 2023.The study results indicate that the expansion of the anthropogenic vegetation covers,such as agriculture parches and grasslands,replacing different types of forests,and producing an adverse effect on the water regulation capacity for the basin.This demonstrated its decrease along with an increase in its variability,indicating that,in addition to its degradation,there is a greater irregularity in this ecosystem service.In conclusion,correlation analysis indicates that 93%of the change in water regulation regime is explained by the contraction of forest cover and the expansion of agricultural areas,degraded lands,and urban development.This study confirms the importance of preserving native vegetation cover in the watershed,especially in areas adjacent to watercourses with riparian forests.展开更多
Snow cover over the Tibetan Plateau(TP)(TPSC)has garnered significant attention as a crucial indicator of climate change,along with its variations and related climate processes.However,due to the complex terrain of th...Snow cover over the Tibetan Plateau(TP)(TPSC)has garnered significant attention as a crucial indicator of climate change,along with its variations and related climate processes.However,due to the complex terrain of the TP,most numerical models exhibit notable uncertainty in simulating snow conditions in this area.This study evaluates historical snow simulations and related climate anomalies over the TP in numerical models from phase 6 of the Coupled Model Intercomparison Project(CMIP6).The CMIP6 model simulations are compared with two observation-based products across different seasons and temporal scales,and the results indicate that the CMIP6 multimodel ensemble(MME)mean reasonably captures the spatial distribution of the annual and seasonal climatological mean TP snow,albeit with weaker magnitudes compared to observations.The CMIP6 MME performs better over the western TP than the eastern regions,showing a higher reproducibility of the long-term warming trends and declining snow cover trends,partly due to the atmospheric circulation anomalies related to global warming.Additionally,some CMIP6 models successfully capture the interannual variability of TPSC and its relationship with associated climate factors.Our work emphasizes the importance of CMIP6 model selection and pays attention to data reliability in interpreting CMIP6 model results across different TP regions when studying snow cover variations and climate effects using numerical models.展开更多
Due to the high elevation and cold climate of the Tibetan Plateau,the western region retains extensive snow cover during the summer,which can exhibit rapid variability over the course of just a few days.This study uti...Due to the high elevation and cold climate of the Tibetan Plateau,the western region retains extensive snow cover during the summer,which can exhibit rapid variability over the course of just a few days.This study utilizes numerical experiments to investigate the atmospheric response to extreme Tibetan Plateau snow cover(TPSC)events on a subseasonal timescale during summer.The results indicate that the subseasonal variations in TPSC exert limited impact on nonlocal atmospheric circulation and temperature during this period.Nevertheless,local surface energy and atmospheric temperature exhibit rapid cooling responses to increased snow cover.Specifically,an increase in snow cover over the western Tibetan Plateau leads to a sharp rise in surface albedo,resulting in a reduction in land surface energy and a negative response in the diabatic heating rate from the surface to 350 hPa locally.This negative diabatic heating response subsequently causes a decline in both surface and overlying atmospheric temperatures.The temperature response is confined to the western Tibetan Plateau and extends vertically from the surface to approximately 350 hPa.These extreme TPSC events and their associated atmospheric impacts occur within a two-week timescale.展开更多
This study investigated the impacts of Tibetan Plateau(TP) snow cover extent(SCE) on the interannual variation in spring precipitation over the Tarim Basin(SPTB) for the period 1980–2019. Significant anomalies in wes...This study investigated the impacts of Tibetan Plateau(TP) snow cover extent(SCE) on the interannual variation in spring precipitation over the Tarim Basin(SPTB) for the period 1980–2019. Significant anomalies in westerly winds,associated with a low-pressure anomaly in the northern Tarim Basin and a high-pressure anomaly in the southwestern basin, enhance moisture conveyance from upstream areas to the inland, thereby promoting increased SPTB. The analysis shows that anomalous snow over the northwestern and central-western TP, persisting from winter to spring, has a close relationship with SPTB variation. A localized energy budget analysis reveals that increased winter TP snow induces a cooling effect on the overlying atmosphere, resulting in an abnormal low-pressure system prevailing over the troposphere above the western TP. This anomalous low-pressure system can persist into the subsequent spring facilitated by the local snow–atmosphere feedback effects and energy conversion from the background flow. This persistence is accompanied by upward motion and moisture convergence, ultimately enhancing the SPTB. Further analysis indicates that anomalous warming in the Indian Ocean sea surface temperature(SST) during winter intensifies the subtropical high, facilitating the uplift and transport of warm moisture from lower latitude oceans to middle latitudes, thereby contributing to the increased TP snow and SPTB. Importantly, the impact of TP snow on SPTB is primarily independent of anomalous Indian Ocean SST in the northern Tarim Basin. This study elucidates a complex mechanism of ocean–land–atmosphere interaction,enhancing our understanding of SPTB variation and highlighting the significant role of TP snow in this process.展开更多
The High Mountain Asia(HMA)is a prominent global mountain system characterized by an average altitude exceeding 4,000 m,intricate topography,and significant spatial variability in climatic conditions.Despite its impor...The High Mountain Asia(HMA)is a prominent global mountain system characterized by an average altitude exceeding 4,000 m,intricate topography,and significant spatial variability in climatic conditions.Despite its importance,there has been a relative paucity of research focusing on the spatiotemporal variations of snow cover,key controlling factors,and variability within HMA sub-basins.This study aims to address this gap by extracting snow cover percentage(SCP)and snow cover days(SCD)data from MOD10A2 snow products,integrating these with precipitation(P)and temperature(T)data from ERA5.Our objective is to analyze the spatiotemporal distribution characteristics of snow cover and to use path analysis to elucidate the key climatic factors and spatial differences influencing snow cover changes.The findings indicate that,on a temporal scale,the overall SCP in HMA exhibited a declining trend from 2001 to 2021.Interannual variations in SCP across HMA sub-basins revealed a decreasing trend in the Pamir(PAM),Western Tibetan Plateau(WTS),Eastern Tibetan Plateau(ETS),Western Kunlun(WKL),Qilian Shan(QLS),and Himalaya(HDS)regions,while an increasing trend was observed in other areas.Spatially,22.97%of the HMA regions experienced an increase in SCD,primarily in the Western Himalaya(WHL),Central Himalaya(CHL),and Southeastern Xizang(SET)regions.Conversely,28.08%of the HMA regions showed a decrease in SCD,predominantly in the Eastern Himalaya(EHL),HDS,and WTS regions.Temperature(T)emerged as the primary influencing factor of SCD change in most HMA sub-basins.However,in the Eastern Kunlun(EKL)and WHL sub-basins,precipitation(P)was identified as the main driver of SCD change,affecting all elevation zones in these regions.Additionally,other climatic conditions can also impact snow cover beyond the primary controlling factor.展开更多
Based on the Google Earth Engine cloud computing data platform,this study employed three algorithms including Support Vector Machine,Random Forest,and Classification and Regression Tree to classify the current status ...Based on the Google Earth Engine cloud computing data platform,this study employed three algorithms including Support Vector Machine,Random Forest,and Classification and Regression Tree to classify the current status of land covers in Hung Yen province of Vietnam using Landsat 8 OLI satellite images,a free data source with reasonable spatial and temporal resolution.The results of the study show that all three algorithms presented good classification for five basic types of land cover including Rice land,Water bodies,Perennial vegetation,Annual vegetation,Built-up areas as their overall accuracy and Kappa coefficient were greater than 80%and 0.8,respectively.Among the three algorithms,SVM achieved the highest accuracy as its overall accuracy was 86%and the Kappa coefficient was 0.88.Land cover classification based on the SVM algorithm shows that Built-up areas cover the largest area with nearly 31,495 ha,accounting for more than 33.8%of the total natural area,followed by Rice land and Perennial vegetation which cover an area of over 30,767 ha(33%)and 15,637 ha(16.8%),respectively.Water bodies and Annual vegetation cover the smallest areas with 8,820(9.5%)ha and 6,302 ha(6.8%),respectively.The results of this study can be used for land use management and planning as well as other natural resource and environmental management purposes in the province.展开更多
Cover cropping is a diversifying agricultural practice that can improve soil structure and function by altering the underground litter diversity and soil microbial communities.Here,we tested how a wheat cover crop alt...Cover cropping is a diversifying agricultural practice that can improve soil structure and function by altering the underground litter diversity and soil microbial communities.Here,we tested how a wheat cover crop alters the decomposition of cucumber root litter.A three-year greenhouse litterbag decomposition experiment showed that a wheat cover crop accelerates the decomposition of cucumber root litter.A microcosm litterbag experiment further showed that wheat litter and the soil microbial community could improve cucumber root litter decomposition.Moreover,the wheat cover crop altered the abundances and diversities of soil bacterial and fungal communities,and enriched several putative keystone operational taxonomic units(OTUs),such as Bacillus sp.OTU1837 and Mortierella sp.OTU1236,that were positively related to the mass loss of cucumber root litter.The representative bacterial and fungal strains B186 and M3 were isolated and cultured.In vitro decomposition tests demonstrated that both B186 and M3 had cucumber root litter decomposition activity and a stronger effect was found when they were co-incubated.Overall,a wheat cover crop accelerated cucumber root litter decomposition by altering the soil microbial communities,particularly by stimulating certain putative keystone taxa,which provides a theoretical basis for using cover crops to promote sustainable agricultural development.展开更多
Based on 5G and IoT technology,this study addresses the issues of manual control dependency,poor reliability,and high labor costs in traditional ceramic kiln exhaust cover operations.An intelligent control system for ...Based on 5G and IoT technology,this study addresses the issues of manual control dependency,poor reliability,and high labor costs in traditional ceramic kiln exhaust cover operations.An intelligent control system for kiln exhaust covers was designed in this paper.The system employs temperature measurement devices to monitor the internal temperature of the kiln in real time.A controller automatically operates the actuator to open or close the kiln exhaust cover based on temperature measurements.Additionally,the system integrates data transmission units and cloud services,enabling remote monitoring of kiln temperature and historical data storage.Experimental results demonstrate that the system effectively reduces labor costs and significantly enhances the IoT capabilities of kiln operations.展开更多
The duration of snow cover has shortened in the boreal region,and the amount of seasonal snow decreased.This affects the coupling between soil and air temperatures and may thus lead to colder soil and deeper soil fros...The duration of snow cover has shortened in the boreal region,and the amount of seasonal snow decreased.This affects the coupling between soil and air temperatures and may thus lead to colder soil and deeper soil frost.We prevented snow reaching the forest floor for two winters in mature boreal forest and studied how that affects tree and forest floor processes.The studied species were Scots pine,Norway spruce,silver birch,and a dwarf shrub bilberry.Decreased soil temperature,due to the lack of snow cover,decreased forest floor respiration in winter and spring.Simultaneously,response of respiration to temperature seemed to increase,perhaps due to the exposure of forest floor vegetation to cold air temperature.Indeed,lack of snow cover induced mortality of bilberry,but the remaining ramets grew more in height and their average leaf size was larger likely to compensate for the lost plant biomass.Lack of snow cover also affected tree hydraulics as tree water uptake was decreased in spring,and the start of the sap season delayed in birch.Pine and birch tended to grow less in the snow exclusion treatment(differences not statistically significant),whereas spruce grew more.Coarse root traits,e.g.water content and cellular frost damages,were not affected by the snow exclusion treatment.The results of this case study increase our understanding on the effects of changing snow cover on spring-time tree and forest floor processes in mature boreal forest,but also reveal the need for further studies on mature trees.展开更多
Editor's Note:Sixty years of nurturing winds and rains,sixty years of protound change.This year marks the 60th anniversary of the founding of the Xizang Autonomous Region.To mark this important historical mileston...Editor's Note:Sixty years of nurturing winds and rains,sixty years of protound change.This year marks the 60th anniversary of the founding of the Xizang Autonomous Region.To mark this important historical milestone,this column presents frontline reports and observations by our journalists.展开更多
BACKGROUND Hemorrhage following pancreaticobiliary surgery is a high-risk complication,with a mortality rate of 16%-38%.At present,minimally invasive endovascular intervention comprising superselective arterial emboli...BACKGROUND Hemorrhage following pancreaticobiliary surgery is a high-risk complication,with a mortality rate of 16%-38%.At present,minimally invasive endovascular intervention comprising superselective arterial embolization(SAE)and covered stent implantation(CSI)is the treatment of choice.However,in certain cases,both SAE and CSI become infeasible.AIM To evaluate the effectiveness of coil-assisted N-butyl cyanoacrylate(NBCA)embolization in comparison with that of CSI in managing delayed hemorrhage after hepatobiliary–pancreatic surgery when SAE is infeasible.METHODS Ninety-eight continuous patients(n=105 cases;mean age,58.4 years)with delayed massive hemorrhage who were treated with coil-assisted NBCA embolization(NBCA group,n=45)and/or CSI(CSI group,n=60)were retrospectively evaluated between March 2014 and December 2023.Data on technical and clinical success,30-day mortality,and severe intervention-related adverse events were collected and analyzed.RESULTS The technical and clinical success rates in the NBCA group(100%and 93.3%,respectively)were significantly higher than those in the CSI group(88.3%and 73.3%,respectively),with a statistically significant difference between the two groups(P=0.019 and 0.010,respectively).The 30-day mortality rates and major intervention-related complications were 17.8%and 0%,respectively,in the NBCA group and 18.3%and 1.7%in the CSI group,respectively,with no statistically significant difference between the two groups.CONCLUSION In terms of technical and clinical success,coil-assisted NBCA embolization was more effective than CSI for managing delayed hemorrhage after hepatobiliary–pancreatic surgery when SAE was not feasible.展开更多
The analysis of the ejaculate,better known as spermiogram,represents the first and main step to identify whether a series of sperm quality parameters are within the norm and therefore are consistent with normal sperm ...The analysis of the ejaculate,better known as spermiogram,represents the first and main step to identify whether a series of sperm quality parameters are within the norm and therefore are consistent with normal sperm fertilizing capacity.Among these,sperm concentration and motility are the first parameters to be evaluated through an estimation carried out by expert examiners.展开更多
The radon control mechanism of Na_(2)O·nSiO_(2)−CaCl_(2)modified soil was studied through the laboratory simulation experiment of tailing covering radon control.The radon exhalation rate(J)is negatively correlate...The radon control mechanism of Na_(2)O·nSiO_(2)−CaCl_(2)modified soil was studied through the laboratory simulation experiment of tailing covering radon control.The radon exhalation rate(J)is negatively correlated with the coverage thickness(H),and it has a non-linear relationship with the temperature.The moisture content variation rate of the covering soil significantly decreases,which helps to reduce soil damage and enhance the resistance of the covering soil to ambient temperature interference.The formation of silicic gel and C−S−H gel effectively optimizes the pore structure and permeability,reduces the diffusion and migration of radon gas in the covering soil,and the average radon exhalation rate is decreased by 1.01×10^(−2)Bq/(m^(3)·s).The research results show that the Na_(2)O·nSiO_(2)−CaCl_(2)modified covering soil can effectively improve the radon control performance of the covering soil and reduce the cost of cover treatment.展开更多
AIM:To evaluate the surgical outcomes of the perfluorocarbon liquid(PFCL)-assisted inverted multilayer internal limiting membrane(ILM)flaps covering technique in macular hole retinal detachment(MHRD)in high myopia wit...AIM:To evaluate the surgical outcomes of the perfluorocarbon liquid(PFCL)-assisted inverted multilayer internal limiting membrane(ILM)flaps covering technique in macular hole retinal detachment(MHRD)in high myopia with axial length(AL)≥30 mm.METHODS:In this retrospective,interventional,consecutive comparative study,44 MHRD eyes were divided into two groups:the PFCL-assisted inverted multilayer ILM flaps covering technique group(Group 1,21 eyes)and the ILM peeling group(Group 2,23 eyes).The follow-up period was>12mo.Postoperative outcomes,including retinal reattachment,macular hole(MH)closure,and bestcorrected visual acuity(BCVA),were assessed.Statistical analysis using the Mann–Whitney U test and Fisher’s exact test was conducted to compare differences between groups.RESULTS:There were no statistically significant differences in baseline preoperative clinical characteristics,including age,sex,AL,diopters,duration of symptom,lens status,posterior staphyloma presence and extent of RD.Retinal reattachment rates were higher in Group 1(90.5%)than in Group 2(82.6%),without statistical significance(P=0.667).MH closure rates were significantly higher in Group 1(85.7%)than in Group 2(17.4%;P<0.001).The Group-1 BCVA(logMAR)improved significantly from 2.13±0.91 preoperatively to 1.21±0.66 postoperatively(P=0.026).The Group 2 BCVA improved significantly from 1.91±0.53 preoperatively to 1.19±0.41 postoperatively(P=0.032).However,there were no significant differences in visual-acuity improvement between groups(P=0.460).CONCLUSION:This technique offers a more effective approach for improving MH closure rates and postoperative visual function in MHRD with AL≥30 mm in high myopia.展开更多
Understanding the impact of meteorological and topographical factors on snow cover fraction(SCF)is crucial for water resource management in the Qilian Mountains(QLM),China.However,there is still a lack of adequate qua...Understanding the impact of meteorological and topographical factors on snow cover fraction(SCF)is crucial for water resource management in the Qilian Mountains(QLM),China.However,there is still a lack of adequate quantitative analysis of the impact of these factors.This study investigated the spatiotemporal characteristics and trends of SCF in the QLM based on the cloud-removed Moderate Resolution Imaging Spectroradiometer(MODIS)SCF dataset during 2000-2021 and conducted a quantitative analysis of the drivers using a histogram-based gradient boosting regression tree(HGBRT)model.The results indicated that the monthly distribution of SCF exhibited a bimodal pattern.The SCF showed a pattern of higher values in the western regions and lower values in the eastern regions.Overall,the SCF showed a decreasing trend during 2000-2021.The decrease in SCF occurred at higher elevations,while an increase was observed at lower elevations.At the annual scale,the SCF showed a downward trend in the western regions affected by westerly(52.84%of the QLM).However,the opposite trend was observed in the eastern regions affected by monsoon(45.73%of the QLM).The SCF displayed broadly similar spatial patterns in autumn and winter,with a significant decrease in the western regions and a slight increase in the central and eastern regions.The effect of spring SCF on spring surface runoff was more pronounced than that of winter SCF.Furthermore,compared with meteorological factors,a variation of 46.53%in spring surface runoff can be attributed to changes in spring SCF.At the annual scale,temperature and relative humidity were the most important drivers of SCF change.An increase in temperature exceeding 0.04°C/a was observed to result in a decline in SCF,with a maximum decrease of 0.22%/a.An increase in relative humidity of more than 0.02%/a stabilized the rise in SCF(about 0.06%/a).The impacts of slope and aspect were found to be minimal.At the seasonal scale,the primary factors impacting SCF change varied.In spring,precipitation and wind speed emerged as the primary drivers.In autumn,precipitation and temperature were identified as the primary drivers.In winter,relative humidity and precipitation were the most important drivers.In contrast to the other seasons,slope exerted the strongest influence on SCF change in summer.This study facilitates a detailed quantitative description of SCF change in the QLM,enhancing the effectiveness of watershed water resource management and ecological conservation efforts in this region.展开更多
Agile earth observation satellites(AEOSs)represent a new generation of satellites with three degrees of freedom(pitch,roll,and yaw);they possess a long visible time window(VTW)for ground targets and support imaging at...Agile earth observation satellites(AEOSs)represent a new generation of satellites with three degrees of freedom(pitch,roll,and yaw);they possess a long visible time window(VTW)for ground targets and support imaging at any moment within the VTW.However,different observation times demonstrate different cloud cover distributions,which exhibit different effects on the AEOS observation.Previous studies ignored pitch angles,discretized VTWs,or fixed cloud cover for every VTW,which led to the loss of intermediate observation states,thus these studies are not suitable for AEOS scheduling considering cloud cover distribution.In this study,a relationship formula between the cloud cover and observation time is proposed to calculate the cloud cover for every observation time,and a relationship formula between the observation time and pitch angle is designed to calculate the pitch angle for every observation time in the VTW.A refined model including the pitch angle,roll angle,and cloud cover distribution is established,which can make the scheme closer to the actual application of AEOSs.A hybrid genetic simulated annealing(HGSA)algorithm for AEOS scheduling is proposed,which integrates the advantages of genetic and simulated annealing algorithms and can effectively avoid falling into a local optimal solution.The experiments are conducted to compare the proposed algorithm with the traditional algorithms,the results verify that the proposed model and algorithm are efficient and effective for AEOS scheduling considering cloud cover distribution.展开更多
文摘This paper gives internal characterizations of some sequence covering compact images and compact covering compact images of paracompact locally compact spaces, which improve some results on compact images of locally compact metric spaces.
文摘Human well-being and livelihoods depend on natural ecosystem services(ESs).Following the increment of population,ESs have been deteriorated over time.Ultimately,land use/land cover(LULC)changes have a profound impact on the change of ecosystem.The primary goal of this study is to determine the impacts of LULC changes on ecosystem service values(ESVs)in the upper Gilgel Abbay watershed,Ethiopia.Changes in LULC types were studied using three Landsat images representing 1986,2003,and 2021.The Landsat images were classified using a supervised image classification technique in Earth Resources Data Analysis System(ERDAS)Imagine 2014.We classified ESs in this study into four categories(including provisioning,regulating,supporting,and cultural services)based on global ES classification scheme.The adjusted ESV coefficient benefit approach was employed to measure the impacts of LULC changes on ESVs.Five LULC types were identified in this study,including cultivated land,forest,shrubland,grassland,and water body.The result revealed that the area of cultivated land accounted for 64.50%,71.50%,and 61.50%of the total area in 1986,2003,and 2021,respectively.The percentage of the total area covered by forest was 9.50%,5.90%,and 14.80%in 1986,2003,and 2021,respectively.Result revealed that the total ESV decreased from 7.42×10^(7) to 6.44×10^(7) USD between 1986 and 2003.This is due to the expansion of cultivated land at the expense of forest and shrubland.However,the total ESV increased from 6.44×10^(7) to 7.76×10^(7) USD during 2003-2021,because of the increment of forest and shrubland.The expansion of cultivated land and the reductions of forest and shrubland reduced most individual ESs during 1986-2003.Nevertheless,the increase in forest and shrubland at the expense of cultivated land enhanced many ESs during 2003-2021.Therefore,the findings suggest that appropriate land use practices should be scaled-up to sustainably maintain ESs.
文摘Land cover changes significantly affect mangrove forests,driven by both anthropogenic activities and natural processes.The Banlaem mangrove in Nakhon Si Thammarat,Thailand,supports numerous mangrove plantation projects but lacks comprehensive assessments and monitoring related to land cover changes.This study aimed to(1)investigate land cover changes in the Banlaem mangrove from 1995 to 2023,and(2)generate a predictive model for future land cover changes.For land cover assessment,satellite imagery from multiple sources,including Sentinel-2(Level 2A)and Landsat(Collection 2 Level 2),was utilized to examine and classify changes in mangrove cover within the Banlaem mangrove forest from 1995 to 2023,using supervised classification with the maximum likelihood algorithm.Various regression models were analysed to develop a predictive model based on area size and time.The mangrove area in the Banlaem mangrove forest steadily grew throughout the study period,with the total area increasing from 56.16 ha in 1995 to 527.55 ha in 2023.This study represents the first analysis of changes in the Banlaem mangrove cover.Throughout the tested models,they reveal an unclear pattern of mangrove expansion,yet they indicate a high rate of expansion in the Banlaem mangrove forest.In addition,these results are expected to encourage greater community involvement in the monitoring and management of the Banlaem mangrove.We recommend establishing a community monitoring network to engage local residents in tracking changes in mangrove cover,supported by training and resources.
基金funded by the National Natural Science Foundation of China(42361058)supported by the Science and Technology Program of Gansu Province(22YF7FA074)。
文摘Snow cover in mountainous areas is characterized by high reflectivity,strong spatial heterogeneity,rapid changes,and susceptibility to cloud interference.However,due to the limitations of a single sensor,it is challenging to obtain high-resolution satellite remote sensing data for monitoring the dynamic changes of snow cover within a day.This study focuses on two typical data fusion methods for polar-orbiting satellites(Sentinel-3 SLSTR)and geostationary satellites(Himawari-9 AHI),and explores the snow cover detection accuracy of a multitemporal cloud-gap snow cover identification model(Loose data fusion)and the ESTARFM(Spatiotemporal data fusion).Taking the Qilian Mountains as the research area,the accuracy of two data fusion results was verified using the snow cover extracted from Landsat-8 SR products.The results showed that both data fusion models could effectively capture the spatiotemporal variations of snow cover,but the ESTARFM demonstrated superior performance.It not only obtained fusion images at any target time,but also extracted snow cover that was closer to the spatial distribution of real satellite images.Therefore,the ESTARFM was utilized to fuse images for hourly reconstruction of the snow cover on February 14–15,2023.It was found that the maximum snow cover area of this snowfall reached 83.84%of the Qilian Mountains area,and the melting rate of the snow was extremely rapid,with a change of up to 4.30%per hour of the study area.This study offers reliable high spatiotemporal resolution satellite remote sensing data for monitoring snow cover changes in mountainous areas,contributing to more accurate and timely assessments.
基金The authors would like to thank the Vice-chancellor of Research at the Universidad Militar Nueva Granada for the opportunity to develop project INV-ING-3966.
文摘Watersheds play a fundamental role in the hydrological cycle because of their contributions to the water regulation of essential tributaries for ecosystems.However,the balance between soil and climatological components of these watersheds has been altered by human activities,which directly impacts them through changes in land use.In Colombia,the lack of control over land-use in watersheds has affected the water regulation services of important tributaries,such as the Onzaga River,whose waters are mainly used for agricultural activities.For this reason,this study aims to evaluate how changes in land use in the basin affected the capacity of water regulation.For this,a statistical correlation analysis was conducted between the Water Regulation Index(WRI)and vegetation cover areas from 1985 to 2023.The study results indicate that the expansion of the anthropogenic vegetation covers,such as agriculture parches and grasslands,replacing different types of forests,and producing an adverse effect on the water regulation capacity for the basin.This demonstrated its decrease along with an increase in its variability,indicating that,in addition to its degradation,there is a greater irregularity in this ecosystem service.In conclusion,correlation analysis indicates that 93%of the change in water regulation regime is explained by the contraction of forest cover and the expansion of agricultural areas,degraded lands,and urban development.This study confirms the importance of preserving native vegetation cover in the watershed,especially in areas adjacent to watercourses with riparian forests.
基金funded by the Natural Science Foundation of China(Grant No.W2412145,42275031)the Natural Science Foundation of Yunnan Province(Grant No.202302AN360006)。
文摘Snow cover over the Tibetan Plateau(TP)(TPSC)has garnered significant attention as a crucial indicator of climate change,along with its variations and related climate processes.However,due to the complex terrain of the TP,most numerical models exhibit notable uncertainty in simulating snow conditions in this area.This study evaluates historical snow simulations and related climate anomalies over the TP in numerical models from phase 6 of the Coupled Model Intercomparison Project(CMIP6).The CMIP6 model simulations are compared with two observation-based products across different seasons and temporal scales,and the results indicate that the CMIP6 multimodel ensemble(MME)mean reasonably captures the spatial distribution of the annual and seasonal climatological mean TP snow,albeit with weaker magnitudes compared to observations.The CMIP6 MME performs better over the western TP than the eastern regions,showing a higher reproducibility of the long-term warming trends and declining snow cover trends,partly due to the atmospheric circulation anomalies related to global warming.Additionally,some CMIP6 models successfully capture the interannual variability of TPSC and its relationship with associated climate factors.Our work emphasizes the importance of CMIP6 model selection and pays attention to data reliability in interpreting CMIP6 model results across different TP regions when studying snow cover variations and climate effects using numerical models.
基金supported by the National Key R&D Program of China[grant number 2022YFF0801603]the Natural Science Foundation of China[grant number 41905074].
文摘Due to the high elevation and cold climate of the Tibetan Plateau,the western region retains extensive snow cover during the summer,which can exhibit rapid variability over the course of just a few days.This study utilizes numerical experiments to investigate the atmospheric response to extreme Tibetan Plateau snow cover(TPSC)events on a subseasonal timescale during summer.The results indicate that the subseasonal variations in TPSC exert limited impact on nonlocal atmospheric circulation and temperature during this period.Nevertheless,local surface energy and atmospheric temperature exhibit rapid cooling responses to increased snow cover.Specifically,an increase in snow cover over the western Tibetan Plateau leads to a sharp rise in surface albedo,resulting in a reduction in land surface energy and a negative response in the diabatic heating rate from the surface to 350 hPa locally.This negative diabatic heating response subsequently causes a decline in both surface and overlying atmospheric temperatures.The temperature response is confined to the western Tibetan Plateau and extends vertically from the surface to approximately 350 hPa.These extreme TPSC events and their associated atmospheric impacts occur within a two-week timescale.
基金funded by the National Natural Science Foundation of China (Grant No.42275031)Natural Science Foundation of Yunnan Province (Grant No.202302AN360006)。
文摘This study investigated the impacts of Tibetan Plateau(TP) snow cover extent(SCE) on the interannual variation in spring precipitation over the Tarim Basin(SPTB) for the period 1980–2019. Significant anomalies in westerly winds,associated with a low-pressure anomaly in the northern Tarim Basin and a high-pressure anomaly in the southwestern basin, enhance moisture conveyance from upstream areas to the inland, thereby promoting increased SPTB. The analysis shows that anomalous snow over the northwestern and central-western TP, persisting from winter to spring, has a close relationship with SPTB variation. A localized energy budget analysis reveals that increased winter TP snow induces a cooling effect on the overlying atmosphere, resulting in an abnormal low-pressure system prevailing over the troposphere above the western TP. This anomalous low-pressure system can persist into the subsequent spring facilitated by the local snow–atmosphere feedback effects and energy conversion from the background flow. This persistence is accompanied by upward motion and moisture convergence, ultimately enhancing the SPTB. Further analysis indicates that anomalous warming in the Indian Ocean sea surface temperature(SST) during winter intensifies the subtropical high, facilitating the uplift and transport of warm moisture from lower latitude oceans to middle latitudes, thereby contributing to the increased TP snow and SPTB. Importantly, the impact of TP snow on SPTB is primarily independent of anomalous Indian Ocean SST in the northern Tarim Basin. This study elucidates a complex mechanism of ocean–land–atmosphere interaction,enhancing our understanding of SPTB variation and highlighting the significant role of TP snow in this process.
基金supported by Tianchi talent project(Granted No.51052401507)。
文摘The High Mountain Asia(HMA)is a prominent global mountain system characterized by an average altitude exceeding 4,000 m,intricate topography,and significant spatial variability in climatic conditions.Despite its importance,there has been a relative paucity of research focusing on the spatiotemporal variations of snow cover,key controlling factors,and variability within HMA sub-basins.This study aims to address this gap by extracting snow cover percentage(SCP)and snow cover days(SCD)data from MOD10A2 snow products,integrating these with precipitation(P)and temperature(T)data from ERA5.Our objective is to analyze the spatiotemporal distribution characteristics of snow cover and to use path analysis to elucidate the key climatic factors and spatial differences influencing snow cover changes.The findings indicate that,on a temporal scale,the overall SCP in HMA exhibited a declining trend from 2001 to 2021.Interannual variations in SCP across HMA sub-basins revealed a decreasing trend in the Pamir(PAM),Western Tibetan Plateau(WTS),Eastern Tibetan Plateau(ETS),Western Kunlun(WKL),Qilian Shan(QLS),and Himalaya(HDS)regions,while an increasing trend was observed in other areas.Spatially,22.97%of the HMA regions experienced an increase in SCD,primarily in the Western Himalaya(WHL),Central Himalaya(CHL),and Southeastern Xizang(SET)regions.Conversely,28.08%of the HMA regions showed a decrease in SCD,predominantly in the Eastern Himalaya(EHL),HDS,and WTS regions.Temperature(T)emerged as the primary influencing factor of SCD change in most HMA sub-basins.However,in the Eastern Kunlun(EKL)and WHL sub-basins,precipitation(P)was identified as the main driver of SCD change,affecting all elevation zones in these regions.Additionally,other climatic conditions can also impact snow cover beyond the primary controlling factor.
文摘Based on the Google Earth Engine cloud computing data platform,this study employed three algorithms including Support Vector Machine,Random Forest,and Classification and Regression Tree to classify the current status of land covers in Hung Yen province of Vietnam using Landsat 8 OLI satellite images,a free data source with reasonable spatial and temporal resolution.The results of the study show that all three algorithms presented good classification for five basic types of land cover including Rice land,Water bodies,Perennial vegetation,Annual vegetation,Built-up areas as their overall accuracy and Kappa coefficient were greater than 80%and 0.8,respectively.Among the three algorithms,SVM achieved the highest accuracy as its overall accuracy was 86%and the Kappa coefficient was 0.88.Land cover classification based on the SVM algorithm shows that Built-up areas cover the largest area with nearly 31,495 ha,accounting for more than 33.8%of the total natural area,followed by Rice land and Perennial vegetation which cover an area of over 30,767 ha(33%)and 15,637 ha(16.8%),respectively.Water bodies and Annual vegetation cover the smallest areas with 8,820(9.5%)ha and 6,302 ha(6.8%),respectively.The results of this study can be used for land use management and planning as well as other natural resource and environmental management purposes in the province.
基金supported by the National Natural Science Foundation of China(32072655 and 32272792)。
文摘Cover cropping is a diversifying agricultural practice that can improve soil structure and function by altering the underground litter diversity and soil microbial communities.Here,we tested how a wheat cover crop alters the decomposition of cucumber root litter.A three-year greenhouse litterbag decomposition experiment showed that a wheat cover crop accelerates the decomposition of cucumber root litter.A microcosm litterbag experiment further showed that wheat litter and the soil microbial community could improve cucumber root litter decomposition.Moreover,the wheat cover crop altered the abundances and diversities of soil bacterial and fungal communities,and enriched several putative keystone operational taxonomic units(OTUs),such as Bacillus sp.OTU1837 and Mortierella sp.OTU1236,that were positively related to the mass loss of cucumber root litter.The representative bacterial and fungal strains B186 and M3 were isolated and cultured.In vitro decomposition tests demonstrated that both B186 and M3 had cucumber root litter decomposition activity and a stronger effect was found when they were co-incubated.Overall,a wheat cover crop accelerated cucumber root litter decomposition by altering the soil microbial communities,particularly by stimulating certain putative keystone taxa,which provides a theoretical basis for using cover crops to promote sustainable agricultural development.
基金supported by Jiangxi 03 Special and 5G Project(20232ABC03A33)Ganpo Talent Support Program(20232BCJ23106)。
文摘Based on 5G and IoT technology,this study addresses the issues of manual control dependency,poor reliability,and high labor costs in traditional ceramic kiln exhaust cover operations.An intelligent control system for kiln exhaust covers was designed in this paper.The system employs temperature measurement devices to monitor the internal temperature of the kiln in real time.A controller automatically operates the actuator to open or close the kiln exhaust cover based on temperature measurements.Additionally,the system integrates data transmission units and cloud services,enabling remote monitoring of kiln temperature and historical data storage.Experimental results demonstrate that the system effectively reduces labor costs and significantly enhances the IoT capabilities of kiln operations.
基金supported by the European Union-Next Generation EU instrument and the Research Council of Finland funding(grants 323843,347782,353218,355142,and 357902)INAR RI research infrastructure。
文摘The duration of snow cover has shortened in the boreal region,and the amount of seasonal snow decreased.This affects the coupling between soil and air temperatures and may thus lead to colder soil and deeper soil frost.We prevented snow reaching the forest floor for two winters in mature boreal forest and studied how that affects tree and forest floor processes.The studied species were Scots pine,Norway spruce,silver birch,and a dwarf shrub bilberry.Decreased soil temperature,due to the lack of snow cover,decreased forest floor respiration in winter and spring.Simultaneously,response of respiration to temperature seemed to increase,perhaps due to the exposure of forest floor vegetation to cold air temperature.Indeed,lack of snow cover induced mortality of bilberry,but the remaining ramets grew more in height and their average leaf size was larger likely to compensate for the lost plant biomass.Lack of snow cover also affected tree hydraulics as tree water uptake was decreased in spring,and the start of the sap season delayed in birch.Pine and birch tended to grow less in the snow exclusion treatment(differences not statistically significant),whereas spruce grew more.Coarse root traits,e.g.water content and cellular frost damages,were not affected by the snow exclusion treatment.The results of this case study increase our understanding on the effects of changing snow cover on spring-time tree and forest floor processes in mature boreal forest,but also reveal the need for further studies on mature trees.
文摘Editor's Note:Sixty years of nurturing winds and rains,sixty years of protound change.This year marks the 60th anniversary of the founding of the Xizang Autonomous Region.To mark this important historical milestone,this column presents frontline reports and observations by our journalists.
基金Supported by Tengfei Project of Third Affiliated Hospital of the Naval Medical University,No.TF2024TJYQ02.
文摘BACKGROUND Hemorrhage following pancreaticobiliary surgery is a high-risk complication,with a mortality rate of 16%-38%.At present,minimally invasive endovascular intervention comprising superselective arterial embolization(SAE)and covered stent implantation(CSI)is the treatment of choice.However,in certain cases,both SAE and CSI become infeasible.AIM To evaluate the effectiveness of coil-assisted N-butyl cyanoacrylate(NBCA)embolization in comparison with that of CSI in managing delayed hemorrhage after hepatobiliary–pancreatic surgery when SAE is infeasible.METHODS Ninety-eight continuous patients(n=105 cases;mean age,58.4 years)with delayed massive hemorrhage who were treated with coil-assisted NBCA embolization(NBCA group,n=45)and/or CSI(CSI group,n=60)were retrospectively evaluated between March 2014 and December 2023.Data on technical and clinical success,30-day mortality,and severe intervention-related adverse events were collected and analyzed.RESULTS The technical and clinical success rates in the NBCA group(100%and 93.3%,respectively)were significantly higher than those in the CSI group(88.3%and 73.3%,respectively),with a statistically significant difference between the two groups(P=0.019 and 0.010,respectively).The 30-day mortality rates and major intervention-related complications were 17.8%and 0%,respectively,in the NBCA group and 18.3%and 1.7%in the CSI group,respectively,with no statistically significant difference between the two groups.CONCLUSION In terms of technical and clinical success,coil-assisted NBCA embolization was more effective than CSI for managing delayed hemorrhage after hepatobiliary–pancreatic surgery when SAE was not feasible.
文摘The analysis of the ejaculate,better known as spermiogram,represents the first and main step to identify whether a series of sperm quality parameters are within the norm and therefore are consistent with normal sperm fertilizing capacity.Among these,sperm concentration and motility are the first parameters to be evaluated through an estimation carried out by expert examiners.
基金supported by the National Natural Science Foundation of China(No.51174116)the National Key Research and Development Program of China(No.2023YFC3010903)the Scientific Research Project of Education Department of Hunan Province,China(No.24A0319).
文摘The radon control mechanism of Na_(2)O·nSiO_(2)−CaCl_(2)modified soil was studied through the laboratory simulation experiment of tailing covering radon control.The radon exhalation rate(J)is negatively correlated with the coverage thickness(H),and it has a non-linear relationship with the temperature.The moisture content variation rate of the covering soil significantly decreases,which helps to reduce soil damage and enhance the resistance of the covering soil to ambient temperature interference.The formation of silicic gel and C−S−H gel effectively optimizes the pore structure and permeability,reduces the diffusion and migration of radon gas in the covering soil,and the average radon exhalation rate is decreased by 1.01×10^(−2)Bq/(m^(3)·s).The research results show that the Na_(2)O·nSiO_(2)−CaCl_(2)modified covering soil can effectively improve the radon control performance of the covering soil and reduce the cost of cover treatment.
基金Supported by Research Incubation Fund of Xi’an People’s Hospital(Xi’an Fourth Hospital)(No.FZ-58).
文摘AIM:To evaluate the surgical outcomes of the perfluorocarbon liquid(PFCL)-assisted inverted multilayer internal limiting membrane(ILM)flaps covering technique in macular hole retinal detachment(MHRD)in high myopia with axial length(AL)≥30 mm.METHODS:In this retrospective,interventional,consecutive comparative study,44 MHRD eyes were divided into two groups:the PFCL-assisted inverted multilayer ILM flaps covering technique group(Group 1,21 eyes)and the ILM peeling group(Group 2,23 eyes).The follow-up period was>12mo.Postoperative outcomes,including retinal reattachment,macular hole(MH)closure,and bestcorrected visual acuity(BCVA),were assessed.Statistical analysis using the Mann–Whitney U test and Fisher’s exact test was conducted to compare differences between groups.RESULTS:There were no statistically significant differences in baseline preoperative clinical characteristics,including age,sex,AL,diopters,duration of symptom,lens status,posterior staphyloma presence and extent of RD.Retinal reattachment rates were higher in Group 1(90.5%)than in Group 2(82.6%),without statistical significance(P=0.667).MH closure rates were significantly higher in Group 1(85.7%)than in Group 2(17.4%;P<0.001).The Group-1 BCVA(logMAR)improved significantly from 2.13±0.91 preoperatively to 1.21±0.66 postoperatively(P=0.026).The Group 2 BCVA improved significantly from 1.91±0.53 preoperatively to 1.19±0.41 postoperatively(P=0.032).However,there were no significant differences in visual-acuity improvement between groups(P=0.460).CONCLUSION:This technique offers a more effective approach for improving MH closure rates and postoperative visual function in MHRD with AL≥30 mm in high myopia.
基金funded by the Key Research and Development Project for Ecological Civilization Construction in Gansu Province(24YFFA010)the Gansu Province Major Science and Technology Project(22ZD6FA005)+2 种基金the Natural Science Foundation of Gansu Province(24JRRA091)the Shanxi Province Basic Research Program(Free Exploration Category)Youth Project(202403021212316)the Science and Technology Innovation Program for Universities in Shanxi Province(2024L327)。
文摘Understanding the impact of meteorological and topographical factors on snow cover fraction(SCF)is crucial for water resource management in the Qilian Mountains(QLM),China.However,there is still a lack of adequate quantitative analysis of the impact of these factors.This study investigated the spatiotemporal characteristics and trends of SCF in the QLM based on the cloud-removed Moderate Resolution Imaging Spectroradiometer(MODIS)SCF dataset during 2000-2021 and conducted a quantitative analysis of the drivers using a histogram-based gradient boosting regression tree(HGBRT)model.The results indicated that the monthly distribution of SCF exhibited a bimodal pattern.The SCF showed a pattern of higher values in the western regions and lower values in the eastern regions.Overall,the SCF showed a decreasing trend during 2000-2021.The decrease in SCF occurred at higher elevations,while an increase was observed at lower elevations.At the annual scale,the SCF showed a downward trend in the western regions affected by westerly(52.84%of the QLM).However,the opposite trend was observed in the eastern regions affected by monsoon(45.73%of the QLM).The SCF displayed broadly similar spatial patterns in autumn and winter,with a significant decrease in the western regions and a slight increase in the central and eastern regions.The effect of spring SCF on spring surface runoff was more pronounced than that of winter SCF.Furthermore,compared with meteorological factors,a variation of 46.53%in spring surface runoff can be attributed to changes in spring SCF.At the annual scale,temperature and relative humidity were the most important drivers of SCF change.An increase in temperature exceeding 0.04°C/a was observed to result in a decline in SCF,with a maximum decrease of 0.22%/a.An increase in relative humidity of more than 0.02%/a stabilized the rise in SCF(about 0.06%/a).The impacts of slope and aspect were found to be minimal.At the seasonal scale,the primary factors impacting SCF change varied.In spring,precipitation and wind speed emerged as the primary drivers.In autumn,precipitation and temperature were identified as the primary drivers.In winter,relative humidity and precipitation were the most important drivers.In contrast to the other seasons,slope exerted the strongest influence on SCF change in summer.This study facilitates a detailed quantitative description of SCF change in the QLM,enhancing the effectiveness of watershed water resource management and ecological conservation efforts in this region.
基金supported by the National Natural Science Foundation of China(72071064,72271074,72001004)the Anhui Provincial Natural Science Foundation(2408085QG221).
文摘Agile earth observation satellites(AEOSs)represent a new generation of satellites with three degrees of freedom(pitch,roll,and yaw);they possess a long visible time window(VTW)for ground targets and support imaging at any moment within the VTW.However,different observation times demonstrate different cloud cover distributions,which exhibit different effects on the AEOS observation.Previous studies ignored pitch angles,discretized VTWs,or fixed cloud cover for every VTW,which led to the loss of intermediate observation states,thus these studies are not suitable for AEOS scheduling considering cloud cover distribution.In this study,a relationship formula between the cloud cover and observation time is proposed to calculate the cloud cover for every observation time,and a relationship formula between the observation time and pitch angle is designed to calculate the pitch angle for every observation time in the VTW.A refined model including the pitch angle,roll angle,and cloud cover distribution is established,which can make the scheme closer to the actual application of AEOSs.A hybrid genetic simulated annealing(HGSA)algorithm for AEOS scheduling is proposed,which integrates the advantages of genetic and simulated annealing algorithms and can effectively avoid falling into a local optimal solution.The experiments are conducted to compare the proposed algorithm with the traditional algorithms,the results verify that the proposed model and algorithm are efficient and effective for AEOS scheduling considering cloud cover distribution.
