A decline in snow cover area of Passu and Ghulkin valleys between 1995 and 2022

The global cryosphere is experiencing accelerated melting due to climate change.Currently,the Karakoram anomaly is under discussion with a debate about the possibility that the anomaly may have recently ended.This study aims to evaluate the up-to-date changes in snow cover in the western Karakoram region.We observed the snow cover changes in Passu and Ghulkin valleys in the Hunza River basin(HRB)of the Karakoram through multitemporal Landsat satellite data between 1995 and 2022.We found a significant reduction in snow cover in these valleys,with an average reduction rate of 0.42 km~2/yr,resulting in a total reduction of~11.46 km~2 between 1995 and 2022.This reduction in snow cover is consistent with the mass loss of glaciers in the Karakoram region in recent years.The decline in snow cover in these valleys is also consistent with the meteorological data.The temperature in summer(June)has significantly increased whereas the precipitation in the accumulation season(March)has decreased.These rapid changes suggest that it is crucially important to monitor the snow cover on a regular basis to support downstream management of snowmelt runoff.In addition,there is a need of planning for mitigation and adaptation strategies for snow-related hazards.

Temporal and Spatial Variation Characteristics of Snow Cover Area in the Pamirs from 2010 to 2020

Scientific and comprehensive monitoring of snow cover changes in the Pamirs is of great significance to the prevention of snow disasters around the Pamirs and the full utilization of water resources. Utilize the 2010-2020 snow cover product MOD10A2, Synthesis by maximum, The temporal and spatial variation characteristics of snow cover area in the Pamirs in the past 11 years have been obtained. Research indicates: In terms of interannual changes, the snow cover area of the Pamir Plateau from 2010 to 2020 generally showed a slight decrease trend. The average snow cover area in 2012 was the largest, reaching 54.167% of the total area. In 2014, the average snow cover area was the smallest, accounting for only 44.863% of the total area. In terms of annual changes, there are obvious changes with the change of seasons. The largest snow area is in March, and the smallest snow area is in August. In the past 11 years, the average snow cover area in spring and summer showed a slow decreasing trend, and there was almost no change in autumn and winter. In terms of space, the snow cover area of the Pamirs is significantly affected by altitude, and the high snow cover areas are mainly distributed in the Karakoram Mountains and other areas with an altitude greater than 5000 meters.

Soil and Vegetation Spectral Coupling Difference (SVSCD) for Minerals Extraction from Hyperion Data in Vegetation Covered Area

Remote sensing data have been widely applied to extract minerals in geologic exploration, however, in areas covered by vegetation, extracted mineral information has mostly been small targets bearing little information. In this paper, we present a new method for mineral extraction aimed at solving the difficulty of mineral identification in vegetation covered areas. The method selected six sets of spectral difference coupling between soil and plant(SVSCD). These sets have the same vegetation spectra reflectance and a maximum different reflectance of soil and mineral spectra from Hyperion image based on spectral reflectance characteristics of measured spectra. The central wavelengths of the six, selected band pairs were 2314 and 701 nm, 1699 and 721 nm, 1336 and 742 nm, 2203 and 681 nm, 2183 and 671 nm, and 2072 and 548 nm. Each data set's reflectance was used to calculate the difference value. After band difference calculation, vegetation information was suppressed and mineral abnormal information was enhanced compared to the scatter plot of original band. Six spectral difference couplings, after vegetation inhibition, were arranged in a new data set that requires two components that have the largest eigenvalue difference from principal component analysis(PCA). The spatial geometric structure features of PC1 and PC2 was used to identify altered minerals by spectral feature fitting(SFF). The collecting rocks from the 10 points that were selected in the concentration of mineral extraction were analyzed under a high-resolution microscope to identify metal minerals and nonmetallic minerals. Results indicated that the extracted minerals were well matched with the verified samples, especially with the sample 2, 4, 5 and 8. It demonstrated that the method can effectively detect altered minerals in vegetation covered area in Hyperion image.

Monitoring of Land-Cover Dynamic Change in Lancangjiang River Cascaded Hydropower Area

The analysis of the 3 stages＇ （1988,1996,2000） variation of land-cover is performed according to Thematic Mapper （TM） and Enhancement Thematic Mapper（ETM） satellite image by combining ground GIS database with GPS field collected data in the area of Xiaowan-Dachaoshan Reservoirs of Lancangjiang River cascaded Hydropower Area. Consequently, the land-cover is divided into five subclasses, namely water, paddy field and wetland, bare dryland and sparse shrub, secondary forest and density forest. The result showed that the areas of bare land, upland and secondary forest decreased in 1988-1996, whereas from 1996 to 2000, water body and density forest keep invariability while the areas of paddy field and wetland, bare dryland and sparse scrub increasing and the area of secondary forest decrease; Features of reciprocal transformation between density forest and other type of land-cover had two points, i.e. secondary forest, bare dryland and sparse shrub converted to density forest; and density forest converted to secondary forest and paddy field and wetland. It reflects the dynamic variation of density forest; the area which slope less than 8° and greater than 15° shows bigger variation, however, less change in 8°-15°.

Satellite monitoring of land-use and land-cover changes in northern Togo protected areas

Remote-sensing data for protected areas in northern Togo, obtained in three different years （2007, 2000, and 1987）, were used to assess and map changes in land cover and land use for this drought prone zone. The normalized difference vegetation index （NDVI） was applied to the images to map changes in vegetation. An unsupervised classification, followed by classes recoding, filtering, identifications, area computing and post-classification process were applied to the composite of the three years of NDVI images. Maximum likelihood classification was applied to the 2007 image （ETM＋2007） using a supervised classification process. Seven vegetation classes were defined from training data sets. The seven classes included the following biomes： riparian forest, dry forest, flooded vegetation, wooded savanna, fallows, parkland, and water. For these classes, the overall accuracy and the overall kappa statistic for the classi- fied map were 72.5% and 0.67, respectively. Data analyses indicated a great change in land resources; especially between 1987 and 2000 proba- bly due to the impact of democratization process social, economic, and political disorder from 1990. Wide-scale loss of vegetation occurred during this period. However, areas of vegetation clearing and regrowth were more visible between 2000 and 2007. The main source of confusion in the contingency matrix was due to heterogeneity within certain classes. It could also be due to spectral homogeneity among the classes. This research provides a baseline for future ecological landscape research and for the next management program in the area.

Preliminary Study on Dynamic Changes of Insect Communities in Airport Ground Cover Areas in Different Weather Conditions

[Objectives]This study was conducted to investigate insect activity rhythms in airport ground cover areas,and provide guidance for insect control and bird strike prevention.[Methods]The daily rhythm of insects in the northern area of the airport was studied,and their activity rhythms and characteristics under different weather conditions were analyzed.[Results]In rainy days,the insect number in the three sample areas was low.In cloudy days,insect activity was relatively stable,and insect number was consistent in the morning and evening,and maintained in a stable range,while in sunny weather,insect activity was increased,and the number changed greatly with time.For a single tussock plant growth area,the number of insects was at a relatively low level under rainy weather.In fine weather,the peak period of insect activity was between 10:00-11:00 and 14:00-15:00.[Conclusions]This study can provide a reference for the formulation of safe flight departure time.

The spatial-temporal changes of the land use/cover in the Dongting Lake area during the last decade

The research on the land use/cover change is one of the frontiers and the hot spots in the global change research. Based on the Chinese resource and environment spatial-temporal database, and using the Landsat TM and ETM data of 1990 and 2000 respectively, we analyzed the spatial-temporal characteristics of land use/cover changes in the Dongting Lake area during the last decade. The result shows that during the last ten years there were three land-use types that had changed remarkably. The cultivated land decreased by 0.57% of the total cultivated land. The built-up land and water area expanded, with an increase of 8.97% and 0.43% respectively. The conversion between land use types mostly happened among these three land-use types, especially frequently between cultivated land and water area. The land-use change speed of land-use type is different. Three cities experienced the greatest degree of land-use change among all the administrative districts, which means that the land use in these cities changed much quickly. The following changed area was the west and south of the Dongting Lake area. The slowest changed area is the north and east area.

Dynamic Analysis of Land Cover in Four-Lake Area of Jianghan Plain Based on MODIS-EVI Time Series Data

According to the time series data of Enhanced Vegetation Index (EVI) in Four-Lake Area of Jianghan Plain during the period 2001-2007, we use Harmonic Analysis of Time Series (HANTS) to conduct cloud removing processing, and calculate the sum of square N of time series value of each pixel. The pixels with N>0.25 are classified as vegetation coverage area; the pixels with N<0.25 are classified as non-vegetation coverage area. As to vegetation coverage area, we use the second-order difference method to judge the frequency of peak value of EVI time series data. Within one year, the vegetation coverage area with peak value happening 1 time is woodland and grassland; the vegetation coverage area with peak value happening 2 times is arable land; the vegetation coverage area with peak value happening 3 times or more is vegetable land. Supervised classification method is used to identify cities, towns, water area in non-vegetation coverage area and woodland, grassland in vegetation coverage area. We draw the land cover classification diagram of Four-Lake Area in the period 2001-2007. In comparison with the land cover classification based on multitemporal ETM data in 2001, the difference of area of arable land is within 10%. Using MODIS-EVI data, we can rapidly and efficiently conduct land cover classification with low cost. The dynamic analysis results indicate that the area of arable land is in the process of declining, while the area of other cover types shows an increasing trend.

Analysis on Change of the Vegetation Cover in Poyang Lake Area from 1991 to 2005

[Objective] The reseamh aimed to analyze variation of the vegetation cover in Poyang Lake area from 1991 to 2005. [Method] Based on Landsat TM remote sensing images of 1991 and 2005 in Poyang Lake area, NDVI dimidiate pixel model was used to calculate vegetation cover- age. By transfer matrix, temporal-spatial change of the vegetation cover grade in the area was analyzed. [ Result] Vegetation cover in this region overall presented increase trend from 1991 to 2005, and forestry area increased somewhat. But at the same time, farmland area decreased to some extent. Sandlot and bare land also increased slightly. [ Conclusion] Governments and relevant departments should reasonably allocate land re- sources and protect natural ecology environment.

Examining Rate of Built-Up Areas on the Vegetation Cover along River Riara Riparian within Kiambu Town, Kenya

Urban river riparian spaces and their natural systems are valuable to urban dwellers;but are increasingly affected and ruined by human activities and in particular, urbanization processes. In this research, land sat and sentinel satellite imagery apt for change detection in vegetation cover, both landsat and sentinel imagery, covering the period between 1970 and 2021 in epochs of 1973, 1984, 1993, 2003, 2015 and 2021 years were used to establish the correlation between vegetation cover and built-up area along River Riara river reserve. The images were analysed to extract the built-up areas along the river reserve, including the buildings, and the rate of human settlements, which influenced vegetation cover. Normalized Difference Built-Up Index (NDBI) and Normalized Difference Vegetation Index (NDVI) were computed using the Short-Wave Infrared (SWIR) and the Near Infra-Red (NIR) bands to show the rate of change over the years. Results indicate NDVI values were high, compared to NDBI values along river Riara in the years 1973 and 1993 implying that there was more vegetation cover then. However, in the year 2021, the NDVI indicated the highest value at 0.88, with the complementary NDBI indicating the highest NDBI value at 0.47. This represents a significant increase in built-up areas since 2015 more than in previous epochs. Either, there was a significant increase in NDBI values, from 0.24 in 1993 to 0.47 in 2021. More so, the R-squared value at 0.80 informed 80% relationship between NDBI and NDVI values indicating a negative correlation.

血管通路顽固性狭窄病变递进处置策略及临床分析

目的对于动静脉内瘘顽固性狭窄病变,采取递进处置策略进行干预治疗,分析该方案治疗的预后,旨在探讨更为有效合理的动静脉内瘘维护手段。方法回顾性分析2020年6月—2021年6月在南京医科大学第二附属医院血液净化中心因高位自体动静脉内瘘(autologous arteriovenous fistula,AVF)头静脉弓狭窄和人工血管动静脉内瘘(arteriovenous graft,AVG)静脉吻合口区域狭窄首次行超声引导经皮腔内血管成形术(percutaneous transluminal angioplasty,PTA)治疗,并采取递进处置策略维护的患者,随访24个月观察内瘘的通畅和再干预情况,另与南京医科大学第二附属医院血液净化中心同类病变单纯以高压球囊维护的随访数据比较得出结论。结果高位AVF头静脉弓狭窄采取递进处置策略维护的患者31例,单纯以高压球囊扩张规律维护的患者16例,随访24个月,两者在再干预次数(t=4.461,P<0.001)、再干预后平均通畅时间(t=3.550,P<0.001)及PTA辅助通畅率(χ^(2)=5.562,P=0.021)方面比较差异有统计学意义;AVG静脉吻合口区域狭窄采取递进处置策略维护的患者68例,单纯以高压球囊扩张规律维护的患者58例,随访24个月,两者在再干预次数(t=5.094,P<0.001)及再干预后平均通畅时间(t=3.251,P=0.002)方面比较差异有统计学意义。结论采取递进处置策略,循序渐进地使用各种介入治疗器械以及手术方案处置动静脉内瘘顽固性狭窄病变可以提高PTA的通畅性,减少干预频次,改善预后。

济南南部山区土地利用/覆被变化对碳储量的影响研究

以黄河下游生态脆弱区-济南南部山区为研究对象,基于区域1980~2020年6期土地利用/覆被数据,结合InVEST模型(Integrated Valuation of Ecosystem Services and Trade-offs model),分析区域土地利用/覆被和碳储量的时空分布特征和动态变化规律,研究土地利用/覆被变化对陆地生态系统碳储量的影响.结果表明,土地利用/覆被变化对碳储量的影响较为显著,1980~2005年土地利用变化较小,人类活动影响较小,由于林草地碳储量的累积,碳储量增长速度明显高于其他时期;2005~2010年城市扩张速度最快,城乡建设用地大量侵占耕地、林地和草地,使区域固碳能力明显下降;2010~2020年,由于城市化扩张限制以及植树造林等生态保护措施的实施,区域碳储量逐渐呈增长趋势;1980~2020年济南南部山区的总碳储量呈“增长-下降-增长”的趋势;并且林地是济南南部山区碳储量的主要供给者,区域碳储量值随着远离城乡居民生活中心的距离增大而增大,说明人类活动对区域碳储量有重要的影响.另外,土地利用类型的转移引起地类碳密度的变化,是区域碳储量变化的主要影响因素,土地利用类型的碳储量变化与各地类的面积变化有一定的关系.该成果可为生态脆弱区塑造良好的陆地碳汇格局提供理论依据.

基于MOD10A1 V6产品下青海省各片区积雪的分布气候特征

利用MOD10A1 V6版积雪产品获取青海省及省内各重要生态功能区的积雪信息,并对积雪变化与气候因子间的响应关系进行分析。结果表明:(1)16年来青海省内积雪覆盖面积变化存在空间差异性,可可西里积雪覆盖面积显著增加(p<0.05)而其他生态功能区变化不显著,从阶段变化来看青海省及各生态功能区在2016积雪季后积雪覆盖面积大幅增加,而在2016积雪季前仅柴达木盆地积雪覆盖面积显著减少(p<0.05),其余地区减少趋势不显著。(2)16年来青海省内积雪日数变化存在空间差异性,可可西里内26.8%的面积积雪日数显著增加(p<0.05),而三江源腹部、柴达木盆地东部和祁连山地区西部积雪日数显著减少(p<0.05)。(3)近16年来青海省及各生态功能区积雪覆盖面积与降水显著正相关(r>0.65,p<0.01),与气温显著负相关(r>0.5,p<0.05),其中在青海省、祁连山、可可西里和柴达木盆地的积雪覆盖面积变化主要受降水主导,而三江源和青海湖流域则是由气温和降水共同影响。

砒砂岩覆土区典型小流域土壤可蚀性K值空间变异特征

[目的]研究砒砂岩覆土区典型小流域土壤可蚀性的空间变异特征,为砒砂岩覆土区土壤侵蚀机理深入探究和土壤侵蚀有效防治提供科学依据。[方法]以内蒙古准格尔旗砒砂岩覆土区二老虎沟小流域为研究对象,采集0—10 cm和10—20 cm土层共144份土壤样品,基于EPIC模型估算土壤可蚀性K值,并利用GIS和地统计学方法分析土壤可蚀性K值空间变异特征。[结果](1)二老虎沟小流域土壤砂粒、粉粒、黏粒和有机碳均呈中等变异程度,除黏粒和有机碳为中等空间自相关性外,其他土壤属性均呈弱空间自相关性。(2)小流域土壤可蚀性K值介于0.018 7~0.047 6 t·hm^(2)·h/(hm^(2)·MJ·mm),0—10 cm和10—20 cm土层K值变异系数分别为15.5%和20.3%,属中等变异强度;0—10 cm土层K值主要受随机性因素影响,呈弱空间自相关性,而10—20 cm土层受随机性因素和结构性因素共同影响,为中等空间自相关性。(3) 3种克里格插值方法结果表明:小流域土壤可蚀性K值空间变异受海拔和坡度影响明显,其总体分布趋势为西部和东南部较高、中部及偏东部较低;普通克里格插值方法较适宜应用于砒砂岩覆土区小流域,其估算结果可较好地显示土壤可蚀性的整体和局部两方面的空间变异特征。(4)在垂直空间变异上,0—10 cm和10—20 cm土层土壤可蚀性K值总体分布规律相似,但10—20 cm土层土壤可蚀性K值较0—10 cm土层空间变异更为明显。[结论]海拔和坡度对砒砂岩覆土区典型小流域土壤可蚀性K值空间变异影响明显,未来应优先对坡面和坡顶区域进行土壤侵蚀防治。

基于多智能体强化学习的防空编队部署方法

针对防空编队智能部署方法无法同时兼顾区域掩护和目标掩护、人为制定复杂规则难以求解、算法执行效率较低的问题,提出一种基于独立多智能体近端策略优化(IN-MAPPO)的防空编队部署方法。设计独立的行动者-评论家网络,以适应火力单元的不同角色,通过集中式价值函数和奖励函数促进火力单元协同合作完成混合部署任务,提高编队的抗击能力和整体部署性能。实验结果表明:IN-MAPPO方法能够依据智能体的角色完成混合部署任务,提高远程火力单元的抗击能力,比其他MAPPO算法减少了13.7%的训练时间;与现有智能算法相比,火力单元覆盖面积提升了4.2%,有效掩护宽度提升了12.3%,算法的执行效率提高了95.9%。

低覆盖草地叶面积指数遥感估算方法

有效估算低覆盖草地叶面积指数(LAI),对监测低覆盖草地生长状况、优化完善草地管理具有重要意义。以往针对草地叶面积指数的研究大多集中于中高覆盖度草地,对低覆盖草地的研究相对较少。利用谷歌地球引擎(GEE),基于Landsat-8卫星数据提取所需特征变量,通过特征变量与叶面积指数的相关性及其在模型中的重要性进行特征优选,确定模型最佳变量个数,以此构建机器学习模型,探寻适合在低覆盖区草地估算叶面积指数的方法。结果显示,基于相关性特征优选的梯度提升回归树模型(r-GBRT)在低覆盖草地估算叶面积指数的效果较好,测试集的R 2为0.686,均方根误差(RMSE)为0.101。结果表明,基于特征优选构建的机器学习模型在低覆盖条件下估算草地叶面积指数方面具有较好的应用价值。

青海省茫崖市马海地区钾矿绿色勘查措施

青海省实施大量的盐湖钻探施工项目,要求实施绿色勘查。本文以青海省茫崖市马海地区钾矿勘查9号孔为例,根据现场实际施工情况,结合矿区矿区自然生态概况,合理规划了生活区和施工区的平面布置,分析了造成环境扰动的主要因素有项目临时道路修筑、车辆行驶、项目驻地建设、钻探工程施工等方面,同时制定了对应的绿色勘查措施。可为提高地质钻探从业者的绿色施工的意识、形成绿色勘查习惯,以及其他单位在风成砂覆盖区开展地质钻探施工时提供了可复制、可参考的绿色勘查经验。

覆盖区矿产调查钻探查证技术方法研究

覆盖区矿产勘查是新一轮找矿突破战略行动的重要内容之一.采用更加绿色和有效的钻探技术,快速获取隐伏基岩信息与样品,是覆盖区找矿亟待总结和推广的工作.本研究基于绿色勘查理念,采用便携式浅层钻探装备与技术,以及空气反循环钻进工艺,在大兴安岭东南缘宝山浅覆盖区铜多金属矿勘查中开展钻探试验,实现了快速穿透覆盖层获取隐伏基岩信息、查证物探异常并采集地球化学样品的效果,同步结合孔内成像等技术,为填制覆盖区隐伏岩石地层单元分布范围和界线等提供了基础资料.试验结果表明,基于浅层绿色钻探技术,结合孔内成像,并为野外地球化学快速分析提供测试样品的多方法组合,可以有效解决浅覆盖区找矿难题,在矿产勘查过程中具有很好的推广价值.

荒漠浅覆盖区萤石矿定位预测技术研究

北山地区是中国西北部重要的萤石成矿带,区内成矿地质条件优越,但地处戈壁荒漠,受浅覆盖层影响,地表仅可观察到极少量露头,需开展综合地球物理研究为区域成矿潜力及覆盖区下方矿脉赋存空间进行定位预测研究。以北山成矿带东段花石头山地区为示范,采用高精度磁法、激电中梯、地面伽马能谱测量、便携式X射线荧光分析及音频大地电磁测深等技术手段进行综合探测,其中面积性激电和磁法工作可有效识别隐伏赋矿空间分布,地面伽马能谱测量、便携式X射线荧光分析约束赋矿空间的矿化异常,音频大地电磁测深构建了隐伏萤石矿赋存位置深部结构模型,并通过工程验证方法组合的有效性。本研究建立了综合地质-地球物理定位预测技术方法组合,可为北山成矿带及戈壁荒漠浅覆盖区萤石矿定位预测提供理论和技术支持。