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1.
随着我国城市化进程的加快,城市热岛难显缓解之势,有关土地利用/覆盖类型、城市规模、城市形态对城市热岛的影响已有较多研究,尚缺少气候背景对我国城市昼夜地表热岛强度的影响研究。本文通过长时序的MODIS地表温度数据,从年均、季节和昼夜3个时间尺度,从全国、气候带、城市3个空间尺度探讨了我国347个城市昼夜地表热岛强度的空间分布特征以及时间变化规律。结果表明：① 昼夜差异：我国城市年均地表热岛强度白天（1.25±0.81 ℃）高于夜晚（0.79±0.43 ℃）;② 季节差异：昼夜地表热岛强度在不同季节表现不同,白天表现为夏季高,冬季弱,夜晚四个季节差异不大;③ 气候带差异：昼夜地表热岛强度分布呈现明显的空间分异。白天地表热岛强度表现为热带及亚热带地区高于温带及高原地区,其中南亚热带表现为最强,高原气候区最弱;夜晚则表现为温带高于亚热带、热带及高原地区,其中中温带最强,北亚热带最弱;④ 时空变化：白天地表热岛强度年际呈非显著下降趋势（|Z|<1.96）,而夜晚呈显著上升趋势（|Z|>1.96）;昼夜地表热岛强度年际变化存在季节差异,白天地表热岛强度夏季上升趋势显著高于其他季节,夜晚四个季节都呈显著上升趋势,其中冬季地表热岛强度上升趋势最大;白天呈显著上升趋势的城市主要分布在热带及南亚热带地区,夜晚呈显著上升趋势的城市广泛分布在中温带和暖温带。 相似文献
2.
本文以贵阳市为研究对象,研究了地表覆盖组分及植被多样性对地表温度的影响。首先基于Landsat8 OLI多时相影像数据在GEE平台上实现了研究区域地表覆盖精细分类;然后结合不同季节8天合成的MODIS温度产品数据,利用时空统计分析、相关分析等方法分析了研究区不同地表覆盖类型地表温度时空分布特征,地表温度与不同地表覆盖组分、地表覆盖多样性和植被覆盖多样性的相关性。结果表明：贵阳市建成区主要分布有常绿阔叶林、常绿针叶林等植被,常绿阔叶林在不同季节对地表温度的降温效应明显,而不透水面对地表温度具有明显的增温效应,尤其以夏季最为显著;地表覆盖多样性与地表温度之间具有较强相关性,其中植被覆盖多样性较植被覆盖率对地表温度的影响更为显著,而不透水面的增加会明显降低植被多样性的影响。因此,要发挥城市绿地对城市温度和热岛效应的调节作用,建议可以适当增加常绿阔叶林的绿化面积,同时在空间上要提升植被多样性水平,能够较大程度改善城市热环境。 相似文献
3.
本研究利用厦门市4个季节的Landsat-5 TM遥感影像和气象资料,反演地表净辐射通量,进而分析其季相变化特征;使用景观格局指数表征和描述地表覆盖的空间组成与配置,采用相关分析、偏相关分析、逐步回归和方差分解相结合的方法,从多季节角度研究地表覆盖格局对地表净辐射通量的影响。结果表明：① 厦门市地表净辐射通量平均值夏季最高,春季次之,秋季和冬季较低,地表净辐射通量在水体和林地区域较高,建设用地和裸地等其他地表覆盖类型区域较低;② 地表覆盖的空间配置对地表净辐射通量没有显著影响;③ 地表覆盖的空间组成对地表净辐射通量产生重要影响,全年内林地和裸地所占面积比例对地表净辐射通量的影响最显著,林地所占面积比例是影响和解释地表净辐射通量跨季节差异的最重要和持续有效的因素。该研究加深了关于地表覆盖格局对地表净辐射通量的影响的科学认知,有助于探索城市热岛的形成和演变机制,也可为城市规划和可持续发展提供理论依据和实践指导。 相似文献
4.
以杭州市为研究区,分析了杭州市2000-2010年生态系统服务变化及其空间分布特征.综合多种地理空间数据和属性数据,采用InVEST模型及基于地表热辐射的计算方法,对研究区碳储量、产水量以及区域气候调节3种生态系统服务进行定量评估;根据生态系统服务的城乡差异因素,将杭州市划分为城镇、郊区、乡村三级,运用GIS技术对生态系统服务的空间分布特征进行分析.研究结果表明:①与2000年相比,2010年杭州市碳储量总量小幅度增加了1492.49t,而产水量则减少了0.2×107m3,区域气候调节能力基本随着土地覆盖变化而变化;②2000—2010年,碳储量服务在城镇和郊区有增加的趋势,且平均值增加量超过5％,而水资源供给服务的总量在城镇、郊区、乡村三级里均呈减少趋势. 相似文献
5.
基于MODIS-NDVI的云南省植被覆盖度变化分析 总被引：2，自引：0，他引：2
植被覆盖变化监测是区域资源环境承载力研究的基础,本文通过计算2001-2016年MODIS-NDVI植被指数,辅以趋势分析、变异系数等方法,估算了2001-2016年云南省植被覆盖度,进而探讨了植被覆盖度的时空变化特征及与地形因子之间的分布关系。结果表明：① 2001-2016年云南省植被覆盖度呈显著增加趋势,增速为4.992%/10 a。② 在空间上,植被覆盖度空间格局呈现由南向北、由西向东逐渐降低的特征,滇西、滇西南地区植被覆盖度最高,滇西北地区最低;植被覆盖度稳定性表现为由西南向东北方向波动性越来越大;滇东北地区植被覆盖度增加趋势明显优于其他区域,研究区内植被覆盖度变化趋势为增加、基本稳定和减少趋势的面积分别占49.53%、43.76%和6.71%。③ 植被覆盖度在2001-2006年、2006-2011年、2011-2016年3个时段的面积转移矩阵结果均表现为植被覆盖进化面积大于退化面积,二者的比值分别为1.42、1.63、2.01,植被覆盖情况呈持续改善趋势。④ 云南省植被覆盖度与地形因子之间的关系表现为,平均植被覆盖度随海拔增加呈先增加再减少、再增加、再减少趋势;随坡度的增加呈先增加再减少趋势;随坡向的变化呈由北向南逐渐减少趋势。 相似文献
6.
利用GRACE卫星重力资料,计算尼泊尔地震震中及周缘重力和地表密度时空变化,并获取震源域特征点重力变化时间序列。结果表明,青藏高原内部、印度北部及华南块体东侧重力以增加为主,喜马拉雅与缅甸弧形带重力呈逐年减少趋势;尼泊尔地震发生在正负重力变化梯度带上,且重力变化在2015年具有明显的时间分段性特征,1~3月及地震发生的4月重力均以减小为主,5~9月以增加为主,12月以后以减小为主逐渐恢复;特征点时序揭示震源域重力呈长期减少趋势,并在2013~2016年呈现出“增加-减少-增加-发震-减小”的变化特征;地表密度变化较好地反映出地表质量迁移与重力变化的关系,为进一步理解尼泊尔地震的大陆动力学机制提供参考。 相似文献
7.
本文基于CG-LTDR土地覆盖数据产品,利用GIS空间统计等方法分析了中国1990-2010年土地覆盖的变化特点。与参考数据的比较检验表明,CG-LTDR土地覆盖数据在中国具有与其他同类数据相当甚至更高的分类精度。经逐年的长时间地表覆盖数据分析发现,由于受气候与人为因素影响,土地覆盖类型有明显的年际变化波动,尤其是云南-内蒙一线的干旱区与湿润区的过渡带。1990-2010年中国的林地和荒漠呈增加趋势,而草地和耕地呈减少趋势。利用5年的合成数据分析其年际变化,结果显示1990-2000年土地覆盖类型变化大,2000-2010年的变化较为平缓。在几种主要覆盖类型中,林地增加最明显,这主要与东南地区大部分耕地、西南和东北地区大面积草地转变为林地有关,但也有部分省份由于树木砍伐和农耕区扩张导致林地面积减小。耕地面积占比最高,其减少趋势主要与耕地变为林地和草地有关。南部的耕地减少最明显,北部略有增加,新增耕地的重心从东南向北转移。林地的增加趋势与耕地的减少趋势主要与全国大范围的退耕还林工程和生态保护政策有关。草地主要分布在生态脆弱区,其面积减少最显著,在西南及东北部分地区主要是草地变为林地,在内蒙中东部-陕西北部一线发生草地与耕地相互转换,而在内蒙北部-青藏高原一线有草地与荒漠的互相转换,在土地覆盖类型交错区,其利用类型容易发生改变。荒漠主要分布于西北地区,由于受到草地退化等因素影响,荒漠化趋势在进一步加剧。 相似文献
8.
本文基于2001-2013年MODIS NDVI多时序数据,采用像元二分模型估算了洞庭湖流域植被覆盖度,分析了区域近13年来植被覆盖度的变化特征及趋势,并结合同期气象数据,阐明了植被覆盖度变化对气候因素的响应。结果表明：（1）近13年洞庭湖流域植被覆盖度的整体变化较为稳定,呈微弱减少趋势,速率为-0.3%/10a。（2）洞庭湖流域绝大部分区域植被覆盖状况良好,植被覆盖度呈自西向东递减趋势,高植被覆盖度及中高植被覆盖度占整个流域面积的88.63%,水体或低植被覆盖度及中低植被覆盖度仅占2.57%。（3）洞庭湖流域植被覆盖度变化趋势为北部强于南部、东部强于西部。流域内植被覆盖度极显著与显著减少的面积比例为5.30%、增加面积的比例为4.29%,植被覆盖度变化不显著占90.40%。该区域植被覆盖度变化受人为因素影响更大。 相似文献
9.
基于RS与GIS的北京市热岛研究 总被引：12，自引：0，他引：12
基于普适性单通道算法,利用2005年5月6日的TM数据反演北京市区的实际地表温度。在此基础上,分析了北京市区的热环境特征、热岛分布的位置。运用GIS空间分析工具,分析了地表温度与地形特征和地表覆盖类型之间的关系。结果表明,北京市热岛分布具有环状和带状分布特征,高程较低处和坡度较小处更容易形成热岛中心,不同地表覆盖类型的热特征具有显著的差异。 相似文献
10.
北京市TM图像城市扩张与热环境演变分析 总被引：1，自引：0，他引：1
北京城市规模的扩大,对城市环境的影响越来越显著。本文利用3期TM数据对北京市城市扩展、植被变化及其环境影响进行了分析。首先对图像进行辐射归一化,然后分别提取城市用地扩展信息和植被变化信息。并利用普适性单通道算法反演了地表温度,分析了热环境的变化。结果表明,城市扩展区和热状况加重区具有很好的对应性,而植被增加区则对应着热状况减轻区和热状况基本未变化区。城市扩展和热状况加重具有相似的规律,都是从市中心向外围呈辐射状蔓延,与北京市的环状城市结构相符合。 相似文献
11.
It is crucial to conduct the land use/cover research to obtain the global change information.Urban area is one of the most sensitive areas in land use/cover change.Therefore land use/cover change in urban areas is very im-portant in global change.It is vital to incorporate the information of urban land use/cover change into the process of decision-making about urban area development.In this paper,a new urban change detection approach,urban dynamic monitoring based on objects,is introduced.This approach includes four steps:1)producing multi-scale objects from multi-temporal remotely sensed images with spectrum,texture and context information;2)extracting possible changed objects adopting object-oriented classification;3)obtaining shared objects as the basic units for urban change detection;4)determining the threshold to segment the changed objects from the possible changed objects using Otsu method.In this paper,the object-based approach was applied to detecting the urban expansion in Haidian District,Beijing,China with two Landsat Thematic Mapper(TM)data in 1997 and 2004.The results indicated that the overall accuracy was about 84.83%,and Kappa about 0.785.Compared with other conventional approaches,the object-based approach was advantageous in reducing the error accumulation of image classification of each datum and in independence to the radiometric correction and image registration accuracy. 相似文献
12.
IINTRODUCTION niques in China（ZHANG。t al，1999； CHEN et al，2000b）．Since the early 1990s，he acceleration of land With its abundant forest，land and water re－use／cover change（LUL乙）has spurred renewed con－sources，the area of the Nenjlang River valley Is one ofcerns about the role ofland use change Indrlvingmany the lmpoFtant lumber products and commodity grainenvironmental problems．Research on the causes and ba… 相似文献
13.
山西省土地覆盖时空变化特征及其驱动因子分析 总被引：1，自引：0，他引：1
以遥感与GIS为技术支撑,对山西省20世纪80年代到2005年的土地覆盖进行了动态监测,并分析了土地覆盖的变化特征及其驱动因子;监测表明,山西省土地覆盖时空变化特征:(1)变化数量:城镇建设用地和农村聚落面积增加显著,草地有所增加;旱地和水浇地减少明显,森林和河湖滩地略有减少。(2)变化速度:城镇建设用地增速迅猛,沼泽和农村聚落面积增速较快;河湖滩地减少速度最快,其次,是旱地和水浇地减少速度较快。(3)空间转换:以农田和聚落之间的转换为主,另外城镇建设用地的增加包括其扩展融入的农村聚落等;典型草地的增加主要来自旱地;灌丛减少主要是转变成典型草地,其次是转变成灌丛草地;河湖滩地减少主要是变为内陆水体,再是转变成水浇地。驱动力分析表明,区域自然因素相对稳定,对土地覆盖变化的影响较小,人口、经济、农业结构调整、政策和交通等是山西省土地覆盖变化的主要驱动力。山西省土地覆盖变化的总体特征与区域经济发展、产业布局及其工业化、城市化演变的特征基本一致。 相似文献
14.
土地利用/土地覆盖受人类活动和城市的快速扩张的影响发生了巨大的变化,这种变化对生态环境和地表景观的影响极大。土地利用/土地覆盖的变化过程既受自然、经济等多种因素的影响,也是人类活动规律和自然因素制约的外部表征。因此研究土地利用/土地覆盖的变化过程具有重要的意义。土地利用/覆盖变化的监测和分析,在传统的方法中侧重于分别对各个时空快照上土地利用结构的整体差异的研究,割裂了不同快照间土地利用单元在演化过程上的有机联系。本文以序列土地利用数据构成的土地变化过程为核心研究对象,在土地变化过程的最邻近时空距离度量的基础上,开展基于蒙特卡洛随机模拟的土地变化过程的时空聚集性度量,量化分析土地利用变化过程时空聚集模式的显著性。使用淮南市市辖区2008-2017年土地利用数据,选取典型的时空演化类型(任意2年间从"耕地"演变为"草地")进行实证研究,结果表明此类土地变化过程在过去10年呈现出时空聚集模式,但统计上并不显著。本文的研究有利于把握土地利用单元在时空上的演变过程,探查土地利用变化过程中潜在的时空演化模式。 相似文献
15.
Land use changes in Northeast China driven by human activities and climatic variation 总被引：5，自引：0，他引：5
Zongming Wang Zhiming Liu Kaishan Song Bai Zhang Sumei Zhang Dianwei Liu Chunying Ren Fei Yang 《中国地理科学(英文版)》2009,19(3):225-230
Human-induced land use/cover change (LUCC) forms an important component of global environmental change. Therefore, it is important
to study land use/cover and its change at local, regional and global scales. In this paper we conducted the study of land
use change in Northeast China, one of the most important agricultural zones of the nation. From 1986 to 2000, according to
the study results obtained from Landsat images, widespread changes in land use/cover took place in the study area. Grassland,
marsh, water body and woodland decreased by 9864, 3973, 1367 and 10,052km2, respectively. By comparison, paddy field, dry farmland, and built-up land expanded by 7339, 17193 and 700km2, respectively. Those changes bore an interactive relationship with the environment, especially climate change. On the one
hand, climate warming created a potential environment for grassland and marsh to be changed to farmland as more crops could
thrive in the warmer climate, and for dry farmland to paddy field. On the other hand, the changed surface cover modified the
local climate. Those changes, in turn, have adversely influenced the local environment by accelerating land degradation. In
terms of socio-economic driving forces, population augment, regional economic development, and national and provincial policies
were confirmed as main driving factors for land use change.
Foundation item: Under the auspices of the Knowledge Innovation Programs of Chinese Academy of Sciences (No. KZCX2-YW-341),
National Natural Science Foundation of China (No. 40871187, 40801208) 相似文献
16.
Land change is a cause and consequence of global environmental change.Land use and land cover have changed considerably due to increasing human activities and climate change,which has become the core issue of major international research projects.This study interprets land use and land cover status and the changes within the Koshi River Basin(KRB)using Landsat remote sensing(RS)image data,and employs logistic regression model to analyze the influence of natural and socioeconomic driving forces on major land cover changes.The results showed that the areas of built-up land,bare land and forest in KRB increased from 1990 to 2015,including the largest increases in forest and the highest growth rate in construction land.Areas of glacier,grassland,sparse vegetation,shrub land,cropland,and wetland all decreased over the study period.From the perspective of driving analysis,the role of human activities in land use and land cover change is significant than climate factors.Cropland expansion is the reclamation of cropland by farmers,mainly from early deforestation.However,labor force separation,geological disasters and drought are the main factors of cropland shrinkage.The increase of forest area in India and Nepal was attributed to the government’s forest protection policies,such as Nepal’s community forestry has achieved remarkable results.The expansion and contraction of grassland were both dominated by climatic factors.The probability of grassland expansion increases with temperature and precipitation,while the probability of grassland contraction decreases with temperature and precipitation. 相似文献
17.
Land cover change in different altitudes of Guizhou-Guangxi karst mountain area,China: patterns and drivers 总被引：1，自引：0，他引：1
Topography, especially altitude, will influence the way, process and characteristics of land cover changes in mountainous area, simultaneously, the vertical difference of land cover changes will affect soil quality and regional ecological environment. Therefore, the gradient relationship analysis between land cover changes and altitude is very important for regional sustainability. This study investigated land cover dynamics based on land cover data from a typical mountainous area in the Guizhou-Guangxi karst mountain area, China, in 2000 and 2010, then explored the relationship between altitude and land cover change and analyzed different drivers of land cover change at different altitudes. Our findings are as follows. 1) From 2000 to 2010, the total area of land cover transition was 7167.04 km~2 or 2.8% of the region. The increasing area of build-up land(926.23 km~2) was larger than that of forest(859.38 km~2), suggesting that the urban construction speed was higher than that of reforestation. 2) Intensity of land cover transition in northwestern Guizhou-Guangxi karst mountain area was much larger than that of southeast part and their transition trend was also significantly different, which was consistent with regional population and economy. 3) Human activity was the most dramatic at altitudes between 0–500 m. For 500–1000 m, grassland mainly converted to forest and build-up land. Area of land cover transition was the greatest between 1000–1500 m, while above 1500 m, the transition of grassland was the most obvious. 4) The drivers of land cover change varied. Land cover change was positively correlated with gross domestic product and population density but was inversely related to relief amplitude. There were correlations between land cover change and distance to roads and rivers, and their correlations varied with altitude. By revealing patterns and causes of land cover changes in different altitudes, we hope to understand the vertical dependence of land cover changes, so as to improve land productivity and protect land ecological environment scientifically. 相似文献
18.
近几十年来, 由气候变化和人类活动共同驱动的内蒙古地区土地利用/覆被变化(LUCC)较为剧烈, 其引发了一系列的生态环境问题。本文基于3 期LUCC数据, 借助于变化率指数、动态度指数、转类矩阵, 在全区和地级市尺度上, 分析了内蒙古地区土地利用/覆被变化的时空特征及驱动因素。研究结果显示, 受地形因素的影响, 研究区土地利用/覆被变化表现出明显的区域差异及区域趋同性。在经济发展和人口增长的双重压力下:(1)平原耕作区深受国家宏观政策的影响, 2000 年之后的“林地、高覆盖草地开垦”总体速度下降了近35%;(2) 平原耕作区北部边缘条带状地区、山区草原区受制于降水不显著的波动呈减少态势, 2000 年之后的“草地退化及荒漠化”趋势加强了近85%。研究结果为内蒙古地区土地资源的可持续利用与科学管理提供了依据。 相似文献
19.
Land cover is recognized as one of the fundamental terrestrial datasets required in land system change and other ecosystem related researches across the globe. The regional differentiation and spatial-temporal variation of land cover has significant impact on regional natural environment and socio-economic sustainable development. Under this context, we reconstructed the history land cover data in Siberia to provide a comparable datasets to the land cover datasets in China and abroad. In this paper, the European Space Agency(ESA) Global Land Cover Map(GlobCover), Landsat Thematic Mapper(TM), Enhanced Thematic Mapper(ETM), Multispectral Scanner(MSS) images, Google Earth images and other additional data were used to produce the land cover datasets in 1975 and 2010 in Siberia. Data evaluation show that the total user′s accuracy of land cover data in 2010 was 86.96%, which was higher than ESA GlobCover data in Siberia. The analysis on the land cover changes found that there were no big land cover changes in Siberia from 1975 to 2010 with only a few conversions between different natural forest types. The mainly changes are the conversion from deciduous needleleaf forest to deciduous broadleaf forest, deciduous needleleaf forest to mixed forest, savannas to deciduous needleleaf forest etc., indicating that the dominant driving factor of land cover changes in Siberia was natural element rather than human activities at some extent, which was very different from China. However, our purpose was not just to produce the land cover datasets at two time period or explore the driving factors of land cover changes in Siberia, we also paid attention on the significance and application of the datasets in various fields such as global climate change, geopolitics, cross-border cooperation and so on. 相似文献