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1.
Spatial variation of altitudinal belts as dividing index between warm temperate and subtropical zones in the Qinling-Daba Mountains 总被引：1，自引：0，他引：1
To determine the dividing index between warm temperate and subtropical zones based on the spectra of altitudinal belts,this paper collected 33 spectra of altitudinal belts in the Qinling-Daba Mountains from published literatures and then analyzed the structures and the spatial patterns from south to north,from west to east and based on exposure directions.The results show that:1)From south to north,the basal belt gradually changes from subtropical evergreen broadleaf forest to warm temperate deciduous broadleaf forest;the spectra of altitudinal belts change from complex to simple;the dominant belt changes from montane broadleaf-conifer mixed forest and evergreen-deciduous broadleaf mixed forest to deciduous broadleaf forest.2)From west to east,the structures of the altitudinal belt spectra show complexity in the east and west but simplicity in the middle section;the upper limits of both the evergreen-deciduous broadleaf mixed forest belt and montane deciduous broadleaf forest belt present a quadratic curve distribution pattern in the longitudinal direction.However,the upper limit of the montane broadleaf-conifer mixed forest belt exhibits a nearly linear decrease in the west-east direction.3)Both the north and south slopes in the Qinling Mountains have the similar basal belt,whereas it varies greatly between the north and south slopes in the Daba Mountains.Comparably,dominant belts are very similar in the Qinling Mountains and the north slope of the Daba Mountains,but the south slope of the Daba Mountains has its own unique dominant belt:evergreen-deciduous broadleaf mixed forest.This implies that the Daba Mountains are more appropriate than the Qinling Mountains to act as the boundary between subtropical and warm-temperate zones in central China. 相似文献
2.
《Norsk geografisk tidsskrift. Norwegian journal of geography》2012,66(1):97-98
Ouren, T. 1974. Distribution maps for plants in three dimensions. Norsk geogr. Tidsskr. 28, 97–102. A grid map with a ‘level scale’ in the middle of each square is used to indicate the vertical distribution of plants in addition to the horizontal pattern. As an example of the method is shown the three dimensional distribution of the bog myrtle (Myrica gale L.) in a part of Norway. 相似文献
3.
南岭山地地域分界性的地理探测 总被引：1，自引：0，他引：1
利用地理探测器模型,选取气温、降水、植被及土壤类型指标,从空间分层异质性的角度对南岭山地的地域分界性进行定量探测识别。结果表明：1）南岭山地具有显著的地域分界性,q值最高达到0.99,岭南与岭北2个子区域的层内方差之和（SSW）远小于全区总方差（SST）,南岭山地两侧区域空间分异性显著。2）南岭山地地域分界性具体主要体现在气温方面,其中最冷月均温、最低多年平均日最低温、日均温≥10℃积温、日均温≥10℃天数、年均温5项指标对南岭山地地域分界性贡献度最大;植被类型、土壤类型及降水指标对南岭山地地域分界性的贡献度不及气温指标,且贡献度依次减小。3）南岭山地地域分界性具有明显的季节差异,在气温方面于春、秋、冬季显著,而夏季明显减弱;在降水方面季节波动明显,且于夏、秋2季显著,并在11月达到峰值。 相似文献
4.
5.
David Alexander 《The Professional geographer》2000,52(3):553-566
Pasta is as much an institution as a food in Italy, where it has made a significant contribution to national culture. Its historical geography is one of strong regional variations based on climate, social factors, and diffusion patterns. These are considered herein; a taxonomy of pasta types is presented and illustrated in a series of maps that show regional variations. The classification scheme divides pasta into eight classes based on morphology and, where appropriate, filling. These include the spaghetti and tubular families, pasta shells, ribbon forms, short pasta, very small or “micropasta” types, the ravioli family of filled pasta, and the dumpling family, which includes gnocchi. Three patterns of diffusion of pasta types are identified: by sea, usually from the Mezzogiorno and Sicily, locally through adjacent regions, and outwards from the main centers of adoption. Many dry pasta forms are native to the south and center of Italy, while filled pasta of the ravioli family predominates north of the Apennines. Changes in the geography of pasta are reviewed and analyzed in terms of the modern duality of culture and commercialism. 相似文献
6.
《The Professional geographer》2013,65(3):553-566
Pasta is as much an institution as a food in Italy, where it has made a significant contribution to national culture. Its historical geography is one of strong regional variations based on climate, social factors, and diffusion patterns. These are considered herein; a taxonomy of pasta types is presented and illustrated in a series of maps that show regional variations. The classification scheme divides pasta into eight classes based on morphology and, where appropriate, filling. These include the spaghetti and tubular families, pasta shells, ribbon forms, short pasta, very small or “micropasta” types, the ravioli family of filled pasta, and the dumpling family, which includes gnocchi. Three patterns of diffusion of pasta types are identified: by sea, usually from the Mezzogiorno and Sicily, locally through adjacent regions, and outwards from the main centers of adoption. Many dry pasta forms are native to the south and center of Italy, while filled pasta of the ravioli family predominates north of the Apennines. Changes in the geography of pasta are reviewed and analyzed in terms of the modern duality of culture and commercialism. 相似文献
7.
Luo Jinfa Xia Zenglu 《地理学报(英文版)》1996,(2)
1CriticalconcentrationofpollutedheaVyn1etalsish1eallowableconcel1trationofheavymetalsinsoilsItisnotonIythecriticalindexofvanousbiologicalandenvironmentalehaofmetalelementsinsoils,blltalsothebasisforworkingoutti1estandardofsoilenvirorunatalquality,anddefilungthesoilenvironn1entalconcentration.Attentionwasthuspaidtoenvironmotalconservationathomeandabroad.Althoughtherearen1anyrePorts[2-4]oneffeCtsofsinglesoilpollutant,yCttherearefewrePoftsoncompansonsofn1etalelema1tcnticalconcatrationinsoilsofd… 相似文献
8.
This paper presents the results of morphotectonic and morphometric research carried out in order to determine the neotectonic development of the volcanic mountains and a drainage network in SW Cappadocia. The study area extends among the Aksaray, Ni?de, and Nev?ehir Provinces. The study area comprises Hasanda?, Melendiz, Keçiboyduran, Göllüda? Mountains and the adjacent parts of these volcanic mountains.Data collected exclusively from 1:25,000 digitised topographic maps and 10 m-resolution DEMs were used to define parameters related to the longitudinal profile of streams. The study area was divided into 10 volcanic units. Longitudinal profiles of 20 streams and stream orders were analysed to determine a regional tectonic differentiation pattern in these units. The streams in the study area drain into four different tectonic depressions. These depressions are Aksaray plain controlled by the Tuz Gölü fault (TGF), Çiftlik plain controlled by the Keçiboyduran–Melendiz fault (KMF), Misli plain controlled by the Derinkuyu fault (DF), and Bor plain controlled by the Ni?de Fault Zone (NFZ). An analysis of morphometric parameters shows that the development of a drainage network is associated with faults and rock resistance. Occurrence of morphometric parameters with different values in units reveals that the volcanic mountains were not uplifted in the same period and were subjected to different morphologic processes. High total order number in the south of Hasanda? (unit 3) and Melendiz Mountains (unit 7) indicate that the uplift ratio of the southern part is much greater than that of the northern part. Moreover, development of the drainage network in the south is in a more advanced phase than in the north. Indeed, the drainage network in the north is in the youngest erosional phase of all parts of the study area. The increased stream length-gradient indices (SL), and stream gradients and an analysis of headward erosion show that the streams displaying the longest and highest reach of the erosional phase are all in the southern part of Keçiboyduran and Melendiz Mountains. The longitudinal profile (Lp) of the present thalweg of the streams is irregular. The irregular Lp are associated with four different causes. These are geological variations in resistance, tectonics, and volcanic topography and downcutting in response to stream incision. The beginning of the fluvial incision in the northern part is younger than in the south. 相似文献
9.
编制南北过渡带地区1∶25万和典型山地1∶5万植被类型图是南北过渡带综合科学考察的主要任务之一。以往植被类型图的编制都是采用大量的地面调查来完成的,地面调查方法虽然精确,但费时费力,并且由于自然条件的限制,地面调查往往只能覆盖较小的范围。遥感数据因为其全覆盖的优势,可以很好地弥补样方调查的局限性,但目前大范围的植被类型遥感信息提取尤其是自动提取方面仍然存在一定的困难和瓶颈。本文以1∶5万太白山植被类型图的编制为例,利用多源多时相的高分辨率遥感数据,结合地面调查数据、以往的各种比例尺的植被类型图数据和森林资源调查数据等,探讨并研究基于山地垂直带谱的中大比例尺植被类型图的遥感提取方法和制图方法。研究结果表明：① 山地植被垂直带谱可以有效地支持1∶5万山区植被类型图的遥感制图。利用太白山植被垂直带谱和1∶1万数字表面模型数据（DSM）可以生成具有垂直带谱信息的地形约束因子;将地形约束因子与多源多时相高分辨率遥感数据、地面调查数据、以往的小比例尺植被类型图数据等相结合,可以有效提取各级植被类型,从而实现中大比例尺植被类型图的编制。② 典型山地1∶5万植被类型图的遥感制图基本流程为植被型组解译→植被群系组、群系、亚群系解译→植被型、植被亚型分类,采取自上而下和自下而上相结合的分类方法来分类。本文的研究成果可以为中大比例尺植被类型图的编制提供示范和科学依据。 相似文献
10.
《Polar Science》2014,8(1):10-23
This study compares the common harmonic constants of the O1, K1, P1, Q1, M2, S2, N2, and K2 tidal constituents from eight global and four regional tide models with harmonic constants from satellite altimeter and tide gauge data for the northern region of the Antarctic Peninsula (58°S–66°S, 53°W–66°W). To obtain a more representative comparison, the study area was divided into three zones with different physical characteristics but similar maximum tidal amplitude variations: Zone I (north of 62°S), Zone II (south of 62°S and west of the Antarctic Peninsula), and Zone III (between 62°S and 64.3°S, and east of 58.5°W). Root sum square (RSS) values are less than or equal to 3.0, 4.2, and 8.4 cm for zones I, II, and III, respectively. No single model shows superior performance in all zones. Because there are insufficient satellite altimetry observations in the vicinity of Matienzo Base (64.9761°S, 60.0683°W), this station was analyzed separately and presents the greatest values of both root mean square misfit and RSS. The maximum, minimum, and average amplitude values of the constituents that follow in importance after the eight common tidal constituents, and which have amplitudes greater than 1 cm, are also analyzed. 相似文献
11.
中国地形起伏度及其与人口分布的相关性 总被引：68，自引：15，他引：53
基于人居环境自然评价的需要, 运用GIS 技术, 采用窗口分析等方法, 提取了基于栅 格尺度(10 km×10 km) 的中国地形起伏度, 并从比例结构、空间分布和高度特征3 个方面系 统分析了中国地形起伏度的分布规律及其与人口分布的相关性。研究表明: 中国的地形起伏度以低值为主, 63%的区域低于1 (相对高差≤500 m); 空间分布呈现西高东低、南高北低的格局; 随着经度和纬度增高, 地形起伏度呈逐渐下降趋势, 28oN、35oN、42oN 纬线和85oE、102oE、115oE 经线上的地形起伏度符合中国三大阶梯的地貌特征; 随着海拔高度增加, 地形 起伏度呈现逐渐升高趋势。实证分析表明: 中国的地形起伏度与人口密度有较好的对数拟合关系, 拟合度高达0.91; 全国85%以上的人口居住在地形起伏度小于1 的地区, 在地形起伏度大于3 的地区居住的人口总数只占全国0.57%。中国地形起伏度与人口分布的相关性区域差异显著, 东北、华北、华中和华南等地相关性显著, 内蒙古与青藏地区几乎不存在相关性。 相似文献
12.
13.
As a contribution to understanding the morphogenesis of the Australian continental dunefield, maps are presented of the main types of dunes, their orientation and mean spacing using the best available sources of data. Major features on previous maps of the Australian dunefield are verified and new information has been obtained. The anticlockwise whorl of dunes has been found to close on both its eastern and western ends. Dunes extend as far north as 16°S and over large parts of the far south‐west of Western Australia. Distributions of dune types are related to former vegetation cover, climate, supply of sand and directional variability of formative winds. Previously documented relationships between dune spacing, height, equivalent sand thickness (EST) and the texture of surfaces over which sand is transported are used to partially explain the map of mean dune spacings. The spatial distribution of EST, and mineralogic and sedimentologic evidence show that aeolian sediment in the Australian dunefield has travelled only short distances. 相似文献
14.
东亚土地覆盖动态与季风气候年际变化的关系 总被引：7，自引：1，他引：7
以东亚地区1982－1989年时间序列降水资料及AVHRR 8km NDVI数据为基本数据源，应用地理信息系统技术，分别研究了东亚地区夏季（5－9月）降水及土地覆盖的年际变化，并揭示了研究时间段内各自的变化规律。进一步用奇异值分解（SVD）模型方法分析了以降水变化为表征的东亚地区气候年际变化与土地覆盖年际变化之间的关系。 相似文献
15.
As the improvement of international status and the implementation of China’s neighboring diplomacy, the development of border regions and the security of border cities, as well as their spatial structure and regional differences are gaining more attention from academic circle. Based on the interdisciplinary perspectives of urban geography, regional economics and geopolitics, this paper explores the regional differences of border geo-cities in China and the surrounding countries with the help of remote sensing information acquisition and ArcGIS spatial analysis. Three primary results are found as follows: (1) The border geo-cities in China and surrounding countries are divided into five geographical regions: geo-cities in South China Sea, geo-cities in Southeast Asia, geo-cities in South Asia, geo-cities in Central Asia and geo-cities in Northeast Asia. (2) In the spatial structure system of China’s border geo-cities, the importance of geo-cities in five major regions is fairly different. In terms of the security and economic development, the rank of priority is geo-cities in North-east Asia, geo-cities in South China Sea, geo-cities in Central Asia, geo-cities in South Asia, geo-cities in Southeast Asia. (3) Considering China’s geo-setting for the development of border geo-cities, the east region is significantly better than the west, and the north region is slightly better than the south. 相似文献
16.
The North Sea Basin contains an almost complete record of Cenozoic sedimentation, separated by clear regional unconformities. The changes in sediment characteristics, rate and source, and expression of the unconformities reflect the tectonic, eustatic and climatic changes that the North Sea and its margins have undergone. While the North Sea has been mapped locally, we present the first regional mapping of the Cenozoic sedimentary strata. Our study provides a new regional sub‐division of the main seismic units in the North Sea together with maps of depocentres, influx direction and source areas. Our study provides a regional synthesis of sedimentation based on a comprehensive interpretation of a regionally covering reflection seismic data set. We relate observations of sediment characteristics and unconformities to the geological evolution. The timing, regional expression and stratigraphic characteristics of many unconformities indicate that they were generated by eustatic sea‐level fall, often in conjunction with other processes. Early Cenozoic unconformities, however, relate to tectonism associated with the opening of the North Atlantic. From observation on a regional scale, we infer that the sediment influx into the North Sea during the Cenozoic is more complex than previously suggested clockwise rotation from early northwestern to late southern sources. The Shetland Platform supplied sediment continuously, although at varying rates, until the latest Cenozoic. Sedimentation around Norway changed from early Cenozoic influx from the southwestern margin, to almost exclusively from the southern margin in the Oligocene and from all of southern Norway in the latest Cenozoic. Thick Eocene deposits in the Central Graben are sourced mainly from a western and a likely southern source, indicating that prominent influx from the south did not only occur from the mid‐Miocene onwards. We infer a new age for the increased progradational sediment influx in the Pleistocene of 2.5 Ma, coeval with Fennoscandian glaciation. 相似文献
17.
Spatial and temporal distribution of diatoms in sediments of Lake Malawi,Central Africa,and ecological implications 总被引：2，自引：0，他引：2
Lake Malawi lies in a major rift valley in Central Africa that is some 700 m deep and 550 km long. A total of 242 cores and 111 grab samples were recovered between 1984 and 1989 and form the data base for a study of diatom distribution in this lake basin. The sediments consist of homogeneous diatomites, pelagic diatomaceous muds, varved diatomite-mud couplets, turbidites, littoral sand sheets and extensive deposits of ferro-manganous nodules.Fossil diatoms show major temporal and regional contrasts between the southern, central and northern areas of the lake. A wide variety of Aulacoseira species occur in the southern lake sediments. To the north, the Nkhotakota region is generally characterised by Stephanodiscus and Aulacoseira, with occasional diatomite laminae composed of Aulacoseira or Nitzschia. The central parts of the lake show the greatest variation, with Stephanodiscus, Nitzschia and Aulacoseira all being prominent. The northern region is dominated by Aulacoseira nyassensis throughout most core sequences.Variability in these assemblages appears to be controlled by Si:P ratios, Si concentrations, turbulence and light penetration. These factors themselves are influenced by differences in the depth and duration of lake mixing due to variations in wind strength, seiches and bottom topography among different regions of the lake and from lakewide circulation patterns. 相似文献
18.
Bong-Joo Jang Suk-Hwan Lee Sanghun Lim 《International journal of geographical information science》2014,28(4):763-779
With the increase in the number of applications using digital vector maps and the development of surveying techniques, a large volume of GIS (geographic information system) vector maps having high accuracy and precision is being produced. However, to achieve their effective transmission while preserving their high positional quality, these large amounts of vector map data need to be compressed. This paper presents a compression method based on a bin space partitioning data structure, which preserves a high-level accuracy and exact precision of spatial data. To achieve this, the proposed method a priori divides a map into rectangular local regions and classifies the bits of each object in the local regions to three types of bins, defined as category bin (CB), direction bin (DB), and accuracy bin (AB). Then, it encodes objects progressively using the properties of the classified bins, such as adjacency and orientation, to obtain the optimum compression ratio. Experimental results verify that our method can encode vector map data constituting less than 20% of the original map data at a 1-cm accuracy degree and that constituting less than 9% at a 1-m accuracy degree. In addition, its compression efficiency is greater than that of previous methods, whereas its complexity is lower for close to real-time applications. 相似文献
19.
Aquatic macrophyte vegetation development in Kråkenes Lake, western Norway, during the late-glacial and early-Holocene 总被引：1，自引：0，他引：1
Hilary H. Birks 《Journal of Paleolimnology》2000,23(1):7-19
Macrofossil analyses were carried out on the late-glacial and early-Holocene sediments of the radiocarbon-dated master core at Kråkenes Lake, western Norway, to investigate the aquatic vegetation changes. Ranunculus sect. Batrachium and Nitella were the earliest pioneers after deglaciation ca. 12,300 14C yr BP. The Allerød vegetational succession was very slow during ca. 1000 14C yrs in a cool climate and conditions that were similar to those above tree-line in Norway today. The rapid cooling at the start of the Younger Dryas stadial caused extensive disturbance, and with the development of an active cirque glacier in the catchment, plants and animals were almost exterminated from the lake by inflow of permanently cold and turbid water. Rising temperatures caused the glacier to melt at the end of the Younger Dryas. The biotic response to the rapid warming was immediate, with pioneer Ranunculus sect. Batrachium and Nitella expanding within 1-3 decades, closely followed by other elodeids. The lake witnessed a remarkable isoetid succession, with phases dominated by Limosella aquatica, Subularia aquatica, Elatine hydropiper, Isoetes echinospora, and, later, I. lacustris. About 800 yrs into the Holocene most of the macrophytes declined. The short-lived isoetids became extinct, but other taxa probably survived vegetatively. The reasons for this decline are unknown, but are probably related to nutrient depletion in combination with other factors. About 550 yrs later, I. lacustris and Nymphaea colonised, and a stable flora and vegetation developed. This study illustrates the large and rapid changes that occurred over the first 1400 yrs of the Holocene in the macrophyte flora and vegetation in Kråkenes Lake before stability was attained, pointing to the value of a palaeoecological study in tracing aquatic successions over time, and highlighting our lack of knowledge of the underlying ecological factors responsible for such rapid and marked changes. 相似文献
20.
Ulrike Hoff Oleg Dirksen Veronika Dirksen Ulrike Herzschuh Hans-Wolfgang Hubberten Hanno Meyer Christel van den Bogaard Bernhard Diekmann 《Journal of Paleolimnology》2012,47(4):549-560
Fossil diatom assemblages in a sediment core from a small lake in Central Kamchatka (Russia) were used to reconstruct palaeoenvironmental
conditions of the late Holocene. The waterbody may be a kettle lake that formed on a moraine of the Two-Yurts Lake Valley,
located on the eastern slope of the Central Kamchatka Mountain Chain. At present, it is a seepage lake with no surficial outflow.
Fossil diatom assemblages show an almost constant ratio between planktonic and periphytic forms throughout the record. Downcore
variations in the relative abundances of diatom species enabled division of the core into four diatom assemblage zones, mainly
related to changes in abundances of Aulacoseira subarctica, Stephanodiscus minutulus, and Discostella pseudostelligera and several benthic species. Associated variations in the composition and content of organic matter are consistent with the
diatom stratigraphy. The oldest recovered sediments date to about 3220 BC. They lie below a sedimentation hiatus and likely
include reworked deposits from nearby Two-Yurts Lake. The initial lake stage between 870 and 400 BC was characterized by acidic
shallow-water conditions. Between 400 BC and AD 1400, lacustrine conditions were established, with highest contributions from
planktonic diatoms. The interval between AD 1400 and 1900 might reflect summer cooling during the Little Ice Age, indicated
by diatoms that prefer strong turbulence, nutrient recycling and cooler summer conditions. The timing of palaeolimnological
changes generally fits the pattern of neoglacial cooling during the late Holocene on Kamchatka and in the neighbouring Sea
of Okhotsk, mainly driven by the prevailing modes of regional atmospheric circulation. 相似文献