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1.
近50年气候变化背景下中国西部冰川面积状况分析(英文) 总被引:2,自引:1,他引:2
Based on the glacier area variation records in the typical regions of China moni-tored by remote sensing, as well as the meteorological data of air temperature and precipitation from 139 stations and the 0℃ isotherm height from 28 stations, the glacier area shrinkage in China and its climatic background in the past half century was discussed. The initial glacier area calculated in this study was 23,982 km2 in the 1960s/1970s, but the present area was only 21,893 km2 in the 2000s. The area-weighted shrinking rate of glacier was 10.1%, and the interpolated annual percentage of area changes (APAC) of glacier was 0.3% a-1 since 1960. The high APAC was found at the Ili River Basin and the Junggar Interior Basin around the Tianshan Mountains, the Ob River Basin around the Altay Mountains, the Hexi Interior Basin around the Qilian Mountains, etc. The retreat of glacier was affected by the climatic background, and the influence on glacier of the slight-increased precipitation was counteracted by the significant warming in summer. 相似文献
2.
Based on the glacier area variation records in the typical regions of China monitored by remote sensing, as well as the meteorological data of air temperature and precipitation from 139 stations and the 0℃ isotherm height from 28 stations, the glacier area shrinkage in China and its climatic background in the past half century was discussed. The initial glacier area calculated in this study was 23,982 km2 in the 1960s/1970s, but the present area was only 21,893 km2 in the 2000s. The area-weighted shrinking rate of glacier was 10.1%, and the interpolated annual percentage of area changes (APAC) of glacier was 0.3% a-1 since 1960. The high APAC was found at the Ili River Basin and the Junggar Interior Basin around the Tianshan Mountains, the Ob River Basin around the Altay Mountains, the Hexi Interior Basin around the Qilian Mountains, etc. The retreat of glacier was affected by the climatic background, and the influence on glacier of the slight-increased precipitation was counteracted by the significant warming in summer. 相似文献
3.
Assessment of nutrient sources and paleoproductivity during the past century in Longgan Lake,middle reaches of the Yangtze River,China 总被引:3,自引:0,他引:3
Total organic carbon (TOC), total nitrogen (TN) and total phosphorus (TP) were determined in combination with stable isotope
ratios of carbon and nitrogen (δ13COrg, δ15N) in a 63 cm sediment core from Longgan Lake, located in the middle reaches of the Yangtze River, China. These geochemical
and isotopic records provide a continuous history of lake productivity and trophic state of Longgan Lake since 1890. Variations
of δ13COrg, TOC, TN and TP indicate that primary productivity of Longgan Lake increased continuously during the last century and that
the trophic state of the lake shifted from oligotrophic to mestrotrophic conditions accordingly. Anthropogenic sources of
organic carbon (OC), nitrogen (N) and phosphorus (P) were distinguished from their natural background in the sediments using
mass accumulation rates. Element mass accumulation rates suggested increased human activities in the lake’s catchment since
1950s, were especially the utilization of artificial fertilizers amplified the anthropogenic input of N and P into the lake.
In the course of the improved availability of dissolved nutrients also primary productivity of Longgan Lake increased, resulting
in an increase of the Suess-effect corrected organic carbon isotope ratios. δ15N of bulk sediments show a marked shift towards lower values around 1950 that has been attributed to the input of nitrogen
from chemical fertilizers characterized by relatively depleted isotopic signatures into the lake. 相似文献
4.
Kant S 《Population geography : a journal of the Association of Population Geographers of India》1995,17(1-2):49-64
"The paper examines urbanisation in Himachal Pradesh [India] in terms of size, growth, evolution, site and functional characteristics of urban centres for [the] 1901-91 period. In addition, the role played by the changing political and administrative geography has also been considered." 相似文献
5.
采用K-means聚类分区,Sen’s斜率估计,Kendall-Tau非参数检验等方法,分析和讨论了近半个世纪(1960—2015年)我国西北地区不同区域的气温变化特征。发现近半个世纪西北地区气温保持了持续的显著上升,年均最低气温上升速率高于年均气温和年均最高气温。从空间的角度来看,新疆北疆地区的东北部,内蒙古北部、西部中东部,甘肃中部、西部,青海北部、中部,宁夏中部、北部地区以及陕西北部是升温最快的区域。虽然西北地区气温总体是上升趋势,但在时间上并不均匀一致。从1998年开始,西北地区气温升温减缓,部分地区出现了下降趋势。近半个世纪西北地区季节气温与年际气温变化趋势并不一致,变暖减缓在该地区不同季节的响应不同。1998—2015年,冬季是增温幅度最小的季节,多数子区冬季存在升温趋势减缓,甚至转为下降趋势。 相似文献
6.
The effects of human activities on climate change are a significant area of research in the field of global environmental change. Land use and land cover change(LUCC) has a greater effect on climate than greenhouse gases, and the effect of farmland expansion on regional drought is particularly important. From the 1910 s to the 2010 s, cultivated land in Songnen Plain increased by 2.67 times, the area of cultivated land increased from 4.92×10~4 km~2 to 13.14×10~4 km~2, and its percentage of all land increased from 25% to 70%. This provides an opportunity to study the effects of the conversion of natural grassland to farmland on climate. In this study, the drought indices in Songnen Plain were evaluated from the 1910 s to the 2010 s, and the effect of farmland expansion on drought was investigated using statistical methods and the Weather Research and Forecasting Model based on UK's Climatic Research Unit data. The resulting dryness index, Palmer drought severity index, and standardized precipitation index values indicated a significant drying trend in the study area from 1981 to 2010. This trend can be attributed to increases in maximum temperature and diurnal temperature range, which increased the degree of drought. Based on statistical analysis and simulation, the maximum temperature, diurnal temperature range, and sensible heat flux increased during the growing season in Songnen Plain over the past 100 years, while the minimum temperature and latent heat flux decreased. The findings indicate that farmland expansion caused a drying trend in Songnen Plain during the study period. 相似文献
7.
From the development of modern transportation to the current era of high-speed transportation networks, the Beijing-Tianjin-Hebei (BTH) region has always played a national leading role in land transportation development of China. In order to explore the long-term evolutionary characteristics of land transportation in the BTH region, this paper utilized a temporal scale of 100 years to systematically interpret the development process of the land transportation network. Taking 13 cities within the BTH region as research anchor cities, we took into account “leaping” mode of transportation in order to investigate the evolution of accessibility. Our research shows the following results: (1) The land transportation network in the BTH region has undergone five stages of development: the initial period of modernization (1881–1937); the period of stagnation of transportation development (1937–1949); the network expansion period (1949–1980); the period of trunk construction (1980–1995), and the period of high-speed transportation network development (1995–present). The network structure centered around Beijing has existed from the outset of modern transportation development. (2) The accessibility spatial pattern of land transportation in BTH region has evolved from expansion along traffic corridors to the formation of concentric circles. The stratified circular structure of transportation in anchor cities has gradually developed into a contiguous development pattern. (3) There are clear hierarchical differences in the transportation structures of anchor cities. Beijing has always been at the top of this hierarchy, while the hierarchical position of Zhangjiakou has fallen noticeably since 1949. The Beijing-Tianjin region was the first region to form a short-duration transportation circle structure, while the transportation advantages of the central part of Hebei Province, which is located in the center of the BTH transportation region, have yet to be realized. 相似文献
8.
9.
京津冀城市生长和形态的径向维数分析 总被引:1,自引:0,他引:1
城市生长与形态是地理学规模与形状研究的重要内容,分维则是刻画城市形态、反映城市生长的标度指数。论文以城市建设用地为研究对象,采用2000、2005、2010年3个年份的遥感数据,利用分形理论的径向维数和相应的标度区概念分析京津冀城市和城镇体系的空间格局及其演变特征。结果表明:其一,北京市第一标度区的范围最大,10 a间增长幅度也最大,对周边城市产生阴影效应;其二,以北京为中心,距离越远,第一标度区范围有越小的趋势;其三,几乎所有研究区内城市的第一标度区空间都被建设用地过度填充,外围则各有特色;其四,经济水平对京津冀整体城市建设用地扩张的影响最大,但北京的城市建设用地扩张已经由经济因素主导转变为人口因素主导;其五,随时间推移,第一标度区拟合径向维数效果提高,第二标度区拟合效果降低。由此得出结论:①北京在京津冀体现了城市首位效应和阴影效应的双重效应。一方面,京津冀地区城镇化区域体现出了以北京为核心的中央集聚特征,另一方面,北京市的巨大吸引力抑制了毗邻城市的生长。②城市中心和外围都出现二元化格局。地区内各个城市的中心部分过于紧凑,而外围则相对凌乱,中心-边缘缺乏一体化过程。③人口可能成为未来京津冀城市发展的第一动力。人口集聚的规模效应未来可能替代经济报酬递增效应。这些结果和结论有助于学术界和管理部门从新的角度认识京津冀城市化现状和未来的发展趋势,以便制定更为合理的城市发展政策和方针。 相似文献
10.
Mass accumulation rates in Asia during the Cenozoic 总被引:17,自引:0,他引:17
François Métivier Yves Gaudemer Paul Tapponnier & Michel Klein 《Geophysical Journal International》1999,137(2):280-318
11.
The Yangtze Delta is one of the economically most developed areas in China. It is located in the eastern China monsoon region. Archaeological excavations and environment-archaeology studies over many years in this region provide exceptional information about climate changes, development of human civilization and also human-environment interactions. Archaeological excavations made in the study region reveal that the development of Neolithic cultures is not continuous, which may be a result of extreme climatic events. The analysis of ^14C-dated buried paleotrees, peat and shell ridges show the rise and fall of human civilization in the study area. The research results presented in this paper confirm that human civilization collapsed six times in the Yangtze Delta, matching six high sea level epoches, peat accumulation and buried paleotrees formation periods respectively. This indicates that human activities in the Yangtze Delta are controlled by local climate changes and changing hydrological conditions. The collapse of the Liangzhu culture (5000 aBP-3800 aBP) in about 4000 aBP, after a tremendous flooding event, followed by a relatively backward Maqiao culture (3800 aBP-3200 aBP) confused researchers and aroused their great interest. The research results in this paper show that the collapse of the Liangzhu culture is a result of several factors, for example war and food shortage, but the flooding event occurred in the late Liangzhu culture epoch is the main factor therein. 相似文献
12.
对巴音布鲁克站点1958—2015年的月降水量、降水日数和平均气温进行集合经验模态分解得到其变化趋势,利用Mann Kendall和累计距平法诊断突变点,并采用Morlet小波和R/S法分析其周期特征和未来变化趋势。结果显示:(1) 巴音布鲁克各月降水量1月、6月和11月增多趋势显著,2月、7月和12月呈“凸”字形变化,减少趋势显著。(2) 降水日数1月和9月呈显著减少趋势,2月和6月呈显著增加趋势,3月和11月呈“凸”字形变化,5月、7月和8月呈不同幅度的“凹”字形变化。(3) 各月平均气温基本呈上升趋势,尤其以5月、7月和10月升温最显著。(4) 年降水量、年降水日数和年平均气温分别在1999年、1993年和1997年发生突变,年降水日数增多早于年降水量增多和年平均气温升高的时间,从90年代中期开始气候由干冷逐渐向暖湿转型。(5) 年降水量、年降水日数和年平均气温的主周期分别为41 a、9 a和30 a。(6) 未来年降水量将增多,年降水日数将减少,年平均气温将升高,极端降水发生的频次将增大,易引发洪涝灾害。 相似文献
13.
The Yangtze Delta is one of the economically most developed areas in China. It is located in the eastern China monsoon region. Archaeological excavations and environment-archaeology studies over many years in this region provide exceptional information about climate changes, development of human civilization and also human-environment interactions. Archaeological excavations made in the study region reveal that the development of Neolithic cultures is not continuous, which may be a result of extreme climatic events. The analysis of 14C-dated buried paleotrees, peat and shell ridges show the rise and fall of human civilization in the study area. The research results presented in this paper confirm that human civilization collapsed six times in the Yangtze Delta, matching six high sea level epoches, peat accumulation and buried paleotrees formation periods respectively. This indicates that human activities in the Yangtze Delta are controlled by local climate changes and changing hydrological conditions. The collapse of the Liangzhu culture (5000 aBP-3800 aBP) in about 4000 aBP, after a tremendous flooding event, followed by a relatively backward Maqiao culture (3800 aBP-3200 aBP) confused researchers and aroused their great interest. The research results in this paper show that the collapse of the Liangzhu culture is a result of several factors, for example war and food shortage, but the flooding event occurred in the late Liangzhu culture epoch is the main factor therein. 相似文献
14.
15.
The Yangtze Delta is one of the economically most developed areas in China. It is located in the eastern China monsoon region. Archaeological excavations and environment-archaeology studies over many years in this region provide exceptional information about climate changes, development of human civilization and also human-environment interactions. Archaeological excavations made in the study region reveal that the development of Neolithic cultures is not continuous, which may be a result of extreme climatic events. The analysis of 14C-dated buried paleotrees, peat and shell ridges show the rise and fall of human civilization in the study area. The research results presented in this paper confirm that human civilization collapsed six times in the Yangtze Delta, matching six high sea level epoches, peat accumulation and buried paleotrees formation periods respectively. This indicates that human activities in the Yangtze Delta are controlled by local climate changes and changing hydrological conditions. The collapse of the Liangzhu culture (5000 aBP-3800 aBP) in about 4000 aBP, after a tremendous flooding event, followed by a relatively backward Maqiao culture (3800 aBP-3200 aBP) confused researchers and aroused their great interest. The research results in this paper show that the collapse of the Liangzhu culture is a result of several factors, for example war and food shortage, but the flooding event occurred in the late Liangzhu culture epoch is the main factor therein. 相似文献
16.
中俄两国建立战略伙伴关系是共同致力于两国社会经济可持续发展的重要举措,加强了解两国地理学发展的特征、扩大合作领域是推进这一战略任务实施的必然选择。本文以对俄罗斯社会经济地理学相关资料与文献收集与分析、以及近10余年俄罗斯地理学者与社会学者联合会年度学术会议资料等为支撑,用传承、革新、创新的视野,对俄罗斯近30余年社会经济地理学思想体系的发展以及近期的主要趋势进行概略性地阐述。在将俄罗斯经济地理学传承变革划分为6个阶段的基础上,重点围绕国家或区域地缘关系变化、多尺度地域空间组织、地域经济网络结构形成与发展、“大欧亚”建设和“东向发展”构想的社会经济地理学思考和对策、社会经济地理学的包容性和实践性,以及伴随全球化和国家发展战略需要涌现出新的分支学科、新思路、新观念等方面进行分析综述;给出近30余年主要地理研究机构对社会经济地理学研究领域的重点研究问题、主要学者及其代表作;并阐述在理论与方法论、落后地区发展、社会公平、贫困等问题研究方面存在的不足。研究结果对加深中俄两国地理学界的相互了解、推进社会经济地理学的创新发展具有现实意义。 相似文献
17.
D.S. Shafer M.H. Young S.F. Zitzer T.G. Caldwell E.V. McDonald 《Journal of Arid Environments》2007,69(4):633-657
Interrelated, biotic (flora and fauna) and abiotic (pedogenesis and hydrology) processes were examined at four sites (30, and approximately 1000–3000, 7000–12 000, and 125 000 years before present) in the northern Mojave Desert. Data collected at each included floral and faunal surveys; soil texture, structure, and morphology; and soil hydraulic properties. Separate measurements were made in shrub undercanopy and intercanopy microsites. At all sites, shrubs made up greater than 86 percent of total perennial cover, being least on the youngest site (4 percent) and most on the 7000–12 000-year-old site (31 percent). In the intercanopy, winter annual density was highest on the 1000- to 3000-year-old site (249 plants/m2) and lowest on the oldest site (4 plants/m2). Faunal activity, measured by burrow density, was highest on the 1000–3000- and 7000–12 000-year-old sites (0.21 burrows/m2) and density was twice as high in the undercanopy versus the intercanopy. Burrow density was lower at the two oldest sites, although density was not statistically greater in the undercanopy than intercanopy. At the older sites, the soil water balance was increasingly controlled by Av horizons in intercanopy soils in which saturated hydraulic conductivity (Ksat) decreased 95 percent from the youngest to the oldest site. No significant reduction in Ksat in undercanopy soils was observed. Decreases in the intercanopy sites correlated with decreases in annual plant density and bioturbation, suggesting these processes are interrelated with surface age. 相似文献
18.
25年来中国旅游容量研究的回顾与反思 总被引:2,自引:0,他引:2
20世纪80年代以来,中国旅游容量研究得到了较快发展.在回顾国内旅游容量研究的基础上,从理论和实践角度反思中国旅游容量研究25年的发展和问题,结论如下:我国旅游容量规划规范亟需补充完善;我国旅游容量管理方法亟需改进;国内学术界对旅游容量的认识尚存在若干误区.针对以上问题,通过综合分析国内外旅游容量的研究成果,深入探讨旅游容量的本质特征,对旅游容量的本质特征和旅游容量在实践中的发展方向形成如下基本认识:①旅游容量体现的是载体与被载体、容器与被容物之间的关系;②旅游容量反映的是景区系统中各种因子(尤其是限制性因子)互相平衡、和谐共处的状态;③旅游容量具有动态性特征;④旅游容量"限制"可以转变为"调控";⑤在实践操作中,旅游容量调控管理需要一套系统的指标体系作为参照. 相似文献
19.
《Polar Science》2014,8(3):298-305
Small copepod species play important roles in the pelagic food webs of the Arctic Ocean, linking primary producers to higher trophic levels. The egg production rates (EPs) and weight-specific egg production rates (SEPs) of two common copepods, Acartia longiremis and Temora longicornis, were studied under experimental conditions in Dalnezelenetskaya Bay (southern Barents Sea) during summer. The average EP and SEP at 5–10 °C were 4.7 ± 0.4 eggs female−1 day−1 and 0.025 ± 0.002 day−1, respectively, for A. longiremis and 13.1 ± 0.9 eggs female−1 day−1 and 0.075 ± 0.006 day−1, respectively, for T. longicornis. EP and SEP were significantly higher at 10°C than at 5°C for both species. The mean egg diameter correlated positively and significantly with female prosome length (PL) in each species. SEP of T. longicornis correlated negatively and significantly with PL. Daily EP and SEP were similar to rates recorded for other Acartia and Temora species in temperate and warm regions. The influence of environmental factors (temperature, salinity, and phytoplankton concentration) on EP of both species is discussed. We conclude that temperature is the main factor determining the reproduction rate and timing in A. longiremis and T. longicornis in the Barents Sea. 相似文献
20.
Coleogyne ramosissima Torr. (blackbrush) and Atriplex confertifolia [Torr. & Frem.] Wats. (shadscale) are cold desert shrubs from different families. Despite very different life histories they often grow in close geographic proximity in the Great Basin and the Colorado Plateau between 800 and 2000 m elevation. The purpose of this study is to compare the ecophysiology of slow growing and reproducing blackbrush with the ecophysiology of faster growing and reproducing shadscale. Metabolic heat and carbon dioxide production rates were measured on leaf tissue from wild plants and on lab-grown seedlings at temperatures from 10 to 35 °C at 5 °C intervals. Heat of combustion, ash content, and carbon and nitrogen contents were also measured. Substrate carbon conversion efficiencies and anabolic (or growth) rates were calculated from the respiration data. The growth rate of blackbrush was found to be approximately half that of shadscale because of lower respiration rate, but blackbrush begins growing earlier in the spring and can grow at higher temperatures when water is available. Blackbrush was observed to reproduce heavily when winter and spring precipitation is abundant. 相似文献