共查询到20条相似文献，搜索用时 571 毫秒
1.
The Beautiful China Initiative(BCI)is a plan for the sustainable development of the Chinese nation as well as for China to fulfill the United Nations’2030 Agenda for Sustainable Development.The Chinese government’s“five-in-one”approach provides strategic arrangements for developing the BCI,and President Xi Jinping proposed a timetable and“road map”for the BCI at the National Conference on Ecological and Environmental Protection.Nevertheless,the theoretical basis,evaluation index system,evaluation criteria and effectiveness of the BCI are currently unclear.This paper begins by exploring the basic content of the BCI from narrow and broad perspectives.It regards the theory of human-nature harmonious coexistence and the five-in-one beauty theory as the core theoretical bases of the BCI and constructs a five-element BCI evaluation index system(ecological environment,green development,social harmony,system perfection and cultural heritage)and utilizes the assessment method of the United Nations’Human Development Index to assess scientifically the effectiveness of the BCI in 341 prefecture-level cities.The results show the average BCI index(the Chinese Academy of Sciences Beauty Index)score to be 0.28,which is quite low,while the average scores for the individual element indexes of the ecological environment index,green development index,social harmony index,system perfection index and cultural heritage index are 0.6,0.22,0.29,0.22 and 0.07,respectively.All of these are relatively low values,with relatively large discrepancies in regional development,indicating that progress in the BCI is generally slow and unbalanced.To realize the BCI’s timetable and roadmap to a high quality and high standard,it is suggested that a common system for evaluating the progress of the BCI is developed and promulgated so that dynamic monitoring and phased evaluations can take place;BCI technical assessment standards are compiled and published;BCI comprehensive zoning is undertaken;pilot projects adapted to local conditions are launched in BCI sample areas;and BCI results are incorporated into performance indicators at all levels of government. 相似文献
2.
Protected areas have a double mandate of both "protection" and "use." Naturebased tourism is considered an effective tool in terms of environmental conservation. Understanding the causes and consequences of a spatiotemporal succession of tourism construction is an important channel to explore the changes of tourism-environment interaction in the protected area. To analyze the spatio-temporal variations in tourism construction lands, we adopted Mt. Bogda as an example. We systematically quantified the interaction between these changes and environmental variables and explored the evolution process of tourism-environment interaction of the mountainous protected area in the northwest arid region. Our results revealed the following:(1) In the Bogda protected area, the proportion of tourism construction lands first appeared to be increasing, then decreasing dramatically, and finally growing slowly. The spatial expansion of tourism construction lands followed the "core-periphery" pattern, respectively showing shapely infilling, reasonable agglomeration, barycenter shift, and outlying growth from 1990 to 2018 as the stages of concentrating on the core.(2) The higher land-use intensity of tourism construction drove the changes of landscape fragmentation, diversity, stability, primitive, and nature degree in the protected area. The coupling coordination between tourism and the environment in the Bogda area decreased at first, and then slowly increased. Meanwhile, tourism did not cause irreversible damage to the natural environment, and the coupling coordination degree between tourism and the environment was still in the state of balanced development. It expressed the states of original balanced, development exceeds environment and barely balanced, and superiorly balanced. The historical evolution of tourism-environment interaction in Bogda reflects the pattern of periodic changes in China’s protected areas to a certain extent. 相似文献
3.
Based on the measured discharge,sediment load,and cross-sectional data from 1986 to 2015 for the lower Yellow River,changes in the morphological parameters(width,depth,and cross-sectional geomorphic coefficient)of the main channel are analyzed in this paper.The results show that before the operation of the Xiaolangdi Reservoir(XLDR)from 1986 to 1999,the main channel shrunk continually,with decreasing width and depth.The rate of reduction in its width decreased along the river whereas that of depth increased in the downstream direction.Because the rate of decrease in the width of the main channel was greater than that in channel depth,the cross-sectional geomorphic coefficient decreased in the sub-reach above Gaocun.By contrast,for the sub-reach below Gaocun,the rate of decrease in channel width was smaller than that in channel depth,and the cross-sectional geomorphic coefficient increased.Once the XLDR had begun operation,the main channel eroded continually,and both its width and depth increased from 2000 to 2015.The rate of increase in channel width decreased in the longitudinal direction,and the depth of the main channel in all sub-reaches increased by more than 2 m.Because the rate of increase in the depth of the main channel was clearly larger than that of its width,the cross-sectional geomorphic coefficient decreased in all sub-reaches.The cross-sectional geometry of the main-channel of the lower Yellow River exhibited different adjustment patterns before and after the XLDR began operation.Before its operation,the main channel mainly narrowed in the transverse direction and silted in the vertical direction in the sub-reach above Aishan;in the sub-reach below Aishan,it primarily silted in the vertical direction.After the XLDR began operation,the main channel adjusted by widening in the transverse direction and deepening in the vertical direction in the sub-reach above Aishan;in the sub-reach below it,the main channel adjusted mainly by deepening in the vertical direction.Compared with the rates of decrease in the width and depth of the main channel during the siltation period,the rate of increase in channel width during the scouring period was clearly smaller while the rate of increase in channel depth was larger.After continual siltation and scouring from 1986 to 2015,the cross-sectional geometry of the main-channel changed from wide and shallow to relatively narrow and deep.The pattern of adjustment in the main channel was closely related to the water and sediment conditions.For the braided reach,the cross-sectional geomorphic coefficient was negatively correlated with discharge and positively correlated with suspended sediment concentration(SSC)during the siltation period.By contrast,the cross-sectional geomorphic coefficient was positively correlated with discharge and negatively correlated with SSC during the scouring period.For the transitional and meandering reaches,the cross-sectional geomorphic coefficient was negatively correlated with discharge and positively correlated with SSC. 相似文献
4.
The town of Agura,a typical region in Horqin Sandy Land,was selected as the study area in this paper.Using 12 remote sensing images and climatic data from the past 20 years,the effects of climate change on surface environments were analyzed.The impact indices of climatic factors,along with their corresponding ranks,were used to characterize the responses of different types of surface environments to climate change.Results show that in the past 20 years,the surface environments of the study area have been deteriorating.Furthermore,there is a positive relationship between the changes in surface environments and those in climatic factors.Various climatic factors influence surface environments in different ways and at different levels.The most sensitive factor is relative humidity,followed by precipitation and evaporation.Overall,moisture is the key factor that affects the changes in surface environments of arid and semi-arid areas. 相似文献
5.
今年是广东省建成北回归线标志25周年。2011-06-22台湾嘉义、广东汕头、从化、封开、广西桂平、云南墨江等海峡两岸6座北回归线标志所在市、县,举行联动观测夏至正午太阳直射的大型活动,华南师范大学地理科学学院刘南威教授在活动筹办期间接受记者采访,畅谈广东地理学界对北回归线标志兴建的主要贡献和海峡两岸联动观测正午太阳直射活动的重要意义。 相似文献
6.
7.
The shapes of the urban lakes in Wuhan city have been strongly influenced by the rapid industrialization and urbanization experienced in recent decades.Based on topographic maps and remote sensing images,the temporal and spatial changes of East Lake,Wuhan city,over the past two decades were analyzed.The landscape shape index(LSI)and centroid method were applied to analyze the evolution of lake morphology and its causes.Several key results were obtained.(1)The surface area of East Lake decreased sharply by 2.13 km2 from 1995 to 2005,and slightly by 1.00 km2 from 2005 to 2015.The shoreline length of East Lake displayed a continuous trend of decline during the study period:The length reduced by 21.89 km from 1995 to 2005,and by 0.67 km from 2005 to 2015.The LSI values,7.04(1995),6.46(2005),and 6.28(2015),displayed an accelerated downward trend,indicating a reduction of complexity in East Lake and the intensification of manual interventions in the water body.(2)The changes to East Lake displayed a clear temporal and spatial heterogeneity.The centroid of East Lake moved northeast from 1995 to 2005 and southeast from 2005 to 2015.(3)The reduction in the area of East Lake was mainly affected by human activities.A lake area of about 4.8 km2 was converted to other land uses during 1995-2005,most of which was unused land,whereas from 2005 to 2015,0.43 km2 of the lake area was converted into built-up land,and 0.25 km2 was converted into other land uses.The reduction in area was caused by infrastructure construction by the government,the development of the real estate industry,illegal construction by villagers,and the development of scenic spots for tourism.The driving forces of this reduction included Wuhan's growing population,and the rapid development of the economy and urbanization between 1995 and 2015,which has resulted in a large demand for land.Finally,a formation mechanism model was constructed by analyzing the causes of East Lake's morphological evolution. 相似文献
8.
Ground temperatures from four of the seven extensively studied highway cross-sections near Gulkana/Glennallen,Alaska during 1954~1962,were chosen to better understand the impacts of highway construction on warm permafrost.Both the thawing of permafrost and seasonal frost action impacted on road surface stability for about 6 years until the maximum summer thaw reached about 3 m in depth.Seasonal frost action caused most of the ensuing stability problems.Unusually warm summers and the lengths of time required to re-freeze the active layer were far more important than the average annual air temperatures in determining the temperatures of the underlying shallow permafrost,or the development of taliks.The hypothesized climate warming would slightly and gradually deepen the active layer and the developed under-lying talik,but its effect would be obscured by unusually warm summers,by warmer than usual winters,and by the vari-able lengths of time of the zero curtains.At least one period of climate mini-cooling in the deeper permafrost during the early 20th century was noted. 相似文献
9.
中国水利学会2007年学术年会于10月29-31日在苏州市召开.本届年会的主题是"现代水利与河湖管理",水利部各司局、长江水利委员会、黄河水利委员会、各省市自治区水利厅局的领导、以及来自全国有关水利科研、设计、施工、管理和教学一线的技术骨干近600人参加了大会.与中国科协其他学会的年会相比,水利学会年会除了学术讨论的性质外,还带有一定的工作会议内容.来自各方面的10位专家作了大会特邀报告. 相似文献
10.
"干旱、半干旱区环境演变与可持续发展国际学术讨论会"(International Workshop on Environmental Changes and Sustainable Development in Arid and Semi-arid Regions)于2007年9月10-14日在内蒙古自治区阿拉善左旗成功举办.会议由国际地貌学家协会(IAG)、国际地理联合会荒漠化与土地退化委员会(COMLAND)、中国第四纪研究会、中国地理学会等学术团体发起,国家自然科学基金、PAGES及中国科学院资助,中国科学院地质与地球物理研究所主办,内蒙古阿拉善盟行署、南京大学协办. 相似文献
11.
ZHU Liping JU Jianting WANG Yong XIE Manping WANG Junbo PENG Ping ZHEN Xiaolin LIN Xiao 《地理学报》2010,20(1):109-120
The chemistry of major cations (Mg2+, Ca2+, Na+, and K+) and anions (HCO3 ?, SO4 2?, and Cl?) in the water of Lake Pumayum Co and its inflow river was studied, revealing the obvious ionic difference among various inflow rivers and the lake. The chemical type of the lake water was Mg2+-Ca2+-HCO3 ?-SO4 2+, but the major ions of the main inflow rivers were Ca2+-Mg2+-HCO3 ?. In the lake inlet of Jiaqu River, the main inflow river, there was significant variance of water chemistry within the depth less than 2 m. However, it was almost homogeneous at other area of the lake. Therefore, with the evidence of distribution of water chemistry and oxygen isotope of lake water, a conclusion can be outlined that Jiaqu River had a distinct effect on the hydrochemistry of the water on the submerged delta, whereas this is not the case for other rivers. The Gibbs plot revealed that the dominant mechanism responsible for controlling chemical compositions of the lake water was rocks weathering in the drainage area. Ion ratios and ternary plots further explored the main processes controlling the water chemistry of the catchment, i.e., carbonate weathering, pyrite weathering, and silicate weathering. The different hydrochemistry characteristics between river water and lake water may result from the CaCO3 precipitation. The findings will benefit the explanation of the environmental significance of carbonate in paleolimnological studies in the lake. 相似文献
12.
Water and sediment chemistry of Lake Pumayum Co,South Tibet,China: implications for interpreting sediment carbonate 总被引：2，自引：0，他引：2
Jianting Ju Li-ping Zhu Junbo Wang Manping Xie Xiaolin Zhen Yong Wang Ping Peng 《Journal of Paleolimnology》2010,43(3):463-474
A combination of water and sediment chemistry was used to investigate carbonate production and preservation in Lake Pumayum
Co (altitude 5,030 m a.s.l.), south Tibet, China. We compared the chemical composition of lake water in various parts of the
lake with that of input rivers and found that the loss of Ca2+ results from calcite sedimentation induced by evaporation and biogenic precipitation. This is supported by evaporation data
from the catchment and δ18O measurements on water. Results suggest that CaCO3 is the predominant carbonate in this lake. There is a positive correlation in the sediments among concentrations of total
inorganic carbon (TIC), Ca, total organic carbon (TOC), and total nitrogen, confirming that most carbonates in sediment are
endogenic. The Jiaqu River is the largest inflow to Lake Pumayum Co and has a strong influence on both lake water chemistry
and sediment composition. The river and lake bathymetry influence carbonate sedimentation by affecting water flow velocity
and growing conditions for macrophytes. Different carbon contents and relationships between TIC and TOC in the two long cores
from different depths in the lake reveal that hypolimnetic conditions also influence carbonate precipitation and preservation. 相似文献
13.
基于氢氧同位素与水化学的 潮白河流域地下水水循环特征 总被引：23，自引：1，他引：23
为了研究变化环境下潮白河流域地下水水循环规律,通过现场调查,结合环境同位素及水化学应用,对潮白河流域浅层和深层地下水采样,测定其氢、氧环境同位素及水化学成分,通过分析其变化特征判明地下水的补给来源以及各含水层的相互联系。降水和地下水中的环境同位素δD和δ18O组成分析表明,降水是山前地下水的主要补给源,山区浅层地下水受蒸发影响非常强烈。水化学研究结果表明,山区地下水水质以 Ca2+和 HCO-3为主,属Ca2+-Mg2+-HCO-3型地下水。山前地下水类型为Ca2+-Mg2+-HCO-3、 Na+-K+-HCO-3、Mg2+-Ca2+-HCO-3和 Ca2+-Mg2+-Cl--SO2-4。平原区地下水为Mg2+, Na+和HCO-3。滨海冲积海积平原为Ca2+-Mg2+-HCO-3型和Ca2+-Mg2+-Cl--SO2-4型地下水。水化学分析证实了越流补给的存在。Ca2+ 和 HCO-3离子均呈山区高、山前和平原低、而滨海增高的趋势。沿潮白河流向地下水类型变化为:Ca2+-Mg2+-HCO-3 Na+＝K+-HCO-3 Ca2+-Mg2+-HCO-3。 相似文献
14.
The hydrochemistry of alpine lakes reflects water characteristic and its response to climatic change. Over 300 water samples had been collected from 52 sites of 5 lakes and 7 inflowing rivers in the Yamzhog Yumco Basin, South Tibet, during 2009–2014, basing which the hydrochemical regime and its mechanism were analyzed along with the adoption of hydrological investigations in 1979 and 1984 as well. Results revealed that the waters were hard with weak alkalinity for the Yamzhog Yumco Basin. Most of them were fresh, and the rest were slightly saline. The hydrochemical types of 5 lakes (i.e., Lake Yamzhog Yum Co, Puma Yum Co, Bajiu Co, Kongmu Co, and Chen Co) were SO4 2––HCO3 ––Mg2+–Na+, HCO3 ––SO4 2––Mg2+–Ca2+, SO4 2––Mg2+–Na+, SO4 2––HCO3 ––Ca2+, and SO4 2––Na+–Mg2+–Ca2+, respectively. As for rivers, HCO3 – and SO4 2– were the major anions, and Ca2+ was the dominant cation. Lake Yamzhog Yum Co, the largest lake in the basin, exhibited remarkable spatial variations in hydrochemistry at its surface but irregular changes with depth. The weathering of evaporates and carbonates, together with evaporation and crystallization, were the major mechanisms controlling the hydrochemistry of waters in the Yamzhog Yumco Basin. Global warming also had significant impacts on hydrochemical variations. 相似文献
15.
Mohsen Jalali 《Natural Resources Research》2012,21(1):61-73
Salinity and sodicity of groundwater are the principal water quality concerns in irrigated areas of arid and semi-arid regions.
The hydrochemical characteristics and sodicity of groundwater in the Shirin Sou area, western Iran were investigated in this
study by chemical analyses of groundwater samples from 49 wells. Chemical analysis of the groundwater showed that the mean
concentration of the cations was in the order: Na+ > Ca2+ > Mg2+ > K+, while that for anions was SO3
2− > Cl− > HCO3
− > NO3
−. The most prevalent water type is Na–SO4 followed by water types Na–Cl and Ca–SO4. The chemical evolution of groundwater is primarily controlled by water–rock interactions: mainly weathering of aluminosilicates,
dissolution of sulfate minerals, and cation exchange reactions. Sulfate dissolution and pyrite weathering may both contribute
to the SO4
2− load of the groundwater. High Na+ concentrations in groundwater participate in ion-exchange processes, resulting in the displacement of base cations into solution
and raised concentrations in groundwater. The principal component analysis (PCA) performed on groundwater identified three
principal components controlling variability of groundwater chemistry. Electrical conductivity, Ca2+, Mg2+, Na+, SO4
2−, and Cl− content were associated in the same component (PC1) (salinity), most likely linked to anthropogenic activities. 相似文献
16.
Chemical composition of saline and subsaline lakes of the northern Great Plains,western Canada 总被引：2，自引：0，他引：2
William M. Last 《International Journal of Salt Lake Research》1992,1(2):47-76
The northern Great Plains of Canada stretch from the Precambrian Shield near Winnipeg, Manitoba, westward for ∼1,700 km to
the Rocky Mountains foothills. This vast region of flat to gently rolling terrain contains a very large number of salt lakes.
Major ion chemical data on ∼500 of them are available. Although the average brine (salinity, 37 ppt) is a Na+−SO4
2− type of water, the lakes exhibit a wide range of salinities and ionic compositions. This diversity is confirmed by Q-mode
cluster analysis; it identified thirteen major water chemistry types. Most ions display distinct trends, both spatially and
with increasing salinity. All dissolved components increase with increasing salinity, but at different rates. The relative
proportions of Ca2+ and HCO3
−+CO3
2− ions show a strong decrease with increasing brine salinity, whereas SO4
2− ions increase with increasing salinity. The ionic proportions of Na+, Mg2+, K+ and Cl− exhibit no significant relationship with salinity. R-mode factor analysis of the lake water chemistry, combined with selected
environmental parameters, identifies groundwater composition, climate, and the elevation of the lake within the drainage system
as most important in controlling brine chemistry and salinity on a regional basis. Variability in source of ions, reaction
processes and products are undoubtedly key factors in helping to explain brine chemistry of an individual basin or variation
from a local perspective, but these factors are generally poorly understood and not quantified on a regional basis.
Palliser Triangle Global Change Project Contribution Number 3. 相似文献
17.
Margarita Caballero Gabriela Vázquez Socorro Lozano-García Alejandro Rodríguez Susana Sosa-Nájera Ana Carolina Ruiz-Fernández Beatriz Ortega 《Journal of Paleolimnology》2006,35(1):83-97
The Sierra de Los Tuxtlas is a recently active volcanic field, with eruptions in 1664 and 1792. It holds one of the reserves
of tropical evergreen forest in Mexico, as well as several maar lakes. One of them, Lago Verde, was chosen for a three-fold
study (1) on its present limnological conditions, (2) on the algal community living in the water column and preserved in the
surface sediments; and (3) on its recent history (ca. 340 yr). The palaeolimnological study was based on multiproxy analyses
on core material dated by 210Pb, 137Cs and 14C. Lago Verde is a small, shallow lake with dilute, slightly alkaline water (CO32− + HCO3− > Cl− > SO42−, Na+ + K+ > Ca2+ > Mg2+). It is turbid, eutrophic, with high phosphorus levels. It is a warm polymictic lake, with thermal and oxygen stratification
establishing by midday during the warm months. The lake does not stratify in winter. Diatoms dominate the phytoplankton community
in the cold ‘nortes’ season, Cyanobacteria in summer, and Chlorophyta in autumn. Cyanobacteria (Chroococcales) are not well
preserved in the surface sediments while Chlorophyta are better preserved. Sedimentary diatoms are well preserved, dominated
by the three most abundant species in the water column: Achnanthidium minutissimum, Fragilaria capucina and Aulacoseira granulata. The base of the studied sequences is constrained by the historic eruption of 1664. The period from 1664 to 1963 is characterised
by a meso-eutrophic lake. Tropical Forest vegetation reaches maximum values between ca. 1800 and 1963. Between ca. 1785 and
1885 the lake was slightly shallower than in the rest of the 1664–1963 period, probably recording climatic variability. An
early pulse of anthropogenic disturbance was recorded by ca. 1921 and after ca. 1963 intense forest clearance and high erosion
rates led to a more turbid, more productive, nutrient-rich lake. The highest anthropogenic impact was reached by ca. 1988;
afterwards the lake and its basin reached a new balance, with the establishment of the present modern conditions. 相似文献
18.
Francis Mwaura 《International Journal of Salt Lake Research》1999,8(2):127-138
The hydrochemistry of three areas of geothermal activity in the Lake Elementaita basin were surveyed. The results indicated
warm temperatures between 30–40°C, high alkalinity (1,200 mg CaCO3/l) and specific conductance (4,300–8,100 μS/cm). pH was above 9 with a high concentration of carbonates, chlorides and sulphates.
Apart from playing a significant role in the lake chemistry, lacustrine springs provide a significant source of water supply,
particularly during the dry season. However, there is a serious lack of scientific information on the hydrogeology and hydrochemistry
of the thermal springs. 相似文献
19.
The main limnological features of Lake Issyk-kul are described. The lake is a large (6,236 km2), deep (zm, 668 m), closed lake in eastern Kirgizia. It lies at ∼1,607 m above sea level, but water-levels have been dropping since
the last century. It is slightly saline (salinity, ∼6g L−1), with Na+, Mg2+, Cl− and SO
4
2−
the dominant ions. Nutrient levels are low and the lake is considered ultra-oligotrophic.
Characeae dominate the macrophytes. About 300 and 117 taxa of, respectively, phytoplankton and zooplankton have been identified,
withArctodiaptomus salinus the most numerous in the zooplankton. Chironomids dominate the benthos. Several endemic taxa of fish occur, of whichLeuciscus bergi was dominant until the 1970s. The fish fauna has been supplemented by many introduced species. Three mysids were introduced
in 1965–8 and are now a significant part of the ecosystem. The present annual fish catch permitted is 320 t.
The most important value of the lake is as a recreational resource. To promote and sustain this value requires careful, ongoing
management. The most significant threats to the lake are local pollution, visitor pressure, and declining water-levels. 相似文献
20.
赣江上游河流水化学的影响因素及DIC 来源 总被引：20，自引：0，他引：20
对赣江上游38 处水体采样点的水化学特征和溶解无机碳稳定同位素的分析, 发现其总溶解质浓度较低, 其中, 阳离子以Na+、Ca2+ 为主, 阴离子以Cl- 和HCO3 - 为主, Si 的浓度较高, 表征了典型硅酸盐地区河流的水化学组成特征。通过海盐校正分析得出, 研究区大气降水对河水溶解质的贡献率为11.5%, 扣除降水的贡献部分, 利用主成分分析的方法, 计算得出赣南流域受硅酸盐岩风化作用强烈, 同时由于受附近盐矿的影响, 蒸发盐岩的风化作用显著。另外, 根据δ13C 溶解无机碳DIC 的测量值约为-8.35‰~-13.74‰, 平均为-11.65‰, 利用质量平衡计算得出, 研究区DIC 的主要来源, 约68.5%来自于土壤CO2, 31.5%来自于碳酸盐矿物的溶解, 进而得出流域岩石化学风化过程消耗的土壤CO2 为2.11×105 mol/yr·km2, 来自碳酸盐本身的HCO3 -含量为9.6×104 mol/yr·km2。由于地理位置和流域环境以及人为因素的差异, 各支流DIC 来源的比例亦有所差异。 相似文献