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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.
The water quality of Dianchi Lake declines quickly and the eutrophication is getting serious. To identify the internal pollution load of Dianchi Lake it is necessary to evaluate its sediment accumulation. Sedimentation rates of Dianchi Lake are determined by 137Cs dating. However, 137Cs vertical distribution in sediment cores of Dianchi Lake has special characteristics because Dianchi Lake is located on the southeast of the Qinghai-Tibet Plateau, the Kunming quasi-stationary front is over the borders of Yunnan and Guizhou where the specific precipitation is distributed. Besides 1954, 1963 and 1986 137Cs marks can be determined in sediment cores, a 137Cs mark of 1976 representing the major period of 137Cs released from China unclear test can be determined and used for an auxiliary dating mark. Meanwhile Dianchi Lake is divided into seven sections based on the water depth, basin topography, hydrological features and supplies of silt and the lakebed area of each section is calculated. The mean annual sedimentation rates for seven sections are 0.0810, 0.1352, 0.1457, 0.1333, 0.0904, 0.1267 and 0.1023 g/cm2a in 1963–2003, respectively. The gross sediment accumulation of the lake is 26.18×104 t/a in recent 17 years and 39.86×104 t/a in recent 50 years. 相似文献
12.
The water quality of Dianchi Lake declines quickly and the eutrophication is getting serious. To identify the internal pollution
load of Dianchi Lake it is necessary to evaluate its sediment accumulation. Sedimentation rates of Dianchi Lake are determined
by 137Cs dating. However, 137Cs vertical distribution in sediment cores of Dianchi Lake has special characteristics because Dianchi Lake is located on
the southeast of the Qinghai-Tibet Plateau, the Kunming quasi-stationary front is over the borders of Yunnan and Guizhou where
the specific precipitation is distributed. Besides 1954, 1963 and 1986 137Cs marks can be determined in sediment cores, a 137Cs mark of 1976 representing the major period of 137Cs released from China unclear test can be determined and used for an auxiliary dating mark. Meanwhile Dianchi Lake is divided
into seven sections based on the water depth, basin topography, hydrological features and supplies of silt and the lakebed
area of each section is calculated. The mean annual sedimentation rates for seven sections are 0.0810, 0.1352, 0.1457, 0.1333,
0.0904, 0.1267 and 0.1023 g/cm2a in 1963–2003, respectively. The gross sediment accumulation of the lake is 26.18×104 t/a in recent 17 years and 39.86×104 t/a in recent 50 years.
Foundation: National Natural Science Foundation of China, No.40771186; The Key Project of the State Key Laboratory of Soil Sustainable
Agriculture, Nanjing Institute of Soil Sciences, Chinese Academy of Sciences, No.5022505
Author: Zhang Yan (1962–), Ph.D and Associate Professor, specialized in environmental change. 相似文献
13.
基于137Cs计年法估算滇池沉积物重金属负荷 总被引：5，自引：5，他引：0
根据滇池流域地貌、湖盆形态、物源供给等,用GIS方法将滇池外海分作7个区域,以137Cs计年法确定各区域上部沉积物3个沉积时段为1954~1963、1963~1986、1986~2003年,测算不同时段各区域的泥沙年均沉积通量和年均蓄积量,与当地实情及他人用其它方法研究对照,结果可以吻合。在此基础上,结合实验室测量,估算各区域的Cu、Cr、Cd、Pb、Hg、Zn在各时段的年均沉积通量,得到1963~2003年期间滇池沉积物几种重金属负荷分别达到1040.8、1054.0、11.2、824.7、2.5、2465.6 t。故应十分重视滇池沉积物中重金属,采用减少重金属和泥沙入湖量并举的措施控制沉积物重金属负荷的进一步增长。 相似文献
14.
借助137Cs估算滇池沉积量 总被引：9，自引：0，他引：9
根据137Cs测量值和具体区位判断,滇池流域土壤与湖泊沉积物中的137Cs是世界与中国核试验生成物叠加的结果,由此在滇池沉积物中识别出1954年、1963年、1976年、1986年几个特定年份的沉积层(时标)。计算不同时标间的沉积物质量,可求出不同时段单位面积上的年均沉积质量,不同湖区该值有差别,但符合湖心沉积低于湖岸的湖泊沉积规律。又参照滇池流域地貌、物源供给、湖盆形态及采样点等,借助GIS方法将滇池湖区划分为远岸湖心区(I)、近岸湖心区(II)、湖西区(III)、湖东区(IV)和湖南区(V),并计算各区底面积;然后将面积与年均沉积质量相乘,得到不同时段各区域的年均沉积总量1954~2003年与I~V区对应的年均沉积总量(104t/a)分别是6.85、8.90、8.43、9.82和5.91,滇池外海的总沉积量为39.91×104t/a。这些结果与当地实情吻合,与他人的研究结果也非常一致。 相似文献
15.
云南抚仙湖近现代沉积速率变化研究 总被引：14，自引：0，他引：14
借助GPS定位,采集了云南抚仙湖不同区域的7 个沉积物柱芯。通过对抚仙湖沉积物柱芯样品的放射性核素210Pb 和137Cs 测试分析,发现所有柱芯中均存在3 个公认的137Cs 计年时标(1954 年137Cs首次沉降、1963 年全球公认的137Cs最大沉降蓄积峰和1986 年前苏联切尔诺贝利核事故产生的137Cs 沉降蓄积峰),部分柱芯中存在20 世纪70 年代中期中国大气核试验形成的1975/1976 年次级蓄积峰,分析了该次级定年时标存在的合理性。借助210Pb CRS计年模式获得了抚仙湖过去百余年来的沉积年代,与137Cs 时标计年结果相比较存在一定偏差,对两种计年结果产生差异的可能原因进行了探讨。基于210Pb 和137Cs 计年结果,结合历史文献记载得出,自19 世纪中期以来,抚仙湖各个沉积物柱芯(FX6 除外) 的沉积速率变化规律具有相似性,大致可以划分为3 个阶段：A：自然演化阶段,B：人为扰动阶段,C：人为改造阶段。这种不稳定的沉积环境与抚仙湖地区相应历史时期的人类活动有密切关系,表明人类活动是影响短时间尺度下环境变化的主要驱动力。 相似文献
16.
Reconstructing recent limnological history often relies on lead-210 dating to accurately ascribe a chronology to a sediment
profile. In Lake Okeechobee, Florida, a large, shallow subtropical lake that may experience severe mixing, multiple dating
methods are required to confirm that conformable sedimentation has been preserved and that the assumptions of the 210Pb method are satisfied. This study uses stratigraphic profiles of heavy metals, 137Cs, PCBs and pollen as independent dating markers to validate the sediment chronology as determined by 210Pb for three cores from the central mud zone of the lake. Unsupported 210Pb and most dating markers show distinct concentration/depth profiles, suggesting that the sediments have not been severely
mixed for at least the last 75 years. Onset and maximum activity of the radioisotope 137Cs in the cores coincides with the 210Pb-dated interval of 1945–1970. This agrees well with the known timing of atmospheric deposition of 137Cs that resulted from above-ground nuclear testing during late 1940s until 1963. Sediment core profiles of atmospherically
deposited metals such as Zn and Pb, which reflect regional increases during industrialization and decreases after regulation
in the 1970s, exhibit expected concentration increases and peaks coinciding within 5–15 years of the predicted 210Pb dates. Uranium, a contaminant in some phosphate fertilizers, shows large concentration increases at core depths dated to
be about 1950 by 210Pb, matching the intensification of agriculture after WWII. PCBs, which are expected to peak in the early 1970s, were measured
in one core, and the observed peak corresponds to a 210Pb date of about 1960. Pollen makers were unable to verify specific events, but increases in disturbance taxa and declines
in native types correspond generally with the expected dates assigned by 210Pb dating. Conformity between the 210Pb defined dates and independent markers of < ±15 years confirm that Lake Okeechobee sediments do preserve a sequential and
reliable stratigraphic history of the lake, useful for reconstructing past limnological conditions. 相似文献
17.
137Cs在年代测定和土壤流失等领域得到了广泛的应用。在认定137Cs时标前,需要消除粘土和有机质（TOC）对137Cs 的富集作用。通过对比新疆多个湖芯钻孔137Cs 序列,发现它们异于北半球137Cs 沉降模式,即出现了1954、1963、1975 和1986 这四种时标且1986 年的137Cs 比活度可能异常的高。通过分析艾里克湖钻孔的137Cs序列,并结合新疆其他地区多个钻孔的137Cs序列,与北半球137Cs沉降特征以及靠近北疆的Belukha冰芯240Pu239Pu沉降记录进行对比,分析了新疆137Cs时标的可靠性以及1986年137Cs比活度异常高的原因。在新疆137Cs多个时标中,仅1963年的时标是高信度的（即北半球137Cs最大沉积年）。1954年137Cs蓄积峰代表其全球初始显著沉降,距今已有2个137Cs半衰期,当年沉积通量低且可能发生137Cs垂直迁移,仅能作为次要时标。1975年的时标反映了1960s- 1970s的中国核试验,但距离罗布泊～300 km的博斯腾湖对中国核试验有截然相反的记录,表明中国核试验不是稳定信号,其核沉降范围以及对湖芯的影响作用还需进一步评估,不能作为可信的时标。1986年蓄积峰对应切尔诺贝利核事故,因核尘埃未大量进入平流层且距离新疆较远（～4 000 km）,但同时考虑到新疆位于核事故的西风环流下风区,所以该事故对新疆有影响但影响不大。1986年的137Cs时标可作为次要时标。新疆湖芯1986年的异常高蓄积峰可能是由新疆最近几十年的人类活动（如过牧、耕种等）加上1987/1988年的高降水导致的地表侵蚀增强引起的。增强的地表侵蚀导致含有高137Cs含量的表层土壤颗粒被冲刷进入湖泊,叠加在切尔诺贝利核事故137Cs沉降之上,进而导致了湖芯沉积物记录到显著的1986年137Cs蓄积峰。 相似文献
18.
Seven cores were collected from different sediment zones of tidal flats at Xinyanggang in north Jiangsu province in August 2007. Sediment grain-size distribution and radioisotopes of 137Cs and 210Pb analysis were carried out for these cores. Sediment rates of the cores and radioisotopes distribution in surface sediment in different zones of the tidal flat were calculated from the 137Cs and 210Pb activities in sediments cores. The results indicated that each tidal zone had experienced different evolution phases, hydrological dynamics in the tidal flats made the grain-size of the surface sediment change gradually. 137Cs and 210Pb activities on the superficial layer of the cores varied spatially and the reason was discussed. On tidal flats, the fluctuation of 137Cs and 210Pb activities in the cores reflected the special sedimentary characteristics. Vegetation affects the grain-size distribution and the vertical profiles of 137Cs and 210Pb in the upper depths. 137Cs and 210Pb chronology got the comparable average sediment rates on the tidal flat. The characteristics of 137Cs and 210Pb in the cores reflected various depositional dynamical environments in different tidal zones and gave information on the different evolvement phases of the tidal zones. Based on the information of grain-size distribution, texture of the cores, sediment rates and topography, the evolution lines of the tidal flat were reconstructed. 相似文献
19.
江苏北部潮滩沉积物中~(137)Cs和~(210)pb的分布特征(英文) 总被引：1，自引：0，他引：1
Seven cores were collected from different sediment zones of tidal flats at Xin-yanggang in north Jiangsu province in August 2007. Sediment grain-size distribution and radioisotopes of ~(137)Cs and ~(210)Pb analysis were carried out for these cores. Sediment rates of the cores and radioisotopes distribution in surface sediment in different zones of the tidal flat were calculated from the ~(137)Cs and ~(210)Pb activities in sediments cores. The results indicated that each tidal zone had experienced different evolution phases, hydrological dynamics in the tidal flats made the grain-size of the surface sediment change gradually. ~(137)Cs and ~(210)Pb activities on the superficial layer of the cores varied spatially and the reason was discussed. On tidal flats, the fluctuation of ~(137)Cs and ~(210)Pb activities in the cores reflected the special sedimentary characteristics. Vegetation affects the grain-size distribution and the vertical profiles of ~(137)Cs and ~(210)Pb in the upper depths. ~(137)Cs and ~(210)Pb chronology got the comparable average sediment rates on the tidal flat. The characteristics of ~(137)Cs and ~(210)Pb in the cores reflected various depositional dynamical environments in different tidal zones and gave information on the different evolvement phases of the tidal zones. Based on the information of grain-size distribution, texture of the cores, sediment rates and topography, the evolution lines of the tidal flat were reconstructed. 相似文献
20.
210Pb and 137Cs dating methods in lakes: A retrospective study 总被引：1，自引：0，他引：1
210Pb has been used for more than two decades to provide the geochronology of annually deposited sediments and to construct pollution histories. Evidence from some lakes suggests that this radionuclide may be adequately mobile to compromise dating reliability. This study provides one test of that possibility by comparing recent measurements of 210Pb and trace metals to ones carried out more than 20 yrs in the past. 137Cs dating is used to confirm sediment accumulation rates in the recent cores. In the three Connecticut, USA, lakes studied, sediment accumulation rates changed abruptly to higher values between 40-50 yrs ago (increasing by factors of 2.2, 2.9, and 3.0). In all three lakes, rates calculated from 210Pb distributions both above and below this horizon agreed, within measurement uncertainty, in recent and older cores. Furthermore, when the older data were corrected for 20 yrs of burial, the changes in slope in 210Pb distributions occurred at the same depth in each pair of cores. The depth of sharp peaks in concentrations of trace metals also matched. In general, this evidence supports the idea that sediments in these lakes have simply been buried, without significant diagenetic remobilization of 210Pb and trace metals . Nevertheless, some important differences were also observed. For two of the three lakes, there was a significant difference in average sediment accumulation rate during the past 33 yrs as calculated from 137Cs and 210Pb in the recent cores. Most potential causes for this difference can be ruled out, and it appears that one of the two nuclides is remobilized compared to the other. There were also significant differences in the total inventories of both 210Pb and trace metals (both up to 2 ×) between recent and older cores in some cases. This may be due to dissimilar sediment focusing, since it is not known for certain whether the new cores were collected at exactly the same sites as in the past. 相似文献