• 2013 Volume 32 Issue 10
    Published: 25 October 2013

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  • MAO Hanying
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    Security of energy supply directly influences China's national security and the process of modernization. In 2011, China's dependence on foreign petroleum has run up to 54.95%, exceeding 50%, the internationally accepted alarm level. Therefore, how to ensure long-term, sustained, secure and reliable energy supply for China becomes the top priority of China's energy security. By energy cooperation in petroleum and natural gas resources with Russia and five Central Asian countries, China can remarkably reduce the costs of freight and time because of not only the geographical proximity but also the efficient pipeline transportation. As opposed to the traditional way of seaborne imports (accounting for 88% of China's crude oil imports), the energy cooperation can greatly improve the safety and reliability of energy supply because there is no need to pass through the maritime strategic channels under the control of other countries. In this paper, from the geopolitical point of view, based on the in-depth analysis of geopolitical background, strategic needs, resource basis and the status of the energy cooperation of China with Russia and five Central Asian countries, the author predicts the prospects of energy cooperation and the scales of the cooperation in different stages to the year of 2030, and proposes energy cooperation projects and development plans. The main conclusions are as follows: (1) In 2015, Russia and Central Asian countries will account for more of China's import, from 12.3% (2010) to 20% in crude oil, from 10% (2010) to 50% in natural gas, and 26% of the import of comprehensive crude oil and gas resources; (2) In 2020, crude oil and natural gas imports from Russia and Central Asian countries will rise to 28% and 70% respectively, accounting for 38% of the import of comprehensive crude oil and gas resources; (3) In 2030, crude oil and natural gas imports from Russia and Central Asian countries will steadily stand at 26% and 75% respectively, accounting for 40% of the import of comprehensive crude oil and gas resources. This paper lists ten essential energy cooperation projects of China with Russia and five Central Asian countries. In order to enhance the level of cooperation, the paper puts forward four energy cooperation modes: loans for petroleum, production- sharing, joint management and technical services.
  • WANG Zheng, ZHAI Shiyan
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    This paper describes the concept of computer-aided experimental human geography, which has been proposed as a methodology in geography. Experimental human geography is defined as a geographical methodology to reproduce human geographical phenomenon experimentally by means of computer sciences and GIS technologies. Its academic function is to study human-environment relationship under explicit geographic structure, implicit characteristics of human behavior, and explicit and implicit environment information. Accordingly, the paper has discussed the scope, principles and technical roadmaps of experimental human geography. In comparison to experimental economics, the paper has found that, in principle, many methods and rules of experimental economics are still effective in experimental human geography, but experimental human geography is more concerned about approaching natural processes simulation of geographic environment. Therefore, certain pre-designed models and special algorithms are necessary for experimental human geography. The experimental human geography rules include "value-induced" principle, "response-game" principle, "experimental control" principle, "statistics-based conclusion" principle, "geographical approximation" principle, and "experimental packaging" principle. Using the methodology of computer-aided experimental human geography, this paper studies the urban residential location choices, with two study objectives: (1) When the layout of urban infrastructure changes, what factors affect the dependence of the subjects on the city center, the reasons for destroying this dependence. (2) Whether the two different urban spatial structures, Burgess Model case and Hoyt Model case, would affect differently when the subjects were asked to choose a residential location. Based on the experiment objectives, the author made five experiment assumptions: urban space layout, residential location, residential location price, job location, incentive mechanisms. And the results are as follows: (1) Differences in urban residential space structures didn't have significant impact on residential location choices of the subjects. (2) In the case of the two typical urban spatial structures, the subjects were more concerned about traffic condition and school district around a residential location when asked to choose. (3) The price factor was not an obvious impact on the residential location choices, which might be the reason that not too many subjects accumulate in a particular area. This case study has shown that the thought and means of computer-aided experimental human geography are feasible. In other words, it is feasible to study the characteristics of human behaviors, such as decision-making behavior, in a controlled experimental environment with clear and realistic geographical structures and designed experimental contents based on GIS and computer technology. In short, this paper tries to develop a basic scientific framework for computer-aided experimental human geography, and much more remains to be done in the future.
  • BI Shuoben, JI Han, LIANG Jingtao, QIAO Wenwen, LI Xiliang
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    To study the distribution mechanism of prehistoric human settlements in Zhengzhou-Luoyang region, the relationships between the settlements distribution and the four environmental factors including elevation, slope, aspect and distance from water are analyzed with the support of GIS. On that basis, in the form of a graph of the region showing different suitability levels, a suitability index evaluation system is constructed and the settlement index model is established. The results of the model are then compared to the specific circumstances of the site distribution to explain the characteristics of, and possible reasons for, the settlements distribution. This approach enables the research based on documents and archaeological survey to reach more rational conclusions, and has great value for the interpretation of man-land relationship. The results show that: (1) Prehistoric settlement site selection was strongly influenced by the four environmental factors mentioned above. Low plain area was more convenient for prehistoric human to live, commute and plant crops. Most sites lied in the almost flat areas for minimum impact caused by the potential energy of the surface runoff, and it also helped build houses and resist natural disasters. Living at places facing the south not only kept out the wind but also promoted vegetation, growing crops and other farm produce. Water resources were made possible by living near lakes and rivers. (2) In Peiligang Period, the survival skills of humans had yet to be developed. They were heavily dependent upon the surroundings. They had to occupy the most suitable areas as much as possible to live on the abundant natural resources. In the Early Yangshao Period, based on the fact that the number of people living in the most suitable places decreased, humans had become adapted to nature and started to explore it. Not only they found out ways to locate the best places for living, but also they began to expand their living environment, suggesting that humans had advanced in their ability to carry out the production activities on their own. In the Late Yangshao Period, the capability of human activities didn't expand, and the suitability played less of role in choosing settlement sites. In Longshan Period, the prehistoric culture boosted, productivity increased, and by contrast the number of humans living at most suitable settlement sites increased, which means social stratification appeared so that the higher class had the power to occupy the most suitable settlement sites. The ability for humans to live by their free will or even remodel the nature had been further improved. To sum up, the research on spatial distribution of the Neolithic settlement sites in Zhengzhou-Luoyang region on the basis of index model provides a new approach to the field of archaeology from managing and decision-making aspects.
  • LUO Haijiang
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    Urbanization is the most intense human modification on natural environment. To understand the effects of urbanization on terrestrial ecosystem, it is valuable to study the differences in plant phenology between urban and rural areas. Taking Beijing as an instance, this paper attempted to address this issue. The MODIS NDVI (MOD13A2) with the spatial resolution of 1 km×1 km and at the 8-day interval during 2002-2009 was used. The time point when the NDVI increased most rapidly in spring was defined as the start of growing season (SOG) and the time point when the NDVI decreased most rapidly in autumn was defined as the end of growing season (EOG). The days from SOG to EOG were the total days of growing season (TD). We illustrated the climatological spatial variations of SOG, EOG and TD, respectively, in Beijing metropolis area. In addition, we illustrated the temporal variations of SOG and EOG from 2002 to 2009 for urban core area, urban margin area, surrounding rural area, respectively. We found that the SOG advanced and EOG delayed from rural area to urban area. The SOG in urban core area was earlier by ~20 d than surrounding rural area, while EOG was later by ~15 d than surrounding rural area. As a result, the TD in urban area was 35 d more than that in the surrounding rural area. More importantly, the inter-annual variability of phenology of urban area and rural area was consistent with each other, but the tendency of phenology of urban area and rural area were reverse. From 2002 to 2009, the SOG in urban area delayed gradually and EOG advanced gradually, while in rural area SOG advanced gradually and EOG delayed gradually. As a result, the TD in urban area decreased gradually whereas that in rural area increased gradually. Although the NDVI-derived phenology might have some uncertainties, the spatial variability and temporal variation mentioned above could be verified by ground-based observations. Moreover, the amplitudes of inter-annual variations were different between urban area and rural area. The SOG and EOG in urban area had larger inter-annual variability than those in rural area. The reasons for these differences remain unclear. These findings quantified the differences of plant phenology between urban area and rural area, and thus revealed the modifications on plant phenology by human urbanization. This study shows the value of providing an instance for studying human modifications on environment. In the future, it is needed to study the reasons for the above mentioned differences in phenology between urban and rural. In addition to the urban heat island effect, it is also worthwhile to study the role of other conditions, such as air pollution and relevant modifications on solar radiation, night light, irrigation, and so on. Furthermore, as a potential research direction in the future, it is needed to further quantify the changes in the carbon sink/source resulted from the different plant phenology between urban area and rural areas.
  • WANG Jiaoe
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    The relationships among urban transportation, land use and urban spatial structure are always the key topics in the studies of urban geography, urban planning and urban transportation. With the emergence of the issues such as urban sprawl, low efficiency of land use and traffic jam, it has become more and more important to study how to coordinate land use and urban transport in the planning of city development. As we all know, public transportation is not only one of the elements of urban lives, but also a driving force of urban spatial devolvement. TOD (Transit Oriented Development) is an urban development model under the guidance of New Urbanism, which emphasize the innovation of transport technology and the recognition of humans themselves. TOD integrates a mass transit system into the urban spatial structure, i.e., residential areas and commercial areas, at the macro-level, and neighborhoods develop around the transit stations or stops at the micro-level. TOD encourages high density development in an appropriate scale, mixed land use, comfortable environment for pedestrians and a good public transit system, to harmonize land use and transport, and finally enables the urban spatial structure to develop compactly and orderly. This paper analyzes TOD's mechanism on urban land use and urban spatial structure, and has found that TOD plays an important role in urban land use by influencing land use density, land use structure, and land value. Meanwhile, TOD influences the urban spatial structure by unique road structures, urban scale and urban spatial distribution. Further study indicates that the construction of mass transit makes the curves of urban rental and land development density show "multi-peaks" characteristics, following the principle of "decreasing from the city center with the increase of travel time". Although there are differences between China and other countries in urban population density, mixed land use, land property and public transport service, this paper attempts to build a suitable TOD model for the cities in China. The TOD model is built in three parts (steps): gross urban development, urban spatial structure and design of TOD unit, which results in a hub-and-spoke urban structure, with mass transit routes as corridors and the TOD node as a hub. Based on the types of public transportations, a TOD can be classified as a BRT-oriented TOD or a Rail-oriented TOD. Each city can choose the type suitable to its urban population, GDP, financial capacity and traffics along the transit lines. Design of TOD units should consider land use principles including distance, density, diversity and design, and adopts a special land use strategy. Finally, this paper puts forward a series of measures, policies and suggestions to ensure a successful TOD implementation, with time and location as two major impacting factors. Generally speaking, when a city is developing and expanding its urban areas rapidly, construction of mass transit will greatly influence its spatial distribution; conversely, when a city is developing slowly or has already reached its mature period, the effect of mass transit on land use is relatively small. In a word, TOD emphasizes the integration of local efficiency and overall efficiency and is a suitable model for urban development in China.
  • ZOU Lilin, YANG Jun, HU Xuedong
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    Since the start of "reform and open" policies, urbanization level of China has increased from 17.92% in 1978 to 51.27% in 2011, urban built-up areas have expanded from 7438.0 km2 to 43603.2 km2, and urban populations have changed from 172 million to 691 million. In the meantime, urban residential housing price has become the focus of attention of general public, and especially the temporal-spatial changes of urban residential housing price have become one of the key research topics in urban geography and urban economics. Urban residential housing price and its distribution, as an important parameter of shaping the tempo-spatial pattern of a city, have its intrinsic regularity in space and time. It is important to explore the mechanism of housing price change and the impacting factors in order to establish a strategy at macro-level to control and regulate the housing price. Review of the literature showed that: (1) The content of the research, based on the theories of urban spatial structure in the West, mainly focus on theoretical exploration and empirical analysis of the mechanism of housing price change in the 21st century, e.g., the tempo-spatial changes, change patterns, the influencing factors. (2) As for the research methods, spatial analysis based on GIS reveals residential housing price changes in time as well as the spatial pattern of housing price differences. A statistical model helps recognize and quantitatively analyze the factors affecting the residential housing price. The results have proven that GIS technology and the statistical model based on econometric theories are both effective means to study the temporal-spatial changes of urban residential housing price. (3) Speaking of research perspectives, the analyses are conducted from the views of geography, sociology, economics, political science, and other multi-disciplinary perspectives, on the temporal-spatial dynamics, the mechanism of the residential housing price changes and influencing factors, which provides a strategic reference to the system and roadmap to control and regulate the housing price. In addition, the review concluded that the current research is still not sufficient, and needs to be deepened in contents and methods. In the future, the research of temporal-spatial changes of urban residential housing price should be based on the special background of the economic transition and system reform, and the construction of a theoretical framework for the research needs to be emphasized. It is necessary to strengthen the quantitative study of macroscopic factors impacting residential housing price, and explore all factors which cause the price to be lower in certain areas, in order to make a comprehensive study of the influencing factors. GIS should be utilized to a greater extent in analyzing the characteristics of temporal-spatial changes of residential housing price, and the dynamic GIS model, including multidimensional space in time series, needs to be created and used in the simulation analysis and trend prediction. All of research results should have universal applicability and complement the monitored results of the dynamic of urban residential price changes. In summary, this paper made a systematic review and summary of the research on tempo-spatial changes of urban residential housing price, i.e., the driving mechanism, change patterns, influencing factors and research methods, and pointed out the prospects of the research, its needs and trends, in promoting the deepening, blending and more innovations of the study, as a reference for further research in this field.
  • WANG Xiangdong, LIU Weidong
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    Since the birth of modern planning in the late 19th and early 20th centuries, numerous planning theories have emerged. Despite that they have fundamental and guiding significance for planning research and practice, it is very difficult to understand and master these planning theories perfectly, due to the diversity and complexity of related theories in the literature. Though related papers already exit, there are serious shortcomings and deficiencies in the studies on this issue. For example, few researches have given comprehensive review of modern planning theories both domestically and internationally. This paper is an effective effort to overcome the obstacles and shortfalls, to help understand and master modern planning theories. In order to do this, by thoroughly combing through both domestic and foreign literature, modern planning theories are explored and analyzed precisely and sequentially. The history of modern planning theories can be divided into four periods, as discussed in four parts of this paper, involving many theoretical factions. The background, ideas, and influences of each theoretical faction are inspected carefully. Physical planning theory and Marxist planning theory before 1950s are discussed at first. Then, in the second part, the 1960s' comprehensive rational planning theory, incremental planning theory, humanist planning theory, and neoliberalism planning theory are reviewed. After that, Neo-Marxist planning theory and neoliberalism planning theory between 1970s and 1980s are commented briefly. At last, in the fourth part, the new emerging theories after 1990s, including communicational planning theory, sustainable planning theory, neo-institutional planning theory, and public policy planning theory are analyzed. Thus, basically all major theoretical factions of modern planning are covered. In addition, some low-impact theories are also discussed, such as mixed scanning methods, action planning theory, and negative planning theory, et al. As the theories emerged one after another, at the same time a wealth of literature has been published. Through the above review of modern planning theories, we can see that these emerging theoretical factions have different perspectives and concerns, such as substantive, procedural, or essential. There are also complex relations between them. For example, Marxist or neo-institutional planning theory is innovational, communicational planning theory is the inheritance of humanist planning theory, incremental planning theory is rebellious against comprehensive rational planning theory, and humanist planning theory is supplemental to comprehensive rational planning theory. We know that modern planning theories have absorbed multi-disciplinary knowledge, involving architectonics, politics, economics, geography, systematics, environmental science, urban studies, and so on. Above that, modern planning theories are impacted greatly by their own practice and the time, showing significant stage-specific characteristics. We also see that, compared to the U.S. and Europe, the Chinese scholars are lagged behind in terms of the contributions to modern planning theories. Greater efforts should be made by Chinese scholars to catch up in the future.
  • ZHENG Peng
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    Tourist flow is the premise of tourism industry and one of the key issues in tourism research. Currently, research on tourist flow is mainly focused on spatial and temporal characteristics and diffusion of inbound tourist flows, and the driving forces of tourist flows have yet to be investigated. As a social phenomenon, tourist flow is one type of mass population movement, and its driving forces are complex and multifaceted. From literature study, we have found that the scholars view the driving forces of tourist flows differently, based on their own professional background, and it boils down to the two perspectives: macro and micro. Yet, in the process of understanding the world, the results we obtain are incomplete if we exclude certain ways or perspectives. If we only rely on annual statistical data at the tourist destinations, a macroscopic point of view, we will likely fall into mechanical materialism. If we only use survey data to analyze the driving forces of tourist flows, a microcosmic point of view, then we will be lost in the abyss of the personal opinions. In social sciences, humans are both social objects and social subjects; people abide to the dominant social laws, but may also take initiatives. Therefore, it is necessary to conduct the research on the driving forces of inbound tourist flows from both angles: destinations and the tourists. In light of the disparity and complementation between the two perspectives, we have built a so-called double-vision driving force model for inbound tourist flows. From the macroscopic view, inbound tourist flows are driven by the social factors at tourist destinations. From the microcosmic view, inbound tourist flows are driven by the factors at the individual level, including personal motives, sensation and the other factors. The study has not only taken into account the comprehensive factors, but also explored the differences between the two perspectives. This model emphasizes the integration of the macroscopic and microcosmic perspectives, and also highlights the differences between the two perspectives, including "tourism resource", "economy", "traffic", "service" and "key attractions", "facility and environment", "knowledge and novelty", "social and health". This study is helpful for more comprehensive and systematic understanding of the driving forces of inbound tourist flows.
  • CHEN Jing, ZHANG Jinhe, LIU Zehua, ZHOU Jing, YANG Lu
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    Travel blogs can provide a virtual platform of sharing travel experiences and feelings for tourists, and is becoming a reliable source of information for tourists' decision-making, which has received extensive attentions from the academia circle and tourism professionals. Thus travel blogs have become a new tourism research object. This paper attempted to make a comprehensive analysis of relevant literature regarding travel blogs from 2005 to 2012 at home and abroad. The analysis procedures and results were as follows: (1) Domestic and foreign research started relatively late, but developed rapidly. Achievements were mainly published on tourism marketing and management journals. (2) The major research contents were categorized. Bloggers, blog's content and travel-blogging techniques were the main research subjects. Firstly, the analysis of bloggers included blogger's demographic characteristics, writing of blogs, and blogger's travel behavior. Writing of blogs was analyzed in terms of writing motivation, writing time, writing skills and blog's sharing. Blogger's travel behavior was analyzed in terms of travel motivation, travel spatial behavior and satisfaction level. Secondly, the analysis of blog's content included its effect on potential tourists, image construction of tourist destinations, and tourist destination marketing. Thirdly, travel-blogging techniques were proposed to solve the problems with blog-using, including information searching, information extraction, information sharing and writing application. Foreign studies have made considerable amount of progress on these subjects, and mainly focused on blogger's travel behavior, blog's effect on destination marketing and blogging techniques. Domestic research has been only focused on blog's influence on image construction and marketing of travel destination. (3) Main research methods were analyzed comprehensively in terms of their characteristics and the insufficiency. Firstly, in the aspect of information searching methods, searching on the Internet has been widely used. The paper listed the searching websites and made a comparison between Website searching and online survey methods in term of the cost, amount of information, authenticity, integrity, operability and so on. Secondly, in the aspect of analysis methods, there were abundant methods to analyze the content of blogs at home and abroad, including word frequency analysis, semantic network analysis, discourse analysis, interpretative analysis, narrative analysis, digital ethnography analysis, phenomenology analysis, stance-shift analysis and so on, among which content analysis and narrative analysis have been most widely used. The paper also made a comparison between content analysis and narrative analysis in term of their advantages and disadvantages. (4) The paper looked into the possible directions of future development from three aspects, namely, research scales, research contents and research methods, providing references and enlightenment for further application and study. In the aspect of research scales, it was suggested that the comparative study of different scales should be enhanced. In the aspect of research contents, it was suggested that the perspective of local community should be considered, and other contents in blogs could also be analysis objects, such as pictures and videos. And the results should be complemented by field research because bloggers are not representative of all tourists. In the aspect of methods, domestic study should learn the advanced theory and research paradigm from foreign research, as well as strengthen regional research constantly, in the hope to construct China-style travel blog research system.
  • LI Yajuan, CHEN Tian, WANG Kaiyong, WANG Jing
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    A community with an ethnic minority group as the majority of the residents is a special type of community. The unique nationality, culture and regionalism within ethnic communities attract the attentions of researchers at home and abroad. This paper first reviews the origin and the history of ethnic community research abroad, summarizes the key areas in urban ethnic community research, and discusses rural ethnic community research from the aspects such as influences, types, transitions of the communities, and tourism and perception studies. Domestic ethnic community research mainly includes the studies on connotation, evolution, development and impact on tourism. This paper compares the differences between the research at home and abroad in terms of field, method, object, theoretical basis and content. (1) From research field aspect, domestic studies focus on community types, influencing factors, spatial structure and development, from ethnologic, sociological and geographic perspectives, while the studies abroad emphasize on organization, social formation and social problem, from micro perspective of sociology and anthropology; (2) From research method aspect, majority of domestic studies adopt quantitative analysis and mathematical models, together with questionnaire, statistical information and satellite image. Foreign research is prone to study power center and relations between communities by using qualitative analysis of sociology, psychology, political economics; (3) From research object aspect, domestic studies pay more attention to rural ethnic communities, while development of urban ethnic communities is a key research area abroad, especially communities of different races within mega cities; (4) Foreign studies utilize the classical theory of typology and then expands to functionalism theory, human ecology theory, urban theory and the theory of community rights. Domestic studies adopt differential pattern theory with local characteristics based on the functionalism theory; (5) From research content aspect, domestic studies value connotation, influence factors, evolution features (traditional culture, land use, livelihood and language, etc.), tourism development and tourism impact research. Foreign researches study the education, medical treatment, employment, health, conflicts and crime problems of different races within an ethnic community. As discussed above, domestic research on ethnic community emphasizes on geographic and historic factors and pays less attention to social-cultural and political factors; the perspective hasn't been transformed from nature oriented to economy and society oriented. The research paradigm still lies at the level of spatial analysis and hasn't been shifted toward humane direction. The existing studies rest on the geographical concept of "community", focus on a single community, and ignore the communication and development between communities. Meanwhile, the studies lack in-depth analysis on residents' development from policy-making perspective. Finally, this paper puts forward seven future focuses for domestic ethnic community research, including, (1) factors influencing ethnic community evolution, (2) dynamic evolution mechanism, (3) residents' livelihood, (4) cultural heritage conservation and utilization, (5) economic structural coordination, (6) spatial form evolution and integrated development, (7) policy making for sustainable development.
  • ZHU Dayun, WANG Jianli
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    Ice core is an important information carrier to reconstruct paleoclimate. Because of its high resolution, high fidelity, huge amount of information and long time scale, it has become a research hot spot. Since the first ice core was found in Qilian Mountain in 1986, in China many other ice cores have been successively drilled in Tibet Plateau, such as Guliya, Malan, Dasuopu, Puruogangri, Dongrongbu and so on. In this paper, we provided a review and summary of study results with the ice cores mentioned above, and discussed the approaches and indicators of ice cores as information carriers reflecting paleoclimate, shown as follows. (1) The significant corresponding relationship between Oxygen isotope and temperature: Oxygen isotope shows a positive correlation with temperature though it is affected by "amount effect of precipitation water" in the southern part of the Tibet Plateau. (2) The relationship between accumulation of ice core and precipitation: accumulation of ice core can be used as a direct record of glacial precipitation, and, at the same time, the amount of accumulation indicates climate change in the past. (3) The relationship between atmospheric aerosols and climate environment: the climate environment reveals the changing history of atmospheric aerosols and helps understand the geomorphological evolution and intensity changes of atmospheric circulation of the surrounding areas on the Tibet Plateau in the past. (4) The relationship between trace elements and paleoclimate: trace elements can be used to explore the connection between ice core records and solar active rhythm. It also indicates the influence of industrial pollution on glacier environment in the high altitude. (5) The relationship between ice core inclusions and paleoenvironment: ice core inclusions are the complete preservation of ancient atmosphere, and can be used for comparing and reconstructing the ancient atmospheric composition from different historical stages and reflecting the information of environmental changes of this region in the long time. (6) The relationship between microorganisms in the ice core and the ancient environment: microorganisms in the ice core record the response to the environmental change in the past through its own unique biological characteristics. Microorganisms of different depths reflect the environmental conditions in different periods. Then, we presented the response of the ice core in Tibet Plateau to paleoclimates, including some extreme climate events in the past, the Medieval Warm Period, the Little Ice Age, glacial-interglacial cycles, ENSO events, solar activity patterns and global warming since the Industrial Revolution, but the Tibet Plateau's response mechanism is not the same as that of polar regions. It has its own characteristics. We also explained the similarities and differences of the ice core in the reconstruction of paleoclimate under the influence of different monsoon systems because of the mutual influences of Indian monsoon, East Asia monsoon and the west wind on the Tibet Plateau. Finally, based on the current research status, we presented in-depth discussions on the prospects of the research such as: strengthening innovation in interdisciplinary studies, use of new technologies, development of alternative indicators, influence of the ice core record on factor assessment, creation of quantitative models, and other future directions.
  • HUANG Yuan, LI Beibei, LI Zhongming
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    Climate change is an important issue in science research, which deeply influences the human society. The historical climate reconstruction is one topic, which can provide reference scenario for analyzing current climate variation and simulating the future climate change. There were many climate proxies from natural recorders of climate variability such as tree rings, ice cores, fossil pollen, ocean sediments, corals and historical data. The dairies are important historical data for historical climate reconstructions, and there have been lots of studies both at home and abroad. The dairies included the private dairy, the private note, and letter with detailed date. There were weather records, phenological informations, and climatic events in the dairies. Although the dairies have some shortcomings such as time gaps and omissions, place limitations and the author's wrong understanding, they are advanced in daily weather records for extracting the details of climate change and weather process during a period and at the local level. In additional, the dairy-based studies can contribute to verifying the high resolution sequence of paleoclimate based on other climate proxies. In this paper, the current dairy-based studies were reviewed from three aspects including reconstructions proxy, research method and research subject. The dairy-based studies usually used the days of rain and snow, the plant phenological period, the life experience records, and etc. These proxies can be divided into three types including quantitative proxy, semi-quantitative proxy, and qualitative proxy. The quantitative proxy can be counted and compared to the modern meteorological data. The semi-quantitative proxy was the record which reflected the range or the rank of the weather condition or climate phenomenon. The qualitative proxy mainly was the feeling of the people which was hard to be quantified. With the process of the research development, the method of dairy-based studies turns from the simple qualitative analysis method to quantify analysis method, like regression equation method. The conclusions were as follows: (1) The frequently-used proxies were the number of days and experience records both in home and aboard studies; and the domestic researches also used natural plant phenological period; and the foreign researches used wind direction and cloud cover as well. The reconstruction proxies were classifies to quantitative proxy, semi-quantitative proxy, and qualitative proxy. Both the domestic and foreign scholars used the quantitative proxy and qualitative proxy more frequently than semi-quantitative proxy. (2) The foreign and domestic academics usually applied the qualitative analysis method and quantitative transformation method. In the data verification, the foreign researches often chose instrumental data, and the domestic researches often used the official files and chorography. (3) The subjects of foreign researches mainly were the local temperature and precipitation, while the domestic studies not only focused on those but also studied dusty weather and precipitation characteristics during sand storm and plum rain period.The advantages of using diaries to reconstruct historical climate include the abundant details in climatic record, high time resolution and high veracity of the reconstruction result. In the future, the ancient diary research should enhance the quantitative transformation method and the verification with other proxies. As the diary-based reconstructions increasing and the method improving, there would be long climate series on large area, which will contribute to the historical climate research.
  • WANG Chuanfei, WANG Xiaoping, GONG Ping, YAO Tandong
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    Plants can absorb persistent organic pollutants (POPs) from air and soil. Roots sorption is one of uptake processes, while evidence showed that POPs absorbed by roots was hardly transferred to the aerial tissues of the plant. The POPs re-volatilized from soil may only influence the parts of plants near the surface of the ground. Compared to the absorption from soil, the absorption of atmospheric POPs by foliage raised more concern. The airborne POPs can be accumulated by plant leaves by wet and dry deposition, which is the main pathway of the atmospheric POPs entering the aerial parts of plants. Air-plant exchange equilibrium is an important state that determines the direction of gas exchange between air and plant. The airborne POPs partition onto plant and approach plant gas-phase equilibrium rather rapidly, within less than 6 days of exposure. Besides exposure time, other environmental factors (temperature, wind speed, humidity, etc.) and the shape, areas and life time of the leaves have impacts on the air-plant exchange equilibrium of POPs. Through the air-plant exchange the airborne POPs were fixed by the plants and finally transferred into soil by falling off the leaves. Therefore, the air-plant exchange of POPs will influence the long-range atmospheric transport and the regional, even global distribution of POPs. Plants such as lichens, mosses, grass and forest have been used as passive samplers to monitor the levels of atmospheric POPs on different time scales and reflect the spatial distribution of POPs. Lichens and mosses are extensively used in environmental pollution studies especially in the polar region, since their collection is relatively easy. For grass, different species have the same ability to absorb the airborne POPs, which was used as bio-monitor to compare the POPs in different regions over the world. Numerous studies indicated that plants act as a "sink" for global cycling of POPs. The POPs absorbed by plants will enter the terrestrial food chains through the consumption of plants by animals and will be transported from one trophic level to a higher one, which will result in bio-concentration and even pose potential threat to the health of humans. However, there are a few studies focusing on the bio-concentration of POPs in the terrestrial food chains currently and most of them utilize models to simulate the bio-concentration process. In this paper, the research progress on the accumulation of POPs by plants including the ways of POPs entering the plants and the air-plant exchange of the airborne POPs were reviewed; the advantage and disadvantage of vegetation passive samplers (lichens, mosses and grass) were discussed.We also pointed out the problems needed to be solved in further studies.
  • CHEN Shiji, ZHOU Limin, ZHENG Xiangmin
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    Total Solar Irradiance (TSI) is defined as total energy of electromagnetic radiation of all bands from the sun to any sphere (including the Earth's surface) in per unit area and per unit time. Change of TSI in solar active cycle has been considered as one of important candidate factors impacting global climate change. Monitoring and reconstruction of TSI is the important foundation for the study of the mechanism of how solar activities drive global climate change. In this article, we first reviewed the history of both ground-based and satellite- based TSI monitoring and the results they produced. Then, we analyzed the research progress on, and the problems in, using cosmogenic nuclides and celestial information to reconstruct TSI series. Finally, we provided an outlook of future directions in this field. Existing ground-based and satellite-based TSI monitoring has access to lots of TSI series of different time-scales and temporal resolution. The TSI monitoring data shows that TSI changes very little in each solar activity cycle, not enough to cause the earth surface temperature rise observed and documented in a variety of records. However, solar physics has not yet fully interpreted the physical process of TSI change, and, with limited TSI monitoring data, it is difficult to find out the mechanism of how solar activities cause TSI changes and drive the climate change. It is also impossible to accurately determine the variations of the past or future solar activities and TSI. In addition, due to instrument capacity, service time, monitoring environment and other objective factors, the TSI data has many uncertainties. Therefore, it is necessary to continue exploring the mechanism of solar activities and the TSI change, develop higher precision equipment, integrate different data composite methods, such as ACRIM, PMOD, and IRMB, and adhere to long-term TSI monitoring. In addition, use of cosmogenic nuclides such as 10Be and 14C in reconstructing TSI change caused by solar activity is also necessary to obtain long-period TSI series. By using cosmogenic nuclides, many historical TSI series have been reconstructed. Since the index of cosmogenic nuclides is an indirect record of TSI, we need to find out the records directly driven by TSI change. Explorations to other planets in the near future may provide a unique opportunity to resolve this issue. Currently, deriving historical TSI from celestial information such as lunar borehole temperatures has proved to be feasible. Furthermore, limitations of these methods should be noticed, and we need to improve the method of TSI reconstruction, so that we can get longer sequences and more accurate reconstruction of historical TSI. With the accumulation of long-term TSI monitoring data and progress in long sequence historical TSI reconstruction, we will obtain more and more detailed and reliable TSI series. It's important to objectively assess the impact of human activities on global climate change, and take effective measures accordingly to achieve the sustainability of earth surface system.