China’s national economy has experienced a long period of rapid growth, but prominent structural problems have already appeared. Instead of following the traditional research approach of investigating the speed of future economic growth through investment, consumption and export, this article analyzes the capacities of systems which support economic growth, including resource (energy), environment (bearing capacity) and the urbanization and development patterns on the basis of resources and environment. It includes seven aspects: ① It points out that the long period of high-speed-but-low-efficiency economic growth has led to the structural problems at the current stage. ② It analyzes the serious situation of China’s environmental pollution. ③ It argues that excessive consumption of natural resources may bring about severe national security issues. ④ It indicates that urbanization is the most important supporting factor of the high-speed economic development of our country.⑤ It holds that the development patterns of “world factory” of low-end products and relying on investment which have been practiced for a long period of time are important concepts and supports of the high-speed economic development of China. ⑥ It also argues that China has taken full advantage of backwardness which has limits in fact. ⑦ Finally, based on practice and international experience, it analyzes the relationships between the speed of economic growth and employment, the influence of the country, and economic transformation briefly. Based on these analyses, a meta-synthetic research is conducted and the following conclusions are arrived at: China’s economic development will enter a stage of moderate-speed growth rather quickly. The economic growth of a moderate speed will create significant opportunities and spaces for building economic superpower and achieving a harmonious society in China.
Regional spatial links is based on the interactivity phenomenon between different objects space, the aviation links is one kinds of space relationship. According to the national domestic flights information data(data of Hongkong, Macau and Tiwan excluding), using GIS spatial analysis method base on O-D network, by means of carve every aviation links within the large dimension data space, this article analyses the network structures of the aviation links between national center cities which open to air traffic, compares with special links in the abstract, and display airline network structure and its spatial atlases by different transport distance in China. Research shows, aviation network distribution highly coincide with population and economic space in China, large city agglomeration characteristics is significantly, the whole spatial distribution is not balanced. Based on the flights data, central cities can be divided into 4 grades as national, regional, provincial and local center, including Beijing, Shanghai, and Guangzhou as the national center. The study also found, national airlines mainly concentrated in the 600-2 000 km space distance range, and the aviation links network with the spatial links shows strong correlation during this range, indicates China’s domestic flights suitable travel during this spatial distance range, aviation links on the whole subject to spatial distance attenuating tendency. The regional distribution of the air passenger flows is extremely out-off-balance, the eastern air transport status is extremely prominent, the west is relatively strong, the central and northeast relatively weak. Air passenger flows interflows mainly concentrate on the eastern coastal to western, central and northeast regional, and extremely less between western, central and northeast regional.
This article focuses on the differences of regional development and the changes of spatial structure resulted in the introduction of some new factors. Based on the data of road efficient, ordinary train, CRH and information network of 13 cities in Jiangsu Province, we analyses characteristics of provincial spatial structure and judge the development trend from the viewpoint of space of flows. The results are as follows: 1) The road and ordinary train network shows a relative disordered spatial structure and its impact scope is also limited. The CRH network highlights the important position of the developed areas and expands the effective range of the city along the Beijing Shanghai High-speed Rail greatly. The information network reflects a more complete, orderly and coordinated spatial structure, which also represent the future of the comprehensive linkage network in Jiangsu Province. 2) Under the impact of CRH and information network, the factors which dominates the regional spatial structure is not the space of places but the space of flows. So some new features and trends which are different from the traditional ones are found, such as connecting with non-adjacent cities and the tendency of “hierarchy+network”. 3) Different from the traditional judgments of spatial structure in Jiangsu Province, this paper which is based on the comprehensive linkage network of traffic and information flow presents the obvious pattern of "core-periphery". The regional connection density declines from HuNing line to the coastal line and the calculation of SSI also supports this assertion. 4) The new element flows generate positive and negative influence to the efficiency and justice of changes of the spatial pattern in Jiangsu province. The former reflects in the improvement of regional accessibility and promotes the development of regional economy and the latter reflects in the huge "siphon effect” in the core cities. But with the improvement of regional comprehensive connecting network and the strengthening of radiation in Shanghai-Nanjing axis, the cities in Middle-Jiangsu and North-Jiangsu will function more as the central cities and transfer stations on the other hand, which can also help the Yangtze River Delta to step into the era of network and polycentricity.
Under the background of the geo-economic era, the economic cooperation and competition among countries will be the main melody of international relations. Based on the perspective of country’s foreign economic relations in different kinds of import and export trade of the industrial product structure, China’s geo-economic characteristics and the influence are probed in the article. The overall situation of China's industrial products import and export trade is that the country's high import dependence on those countries which are rich in energy resources products and the uneven characteristics of the strong demand of the international market. While in the spatial pattern, a single and relatively stable situation has been showed in country, region, and approach, which may lead China to be a certain bias with other countries on the geo-economics. The index integrated with import of resources products and import and export of manufactured goods reveals that the uppermost factor affecting China's current geo-economic pattern is the export-oriented economy that dominated by import and export of manufactured goods. While the role of import of resources products is inferior to that of manufactured goods, and the effect of oil and iron ore is higher than that of natural gas. In spatial distribution, "area point" geo-economic spatial pattern has been formed by developed countries and its peripheral neighboring countries as well as countries rich in energy resources. China has generally formed a multi-circle hierarchy pattern from the near to the distant. Countries with low correlation lie in them and show a fragmented feature. This pattern indicates that China's geo-political situation is generally stable for some time to come, while in consideration of the accumulation and evolution of many uncontrollable factors, actively exploring and seeking diversified geo-economic space is one of the effective ways to deal with foreign economic contact emergency.
As one of the important tourism products, lake tourism develops rapidly. However, lake tourism research significantly lags behind its practice. This article analyzes the development trend and tourism efficiency of natural-level lake scenic area in China, and reveals the efficiency characteristics and spatial distribution characteristics. Based on which we divide it into four types, and finally puts forward the development measures and suggestions. The results show that: 1) the number and tourism income of natural-level lake scenic area are growing, lake tourism resource development has transferred from famous lake to general lakes. Tourism product types are diversified, while regional differences are fairly obvious. 2) The tourism efficiencies of natural-level lake scenic area are relatively low, the majority are still in the process of increasing returns of scales. Through decompositions of overall efficiency, the results show that the scale efficiencies are higher while pure technical efficiencies are lower. The interpretation ability of the pure technical efficiency on the overall efficiency ability is stronger than the scale efficiency, whose correlation coefficient is 0.722, is the major reason for the low overall efficiency. 3) We divide these 38 natural-level lake scenic area into four types according to the efficiency characteristics. The formation with higher efficiency is correlated with development period of lake resources, tourism capital investment and location conditions. The fourteen lake scenic spots have two of the following four characteristics at least. First of all, they are famous in the whole country or the whole region. As the high quality tourism resources, lakes can be developed to tourism products with large market competitiveness with higher output. Secondly, due to the early development period, traffic facilities and service facilities of the lake scenic spots are perfect, the experience and technology of product maintenance and marketing are more mature, also, the lake scenic spots are liable to contact with the neighboring scenic spots to form regional tourism routes. Thirdly, the moderate lake area is help to development, and the centralized production factors could enhance the level of construction operations. Last but not at least, the high economic development level of the cities which the 14 lake scenic spots rely on, the mature tourism market of these cities, the close distance between lake scenic spots and the central downtowns, as well as the good development of other types of tourism products nearby, make lake tourism products have the opportunity to merge with other types of tourism product to better development.
The industry structure locking-in is a common economic phenomenon, which is also not conducive to the resource-based cities’ sustainable development obviously. Huaibei is a typical coal resource-based city, which being have development foundations. The resource-based industry occupies an important proportion in the national economy, and the industrial structure locking-in is serious in long development terms. This paper makes the tracking study on the succession process of the industrial structure by shift-share analysis method for Huaibei. The research reveals some truth for us. Before the period of prosperity, the industrial structure had been locked in the coal mining industry, the electricity industry, the textile and clothing processing industry, and the agricultural product processing industry. During the recession period, the alternative industry, such as the industry of fine chemicals, the building material processing industry, the machinery manufacturing industry, the metal smelting industry and the metal product industry, developed gradually. In the transition development period, the locked industry deblocked step by step. For the difference, which between the industrial structure similarity coefficient, the Industrial concentration coefficient, the output locking-in coefficient, and the employment locking-in coefficient in different stages, were notable. The formation and evolution Process of the coal resource-based cities' industry locking-in includes five stages, that are the industrial introduction period, the minor locking in period, the medium locking in period, the serious locking in period, and the deblocking period. Each of these factors, including the resource endowment, the social, the technical, the market, the industrial policy and the people’s idea, had influence on the coal resource-based cities' industry locking-in. The alternative industries, which selected and cultivated in the transition development period, should be based on the existing industrial base.
With the continuous penetration of information and communication technology (ICT) in today’s society as well as its progressive development, research into the urban spatial structure influenced by ICT has attracted the attention of geographers. As ICT is integrated into the various aspects of the life and profession of individuals, each person has become an important medium for exploring the relationship between physical and network spaces. Consequently, research focus has shifted from such spaces to Internet users. Geographical space research is influenced by the rapid changes in social phenomena. Thus, new data, methods, and ideas are needed to further explore the relationship between network and physical spaces at the micro level.This article introduces the novel notion of “geography relevance” from the field of information science to the space research on information geography. We determine the level of cyberspace activity of urban residents from the micro-perspective of individuals and explore the index of space relevance between network and physical spaces. The aim is to highlight the role and position of the level of resident information and mobility in space research. With the city of Nanjing as an example, we conduct an urban resident survey using a questionnaire and obtain 973 samples for the database. Three indicators, namely, residence, workplace, and mobility network activities are adopted to measure the relevance between physical and network spaces. An index of resident information is constructed from two aspects: information level of urban residents and mobility. The index mainly includes the willingness of residents to share information, the degree of information sharing, residents’ information cognition, the residents’ habit of information sharing, the devices used for information sharing, information dissemination and acquisition, and mobility. The conclusions are as following . First, the index of space relevance between network and physical spaces at the micro level includes the degree of information sharing, residents’ information cognition, residents’ habit of information sharing, and mobility (p< 0.05). Second, mobility is the most important metric in space relevance, followed by residents’ information cognition, residents’ habit of information sharing, and the degree of information sharing. Third, the workplace is the most typical setting that demonstrates the close link between network and physical spaces. and enriches the perceived function of physical spaces.
The research of the evolution of rural settlement function plays an important role in solving the problems of rural development. With the rapid development of social economy, functions of rural settlement have tended to variety. However, there are few studies of evaluation of rural settlement functions and its driving factors. Based on the remote sensing and GIS technology, this article takes Hetaoyuan village in Yimeng Mountains as an example, and explore an analysis frame work of the evolution of rural settlement functions to study the evolution of rural s ettlement functions through farmers’ livelihoods and inner structure of rural settlements with participatory rural appraisal (PRA). In this study, three functions (daily life function, agricultural productive function and non-agricultural productive function ) are recognized according to actual conditions in Hetaoyuan village. The data employed in this article was collected by household investigation and authoritative interview in 2013. The results are shown as follows. 1) According to the phase characteristics of farmers’ livelihood strategies, the evolution of rural settlement functions in Hetaoyuan village can be divided into three phases, agricultural production-oriented phase (I, 1949-1977), phase of diverse livelihood activities (II, 1978-1999), non-agricultural productive transformed phase (III, 2000-2012). 2) As time goes, livelihood strategies of rural households transformed from farming to farming, livestock breeding and cross-regional non-agricultural employment, and then turned to farming and cross-regional non-agricultural employment. Agricultural production is consistently dominant production function of rural settlement. Courtyard of rural households is used for vegetable planting in phase I, and livestock breeding in phase II, and grain drying and storage in phase III. Overall, there was a lack of land for non-agricultural production in rural settlement. 3) With the achievements of livelihoods, to pursue daily life function of rural settlement is increasing. It can be reflected from the optimized of residential building materials, the extension of daily life space and the renovation of old houses. 4) Currently, farming and cross-regional non-agricultural employment are the main livelihood strategies of rural households. Courtyard of rural households is used for grain drying, and storage room is used to store grain and agricultural implements. That is, agricultural production and life function of rural settlement are very compatible. It is scientific and reasonable to implement rural residential consolidation by considering the multi-function and structure of rural settlements. 5) The idle houses in Hetaoyuan village are caused by young labor force’s seasonal flow between urban and rural areas, and daily life function of these houses exit. Owing to lacking incremental indicators of homesteads, the idled and abandoned homesteads have potentialities in daily life function of rural settlements, which can be the sources of rural reconstruction.
The real estate industry of China has developed high-speed since 1998, when the welfare housing distribution was cancelled and the housing was commercialized completely. Especially since 2003, China's per capita GDP went over $1 000, the economy transformed into the take-off stage, and the commercial housing price rose into a fast lane. The housing problem is becoming prominent increasingly. For Chinese residents, owning a house has become an important part of Chinese Dream. Housing price to income ratio (PIR) is a commonly used indicator on the housing problem study. First of all, this article summarized and extended the connotation of PIR from the perspective of social, economic, and humanistic care. PIR is the measurer of housing affordability, the indicator of bubbles in the real estate market, and one of the important measurement indexes for measuring subjective well-being of citizens. In view of the lack of space and scale in the current research, the significance of studying PIR from the perspective of geography was put forward. On this basis, using ESDA and coefficient variation, the space-time evolution characteristics and distribution rules of China's urban PIR from 1999-2012 were analyzed from multi-scale (nation, province and city) systematically. Major conclusions can be drawn as follows: 1) The space-time evolution characteristics of China's urban PIR presented scale effect clearly. National scale showed fluctuations in the rising, provincial scale changed from rise to variance, and city scale rose like a flying geese. Besides this, PIR existed an obvious spatial autocorrelation under the provincial and city scale from 2007-2011, which indicated the co-movement of adjacent real estate market space enhanced significantly in China in recent years. 2) There were about 70% of the citizens living in big and medium-sized cities, whose revenue growth could not catch up with the housing price growth. Some of the cities were more likely to generate bubbles. With the housing affordability declining, the well-being of citizens also decreased gradually. 3) The spatial difference of PIR between provinces in the east and whole of China reduced before 2003, and increased after that. The difference between provinces in the central and western region shrank consecutively. The difference under city scale was larger than that of provincial scale dramatically. This change indicated the existence of scale effect and zoning effect. In brief, the conclusion revealed the regional difference and scale effect of PIR in China, which eliminated the common misunderstanding and could provide regional policy orientation and theoretical basis.
Coastline is not only identified the coastal shoreline land and water boundaries but also contains a wealth of environmental information. Coastline change is a dynamic process of evolution, whose changes directly affected intertidal mudflat resources and coastal environment, also cloud cause a variety of changes in the coastal zone resources and ecological processes. These changes can impact on coastal human survival and development.In this study,referencing the economy, marine legal system and the development process of management of sea areas of the ocean, Remote sensing images from Landsat and HJ satellite, of which 12 images from Landsat TM in 1990 and 2007, Landsat ETM+ in 2000 and HJ-1A HJ in 2012 were chosen. Color Canny operator automatic extraction technology was used to extract four periods of continental coastline, then the average Depth degree’s calculating model was built to get the AveD- AveD+ and SY of continental coastline in China. Then the rules of spatial variation characteristics and the stability were obtained nearly 22 years. 1) The promoting seaward distance is the major the variation of spatial distances of continental coastline in China; 2) The stable and strongly forward coastline are the major components of continental coastline in China, and thestable coastline is all over coastal provinces ,then the strongly recessing distributed mainly in the Jiangsu and Liaoning provinces. 3) Over the past 22 years, the stability of continental coastline were declining and its index fell by 1.1. The stability indexes of continental coastline the dividing line is in the Changjiang River estuary, southern coastline are generally higher than the northern coastal cities. It's found that the reason of the changes of shoreline position is the interaction of natural factors and human factors. Their affection are not the same.Natural factors are the main factors affecting the landward retreat of the coastline, such as seawater erosion, sea level rise and land subsidence. Storm surges and other marine disasters also caused shoreline landward retreat. Human use of the sea is a major factor in advancing to the sea coast.Reclamation farming, port construction, land filling, accelerated shoreline seaward. In addition to the extreme marine disasters, the impact of natural factors is mostly continuous and slow, but impact of human activities is quick and direct.
In recent twenty years, the study of plant geography has gained essential achievement in its theory and methodology, tended to synthetically interpret and analyze plant’s distribution pattern mode, formative process and mechanism from different levels at different temporal and spatial scales. However, current plant geography textbooks published in China still followed the outdated structure framework and content proposed during the period of 1960 to 1970. This status lagged obviously behind new development of the discipline. Therefore, some detailed suggestions are proposed to adjust, delete, update and supplement structure and content of current plant geography textbook as following. 1) The effect of global change on plant distribution pattern and practical applications in plant geography should be added into current textbook’s structure framework and content. 2) Some common knowledge and content in botanical and ecological textbook or in flora and vegetation monographs of the world and China are should be deleted or reduced. 3) Main advancement and future trend on plant geography, major theory and methodology, an introduction to international important academic journals should be supplemented into introduction part, some classical monographs and literatures should be attached to the end of each chapter. 4) All old black and white figures and photos should be replaced and updated with current colorful pictures. 5) High-quality multimedia teaching courseware, videos and CD should be made elaborately as a part of textbook. 6) New methodology are should be supplemented and updated into experimental materials and fieldwork guides of plant geography, such as plant phylogeography, plant community sampling and field monitoring techniques, data processing and analysis, remote sensing of vegetation, and vegetation mapping.
Based on the analysis of typical Arctic Oscillation (AO) years, this article classifies the January AO strength into normal, abnormal and extreme anomaly categories and investigates the characteristics of the atmospheric circulations associated with these three different AO strength as well as their effects on the North Hemisphere January surface temperature. The results show that the atmospheric circulations associated with these three AO strength and their effects on North hemisphere January surface temperature have significant similarities and differences. When AO is in abnormal or extreme anomaly phases, the similar and typical AO positive and negative phase distribution are observed from the lower troposphere to the tropopause. The atmospheric circulations in 500hPa are shown as the continual and stable east Asia trough, Ural Mountains and Lake Baikal blocking high, and Aleutian low. However, the corresponding intensity, area, southward and northward extension of polar vortex associated with these two AO patterns are different, which caused the different range of cold air activities in the middle and high latitude as well as the polar region. During the extreme anomaly years, the strength and the range of influence of AO are larger and more southward than that in the abnormal AO years, the corresponding configuration of high and low level atmospheric circulations cause the cold air extend to the middle and lower latitude of North Hemisphere, and the abnormally low temperature can extend to the North Pacific warm pool.
Using the daily rainfall data collected in 1980-2013 from 22 meteorological sites located across Northwest Yunnan, rainfall erosion force was calculated. According to Daily rainfall, by using those methods like Mann-Kendall trend test, inverse distance weighted method, sequential Mann-Kendall test, inverse distance weighted method and R/S test, etc. We analyzed the rainfall erosivity, moderate rain, heavy rainfall, erosive rainfall, the corresponding number of days of rainfall erosivity, temporal and spatial variation, mutation time and future trends. The result showed that: in terms of the erosivity for the rainfall at each level in Northwest Yunnan, the spatial distribution of the erosivity of heavy rain was basically consistent with the spatial distribution of the erosivity of the annual rainfall, but it was much different for the spatial distribution of the annual precipitation days, the rainfall erosivity of rainstorm and the rainfall erosivity of moderate rain. For the rainfall at each level, the distributional differences of the erosivity were decreased with the smaller rainfall precipitations; 67% of the annual rainfall erosivity was generated from the rainfall erosivity of heavy rain or at a higher level that accounted for 6% of the annual precipitation days; 28% of erosive precipitation days was generated from the rainfall erosivity of heavy rain that accounted for 45% of the annual rainfall erosivity. The precipitation days for the rainfall at each level were arranged as moderate rain>heavy rain>rainstorm while the rainfall erosivity was arranged as heavy rain>moderate rain>rainstorm. The unimodal type distribution was presented with the center in July. More than 85% of the erosivity for the rainfall at each level was taken place in the rainy season (from May to October). At the same time, the higher level the rainfall was, the greater the concentration was; over the past 34 years, the corresponding rainfall erosivity, precipitation days and rainfall precipitations were increased or decreased in the Northwest Yunnan. The erosive rainfall and the annual rainfall erosivity were increased of which the growing scopes were 6.7 mm/10 a and 26.6 MJ·mm/(hm2·h·a)/10 a, respectively. The variation trends of precipitation days, precipitation and rainfall erosivity were sustainable in the future. In the small parts of the Northwest Yunnan, the rainfall erosivity for the rainfall at each level and erosive rainfall were relatively reduced. However, the variation tendency was largely distinguished for most of the parts; the erosivity for the rainfall at each level and the annual rainfall erosivity were drastically changed in 1983 of which its growth point exceeded 0.05 of the borderline at the significance level. After the period from 2002 to 2006, the growth trend was no longer apparent.
As the global climate change and accelerating the process of urbanization, flood disaster becomes increasingly serious. Based on risk identification, evaluation index is selected from hazard factors, disaster environment, hazard bearing body and disaster prevention and mitigation. Evaluation index system is established. Using the analytic hierarchy process (AHP) to determine the criteria weights, Based on ordered weighted average (OWA) to calculate the order weights. Build OWA-GIS flood risk assessment model to evaluate flood risk in Chaohu Basin. The results show that the high risk is in southeast of Chaohu Basin, especially Lujiang, Wuwei, Juchao district and He county. Low risk areas are mainly distributed in the southwest, northwest and north of Chaohu basin, especially in Shucheng, Feixi and Feidong county. With the increase of the decision coefficient, the decision maker's attitude from optimism to pessimism, risk is also growing. The flood risk assessment based on OWA-GIS is a scenario analysis, evaluating risk status under different decision attitudes. More complex scenarios can be developed to predict the risk under certain natural and economic conditions and different decision attitudes in the future. The study provided scientific basis for planning and disaster risk management.
Lacustrine sediments are ideal natural archives for studying environmental changes in the past. A sediment core, namely CHX, was collected from the western Chaohu Lake, east of China and its grain-size features at the intervals of 2 cm were investigated in the present study. The changes of grain-size compositions throughout the profile CHX were reconstructed. Grain size parameters, including mean grain-size (Mz), standard deviation (Sd), skewness (Sk) and kurtosis (Ku) were calculated. It is found that those sediments are mainly composed of fine grained silt and clay. Mz, Sd, Sk and Ku and fractal dimension of the sediments suggest that those deposits were well to very well sorted, positive to very positive-skewed, very to extremely leptokurtic and also show evident fractal features. C-M pattern and probability cumulative curve of the sediments from core CHX unveiled an low-energy environment, and revealed that grains move in the major forms of saltation and suspension, which accounts for about 70% and 25%~30%, respectively. Principal component analysis (PCA) was applied to identify controlling factors for grain size features of sediments from the Chaohu Lake. From principal component analysis, it is identified that the first principal component (PC1) controls fine-grained clay content in the bulk sediments and further reflects the offshore distance of detritus in the lake. PC1 and mean grain-size Mz are thus robust markers for lake water level and local precipitation. These sediments can be further used to reconstruct regional precipitation history.
Based on the daily precipitation data of 30 stations in Loess Plateau of Gansu Province from 1961 to 2010, the spatial and temporal changes of precipitation were analyzed by the methods of liner trend, Mann - Kendall method and inverse distance weighted interpolation methods, Mann-Kendall method and IDW. analyzed the cycle characteristics and the relationship between the precipitation and PDO and ENSO by the continuous wavelet transform, cross wavelet and wavelet coherence techniques．Then, based on the above analysis, the future trends of precipitation were forecast by the method of rescaled range analysis. The results indicated that the average annual rainfall decreased by -1.54 mm per year, especially since the 1990s precipitation decrease obviously. In terms of season, In addition to winter precipitation showed a slight increase, the other quarter showed a decreasing trend, which decreased the most in autumn, followed by spring, summer. Spatial distribution, annual precipitation decreased in most areas in the Loess Plateau of Gansu Province, decrease in precipitation in the southeast region above the northwest. Precipitation had 2-3 year, 4.3-5 year oscillation circles, which was similar to the pattern of the two large-climate indices. There were the common patterns of 5-5.6 year oscillation circles between precipitation and PDO, ENSO, phase spectrum month precipitation change compared to the PDO and ENSO in advance. Precipitation had 3-3.5 year significant resonance circles with PDO, and close to the same phase shift, as well as has 0-3 year and 3-6 year showed a negative phase of the resonance cycles with ENSO. The Hurst indices of the precipitation are all bigger than 0.5 for all the stations, the fractal dimensions, meanwhile, are all less than 1.5, which indicate that precipitation would keep the same trend with the past in a period of time in the future.
Using 44 stations temperature and precipitation data of day by day in Southwest China in 1953-2012, latency evaporation is calculated by Thornthwaite method, from inter-decadal, inter-annual, inter-seasonal variability, extreme and persistent characteristic of drought and flood analyzed over southwest China in past 60 years by homogenized drought-flood index of precipitation and latency evaporation. The results showed that: From the point of view of space trends to see, it displayed consistent drought trend in autumn and whole year over southwest China in past 60 years, but it displayed regional drought-flood trend feature in spring, summer and winter. Precipitation is main driven factor of drought-flood change in spring and summer, temperature is main driven factor of drought-flood change in winter and whole year, but driven function of precipitation and temperature are all notable in autumn. Therefore it is not objective to analyze drought-flood change only by precipitation, driven function of temperature must be considered. From the point of view of time evolution to see, it displayed drought trend by driven of temperature and precipitation double factor in spring, summer, autumn and winter over southwest China in past 60 years. By comparison, drought degree is strongest in autumn, but it is weakest in spring, and it is quite in spring and winter. However annual drought degree is stronger than that of seasons. From multiple time scales of view of extreme drought-flood to see, on interannual and decadal scales, extreme floods occur frequency gradually decreased, and extreme drought occur frequency gradually increased in past 60 years over southwest China. From inter-seasonal scales of view of extreme drought-flood to see, there is a greater probability of extreme drought in spring and winter, but it is smaller in summer, and there is a greater probability of extreme flood in summer, followed by spring ,but it is smaller in autumn. From month scales of view of extreme drought-flood to see, there is a greater probability of extreme drought on August, followed by February, but it is smaller in June, and there is a greater probability of extreme flood on August, followed by February, but it is smaller in January. Therefore it is most unusual month of drought-flood on August and February. From the point of view of persistent characteristic to see, from trend of persistent drought and flood event to see, duration of persistent drought event gradually lengthen, frequency gradually increased, intensity gradually strengthen, and it occurs mainly in winter and spring, but duration and strength of persistent flood event have not clear trend, frequency gradually decreased, and season of appearance have not significantly difference. In addition by comparing frequency of persistent drought and flood event to south China and southwest China in the past 60 years, nine times is consistent in the time of occurrence of persistent drought, especially it is entirely consistent autumn winter and spring drought in 1998, nine times is not consistent. Seven times is consistent in the time of occurrence of persistent flood, eleven times is not consistent, therefore affect system of persistent drought and flood is not entirely consistent over southwest and south China.
The bitter cold, an extreme weather event, is the main climate disaster in the winter in Jinlin Province and has deeply influenced on the production and people’s living. Analysis on spatial-temporal distribution and climate change pattern of the bitter cold , research on evaluation index of the bitter cold and effective pre-assessment before the event are of great significance on improving the emergency response and service capability.In this study, through using some index, such as grey correlation, climatic trend rate and Gumbel extreme value distribution, on the daily lowest temperature of 50 meteorological stations in Jilin Province from 1951 to 2013, the spatial-temporal distribution and climate change pattern of the bitter cold in Jinlin Province were analyzed. Then index on rating bitter cold process and on the return period of abnormal weather were proposed. Finally, the evaluation was conducted on the bitter cold process from 2011 to 2013.The results showed that in Jinlin Province, the bitter cold event mainly occurred in winter and reached a peak in about mid-January. This bitter cold event mostly happened in the central and southern regions and rarely occurred in other regions. The annual occurrence number of the bitter cold in the whole Jinlin Province showed the tendency of decline. However, the number of occurrences in central and western regions was increasing and the number in southeastern areas was decreasing. The occurrence number of the bitter cold in Jinlin Province had significantly periodic changes: the number was on the ‘large’ phase from 1951 to 1980 but it was on the ‘small’ phase from 1981 to 2012. The bitter cold process in Jinlin Province mainly occurred in January. Therefore, the defense against bitter cold should mainly been implemented in January and in the central and southern areas. Although it is in warming period now and the occurrence number of bitter cold is on the ‘small’ phase, bitter cold still abnormally occurred many times in some years. Therefore, attention should always be paid to the defense against the bitter cold. In this study, the methods that using index of orders, rating and the return period of abnormal weather to evaluate the process of the bitter cold are practical and feasible, which can meet the demands of meteorological services for timely and fast assessment.
