A theory on the corresponding relationships between the industrialization (I), urbanization (U), and demographic transition (D), is presented and the framework is termed as IUD model in this paper. Based on the logistic function, the urbanization curve is divided into four stages: initial state, acceleration stage, deceleration stage, and terminal stage. This presents a striking contrast to R.M. Northam's urbanization curve which was divided into three phases in 1979. The four stages of urbanization remind us of the demographic transition model (DTM) which includes four phases: high stationary phase, early expanding phase, late expanding phase, and low stationary phase. In fact, industrial development can also be divided into four stages: agricultural stage, pre-industrial stage, post-industrial stage, and informational stage. A new principle is advanced as follows. Because of interaction and coupling relationships between industrialization, urbanization, and demographic transition, the four stages of urbanization should coincide with the four stages of industrial structure change, and with the four phases of demographic transition. If not, there are some disharmonious factors in the socio-economic systems, which should be revealed and removed or treated properly. The corresponding theory is then applied to China, and the processes of industrialization, urbanization, and demographic transition are studied by using the statistical data. From 1949 to 2008, China's industrialization and urbanization went from the first stage into the second stage, and are in the second stage now. However, because of the strict policy of family planning, the demographic transition went from the second stage into the third stage. On the whole, the speed of industrialization is faster than that of urbanization to a certain extent, but the speed of demographic transition is much faster than that of both industrialization and urbanization. A conclusion can be drawn as follows. The problem of population ageing will come into being ahead of schedule in comparison with industrialization and urbanization. Twenty years later, the so-called "demographic dividend" will become a "demographic divider", a real population burden for developing industries and cities. The countermeasures and precautions should be researched and taken in advance against the socio-economic syndrome resulting from aging population.
This study takes crude oil flow in China as the research subjects, and takes provincial-level administrative units as the nodes of crude oil flow. Meanwhile, selecting five typical years in 1985-2007 as the time points for research and with Zipf law, this paper discusses the rank-size distribution variation of input and output flow of crude oil in China. Some results are obtained as follows. (1) The rank-size distributions of input and output flow is consistent with Zipf law in the five typical years. (2) The non-scaling range of the output flow varies very little, while the one of input flow is narrowed at first and then enlarged gradually. (3) As to the spatial fractal structure, the output flow has no segmentation in its non-scaling range, and appears as a single fractal all along. However, the input flow experiences a process from double fractals to single fractal. (4) There are differences between the spatial distribution pattern of input flow and output flow. The one of input flow changed from lognormal distribution in 1985 to Pareto distribution in 1995, then lognormal distribution again in 1999, and it finally became Pareto distribution in 2003 and 2007. Meanwhile, the spatial distribution pattern of output flow maintains Pareto distribution. (5) Generally, the variations of output flow and input flow are not synchronous, which is closely related to the spatial distribution of huge oil fields, the distribution of petrochemical industries, the oil distribution system and so on in China.
The spatial separation is the important tendency of the organizing model in the process of product manufacturing. It is of great theoretical and practical significance to explore the methods of the quantitative measurement and demonstrate the general characters of spatial pattern of the intra-product specialization. The paper takes the Yangtze River Delta Region (YRDR) as an example, where the auto manufacturing industry growth is more mature than elsewhere in China and the diffusion and re-combination of its production sector is very active. According to the producing process, the automobile industry chain is divided into three sections, namely the Parts Manufacturing (PM) section, the Parts Assembly (PA) section and the Complete and Re-assembled Vehicle Manufacturing (CRVM) section respectively. After calculation of every section's output value of each county in YRDR and comparison of the changes among different periods, this article summarizes the spatial evolution process of auto manufacturing chain in YRDR. The spatial process from 1990 to 2005 evaluated by the method of niche width and niche overlap shows that: (1) the diffusing performance of the three sections differs from each other. Unlike the CRVM section's diffusing at first and then concentrating, the PM section diffuses all along and moves faster than the PA section which also spreads through the study period; (2) the niche overlap among the three sections are relatively high and have somewhat decreased, which demonstrates that the combination between them is somehow prevalent. To some extent, the combination between CRVM section and PA section is increasing. However, the phenomenon of coupling CRVM section and PM section, especially PA section and PM section is lessening.
At present, only a spot of cities, for instance, Guangzhou and Shenzhen conduct the industrial statistics of exhibition. There is a serious lack of statistical data from nation wide exhibitions. At the same time, the comparability of provincial or civic data is limited due to considerable differences in statistic caliber. In these cases, this paper aims at a study on the spatial-temporal features of Chinese Exhibition Industry (EI),and the Internet Chinese WebPages with issues of Chinese "Exhibition" from November 2006 to May 2008 are analyzed, by using Content Analysis Method (CAM), and statistically analyzed through SPSS. The spatial-temporal features of Chinese main provincial (and autonomous regions) exhibitions are studied, focusing on aspects such as themes, character, time, scale and etc. The results reveal that there are significant seasonal, spatial and industrial concentrations in the EI: (1) temporal distribution: by the average of a total of 630 exhibitions, the seasonal concentration is not obvious, but exhibitions of most provinces appear to be concentrated in summer and fall; (2) spatial distribution: the quantity of exhibitions in the eastern part of China is far larger than that in the western and central parts, with a decreasing trend from the east to the west, and also there are 5 exhibition concentrated regions in the whole country; (3) there are top 10 industries whose exhibitions are concentrated in different regions; (4) there are different characteristics of the themes, types, scale and duration of the exhibitions in different regions; (5) the above concentrated regions are well connected with the regional economic development, especially the foreign trade situation, and the construction situation of exhibition halls play an important role as well.It should be noted that the analyses of this article also have limitations of these defects which are related to the limitations of web page content analysis. Further study may focus on research in comparison of exhibition themes, classification, and effect and so on.
Employing DEA model and Malmquist productivity index, this paper probes into the urban efficiency of 24 typical resources-based cities in China and its changes from 2000 to 2008. The research finds that the comprehensive efficiency of the resources-based cities is just at a general level, and only a few of them reach the optimal level. The scale efficiency is the major determining factor of the achievement of comprehensive efficiency, the effect of which, nevertheless, is reducing. From the perspective of classification characteristics, the resources-based cities in northeastern area have been in the front rank in terms of comprehensive efficiency, pure technical efficiency and scale efficiency. There is a certain positive correlation between urban population scale and urban efficiency. The comprehensive efficiency, pure technical efficiency and scale efficiency of big cities are higher than those of small and medium-sized cities. The analysis of urban efficiency changes shows that the changes in comprehensive efficiency of resources-based cities from 2000 to 2008 had a weak improving tendency. Both the technical change index and productivity change index decreased, indicating that the urban efficiency did not improve during this period, and the tendency of technical regress and productivity decline was obvious. In terms of the classification of urban efficiency changes, ① the urban comprehensive efficiency improved in each of the four regions from 2000 to 2008, among which western region had the greatest increase. ② The urban comprehensive efficiency increased in all kinds of resources-based cities except steel resources-based ones. As for the relative superiority of productivity changes, oil-gas resources-based cities＞nonferrous-metal resources-based cities＞coal resources-based cities＞forest industry-based cities＞industrial-mineral resources-based cities＞steel resources-based cities. However, due to the slow technical progress, the productivity tended to drop in all kinds of mineral resources-based cities. ③ the urban comprehensive efficiency increased in resources-based cities of different scales, with greater improvement in small and medium-sized cities than in big cities. The productivity was generally decreasing because of technical regress, which was found more obvious in big cities.
The producer services exportation changes the traditional viewpoint that services can only sell within a limited area and can not make income for the local regions. Actually, no matter it is cross-country-border or not, the producer services exportation, which is called producer services trade, is an important item in the research of producer services.The central place theory discusses mainly about the exportation of traditional services industries, rather than the producer services which have developed rapidly in recent 50 years. The paper tries to answer two questions. Does the producer services exportation from the central city still follow the thought of central place theory? And what are the spatial features of the producer services exportation of the central city?According to the questionnaire and interviews to the producer services corporations in Guangzhou, one of the most developed cities for producer services in China, three features of producer services exportation which are different from the traditional services are identified: (1) The range of service for the central city is not limited in a single urban system region. And the exportation from the central city does not diffuse completely in terms of the urban hierarchy. (2) The direction of the exportation is not only from the high-level city to the low-level city, but also, even more, between the high-level cities. (3) The distributions of quantum for service selling and clients are inconsistent. Based on the interpretation of the corporations behavior, four deductions for the producer services exportation in the services economy era are put forward: (1) Spatial distance do not exert a great effect on the service producer, because the providers of producer services can travel for a long distance as long as the client can pay for the service. So the upper limit for the range of producer services exportation depends on the influence that the provider's power can reach. (2) The non-hierarchy-diffusion exportation model in Guangzhou, with the characteristics of a global city, reflects that the producer services exportation correlates with the status of the city in the global urban system. (3) For the producer services institutions, to sell more service in a market that has been developed is even more important than to develop more new markets. Thereby, in the analysis of urban hierarchy, the intention of service should be considered as another index besides the range of service. (4) The producer services exportation can reflect the connection between industries, and even the connection between cities.
Local residents' perception of tourism impacts in tourist destinations has been found to affect their attitude towards tourism; however, there have been relatively few studies on the influence of residents' tourism development expectation on their attitude towards tourism. With the utilization of SPSS16.0 software, this paper, taking China's Jiuzhaigou and the UK's New Forest National Parks as case study areas, makes a comparative study on the influence of local residents' tourism development expectation and touirism impacts perception on their attitude towards tourism. And potentially possible reasons for the influence and the differences between these two cases have been conducted with a qualitative analysis. Some conclusions can be obtained as follows. (1) Local residents' tourism impacts perception, especially tourism benefit perception, directly influences their support of tourism development. (2) Tourism development expectation of local residents directly influences their tourism impacts perception, espetially their tourism benefit perception, and indirectly influences their attitude towards tourism development in the parks via the medium of tourism benefit perception. (3) Residents in both destinations hold positive tourism development expectation with minor differences between the two cases due to cultural differences. Tourism benefit perception of local residents in the two national parks is less and worse than their tourism development expectation, indicating that there is a great gap between their tourism development expectation and tourism impacts perception in these two case study areas. But the majority of local residents in these two parks still hold no negative attitude towards local tourism development in spite of the existing gap.
Applying the travel areas model and GIS to obtain the data of tourism attraction systems in various travel circles in the Yangtze River Delta, this paper measures each aggregation fractal dimension on spatial structure of each tourism attraction system. Aggregation fractal non-scaling intervals have showed three sections of tourism attractions systems' spatial structure in travel circles of Nanjing, Suzhou and Hangzhou, and non-scaling intervals dividing points of three sections correspond to RS=10 km and RS=30 km; those of Changzhou, Wuxi, Shanghai and Shaoxing have showed two sections, and the dividing point corresponds to about RS=30 km; the tourism attractions system' spatial structure of travel circles of Ningbo is simple, and its non-scaling interval is one section and wide. There are differences on the changing trend of aggregation fractal dimension values in the same type of tourist attraction system. We have drawn the conclusion that tourism attraction systems' spatial structure represents the density decay characteristics from the center tourism attraction point to the surrounding hinterland, in the corresponding RS ≤30 km non-scaling interval, aggregation fractal dimension values are clustered around 0.5, in the corresponding 30＜RS≤75 km non-scaling interval, which gathered around 1.35 or 1.80. Tourism attractions systems' spatial structure aggregation fractal dimension values of the northern travel circle including Nanjing, Suzhou, Changzhou, Wuxi and Shanghai are around 1.35, and those of the southern travel circle including Hangzhou, Shaoxing and Ningbo are around 1.80, which indicate that the spatial structure of northern city travel circles are more compact than those of southern city travel circles. Northern city travel circles play a bigger central role, and the travel areas are coordinated with travel circles. These tourism central cities can fully support a three-day travel circles of 110 km radius, and can fully realize the function of tourism management, service and tourism transportation, thus these cities tourism facilities are efficiently used. Southern city travel circles play a relatively weak central role, and these cities deficiently perform the tourism function; then, these cities tourism facilities are used with relatively low efficiency and those actual travel circles' radius are probably less than 110 km. Therefore, we should not build superabundant tourism facilities in these tourism central cities to support a three-day travel, and should build some tourism facilities in these ordinary tourism cities in the scope of 110 km radius.
Inter-annual to inter-decadal sea level variations and its coupling characteristics with corresponding climate fluctuations have received wide attention in such fields as climate and oceanography research. It is one of the most important parts in analyzing multi-scale spatio-temporal transmissions and dynamical mechanisms of the complex coupled ocean-atmosphere interactions. Multichannel Singular Spectrum Analysis (MSSA) is a proper multiscale spectrum method which can extract and reconstruct the spatio-temporal characteristics of the significant periodic and low frequency quasi-periodic variations from high noisy data. It is applied to the Northwest Pacific region (10°N-38°S) using 1968-2007 sea level data from 14 tide gauge stations released by Permanent Service for Mean Sea Level (PSMSL) and University of Hawaii Sea Level Center (UHSLC). These data are filtered by Empirical Mode Decomposition (EMD) to remove the long-term trend. Then inter-annual to inter-decade variability of sea level fluctuation is examined by MSSA. It is showed that, there is a scale coupling of inter-annual to inter-decade periods in amplitude and phase. The coupling characteristics change with El Nin o-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) variability. The significant zonal propagation with the decrease of amplitude and energy from low to high latitude can be revealed as well. The response ranges of PDO in spatial dimension are significantly narrower than that of ENSO. ENSO can affect the sea level of Dalian station (38°56'N) but PDO can only affect those of Uragrami (33°33'N) and Lusi stations (32°08'N). Singular Spectrum Analysis (SSA) is used to extract the principle scale components from Multivariate ENSO Index (MEI) and PDO index. Analyses based on the principle scale components and sea level variations also show that 2.5a periods and 4.5a periods exactly matched with ENSO variability. Meanwhile, 4.5a periods and 8a periods are significantly correlated with PDO variability. And these responses are greatly influenced by global warming. There are two distinct fluctuation transformations around 1973 and 1998. The correlation coefficient of 2.5-8a periods and PDO reach -0.40, indicating that there is some relationship between PDO and the transformations.
Dalian, a coastal city located in the southern Liaodong Peninsula, is prone to natural hazards. The natural hazards that Dalian suffers most are diverse, with high frequency and wide distribution. Various hazards have become a major concern in urban economic and sustainable development currently. Natural hazards risk assessment involves a number of data, which are much of spatial, non-linear and random features. GIS, as a useful tool to analyze and manage spatial information, has a huge superiority. A case study in Dalian City explored the assessment mechanism for natural hazards, and developed a method of spatial differences assessment based on GIS in this paper. The method includes 4 steps: (1) Developing natural hazards risk assessment indicators system concerning five types of hazard related to flood, geology, earthquake, meteorology and environmental pollution on the basis of probability of hazard, endangering time and loss; (2) Digitizing Dalian City and setting its 106 county units database and kilometric GRID database of natural hazards indicators, referring to Dalian history records on the basis of remote sensing data and site data, which can provide accurate and substantial data for natural hazards study of Dalian City; (3) Figuring out single element risk index and multi-elements risk composite index of natural hazards indicators by using Graham method and the principal components-entropy with the weight of indicator; (4) Classifying the composite risk zone and mapping the assessment result of natural hazards risk in grid by MapInfo of assigning method and vertical map tools, and ranking the major hazard factors. The visual and quantitative spatial differences of natural hazards risk based on GIS enable regional planners to know the zonation of hazard risk accurately in planning the principal function region. The results can provide references for hazard prevention and reduction of Dalian City.
It is very important to solve increasingly serious issues related to farmland bio-energy, such as energy crisis, environmental protection, and farmers' economic problems. For a long time, the research on bio-energy has mainly relied on traditional statistic data. As we know, because of data quality and spatial scales, the current available data cannot meet the needs of thorough research on bio-energy utilization. Therefore, it is very urgent to set up a new and comprehensive methodology using remote sensing and GIS technology to advance bio-energy research. Studies on farmland bio-energy's quantity, spatial distribution pattern and inter-annual changes are particularly important to intensive use planning, site selection of energy plants and follow-up raw material supply and demand forecasting. Based on NPP data derived from the EOS/MODIS satellite MOD17A3 datasets during 2000 to 2006, we estimated cropland bio-energy's quantity in Guangdong Province and analyzed the characteristics of its spatial change, and extracted bio-energy advantage distribution by using neighborhood statistical analysis. We then used the trend line analysis method to analyze inter-annual dynamic stability. The results show that total biomass of cropland in Guangdong Province declined during the study period, which is mainly caused by the steady decrease in cropland area during the same period; the average value of cropland bio-energy showed a slightly rising trend, but with great variance. The average value declined during 2000 to 2002, increased from 2002 to 2004, and declined again after 2004. The maximum and minimum average unit values are 5775.10KJ/(m2·a) in 2004 and 4697.87 KJ/(m2·a) in 2002, respectively. Growth of biomass per unit can provide a solid basis for the cropland bio-energy industry.
As the eco-environment problem in city group becomes more serious and the eco-environment constraint becomes more obvious, the effect of industrial development on eco-environment is receiving more and more attention. Based on the previous research, taking resources utilization and environment influence as an important factor, the paper constructs the eco-environment influence coefficient of industrial branches and the eco-environment influence index of industrial structure, and quantitatively evaluates the eco-environment effect of industrial development in Wuhan City Group from 1997 to 2006. Results show that: in 1997~2006, the scale of industry in Wuhan City Group expanded continuously, the proportion of light industry dropped and the heavy industry increased, and the high-tech industries developed rapidly. The eco-environment influence index of industrial structure dropped first and rose later. The index in all cities kept increasing except Wuhan city. The index in different cities varied greatly with Tianmen being lowest and Huangshi highest. However, the relative difference was enlarged at first and then narrowed. The spatial differentiation of the eco-environment influence index of industrial structure tended to be apparent, the effect of industrial development on eco-environment were prominent especially in Huangshi, Ezhou and Huanggang. The industrial growth in cities presented an unsustainable development pattern except Wuhan City. Accordingly, the paper presents the proposals to promote resource-saving and environment-friendly society construction in Wuhan City Group, including strictly controlling the development of high energy consumption or heavy pollution industry, widely applying advanced technologies to upgrade traditional industries, extending the industry chain and making great effort to develop circular economy.
The land-use change is a typical manifestation of the interaction between human beings and the nature, and urbanization finds expression in the transformation from non-construction land to construction land. The assessment of the construction land within a certain area is not only closely related to factors such as landform, land surface water, basic/cultivated land, forest land and ecological reserves, but also interrelated with the population, urbanization, industrialization, regional industrial restructuring, foreign investment, land prices, policies and other factors, including both the external expansion of the land for future construction and its internal updating such as the higher rate of the intensive land use. With the acceleration of urbanization process in Dalian, the demand for various types of construction land, represented by urban land, is inevitably in rapid growth. Therefore, the measurement and evaluation of the hierarchical structure and distribution of construction land in Dalian are the foundation and prerequisite for Dalian's economic and social development planning, especially for the urban construction planning, the industrial layout and the land use planning. This article, as an interim result of "Study on the abundance of Dalian city's construction land", starts from the previous findings and employs a variety of methods such as AHP index layer of factor analysis, the spatial overlay analysis in GIS spatial analysis, and etc. Some conclusions can be obtained as follows. In terms of the hierarchical structure, Dalian's construction land belonging to Grade Ⅰ (abundant), Grade Ⅱ (relatively abundant), Grade Ⅲ (deficient) and Grade Ⅳ (extremely deficient) accounts for 17.92%, 18.15%, 28.59% and 35.34%, respectively. The construction land of grades I & II is mainly distributed in the coastal plain along the Bohai Sea and the Yellow Sea, and the rest is scattered in lowland valleys or hills, etc. The construction land of grades III & IV is mostly distributed in the shape of semi-circle or ribbon, apart from that densely distributed in the northern mountains area.
In recent years, the study on hydrological effect of land use change has become a focus. In the Tarim River Basin, land use change has exerted great effect on hydrological process of a river, so it is necessary to study the hydrological effect of land use change in the river basin. As cultivated land dominates the land use type in the Tarim River Basin, based on the statistical data of cultivated land of each prefecture and tested data of each main water station in Tarim River Basin, this paper analyzes the total variation trend, variation speed, regional difference and hydrological effect on water quantity of the river. The results are shown as follows. (1) The cultivated land area in the Tarim River Basin shows a fluctuating increasing trend with an annual rate of 2.37%, but per capita cultivated land area saw a gradual decrease with an annual rate of 0.44%. There is a significant spatial disparity in the cultivated land changes. The change of cultivated land area in Bayingolin Mongol Autonomous Prefecture where the reserved land and water resources are plentiful is large, and that in Hotan Prefecture located at the northern foot of Kunlun Mountains is small. (2) As a result of the expansion of cultivated land area in the Tarim River Basin, the hydrological effect such as river process, river discharge, flood, water quality and silt are more remarkable than before, and the spatial effect on river discharge is striking. As a result of cultivated land expansion, cultivated land and consuming water rise by 34.80% and 21.78% from 1957 to 2006, respectively. At the same time, water pollution and the decreasing of the water quality have become the confinement of social development in the Tarim River Basin. At present, the project of water saving has taken effect, and the trend of the venting water quantity from streams to the Tarim River has been under control. In order to keep the sustainable development in this region, it is urgent to harness the Tarim River in a long term, set up coherent management system of water resources, and use water resources reasonably.
Scarcity of cultivated land, rapid industrialization and urbanization process have resulted in the expansion and high demand of construction land, causing heavy contradiction between the protection of cultivated land and the expansion of construction land. To alleviate this kind of contradiction in developed regions and harmonize the relationship between them, a quantitative evaluation method for reasonable and scientific location of cultivated land conservation is required, which has a significant meaning for harmonizing the relationship. Therefore, the paper explores the Probit measurement model and Zoning method to study the location of cultivated land conservation problem in Changshu city. Firstly, the analysis of modeling operation shows that factors such as the quality of land, terrain condition, GDP growth rates, accessibility to downtown and harbor, the distance to downtown and so on, have evident influences on the changing process of cultivated resource. According to the factors, an indictor system of zoning is established. Secondly, based on the evaluation results, the study area is divided into five sub-regions: the most suitable region, the relative suitable region, the suitable region, the relative unsuitable region and the unsuitable region, which account for 30.2%, 40.7%, 17.9%, 5.2% and 6% of the total areas respectively. Finally, on the basis of the zoning results, guidelines for protecting farmland and developing construction land are offered, which can not only improve the rate of protection farmland but also reserves scientific construction land. This paper has provided scientific implications for site selection of Comprehensive Land Use Planning, Primary Farmland Conservation Subject Plan, Urban and Regional Planning and Project .
In line with the global climate change, the surface air temperature in the Bohai Rim area significantly increased for the 20th century. Accompanying the change of surface air temperature, heavy and very heavy precipitation has greatly changed, especially in recent years. Changes in patterns of extreme precipitation events and the possible mechanism for the changes have received more and more attention worldwide. The study aims to investigate the climatic characters and changing trend of rainfall days, rainfall amount and rainfall intensity in the Bohai Rim area by using daily precipitation data from 1961 to 2007. The results show that the number of annual and seasonal rainfall days (days with rainfall more than 0.1 mm) significantly decreases, and the decrease of rainfall days dominantly results from the significant decline in trace and light rainfall days, especially in autumn. In contrast, rainfall intensity shows a weak increase, mainly due to the increase in trace and light rainfall intensities. In comparison of the contribution of different categories of precipitation to annual total rainfall, it is found that there is a significant interannual variation in the contribution. Since the 1990s, annual rainfall has mainly come from light and moderate rainfall, whereas extreme heavy rainfall has contributed less to the annual rainfall due to the decrease in frequency and amount of extreme heavy rain. The results indicate that the decrease of trace and light rainfall days, which leads to the increase in frequency of events of continuous non-rain days, might have partly exacerbated the extent of drought in this area. However, the decline of annual rainfall as a result of the decrease of heavy rain or rainstorms, which is the dominant contribution to total rainfall, is the main factor for producing the severe meteorological drought after 1980.
This paper analyzed basic characteristics of major climatic factors on the Qinghai-Tibet Plateau during 1961~2005. The result are shown as follows. In the past 45 years, the annual mean temperature was on the rise, with a rate of 0.265℃/10a. The warming tendency in winter was remarkable and that in spring was faint. The temperature rise from 1980 to 2005 was higher than that from 1961 to 1980 and from 1961 to 2005, indicating that there has been a warming trend since the 1980s. In the 45-year period, the annual mean precipitation on the Qinghai-Tibet Plateau was on the faint rise, with a rate of 8.21 mm/10a; annual mean precipitation from 1961 to 1975 was below the average, that from 1975 to 1989 held the line and that after 1990s above the average. Generally speaking, precipitation in spring and winter tended to increase, but the tendency in spring was far greater than that in winter. Annual mean precipitation showed a certain periodicity. At 32 sites on the Qinghai-Tibet Plateau existed a 2~4a short cycle, at 11 sites a 5~8a medium cycle and at 6 sites a long cycle of above 10a. From 1961 to 2005 climatic synthetic tendency was mainly warming-wetting, with sites accounting for 67% of the all.
This paper made an analysis of the relationship between climate change and agricultural development in China since the Qin Dynasty. The following conclusions are obtained about how historical climate fluctuation influenced ancient agricultural production. Warm periods were beneficial to agricultural development while cold periods made against to it. When the climate was warm (e.g. Qin, Han, Sui and Tang dynasties), the northern boundary of farming moved northward. Thus, cultivation area expanded. And crop growing time and cropping patterns would also increase due to relatively high temperature. As a result, crop yields were greatly improved. However, during cold periods, (e.g. Wei, Jin, Northern and Southern Dynasties, Late Tang Dynasty and Five Dynasties period), the boundary of farming moved southward, cropping patterns became single, cultivation land and crop growing time reduced. These changes caused the decrease of crop yield. Moreover, the history of rice distribution in ancient China shows that during warm periods, single cropping rice was widely planted in the Yellow River Basin, and double cropping rice could grow in the Yangtze River Basin. But when the climate became cold, the range of the distribution of single cropping rice plant in the Yellow River Basin was significantly diminished, and double cropping rice retreated to the south of the Yangtze River Basin.
