2011 Vol. 21, No. 1
Display Method:
2011, 21(1): 1-16.
Abstract:
History has brought us into a significant moment when the majority of the human kind has taken up residence in urban settlements. The focus of global urbanization has shifted to the developing world and the center of manufacturing is no longer confined to the Global North. This paper provides a periodical assessment of the current status of China’s urban transformation in the global context of a shifting emphasis of industrialization and urbanization. China’s phenomenal urban transformation deserves a special attention not only because of its unparalleled scale and speed but also because of its distinct trajectory of growth that does not confirm normal theoretical expectations. An evaluation of the current status of China’s urban transformation has revealed an urban economy with remarkable hybridity, a society that is increasingly stratified, polarized, and segregated, and a juxtaposed urban space undergoing restless and pervasive transformation. A decentering world should entail a decentering knowledge production. A critical reflection upon the Chinese patterns and processes of urban transformation has identified four main areas of research with great potentials for innovative knowledge production, namely 1) privatization and economic development; 2) state, society, and space; 3) urbanization of capital, labor, and land; and 4) the environment and Chinese political ecology. The paper closes with the remark that a rapidly transforming urban China has presented itself as a fertile and resourceful testing ground for critical and innovative geographic enquiries
History has brought us into a significant moment when the majority of the human kind has taken up residence in urban settlements. The focus of global urbanization has shifted to the developing world and the center of manufacturing is no longer confined to the Global North. This paper provides a periodical assessment of the current status of China’s urban transformation in the global context of a shifting emphasis of industrialization and urbanization. China’s phenomenal urban transformation deserves a special attention not only because of its unparalleled scale and speed but also because of its distinct trajectory of growth that does not confirm normal theoretical expectations. An evaluation of the current status of China’s urban transformation has revealed an urban economy with remarkable hybridity, a society that is increasingly stratified, polarized, and segregated, and a juxtaposed urban space undergoing restless and pervasive transformation. A decentering world should entail a decentering knowledge production. A critical reflection upon the Chinese patterns and processes of urban transformation has identified four main areas of research with great potentials for innovative knowledge production, namely 1) privatization and economic development; 2) state, society, and space; 3) urbanization of capital, labor, and land; and 4) the environment and Chinese political ecology. The paper closes with the remark that a rapidly transforming urban China has presented itself as a fertile and resourceful testing ground for critical and innovative geographic enquiries
2011, 21(1): 17-26.
Abstract:
The objective of this study was to provide reliable basis for decision making for national food security and layout and structure adjustment of grain production in Northeast China. The data of mean daily air temperature of 1961-2009 from 106 meteorological stations in Northeast China were chosen in the study. Using statistical methods and isoline method, the course of change of various decadal accumulated temperature above 10 degrees Celsius (≥10℃) and distribution and change of climatic means of ≥10℃ accumulated temperature were studied in this paper. The results showed that 1) geographical distribution of means of various decades and climatic means of ≥10℃ accumulated temperature were mainly subjected to latitude, longitude and altitude in study area; 2) means of decadal ≥10℃ accumulated temperature rose obviously since the 1980s, their warming amplitudes became larger in the 1990s and 2010s; compared with those of the 1980s, ≥10℃ accumulated temperatures in mountain and plain areas increased by about 100℃ in the 1990s; compared with those of the 1990s, the accumulated temperatures increased by about 200℃ in Hulunbeier high plain and Songnen Plain, and 100℃ in Sanjiang Plain and Liao He Plain in the 2010s; 3) means of the decadal accumulated temperatures for 106 meteorological stations in Northeast China increased with the rate of 145.57℃/10year since 1961; 4) compared with the positions of the isolines of climatic mean of 1961-1990, maximum shifts northward of 3100℃, 3300℃ and 3500℃ isolines were 145km, 154km and 100km respectively, maximum extension eastward of 3100℃ and 3300℃ isolines were 109km and 54km and their extension westward were both 64km; 5) compared with the climatic mean of ≥10℃ accumulated temperature of 1961-1990, the mean of the accumulated temperature of 1981-2009 increased by above 100℃ in most parts of the study area; most parts of Songnen Plain, Songliao Watershed and Xiliao He Plain were the areas in which the climatic mean of the accumulated temperature changed dramatically and their accumulated temperature increased by above 150℃, the accumulated temperature in Dalian, Jinzhou, Chaoyang, Anshan, Siping, Changchun, Sunwu and Erguna stations increased by about 200℃.
The objective of this study was to provide reliable basis for decision making for national food security and layout and structure adjustment of grain production in Northeast China. The data of mean daily air temperature of 1961-2009 from 106 meteorological stations in Northeast China were chosen in the study. Using statistical methods and isoline method, the course of change of various decadal accumulated temperature above 10 degrees Celsius (≥10℃) and distribution and change of climatic means of ≥10℃ accumulated temperature were studied in this paper. The results showed that 1) geographical distribution of means of various decades and climatic means of ≥10℃ accumulated temperature were mainly subjected to latitude, longitude and altitude in study area; 2) means of decadal ≥10℃ accumulated temperature rose obviously since the 1980s, their warming amplitudes became larger in the 1990s and 2010s; compared with those of the 1980s, ≥10℃ accumulated temperatures in mountain and plain areas increased by about 100℃ in the 1990s; compared with those of the 1990s, the accumulated temperatures increased by about 200℃ in Hulunbeier high plain and Songnen Plain, and 100℃ in Sanjiang Plain and Liao He Plain in the 2010s; 3) means of the decadal accumulated temperatures for 106 meteorological stations in Northeast China increased with the rate of 145.57℃/10year since 1961; 4) compared with the positions of the isolines of climatic mean of 1961-1990, maximum shifts northward of 3100℃, 3300℃ and 3500℃ isolines were 145km, 154km and 100km respectively, maximum extension eastward of 3100℃ and 3300℃ isolines were 109km and 54km and their extension westward were both 64km; 5) compared with the climatic mean of ≥10℃ accumulated temperature of 1961-1990, the mean of the accumulated temperature of 1981-2009 increased by above 100℃ in most parts of the study area; most parts of Songnen Plain, Songliao Watershed and Xiliao He Plain were the areas in which the climatic mean of the accumulated temperature changed dramatically and their accumulated temperature increased by above 150℃, the accumulated temperature in Dalian, Jinzhou, Chaoyang, Anshan, Siping, Changchun, Sunwu and Erguna stations increased by about 200℃.
2011, 21(1): 27-35.
Abstract:
Wetlands store substantial amount of carbon and may contribute greatly to climate change. However, few studies have investigated the effects of global climate change on carbon mineralization in Zoige wetlands. By measuring CO2 and CH4 production rate from incubated, undisturbed soils, we studied the effects of temperature and soil moisture on carbon mineralization in two types of alpine wetlands (peatland and marsh) on Tibetan plateau. CO2 production rate increased about 3.3~3.7 times with temperatures from 5 oC to 35 oC in marsh soils and 2.4~2.6 times in peat soils, but decreased 5%~45% in marsh soils and 20%~50% in peat soils with soil moistures increasing from non-inundation to inundation. The responses of CO2 production rate to temperatures were more sensitive in marsh soils than in peat soils, but the responses of CH4 production rate were similar. Temperatures played a more important role in CO2 production rate than soil moistures did, while soil moistures played a more important role in CH4 production rate. The Q10 values for CO2 production rate were higher at 5~25℃ than at 25~35℃, implying that carbon mineralization is more sensitive at low temperatures in Tibetan alpine wetlands.
Wetlands store substantial amount of carbon and may contribute greatly to climate change. However, few studies have investigated the effects of global climate change on carbon mineralization in Zoige wetlands. By measuring CO2 and CH4 production rate from incubated, undisturbed soils, we studied the effects of temperature and soil moisture on carbon mineralization in two types of alpine wetlands (peatland and marsh) on Tibetan plateau. CO2 production rate increased about 3.3~3.7 times with temperatures from 5 oC to 35 oC in marsh soils and 2.4~2.6 times in peat soils, but decreased 5%~45% in marsh soils and 20%~50% in peat soils with soil moistures increasing from non-inundation to inundation. The responses of CO2 production rate to temperatures were more sensitive in marsh soils than in peat soils, but the responses of CH4 production rate were similar. Temperatures played a more important role in CO2 production rate than soil moistures did, while soil moistures played a more important role in CH4 production rate. The Q10 values for CO2 production rate were higher at 5~25℃ than at 25~35℃, implying that carbon mineralization is more sensitive at low temperatures in Tibetan alpine wetlands.
2011, 21(1): 36-47.
Abstract:
The density of fresh snow from February 21st to March 5th 2009 was observed using snow analyzer (Snow Fork) at Tianshan Research Station for Snow-cover and Avalanche of Chinese Academy of Sciences (TRS). Results show that fresh snow density increases from 5 h to 291 h with a coefficient of determination equal to 94% dramatically, representing an average rate of increase of 4.0×10-4 gcm-3/h. Analysis shows that fresh snow density is negatively correlated with compaction rate (R2 = -0.96). Inversely, fresh snow viscosity is positively correlated with density (R2 = 0.90). In relation to meteorological factors, increasing ground temperature (taken at 40 cm beneath the ground surface) is the major driving factor of snow density. Temperature increase in fresh snow layer and decrease in depth hoar layer have the most prominent impact on the snow density increase in the afternoon. Principal component analysis shows that the determinant factors of fresh-snow density change can be grouped into three as follows: a) dynamic factor contributes about 69.71% of density change during 5-106 h of snowfall; b) exogenous energy factor contributes about 20.91% of snow density change at the 130th h; and c) endogenous energy factor contributes about 9.38% of snow density change at the 130th and 195th h of snowfall.
The density of fresh snow from February 21st to March 5th 2009 was observed using snow analyzer (Snow Fork) at Tianshan Research Station for Snow-cover and Avalanche of Chinese Academy of Sciences (TRS). Results show that fresh snow density increases from 5 h to 291 h with a coefficient of determination equal to 94% dramatically, representing an average rate of increase of 4.0×10-4 gcm-3/h. Analysis shows that fresh snow density is negatively correlated with compaction rate (R2 = -0.96). Inversely, fresh snow viscosity is positively correlated with density (R2 = 0.90). In relation to meteorological factors, increasing ground temperature (taken at 40 cm beneath the ground surface) is the major driving factor of snow density. Temperature increase in fresh snow layer and decrease in depth hoar layer have the most prominent impact on the snow density increase in the afternoon. Principal component analysis shows that the determinant factors of fresh-snow density change can be grouped into three as follows: a) dynamic factor contributes about 69.71% of density change during 5-106 h of snowfall; b) exogenous energy factor contributes about 20.91% of snow density change at the 130th h; and c) endogenous energy factor contributes about 9.38% of snow density change at the 130th and 195th h of snowfall.
2011, 21(1): 48-56.
Abstract:
In order to measure the spatial heterogeneity of shelterbelt networks on landscape scale, the distance coefficients of the reasonable and existent landscape indexes of the farmland shelterbelt networks are compared and analyzed on the basis of landscape ecology, combining the spot5 high resolution satellite imagery with GIS .On the basis, the methods are advanced to evaluate comprehensively the spatial heterogeneity through the spatialization of the evaluation indicators, so as to show the spatial differentiation of shelterbelts distribution. The methods resolve the disadvantages of lacking spatiality of overall evaluation, and make the evaluating results have more directive significances for shelterbelt management. With the methods, the spatial heterogeneity of shelterbelt network was measured and evaluated in the Midwest of Jilin province. The results show that the spatial landscape pattern of the farmland shelterbelt networks is not reasonable in the region. The region of acute shortage area account for 42.95%, but few regions have reasonable pattern of shelterbelts. Therefore, it is necessary to make strenuous efforts to construct the farmland shelterbelt networks in the study area.
In order to measure the spatial heterogeneity of shelterbelt networks on landscape scale, the distance coefficients of the reasonable and existent landscape indexes of the farmland shelterbelt networks are compared and analyzed on the basis of landscape ecology, combining the spot5 high resolution satellite imagery with GIS .On the basis, the methods are advanced to evaluate comprehensively the spatial heterogeneity through the spatialization of the evaluation indicators, so as to show the spatial differentiation of shelterbelts distribution. The methods resolve the disadvantages of lacking spatiality of overall evaluation, and make the evaluating results have more directive significances for shelterbelt management. With the methods, the spatial heterogeneity of shelterbelt network was measured and evaluated in the Midwest of Jilin province. The results show that the spatial landscape pattern of the farmland shelterbelt networks is not reasonable in the region. The region of acute shortage area account for 42.95%, but few regions have reasonable pattern of shelterbelts. Therefore, it is necessary to make strenuous efforts to construct the farmland shelterbelt networks in the study area.
2011, 21(1): 57-64.
Abstract:
This paper proposes a semi-supervised regression model with co-training algorithm based on support vector machine, which retrieve water quality variables from SPOT5 remote sensing data. The model consists of two support vector regressors (SVR). Nonlinear relationship between water quality variables and SPOT5 spectrum are described by the two support vector regressors, and semi-supervised co-training algorithm for the SVRs is established. The model is used for retrieving concentrations of four representative water quality organic pollution indicators – permanganate index (CODmn), ammonia nitrogen (NH3-N), chemical oxygen demand (COD) and dissolved oxygen (DO) of the Weihe River in Shaanxi Province, China. The spatial distribution mappings for these variables over a part of the Weihe River in Shaanxi are also produced. SVR can implement any nonlinear mapping readily and semi-supervised learning can make use of both labeled and unlabeled samples. By integrating two support vector regressors and using semi-supervised learning, we provide an operational method when paired samples are limited. The results show that it is much better than the multiple statistical regression method, and can provide the whole water pollution conditions for management fast and can be extended to hyperspectral remote sensing applications.
This paper proposes a semi-supervised regression model with co-training algorithm based on support vector machine, which retrieve water quality variables from SPOT5 remote sensing data. The model consists of two support vector regressors (SVR). Nonlinear relationship between water quality variables and SPOT5 spectrum are described by the two support vector regressors, and semi-supervised co-training algorithm for the SVRs is established. The model is used for retrieving concentrations of four representative water quality organic pollution indicators – permanganate index (CODmn), ammonia nitrogen (NH3-N), chemical oxygen demand (COD) and dissolved oxygen (DO) of the Weihe River in Shaanxi Province, China. The spatial distribution mappings for these variables over a part of the Weihe River in Shaanxi are also produced. SVR can implement any nonlinear mapping readily and semi-supervised learning can make use of both labeled and unlabeled samples. By integrating two support vector regressors and using semi-supervised learning, we provide an operational method when paired samples are limited. The results show that it is much better than the multiple statistical regression method, and can provide the whole water pollution conditions for management fast and can be extended to hyperspectral remote sensing applications.
2011, 21(1): 65-73.
Abstract:
Based on the meteorological sounding data for 1970~2005 over Harbin, this research carries on the analysis and the forecast to the Harbin ground and the upper air climate change using the linear simulation, correlation analysis, and regression analysis. The main conclusions are as follows: (1) climatic change is obvious in the middle and lower troposphere and the lower stratosphere. It becomes warmer and wetter in the middle and lower troposphere; the meridional wind becomes weaker in the lower troposphere, the annual mean wind speed also decreases. In the lower stratosphere the temperature drops, and the westerly wind speed noticeably increases, but other essential factors does not change significantly. (2) The increase of ground temperature is related to not only carbon dioxide, but also the water vapor. The carbon dioxide contributes more than the water vapor to the ground temperature increase. (3) This paper has established quantitative equations between the ground temperature, the carbon dioxide and water vapor. The forecast results show that if the emission concentration of carbon dioxide remains unchanged, the rate of Harbin surface temperature increasing is 0.85℃/10a; if it decreased to 75%, the rate is 0.65℃/10a; if it decreased to 50%, the rate is 0.46℃/10a; if it decreased to 25%, the rise rate is 0.27℃/10a. (4) This paper has also established equations between the temperature and the water vapor for various upper air levels. The water vapor has an increased impact on the warming of the temperature with the increase of the altitude.
Based on the meteorological sounding data for 1970~2005 over Harbin, this research carries on the analysis and the forecast to the Harbin ground and the upper air climate change using the linear simulation, correlation analysis, and regression analysis. The main conclusions are as follows: (1) climatic change is obvious in the middle and lower troposphere and the lower stratosphere. It becomes warmer and wetter in the middle and lower troposphere; the meridional wind becomes weaker in the lower troposphere, the annual mean wind speed also decreases. In the lower stratosphere the temperature drops, and the westerly wind speed noticeably increases, but other essential factors does not change significantly. (2) The increase of ground temperature is related to not only carbon dioxide, but also the water vapor. The carbon dioxide contributes more than the water vapor to the ground temperature increase. (3) This paper has established quantitative equations between the ground temperature, the carbon dioxide and water vapor. The forecast results show that if the emission concentration of carbon dioxide remains unchanged, the rate of Harbin surface temperature increasing is 0.85℃/10a; if it decreased to 75%, the rate is 0.65℃/10a; if it decreased to 50%, the rate is 0.46℃/10a; if it decreased to 25%, the rise rate is 0.27℃/10a. (4) This paper has also established equations between the temperature and the water vapor for various upper air levels. The water vapor has an increased impact on the warming of the temperature with the increase of the altitude.
2011, 21(1): 74-83.
Abstract:
A hydrologic model consists of several parameters that are usually considered certain. Hydrologic model parameters are calibrated through observed hydrologic processes whose uncertainty result in uncertainty of hydrologic model parameters, so hydrologic forecasting is uncertain. Working with the Bayesian Forecasting System (BFS), Markov Chain Monte Carlo based Adaptive Metropolis method (AM-MCMC) is used to research uncertainty of parameters of Nash model, while the probabilistic flood forecasting being made with the simulated samples of parameters of Nash model in this paper. Study case showed that the AM-MCMC based on BFS proposed in the paper can obtain the posterior distribution of parameters of Nash model according to known information of parameters. Worked with Nash model, AM-MCMC based on BFS was able to make the probabilistic flood forecast as well as get predictands of mean and variance of flood discharge, which may be used to estimate risk of flood control decision.
A hydrologic model consists of several parameters that are usually considered certain. Hydrologic model parameters are calibrated through observed hydrologic processes whose uncertainty result in uncertainty of hydrologic model parameters, so hydrologic forecasting is uncertain. Working with the Bayesian Forecasting System (BFS), Markov Chain Monte Carlo based Adaptive Metropolis method (AM-MCMC) is used to research uncertainty of parameters of Nash model, while the probabilistic flood forecasting being made with the simulated samples of parameters of Nash model in this paper. Study case showed that the AM-MCMC based on BFS proposed in the paper can obtain the posterior distribution of parameters of Nash model according to known information of parameters. Worked with Nash model, AM-MCMC based on BFS was able to make the probabilistic flood forecast as well as get predictands of mean and variance of flood discharge, which may be used to estimate risk of flood control decision.
2011, 21(1): 84-93.
Abstract:
Passive microwave remote sensing has many significant advantages such as all-day observation, penetrability and uninfluenced by clouds. As the longer wavelengths are not susceptible to atmospheric scattering which affects shorter optical wavelengths, passive microwave remote sensing can overcome shortcomings of spectral remote sensing. As a result, it has wide applications in the research fields of global environmental change. As the satellite-based passive microwave remote sensor, the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) is popularly used in the field of global environmental observation. Microwave Radiation Imager (MWRI) loaded on Chinese FY-3A satellite is an AMSR-E-like conical scanning microwave imager. Comparison analysis of microwave brightness temperature data derived from AMSR-E and MWRI based on Northeast China is described in this paper. An optimal position matching algorithm from rough to exact is proposed for the position matching between AMSR-E and MWRI data. The experimental results show that the error values of brightness temperature between AMSR-E and MWRI usually are in the range of -10K and +10K for the region covered by unified surface type. Effective evaluation of MWRI data quality can provide useful information and broaden data applications.
Passive microwave remote sensing has many significant advantages such as all-day observation, penetrability and uninfluenced by clouds. As the longer wavelengths are not susceptible to atmospheric scattering which affects shorter optical wavelengths, passive microwave remote sensing can overcome shortcomings of spectral remote sensing. As a result, it has wide applications in the research fields of global environmental change. As the satellite-based passive microwave remote sensor, the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) is popularly used in the field of global environmental observation. Microwave Radiation Imager (MWRI) loaded on Chinese FY-3A satellite is an AMSR-E-like conical scanning microwave imager. Comparison analysis of microwave brightness temperature data derived from AMSR-E and MWRI based on Northeast China is described in this paper. An optimal position matching algorithm from rough to exact is proposed for the position matching between AMSR-E and MWRI data. The experimental results show that the error values of brightness temperature between AMSR-E and MWRI usually are in the range of -10K and +10K for the region covered by unified surface type. Effective evaluation of MWRI data quality can provide useful information and broaden data applications.
2011, 21(1): 94-101.
Abstract:
The dielectric constant of the surface material may be found from the reflection and transmission coefficients, and plays an important role in the lunar regolith study. In order to study the dielectric properties of the lunar regolith, the lunar regolith simulant is made according to the making procedure of the CAS-1 simulant. Then the dielectric constants of the lunar regolith simulant are measured with 85070E Aiglent microwave network analyzer over the range of 0.2-20 GHz and the temperature in 25.1, 17.7, 13.1, 11.5, 9.6, 8.0, 4.1, - 0.3, - 4.7, - 9.5, - 18.7, - 27.7, - 32.6℃, respectively. The Odelevsky model is employed to remove the influence from the water in the air on the final effective dielectric constant. The result indicates that frequency and temperature have clearly influences on the dielectric constants of the lunar regolith simulant. The real parts of the dielectric constant increase fast over the range of 0.2-3 GHz, but the real parts decrease slowly over the range of 4-20 GHz in total. The opposite phenomenon occurs to the imaginary part. The influences of the frequency and temperature on the brightness temperature are also estimated based on the radiative transfer equation. The result shows that the variation of frequency and temperature results in great changes to the microwave brightness temperature of the lunar regolith.
The dielectric constant of the surface material may be found from the reflection and transmission coefficients, and plays an important role in the lunar regolith study. In order to study the dielectric properties of the lunar regolith, the lunar regolith simulant is made according to the making procedure of the CAS-1 simulant. Then the dielectric constants of the lunar regolith simulant are measured with 85070E Aiglent microwave network analyzer over the range of 0.2-20 GHz and the temperature in 25.1, 17.7, 13.1, 11.5, 9.6, 8.0, 4.1, - 0.3, - 4.7, - 9.5, - 18.7, - 27.7, - 32.6℃, respectively. The Odelevsky model is employed to remove the influence from the water in the air on the final effective dielectric constant. The result indicates that frequency and temperature have clearly influences on the dielectric constants of the lunar regolith simulant. The real parts of the dielectric constant increase fast over the range of 0.2-3 GHz, but the real parts decrease slowly over the range of 4-20 GHz in total. The opposite phenomenon occurs to the imaginary part. The influences of the frequency and temperature on the brightness temperature are also estimated based on the radiative transfer equation. The result shows that the variation of frequency and temperature results in great changes to the microwave brightness temperature of the lunar regolith.
2011, 21(1): 102-109.
Abstract:
Catchments health assessment is fundamental to effective catchments management. Generally, an assessment method should be selected to reflect both the purpose of assessment and local characteristics. A trial in Shanghai was conducted to test the method for catchments health assessment in urbanized river network area. Seven indicators that described four dimensions of river, river networks, land use and functions, local features were used to assess catchments values; while possible change rate of urbanization and industrialization in the next three years were chose for catchments pressure assessment. Aspects related to catchments classification, indicators measurement and protection priority have been considered in the development of the strategies for catchments health management. The results showed that value-pressure assessment was applicable in urbanized catchments health management, particularly when both human and catchments had multiple demands. As a result of over 30 years rapid urbanization, more than 70% of Shanghai river network area was still in a healthy condition with high catchments values, among them, 39% was under high pressure. Poor water quality, simplifying river system and weakening local feature of river pattern had largely affected catchments health in Shanghai. Lack of long-term monitoring data would seriously restrict the development and validity of catchments health assessment.
Catchments health assessment is fundamental to effective catchments management. Generally, an assessment method should be selected to reflect both the purpose of assessment and local characteristics. A trial in Shanghai was conducted to test the method for catchments health assessment in urbanized river network area. Seven indicators that described four dimensions of river, river networks, land use and functions, local features were used to assess catchments values; while possible change rate of urbanization and industrialization in the next three years were chose for catchments pressure assessment. Aspects related to catchments classification, indicators measurement and protection priority have been considered in the development of the strategies for catchments health management. The results showed that value-pressure assessment was applicable in urbanized catchments health management, particularly when both human and catchments had multiple demands. As a result of over 30 years rapid urbanization, more than 70% of Shanghai river network area was still in a healthy condition with high catchments values, among them, 39% was under high pressure. Poor water quality, simplifying river system and weakening local feature of river pattern had largely affected catchments health in Shanghai. Lack of long-term monitoring data would seriously restrict the development and validity of catchments health assessment.
2011, 21(1): 110-118.
Abstract:
The spatial distribution of urban population can reflect significantly urban functions and development status. Shenyang, as a typical old-industrial city in China, has changed obviously in population spatial distribution in the process of urban transformation, which is causing the change of urban spatial structure. Based on the subdistrict data from 1982, 1990 and 2000 Chinese national population censuses, this study simulate the evolution pattern of urban population spatial distribution in Shenyang city. Using statistical and spatial association approach, we find that the population distribution, on the whole, have shown an even and decentralized trend since 1980s, which characterize with China’s suburbanization. Furthermore, employing density models to investigate the pattern of population distribution, it is concluded that the negative exponential model fitted the distribution best, and population concentration in the inner suburban keep increasing gradually, meanwhile, the spatial structure of population distribution have presented polycentric characteristic in 1980s. The parameters of model show that population concentration in the urban core keep significantly all the time. The increase of population in the inner suburb influence on the population distribution pattern more and more importantly, but the concentration intensity of population cores in inner suburb is still small.
The spatial distribution of urban population can reflect significantly urban functions and development status. Shenyang, as a typical old-industrial city in China, has changed obviously in population spatial distribution in the process of urban transformation, which is causing the change of urban spatial structure. Based on the subdistrict data from 1982, 1990 and 2000 Chinese national population censuses, this study simulate the evolution pattern of urban population spatial distribution in Shenyang city. Using statistical and spatial association approach, we find that the population distribution, on the whole, have shown an even and decentralized trend since 1980s, which characterize with China’s suburbanization. Furthermore, employing density models to investigate the pattern of population distribution, it is concluded that the negative exponential model fitted the distribution best, and population concentration in the inner suburban keep increasing gradually, meanwhile, the spatial structure of population distribution have presented polycentric characteristic in 1980s. The parameters of model show that population concentration in the urban core keep significantly all the time. The increase of population in the inner suburb influence on the population distribution pattern more and more importantly, but the concentration intensity of population cores in inner suburb is still small.
2011, 21(1): 119-128.
Abstract:
Contingent valuation method（CVM） is an evaluation instrument for public goods on the basis of attitude and preference. This paper employs CVM to value the recreational benifits of Jiuzhaigou, one of the World Natural Heritage sites in China, and analyzes the biases in the survey. The results show that: 1) In 2009, Jiuzhaigou’s recreational value is ￥346 million, and the per capita WTP is ￥137.31. Compared with other methods, this result is significantly lower. 2) Among the factors that influence Jiuzhaigou tourists’ Willingness to Pay(WTP), psychological perception factors take the greatest effect while demographics and Socio-Economic Characteristics have little correlation with WTP. 3）The hypothesis in CVM brings biases both in CVM itself and in the procedures that CVM is implemented.The former includes hypothetical bias, information bias, protest response bias, and strategic bias; and the latter appears during the valuation process, such as the questionnaire design, population and sample definition, sampling and data processing. This paper analyses those biases considering questionnaire design and survey process and illustrates their potential influences on the accuracy of CVM measurement. 4) Although there are varies defects in CVM measurement, it is still an effective valuation method. And we should emphasis more on validity and reliability test than on case study or theory building.
Contingent valuation method（CVM） is an evaluation instrument for public goods on the basis of attitude and preference. This paper employs CVM to value the recreational benifits of Jiuzhaigou, one of the World Natural Heritage sites in China, and analyzes the biases in the survey. The results show that: 1) In 2009, Jiuzhaigou’s recreational value is ￥346 million, and the per capita WTP is ￥137.31. Compared with other methods, this result is significantly lower. 2) Among the factors that influence Jiuzhaigou tourists’ Willingness to Pay(WTP), psychological perception factors take the greatest effect while demographics and Socio-Economic Characteristics have little correlation with WTP. 3）The hypothesis in CVM brings biases both in CVM itself and in the procedures that CVM is implemented.The former includes hypothetical bias, information bias, protest response bias, and strategic bias; and the latter appears during the valuation process, such as the questionnaire design, population and sample definition, sampling and data processing. This paper analyses those biases considering questionnaire design and survey process and illustrates their potential influences on the accuracy of CVM measurement. 4) Although there are varies defects in CVM measurement, it is still an effective valuation method. And we should emphasis more on validity and reliability test than on case study or theory building.
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