2012年 第22卷 第3期
2012, 22(3): 255-263.
摘要:
Soil organic carbon (SOC) plays an important role in global carbon cycles. Large spatial variations in SOC contents result in
uncertain estimates of the SOC pool and its changes. In the present study, the key variables explaining the SOC contents of croplands
(CPs) and non-croplands (NCPs) in Chinese provinces were investigated. Data on SOC and other soil properties (obtained from the
Second National Soil Survey conducted in the late 1970s to the early 1990s), climate parameters, as well as the proportion of the CP to
the total land area (Pcp) were used. SOC content variations within a province were larger than those among provinces. Soil clay and
total phosphorus content, ratio of annual precipitation to mean temperature, as well as Pcp were able to explain 75% of the SOC content
variations in whole soil samples. Soil pH, mean temperature during the growing season from May to October, and mean annual wind
velocity were able to explain 63% of the SOC content variations in NCP soils. Compared with NCP soils, CP soils had lower SOC contents,
with smaller variations within and among provinces and lower C/N ratios. Stepwise regression showed that the soil clay content was a
unique factor significantly correlated with the SOC content of CP soils. However, this factor only explained 24% of the variations. This
result suggested that variables related to human activities had greater effects on SOC content variations in CP soils than soil properties
and climate parameters. Based on SOC contents directly averaged from soil samples and estimated by regression equations, the total
SOC pool in the topsoil (0–20 cm) of China was estimated at 60.02 Pg and 57.6 Pg. Thousands of years of intensive cultivation in China
resulted in CP topsoil SOC loss of 4.34–4.98 Pg.
Soil organic carbon (SOC) plays an important role in global carbon cycles. Large spatial variations in SOC contents result in
uncertain estimates of the SOC pool and its changes. In the present study, the key variables explaining the SOC contents of croplands
(CPs) and non-croplands (NCPs) in Chinese provinces were investigated. Data on SOC and other soil properties (obtained from the
Second National Soil Survey conducted in the late 1970s to the early 1990s), climate parameters, as well as the proportion of the CP to
the total land area (Pcp) were used. SOC content variations within a province were larger than those among provinces. Soil clay and
total phosphorus content, ratio of annual precipitation to mean temperature, as well as Pcp were able to explain 75% of the SOC content
variations in whole soil samples. Soil pH, mean temperature during the growing season from May to October, and mean annual wind
velocity were able to explain 63% of the SOC content variations in NCP soils. Compared with NCP soils, CP soils had lower SOC contents,
with smaller variations within and among provinces and lower C/N ratios. Stepwise regression showed that the soil clay content was a
unique factor significantly correlated with the SOC content of CP soils. However, this factor only explained 24% of the variations. This
result suggested that variables related to human activities had greater effects on SOC content variations in CP soils than soil properties
and climate parameters. Based on SOC contents directly averaged from soil samples and estimated by regression equations, the total
SOC pool in the topsoil (0–20 cm) of China was estimated at 60.02 Pg and 57.6 Pg. Thousands of years of intensive cultivation in China
resulted in CP topsoil SOC loss of 4.34–4.98 Pg.
2012, 22(3): 264-277.
摘要:
To improve the understandings on regional climatic effects of past human-induced land cover changes, the surface albedo
changes caused by conversions from natural vegetation to cropland were estimated across northeastern China over the last 300 years,
and its climatic effects were simulated by using the Weather Research and Forecasting (WRF) model. Essential natural vegetation records
compiled from historical documents and regional optimal surface albedo dataset were used. The results show that the surface albedo
decreased by 0.01–0.03 due to conversions from grassland to cropland in the Northeast China Plain and it increased by 0.005–0.015 due
to conversions from forests to cropland in the surrounding mountains. As a consequence, in the Northeast China Plain, the surface net
radiation increased by 4–8 W/m2, 2–5 W/m2, and 1–3 W/m2, and the climate was therefore warmed by 0.1℃–0.2℃、0.1℃–0.2℃、0.1
℃–0.3℃ in the spring, autumn and winter, respectively. In the surrounding mountain area, the net radiation decreased by less than 1.5
W/m2, and the climate was therefore cooled too slight to be detected. In summer, effects of surface albedo changes on climate were
closely associated with moisture dynamics, such as evapotranspiration and cloud, instead of being merely determined by surface radiation
budget. The simulated summer climatic effects have large uncertainties. These findings demonstrate that surface albedo changes
resulted in warming climate effects in the non-rainy seasons in Northeast China Plain through surface radiation processes while the
climatic effects in summer could hardly be concluded so far.
To improve the understandings on regional climatic effects of past human-induced land cover changes, the surface albedo
changes caused by conversions from natural vegetation to cropland were estimated across northeastern China over the last 300 years,
and its climatic effects were simulated by using the Weather Research and Forecasting (WRF) model. Essential natural vegetation records
compiled from historical documents and regional optimal surface albedo dataset were used. The results show that the surface albedo
decreased by 0.01–0.03 due to conversions from grassland to cropland in the Northeast China Plain and it increased by 0.005–0.015 due
to conversions from forests to cropland in the surrounding mountains. As a consequence, in the Northeast China Plain, the surface net
radiation increased by 4–8 W/m2, 2–5 W/m2, and 1–3 W/m2, and the climate was therefore warmed by 0.1℃–0.2℃、0.1℃–0.2℃、0.1
℃–0.3℃ in the spring, autumn and winter, respectively. In the surrounding mountain area, the net radiation decreased by less than 1.5
W/m2, and the climate was therefore cooled too slight to be detected. In summer, effects of surface albedo changes on climate were
closely associated with moisture dynamics, such as evapotranspiration and cloud, instead of being merely determined by surface radiation
budget. The simulated summer climatic effects have large uncertainties. These findings demonstrate that surface albedo changes
resulted in warming climate effects in the non-rainy seasons in Northeast China Plain through surface radiation processes while the
climatic effects in summer could hardly be concluded so far.
2012, 22(3): 278-287.
摘要:
This study proposes an equivalent-elevation method to evaluate the integrated effects of latitude and elevation on regional
and local-scale permafrost distribution in the Qinghai-Tibet Plateau, and to model the general permafrost-distribution patterns in regional
and local-scale area. It is found that the Gaussian curve―an empirical model describing the relation between variations of altitudinal
permafrost lower limit (PLL) and latitude in the Northern Hemisphere―could be applied in regional- and local-scale areas in the Qinghai-
Tibet Plateau in a latitude-sensitive interval of 30°–50°N. The curve was then used to evaluate the latitudinal effect on permafrost
distribution through transforming the latitudinal effect into a kind of altitudinal difference of PLL. This study then calculated the local
equivalent-elevation value by overlaying the altitudinal difference of PLL onto real elevation at a certain location. The equivalent-
elevation method was verified in an experimental subwatershed of the Qinghai-Tibet Plateau. However, feasibility of the method should be
further tested in order to extend for future studies. The use of equivalent-elevation values can build a platform for comparing the regional
general permafrost distribution in the plateau, and for basing further evaluations of local factors′ effects on regional permafrost
distribution.
This study proposes an equivalent-elevation method to evaluate the integrated effects of latitude and elevation on regional
and local-scale permafrost distribution in the Qinghai-Tibet Plateau, and to model the general permafrost-distribution patterns in regional
and local-scale area. It is found that the Gaussian curve―an empirical model describing the relation between variations of altitudinal
permafrost lower limit (PLL) and latitude in the Northern Hemisphere―could be applied in regional- and local-scale areas in the Qinghai-
Tibet Plateau in a latitude-sensitive interval of 30°–50°N. The curve was then used to evaluate the latitudinal effect on permafrost
distribution through transforming the latitudinal effect into a kind of altitudinal difference of PLL. This study then calculated the local
equivalent-elevation value by overlaying the altitudinal difference of PLL onto real elevation at a certain location. The equivalent-
elevation method was verified in an experimental subwatershed of the Qinghai-Tibet Plateau. However, feasibility of the method should be
further tested in order to extend for future studies. The use of equivalent-elevation values can build a platform for comparing the regional
general permafrost distribution in the plateau, and for basing further evaluations of local factors′ effects on regional permafrost
distribution.
2012, 22(3): 288-301.
摘要:
Based on data from 22 sample plots and applying the Canonical Correspondence Analysis (CCA), this paper discusses the
vegetation-environment relationships between the northern slope of Karlik Mountain and Naomaohu Basin, which is situated in the
easternmost end of the Tianshan Mountains, Xinjiang Uygur Autonomous Region, China. For the zonal vegetation, community diversity of
mountain vegetation is higher than that of the desert vegetation due to environmental factors. The CCA ordination diagram revealed that
the composition and distribution of vegetation types are mainly determined by altitude, soil pH and soil salt content. With increasing
elevation, the soil pH and total salt content decrease but the contents of soil organic matter, soil water, total nitrogen and total
phosphorus increase gradually. In the CCA ordination diagrams, the sample plots and main species can be divided into five types
according to their adaptations to the environmental factors. Type I is composed of desert vegetation distributed on the low mountains,
hills, plains and deserts below an elevation of 1900 m; type II is distributed in the mountain and desert ecotone with an elevation of 1900
–2300 m, and includes steppe desert, desert steppe and wetland meadow; type III is very simply composed of only salinized meadow;
type IV is distributed above an elevation of 2300 m, containing mountain steppe, meadow steppe, subalpine meadow and alpine meadow;
type V only contains salinized meadow. The results show that with increasing elevation, species combination changes from the xerophytic
shrubs, semi-shrubs and herbs distributed in the low altitude zone with arid climate to the cold-tolerant perennial herbs growing in the
high altitudinal zone with cold climate.
Based on data from 22 sample plots and applying the Canonical Correspondence Analysis (CCA), this paper discusses the
vegetation-environment relationships between the northern slope of Karlik Mountain and Naomaohu Basin, which is situated in the
easternmost end of the Tianshan Mountains, Xinjiang Uygur Autonomous Region, China. For the zonal vegetation, community diversity of
mountain vegetation is higher than that of the desert vegetation due to environmental factors. The CCA ordination diagram revealed that
the composition and distribution of vegetation types are mainly determined by altitude, soil pH and soil salt content. With increasing
elevation, the soil pH and total salt content decrease but the contents of soil organic matter, soil water, total nitrogen and total
phosphorus increase gradually. In the CCA ordination diagrams, the sample plots and main species can be divided into five types
according to their adaptations to the environmental factors. Type I is composed of desert vegetation distributed on the low mountains,
hills, plains and deserts below an elevation of 1900 m; type II is distributed in the mountain and desert ecotone with an elevation of 1900
–2300 m, and includes steppe desert, desert steppe and wetland meadow; type III is very simply composed of only salinized meadow;
type IV is distributed above an elevation of 2300 m, containing mountain steppe, meadow steppe, subalpine meadow and alpine meadow;
type V only contains salinized meadow. The results show that with increasing elevation, species combination changes from the xerophytic
shrubs, semi-shrubs and herbs distributed in the low altitude zone with arid climate to the cold-tolerant perennial herbs growing in the
high altitudinal zone with cold climate.
2012, 22(3): 302-318.
摘要:
Hong Kong has undergone substantial economic transformations and developed into a sophisticated business and financial
center in the Asia-Pacific region, since the return of sovereignty to China as a Special Administrative Region under the One Country Two
Systems (OCTS) in 1997. This paper discusses and analyzes the industrial structural changes of Hong Kong in recent decades as well as
its future challenges and opportunities. The data and finding reveal that even though Hong Kong will face fierce competition from the
Mainland′s cities as the rise of China, the important role as a bridge between China and the rest of the world will brace Hong Kong itself
under the OCTS for developing into a service hub for business and trade in the Asia-Pacific region.
Hong Kong has undergone substantial economic transformations and developed into a sophisticated business and financial
center in the Asia-Pacific region, since the return of sovereignty to China as a Special Administrative Region under the One Country Two
Systems (OCTS) in 1997. This paper discusses and analyzes the industrial structural changes of Hong Kong in recent decades as well as
its future challenges and opportunities. The data and finding reveal that even though Hong Kong will face fierce competition from the
Mainland′s cities as the rise of China, the important role as a bridge between China and the rest of the world will brace Hong Kong itself
under the OCTS for developing into a service hub for business and trade in the Asia-Pacific region.
2012, 22(3): 319-333.
摘要:
Scientific development is an invaluable asset to a country. Policies and development modes should be carried out based on
scientific findings not only in industry, but also in transportation infrastructure construction. Building an integrated transportation system,
which is in line with the national requirements of China and supports sustainable socio-economic development, is a key strategic issue
related to building a moderately prosperous society and achieving realistic goals of a medium-level developed country. Based on a
systematic review of the advances in China's transportation infrastructure over the last 60 years, this paper explores the main drivers of
transportation development, including national policy, transportation structure, investment efficiency, and technological innovation.
Analysis shows that China′s comprehensive transportation infrastructure construction since 1949 can be divided into five stages initiated
by these drivers, which correspond to four transition modes: policy transition, structural transition, efficiency transition, and technology
transition. The transition path of China's transportation development shows that the dominant factors have changed, and the interval for
each transition has shortened. With the implementation of the ′12th Five-Year Plan′, China's transportation infrastructure construction is
showing some new characteristics and facing a new development transition. Finally, this paper analyzes the trends in transportation
development in China and concludes that technological innovation will be the main driving force to increase the transportation supply and
service area in the future.
Scientific development is an invaluable asset to a country. Policies and development modes should be carried out based on
scientific findings not only in industry, but also in transportation infrastructure construction. Building an integrated transportation system,
which is in line with the national requirements of China and supports sustainable socio-economic development, is a key strategic issue
related to building a moderately prosperous society and achieving realistic goals of a medium-level developed country. Based on a
systematic review of the advances in China's transportation infrastructure over the last 60 years, this paper explores the main drivers of
transportation development, including national policy, transportation structure, investment efficiency, and technological innovation.
Analysis shows that China′s comprehensive transportation infrastructure construction since 1949 can be divided into five stages initiated
by these drivers, which correspond to four transition modes: policy transition, structural transition, efficiency transition, and technology
transition. The transition path of China's transportation development shows that the dominant factors have changed, and the interval for
each transition has shortened. With the implementation of the ′12th Five-Year Plan′, China's transportation infrastructure construction is
showing some new characteristics and facing a new development transition. Finally, this paper analyzes the trends in transportation
development in China and concludes that technological innovation will be the main driving force to increase the transportation supply and
service area in the future.
2012, 22(3): 334-342.
摘要:
The global economic downturn caused primarily by the US sub-prime mortgage crisis in 2007 engendered revenue loss of the
multinational corporations. Existing studies have yet to depict the detrimental impacts on city′s command and control functions induced
by the sub-prime mortgage crisis together with its residual wave of global economic recession on the global spatial economy. Recent and
previous studies have produced an ′instant history′ of the global spatial economy before the global economic downturn undermines the
global economy in late 2008. However, the waxes and wanes of major cities′ command and control functions on the global economic
arena before and after the outbreak of financial crisis and its associated geo-economic transitions are still poorly understood. This paper
attempts to contribute a new set of customized data to update and fill in the gap in the literature with the investigation of the command
and control functions of cities around the world from 2005 to 2009. Particular attentions are paid to the time-space relationship of the
geo-economic transition that can capture the recent historical images of the command and control situation of different cities in the
world.
The global economic downturn caused primarily by the US sub-prime mortgage crisis in 2007 engendered revenue loss of the
multinational corporations. Existing studies have yet to depict the detrimental impacts on city′s command and control functions induced
by the sub-prime mortgage crisis together with its residual wave of global economic recession on the global spatial economy. Recent and
previous studies have produced an ′instant history′ of the global spatial economy before the global economic downturn undermines the
global economy in late 2008. However, the waxes and wanes of major cities′ command and control functions on the global economic
arena before and after the outbreak of financial crisis and its associated geo-economic transitions are still poorly understood. This paper
attempts to contribute a new set of customized data to update and fill in the gap in the literature with the investigation of the command
and control functions of cities around the world from 2005 to 2009. Particular attentions are paid to the time-space relationship of the
geo-economic transition that can capture the recent historical images of the command and control situation of different cities in the
world.
2012, 22(3): 343-355.
摘要:
The mortgage loan has evolved from a local lending instrument into a major global security and its role is unparallel to other
financial instruments in the process of financial globalization. This paper explains how technology and financial innovation transformed the
mortgage loan from a local security into a premier global security traded worldwide. It examines the fundamental flaws of this process and
why it does not work in regards to mortgage lending and the re-securitization products that were created through financial innovation.
The findings show that regulation was unable to keep pace with financial innovation, which created an environment where actors in the
financial service sector were able to behave geographically irresponsibly by using information asymmetries to their advantage by
participating in moral hazard activities and engaging in other immoral and unethical business practices that were centered around
localized geography, which ultimately contributed to the global financial crisis. It also examines the roll of financial innovation in regard to
the Lehman Brothers Mini-Bond in Hong and its role as a driving force behind China′s newly emerging shadow banking sector. It concludes
with a policy recommendation and its implication for China′s continued economic development.
The mortgage loan has evolved from a local lending instrument into a major global security and its role is unparallel to other
financial instruments in the process of financial globalization. This paper explains how technology and financial innovation transformed the
mortgage loan from a local security into a premier global security traded worldwide. It examines the fundamental flaws of this process and
why it does not work in regards to mortgage lending and the re-securitization products that were created through financial innovation.
The findings show that regulation was unable to keep pace with financial innovation, which created an environment where actors in the
financial service sector were able to behave geographically irresponsibly by using information asymmetries to their advantage by
participating in moral hazard activities and engaging in other immoral and unethical business practices that were centered around
localized geography, which ultimately contributed to the global financial crisis. It also examines the roll of financial innovation in regard to
the Lehman Brothers Mini-Bond in Hong and its role as a driving force behind China′s newly emerging shadow banking sector. It concludes
with a policy recommendation and its implication for China′s continued economic development.
2012, 22(3): 356-366.
摘要:
China still use sketch maps as control devices that guarantees consistency and accuracy of population counting in previous
census. Although the rapid advancement of geospatial technologies provides many possible solutions of digital census mapping, existing
researches do not answer which solution is suitable to China. Subject to many constraints originated from characteristics of China, a
practical solution of census mapping based on remote sensing imagery and auxiliary geographic information was proposed and proved to
be feasible through evaluation analysis and a three-stage pilot study. Imagery with 2.5 meters and higher resolution, innovative workflow
of census areas delineation, easy-to-use census mapping software packages and training organization all together provide the all-around
supports for the 2010 rounded census (the 6th census) mapping activities. A digital census geographic framework detailed at the level of
enumeration area was established in the 2010 rounded census which fills in the gaps in the field of modern geospatial census in China.
The spatially referenced digital census database, especially the detailed census units, is of great value in successive census, sampling
survey and many other census-related fields. Future work including quality evaluation of census areas, census mapping solution in the
Tibet Autonomous Region are also discussed.
China still use sketch maps as control devices that guarantees consistency and accuracy of population counting in previous
census. Although the rapid advancement of geospatial technologies provides many possible solutions of digital census mapping, existing
researches do not answer which solution is suitable to China. Subject to many constraints originated from characteristics of China, a
practical solution of census mapping based on remote sensing imagery and auxiliary geographic information was proposed and proved to
be feasible through evaluation analysis and a three-stage pilot study. Imagery with 2.5 meters and higher resolution, innovative workflow
of census areas delineation, easy-to-use census mapping software packages and training organization all together provide the all-around
supports for the 2010 rounded census (the 6th census) mapping activities. A digital census geographic framework detailed at the level of
enumeration area was established in the 2010 rounded census which fills in the gaps in the field of modern geospatial census in China.
The spatially referenced digital census database, especially the detailed census units, is of great value in successive census, sampling
survey and many other census-related fields. Future work including quality evaluation of census areas, census mapping solution in the
Tibet Autonomous Region are also discussed.
2012, 22(3): 367-380.
摘要:
Existing quantitative migration studies are mainly at the inter-region or inter-province level for lacking of detailed geo-
referenced migration data. Meanwhile, few of them integrate explorative spatial data analysis and spatial regression model into migration
analysis. Based on aggregated registered floating population data from 2005 to 2008, the phenomena that population floating to Yiwu
City in Zhejiang Province is analyzed at the provincial and county levels. The spatial layout of Yiwu′s pull forces is proved as a V-shaped
pattern excluding Sichuan Province based on map visualization method. Using the migration ratio in 2007 as an explanatory variable, two
models are compared using ordinary least square, spatial error model and spatial lag model methods for county-level data in Jiangxi and
Anhui provinces. The model with migration stock provides an improved fitting over the model without migration stock according to the
model fitting results. The floating population flocking into Yiwu City from Jiangxi is determined mostly by migration stock while the
determinant factors are migration stock and distance to Yiwu City for Anhui. The distance-decay effect is true for migration flow from
Anhui to Yiwu City while the distance rule is not confirmed in Jiangxi with the best fitting model. The correlation between per capita net
income of rural labor forces and migration ratio is not significant in Jiangxi and significant but at the 0.1 level only in Anhui. Further
analysis shows that the distance, income and man-land ratio are important factors to explain population floating at earlier stage.
However, as the dynamic population floating process evolves, the determinant factor would be migration stock.
Existing quantitative migration studies are mainly at the inter-region or inter-province level for lacking of detailed geo-
referenced migration data. Meanwhile, few of them integrate explorative spatial data analysis and spatial regression model into migration
analysis. Based on aggregated registered floating population data from 2005 to 2008, the phenomena that population floating to Yiwu
City in Zhejiang Province is analyzed at the provincial and county levels. The spatial layout of Yiwu′s pull forces is proved as a V-shaped
pattern excluding Sichuan Province based on map visualization method. Using the migration ratio in 2007 as an explanatory variable, two
models are compared using ordinary least square, spatial error model and spatial lag model methods for county-level data in Jiangxi and
Anhui provinces. The model with migration stock provides an improved fitting over the model without migration stock according to the
model fitting results. The floating population flocking into Yiwu City from Jiangxi is determined mostly by migration stock while the
determinant factors are migration stock and distance to Yiwu City for Anhui. The distance-decay effect is true for migration flow from
Anhui to Yiwu City while the distance rule is not confirmed in Jiangxi with the best fitting model. The correlation between per capita net
income of rural labor forces and migration ratio is not significant in Jiangxi and significant but at the 0.1 level only in Anhui. Further
analysis shows that the distance, income and man-land ratio are important factors to explain population floating at earlier stage.
However, as the dynamic population floating process evolves, the determinant factor would be migration stock.
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