Tesi sul tema "Shenzhen (Guangdong Sheng, China : East)"

The Special Economic Zones have been designed by the Chinese Government as a two-pronged strategy in its ‘open-door’ policy: expanding exports and encouraging foreign technology imports. Also, they are intended to be test-grounds for hybrid socialistcapitalist experiments - a reflection of the country’s search for efficient methods of production to bring about the country’s much-delayed modernization. The Shenzhen Special Economic Zone, in particular, has been given a pivotal role, because it is planned to incorporate both a full -fledged economy and a well-developed urban area. Its progress, therefore, has attracted much attention. The assessments of Shenzhen’s initial performance have, however, resulted in polarized opinions. Yet a detailed evaluation of Shenzhen's progress as an export processing zone - a phenomenon similar to those in other developing countries - has not been made. Hence, this study has undertaken the task. Industrial performance and social conditions within the zones have been perennial themes of export processing zone studies. As a result, the economic progress of Shenzhen is measured in this study against its specific planning goals and directives. Particular attention is centred on industrial performance and the outward-orientation of the Zone’s economy - the twin objectives of its economic development. Then the ‘well-being’ of Shenzhen’s population, specifically income and accessibility to social goods, is canvassed. In turn, the economic and social developments are evaluated with reference to the performance of other export processing zones. Finally, Shenzhen’s initial contribution and its potential to promote modernization in China as a large coastal city possessing export processing facilities are estimated.

The rapid pace of urbanization heightens our interest to understand the role of urban areas in mediating climate changes at local, regional and global levels. The increasing amount of carbon (C) released by growing cities may influence the surrounding climates and lead to a rise in global ambient temperature. Fortunately, urban greenery may mitigate the risk of rising C by storing it in vegetation and soils. On the other hand, urban greenery may become a net CO₂ or other greenhouse gas emitter due to heavy maintenances. Thus, the exact impact of urban greenery on carbon balance in major metropolitan areas remains controversial.
We first investigated C footprints of urban turf operation and maintenance by conducting a research questionnaire on different Hong Kong turfs, and showed that turf maintenance contributed 0.17 to 0.63 kg Ce m⁻² y⁻¹ to C emissions. We then determined C sequestration capacity by urban turfgrasses and soils through both field study and laboratory-based investigation. Our data from field study showed that the C stored in turfgrass systems at 0.05 to 0.21 kg C m⁻² for aboveground grass biomass and 1.3 to 4.9 kg C m⁻² for soils (to 15 cm depth). We estimated that the C sink capacity of turfs could be offset by C emissions in 5-24 years under current management patterns, shifting from C sink to C source.
We further showed that dissolved organic C (DOC) export also contributed to C release from urban soils, under the influence of the maintenance practices of turfgrasses. Both irrigation and nitrogen (N) fertilizer inputs could enhance DOC export. We also observed that soil enzyme activity was sensitive to turfgrass maintenances practices, and played a key role in soil organic C (SOC) decomposition. In particular, cellulase was found to be a major player in regulating DOC and dissolved organic N (DON) export. On the other hand, urease activity was shown to be dependent on grass species, fertilizer inputs and substrates.
Finally, we then determined the CO₂ fluxes of turfgrass systems by chamber-based measurement. Our data demonstrated that grass species and photosynthetically active radiation (PAR) played a dominant role in CO₂ fluxes in greenhouse study. Maintenance practices also contributed to CO₂ fluxes of turfgrass systems. Both fertilizer and irrigation showed species-specific effect on CO₂ fluxes. We then showed in field studies that CO₂ fluxes and respiration rates of urban turfs varied with grass species, and were higher in wet season than dry season.
Together, our studies suggested that maintenance practices for urban greenery played a key role in SOC decomposition through regulating DOC export and C cycle associated enzymes, therefore may determine the C balance of urban greenery. Our studies further suggest that we can improve maintenance practices to reduce C footprint and enhance the environmental benefits of urban turfgrass systems. We propose that the environmental impact of turfgrass systems should be optimized by the rational design of maintenance schedules based on C sink and emission principles.
城市化的快速發展提高了我們研究城市的興趣，具體在其對城區和地域性氣候及其對全球气候变化的調節。城區大量碳排放可能影響周圍氣候進而導致全球環境溫度的上升。城市綠化可以緩解這個危機因為植被和土壤能夠通過存儲碳。但是城市綠化系統的大量維護可能是導致二氧化碳或其他溫室氣體的排放。因此城市綠化對碳平衡的影響仍存在爭議。
我們以問卷方式調查了香港不同的草坪，計算了維護過程中的碳足跡。研究表明草坪每年的維護造成了相當於每平米0.17至0.63千克碳排放。我們還結合野外和實驗室分析測定了草坪地上生物量和15厘米深土壤的碳儲存量，每平米分別是0.05至0.21，1.3至4.9千克碳。據此我們估計，按照目前的管理模式，草坪的碳儲存量在5至24年可與維護的碳排放相抵，由碳匯轉變為碳源。
我們還發現溶解有機碳的流失也加劇了城市土壤碳釋放同時受草坪維護的影响。灌溉和施加氮肥會促進溶解有機碳的釋放。土壤酶對是草坪維護很敏感，而且對土壤有機有機碳分解起關鍵作用。特別是纖維素酶參與并有效調節了溶解有機碳和溶解有機氮的釋放。另外脲酶的活性受草種，施肥和土壤基質的影響。我們用二氧化碳分析儀测定了草坪的碳通量。溫室研究表明，草種和光合有效輻射對碳通量起主導作用。草坪的維護同樣影響草坪的碳通量，其中施肥和灌溉對不同草種的碳通量有不同程度的影響。野外實驗則發現城市草皮的碳通量和呼吸速率隨草種变化，且雨季高於旱季。
以上研究表明城市綠化系統的維護可以有效調節溶解有機碳和碳循環相關土壤酶，進而影響土壤有機碳的分解，最終決定城市綠化系統的碳收支。因此我們建議，由以經驗設計轉變為以碳匯和碳排放原則優化維護模式，以減少碳足跡從而提升城市綠化的環境效益。
Kong, Ling.
Thesis Ph.D. Chinese University of Hong Kong 2014.
Includes bibliographical references (leaves 191-212).
Abstracts and appendixes also in Chinese.
Title from PDF title page (viewed on 24, October, 2016).
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.

Finally, the newly integrated model was firstly applied to analyze the relationship of land use and hydrologic regimes based on the land use maps in 1980 and 2000. Then the newly integrated model was applied to simulate the potential impacts of land use change on hydrologic regimes in the East River Basin under a series of hypothetical scenarios. The results show that ET has a positive relationship with Leaf Area Index (LAI) while runoff has a negative relationship with LAI in the same climatic zone, which can be elaborated by surface energy balance and water balance equation. Specifically, on an annual basis, ET of forest scenarios is larger than that of grassland or cropland scenarios. On the contrary, runoff of forest scenarios is less than that of grassland or cropland scenarios. On a monthly basis, for most of the scenarios, particularly the grassland and cropland scenarios, the most significant changes occurred in the rainy season. The results indicate that deforestation would cause increase of runoff and decrease of ET on an annual basis in the East River Basin. On a monthly basis, deforestation would cause significant decrease of ET and increase of runoff in the rainy season in the East River Basin.
In order to effectively simulate hydrologic impact of LUCC, an integrated model of ESEBS and distributed monthly water balance model has been developed in this study. The model is capable of considering basin terrain and the spatial distribution of precipitation and soil moisture. Particularly, the model is unique in accounting for spatial and temporal variations of vegetation cover and ET, which provides a powerful tool for studying the hydrologic impacts of LUCC. The model was applied to simulate the monthly runoff for the period of 1980-1994 for model calibration and for the period of 1995-2000 for validation. The calibration and validation results show that the newly integrated model is suitable for simulating monthly runoff and studying hydrologic impacts ofLUCC in the East River Basin.
Land use/cover change (LUCC) has significantly altered the hydrologic system in the East River (Dongjiang) Basin. Quantitative modeling of hydrologic impacts of LUCC is of great importance for water supply, drought monitoring and integrated water resources management. An integrated eco-hydrologic modeling system of Distributed Monthly Water Balance Model (DMWBM), Surface Energy Balance System (SEBS) was developed with aid of GIS/RS to quantify LUCC, to conduct physically-based ET (evapotranspiration) mapping and to predict hydrologic impacts of LUCC.
The physically-remote-sensing-based Surface Energy Balance System (SEBS) was employed to estimate areal actual ET for a large area rather than traditional point measurements . The SEBS was enhanced for application in complex vegetated area. Then the inter-comparison with complimentary ET model and distributed monthly water balance model was made to validate the enhanced SEBS (ESEBS). The application and test of ESEBS show that it has a good accuracy both monthly and annually and can be effectively applied in the East River Basin. The results of ET mapping based on ESEBS demonstrate that actual ET in the East River Basin decreases significantly in the last two decades, which is probably caused by decrease of sunshine duration.
These results are not definitive statements as to what will happen to runoff, ET and soil moisture regimes in the East River Basin, but rather offer an insight into the plausible changes in basin hydrology due to land use change. The integrated model developed in this study and these results have significant implications for integrated water resources management and sustainable development in the East River Basin.
To begin with, in order to evaluate LUCC, understand implications of LUCC and provide boundary condition for the integrated eco-hydrologic modeling, firstly the long-term vegetation dynamics was investigated based on Normalized Difference Vegetation Index (NDVI) data, and then LUCC was analyzed with post-classification methods and finally LUCC prediction was conducted based on Markov chain model. The results demonstrate that the vegetation activities decreased significantly in summer over the years. Moreover, there were significant changes in land use/cover over the past two decades. Particularly there was a sharp increase of urban and built-up area and a significant decrease of grassland and cropland. All these indicate that human activities are intensive in the East River Basin and provide valuable information for constructing scenarios for studying hydrologic impacts of LUCC.
Wang, Kai.
"December 2010."
Adviser: Yongqin Chen.
Source: Dissertation Abstracts International, Volume: 73-04, Section: A, page: .
Thesis (Ph.D.)--Chinese University of Hong Kong, 2011.
Includes bibliographical references (leaves 203-227).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.

Monthly water balance models are important tools for hydrological impact assessment of climate change. Traditionally monthly models adopt a conceptual, lumped-parameter approach. Based on an extensive survey and review of existing monthly water balance models, six models with different conceptualization and structure, i.e., Thomthwaite-Mather, Belgium, Xinanjiang, Guo, WatBal and Schaake, were compared through calibration and validation using observed data of hydrology and climate of 1960-1988 in the Dongjiang basin. The model comparison offered insights for the development of a monthly distributed model which integrates the spatial variations of basin terrain and rainfall into runoff simulation. An innovative feature of the new model is that the spatial distribution of soil moisture capacity which is described as a parabolic curve in Xinanjiang model is represented by a cumulative frequency curve of index of relative difficulty of runoff generation based on the concept of topographic index in TOPMODEL. The calibration and validation results show that the developed model with only three parameters is suitable for monthly runoff simulation in the Dongjiang basin.
The developed model was applied to evaluate the changes in water availability in the Dongjiang basin under hypothetical climate change scenarios and those derived from projections of three General Circulation Models (GCM), i.e., CGCM1, CSIRO and ECHAM4. Sensitivity analyses based on hypothetical scenarios suggest that climatic change has greater effects on runoff than on soil moisture and greater effects on water availability in dry months than in wet months. The effects of precipitation changes on the amount of runoff and soil moisture can be characterized by a magnification factor whereas temperature increases alone produce negligible effects. Hydrological simulation with inputs of three GCM-generated scenarios indicates that annual and rain-season runoff will increase by 0.3°io to 13.9% and 7.6% to 12.0%, respectively, by the 2050s. Dry-season runoff will change between -23.2% and +26.4%. Average annual and dry-season soil moisture will decrease by 1.3% to 6.9% and 1.0% to 8.1%, respectively. Soil moisture will demonstrate little change in rain-season. Increase in annual runoff and reduction in annual soil moisture will be apparent over the whole basin, but there is relatively little consistency among the three GCM-generated scenarios as to the magnitudes of spatial change in runoff and soil moisture. Although these results are not definitive statements as to what will happen to runoff and soil moisture in the Dongjiang basin, they rather have significant implications for the study of response strategies of water supply and flood control to climate change.
Jiang Tao.
"July 2005."
Advisers: Chen Yongqin; Lam Kin-che.
Source: Dissertation Abstracts International, Volume: 67-01, Section: B, page: 0149.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2005.
Includes bibliographical references (p. 174-190).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
School code: 1307.