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1.
The Coastal Vulnerability and Exposure Degree (CVED) of the Gran Canaria Island and the coastal risk of Playa de Las Canteras (Las Palmas de G.C.) have been assessed by means of a GIS analysis. The evaluation of coastal vulnerability (H) has been performed by using two different levels of analysis: the first one regarding the entire Island (Coastal Vulnerability Index method - CVI), the second one regarding specifically Las Canteras Beach, selected for its socio-economic importance (Coastal Vulnerability Assessment method - CVA). The application of the CVI method, based on geologic-geomorphologic and meteomarine data easily available, has allowed the regional scale assessment of coastal vulnerability (H) along the Gran Canaria coastline and, therefore, the individuation of more critical coast stretches deserving further analysis. The application of the CVA method, based on more specific morphologic-sedimentary beach features that allow to consider both the beach retreat due to storm surge and the coastal inundation due to run-up on the beach, has provided a large scale detail on the coastal vulnerability of Las Canteras Beach. Socio-economic and damage indexes have been determined for the 15 coastal municipalities included in the study area and, by means of the resulting matrix product, the degree of exposure (Ex) along the Gran Canaria coast has been assessed. Finally, the combination of coastal vulnerability and exposure levels has allowed to obtain the Coastal Vulnerability and Exposure Degree (CVED) for the entire Island and the risk levels that characterize specifically Las Canteras Beach. Major results in terms of CVED highlight prevailing low vulnerability and exposure levels along the western coast, and overall high vulnerability and exposure levels along the eastern coast, from Las Palmas de G.C. to San Bartolomé de Tirajana. The focus made on Playa de Las Canteras has allowed to identify the areas characterized by medium and high risk levels that represent approximately one third (940 m) of the entire beach and are located in its central part. The used two-level analysis approach has proved its efficiency by highlighting the degree of coastal vulnerability along the study coast and, especially, more critical coast stretches (CVI method) such as the Playa de Las Canteras that can be successfully analysed with the CVA approach allowing for a large-scale assessment of risk aspects, essential for a correct definition of priority management strategies. Results obtained with the present study, along with the awareness of the increasing phenomena of coastal erosion and marine flooding arising on the mid-long term due to the effects of global climate change, highlight the need for the competent public administrations of Gran Canaria to develop a strategic approach to coastal management and sustainable development that considers as a whole socio-economic values and natural resources, coastal vulnerability and exposure degree, and risk aspects.  相似文献   

2.
Coastal systems are characterized by high geophysical and biophysical sensitivity as being their massive occupation a serious issue concerning their self-regulation. Worldwide coastal areas are exposed to problems such as coastal erosion, degradation and destruction of marine habitats, pollution and rising sea level. Thus, it is crucial to design models of coastal vulnerability assessment to ensure a better management of coastal areas. This study characterizes the vulnerability of the coastal stretch between the beaches of Porto de Mós and Falésia in the Algarve, corresponding to 52?km of the south coast of Portugal. The expansion of urban areas was modelled using a Cellular Automata (CA) based approach. Results show that 65% of the coastal stretch has high and very high vulnerability caused by both physical and human factors. Results further indicate that urban growth may interfere with the natural evolution of the coastal geomorphology. The scenario of urban expansion for the year 2015 highlights the need to develop effective urban planning processes to ensure a correct balance between the geophysical resilience of coastal systems and the promotion of the coastal sector as a strategic asset for the regional and national economy.  相似文献   

3.
Coastal erosion poses serious threat to life and properties along Ghana??s coast. This is because major industries, urban settlements, recreational facilities, heritage and conservation sites are located few metres from the coast. In spite of this threat, management strategies, both past and present, remain an ??ad hoc?? and site specific. Limited attention has been given to large scale assessment and investigation to detect the rate of coastal recession and the size of land lost to the sea to inform integrated management plan and to formulate sustainable management strategies to deal with the problem. This paper provides large scale assessment of coastal recession in Ghana through field investigation, applied coastal geomorphology and GIS techniques to selected case study areas. The assessment covered 203?km out of the 540?km coastline of Ghana. Results of the assessment indicate that coastal erosion is very substantial and wide spread along the coast, but the rate of recession varies across the entire coastline. Significant amounts of losses of settlements have been experienced in some localities in the eastern coast (Keta and Ada) and the central coast (Accra, Shama and Sekondi-Takoradi). In some areas, coastal defences have been built to reduce the impacts, yet many areas are still very vulnerable. Interestingly, the paper identified that the high rates of retreat recorded in many areas have yet to cause major risks in some local communities because of the presence of a buffer of largely undeveloped land that has existed historically between the shoreline and the developments. However, recent increase in coastal tourism in Ghana has led to ??scramble?? for purchase of these buffer lands for development, which increase the risk. Ghana has the opportunity to use education and land use planning to keep the coastline clear of major developments and avoid the temptation of engaging in costly cycle of development-risk-defence experienced in many countries including the UK and the Netherlands. The paper recommends that Ghana should adopt the UK SMP, which has progressively moved away from the traditional re-active and parochial approaches of providing localised hard-engineered coastal defence work to solve what was perceived to be a local problem, to a more pro-active and holistic approach that take full account of coastal dynamics, interrelationships of coastal systems, knock-on effects, environment concerns and developments at the backshore.  相似文献   

4.
Coastal erosion is a serious environmental problem that has caused the loss of private infrastructure and national assets along Ghana’s coast. Several hard engineering measures have thus been used to protect some communities and vital state assets when they became threatened. Regardless of this problem, sediment mining activities are increasingly practiced along most of Ghana’s coast, further exacerbating coastal erosion intensity and degrading coastal ecosystems. This paper provides an overview of the activities of coastal sediment miners along four administrative Districts in the Central Region of Ghana and identifies how issues arising from the practice are managed at the local community level as well as by state environmental regulators. The study uses a mixed-method approach, involving individual and group interviews, administration of a set of structured questionnaire and field observations, to identify coastal sediment mining and emerging management issues. Overall, three main categories of coastal sediment mining activities were identified in the area. Results indicate that coastal sediment mining is widely practiced by both commercial contractors and community members, giving rise to the high perception among residents that it is the reason for the degradation of the coastline in the studied areas. The study also established that state environmental regulators have weak inter-agency cooperation leading to poor enforcement of environmental laws and non-prosecution of offending individuals. The paper suggests that since each identified sediment mining activity has its own peculiar issues and mode of operation, coastal managers should address each category independently in order to derive lasting impacts in curtailing the practice.  相似文献   

5.
Bandon Bay (Surat Thani Province) is one of the most productive coastal areas in southern Thailand. The Tapi River and 18 channels are the main sources of freshwater, nutrients, organic matter and sediment to the bay and the loading of freshwater and nutrients provide essential support for the production of phytoplankton in the estuarine ecosystem. Bandon Bay is important as natural spawning, nursery and feeding grounds for shellfish such as oysters, blood cockles, green mussels, short-necked clams, mud crabs and shrimps, and the estuary also serves as an excellent area for mariculturing of shellfish. In fact, oysters and blood cockles cultured in Bandon Bay are now being exported worldwide. However, Bandon Bay is also a textbook example of overexploitation of coastal resources in the tropics including all the derived changes in the estuarial ecosystem with severe socio-economic consequences. Hence, there is an urgent need for setting up an integrated management plant for a sustainable use of shellfish resources in Bandon Bay. The present study attempts to integrate water quality simulation results, socio-economic data and information on existing shellfish resource use in the process of proposing a set of sustainable management strategies for shellfish resources in Bandon Bay. These strategies involve: (1) using water quality modeling to monitor ecological and environmental changes in shellfish culture beds and their natural habitats in the process of setting up a master plan for management of waste water discharge into Bandon Bay; (2) zoning of shellfish mariculture in the coastal area in order to solve conflicts between resource users; (3) setting up a clear system for taxation of mariculture where the revenue may be used for (4) setting up and managing mangrove strips as filters of pollution and sediment around Bandon Bay; and finally (5) it is suggested to form a committee with members representing all relevant stakeholders plus the local government in order to work on resolving the existing and potential future conflicts over resource usage in Bandon Bay. This methodology may be seen as an important contribution towards a Bandon Bay sustainable management approach, based on the principles of integrated coastal zone management because it is science-based and takes into consideration the needs and perceptions of people involved in coastal resource extraction.  相似文献   

6.
Coastal dunes are increasingly at risk due to pressures deriving from global climate change, sea level rise, recreation and development. The consequences of the “coastal squeeze” in which dunes are placed, such as erosion and the loss of critical ecosystem services, are usually followed by expensive restoration and protection measures, many of which are unsuccessful. Due to the poor understanding and acknowledgement of the key attributes of coastal dunes in decision making processes, it is essential to provide scientific data on the impacts of human interference on coastal dunes so as to inform executives and guide them towards a sustainable management of the coastal zone. The aim of this study was to investigate the impact of five different levels of infrastructure development on the vegetation community structure of coastal dunes in Jeffreys Bay, South Africa. The effects of infrastructure development on dune vegetation were quantified by measuring the richness, diversity, cover, height and composition of plant species. With an increase in infrastructure development a significant decrease in dune width, average species richness and height of the plants occurred, accompanied by a shift in plant community composition. The foredunes that were backed immediately by infrastructure presented significantly greater species richness, diversity, cover and height compared with the foredunes abutted by primary dunes. This study demonstrated that coastal dunes are environments which are sensitive to varying levels of human impact. Informed and comprehensive management planning of these environments is therefore imperative for the restoration and maintenance of remnant dunes and for the conservation of undeveloped coastal dunes.  相似文献   

7.
The practice of coastal zone management in Portugal is very recent. Key issues and considerations about natural shoreline dynamics, main policy instruments, and lessons learned from the EU Demonstration Programmes on Integrated Coastal Zone Management in Portugal will be outlined in this paper in an attempt to understand how the practice of ICZM and its prospects are. Coastal zone management problems and their associated side effects, as well as national and international evolution patterns will be drawn. Some means of achieving better coastal zone management practices and ways of addressing some of its forefront issues are also identified. Special attention will go to erosion problems. The pressure induced by urban development and economic activities on coastal areas is increasing. Poor sediment availability combined with years of neglected management and over-exploitation of resources have had a negative impact, and there are many areas showing evidence of coastal erosion. There is a need to improve policies and instruments of coastal planning and management. Coastal zone management plans are being developed for the nine sectors of the continental Portuguese coast, providing a full analysis of coastal systems and a delimitation of uses in relation to the carrying capacity of the shoreline.  相似文献   

8.
Traditionally the coastal zone of the easternmost (Russian) part of the Gulf of Finland has not been considered as an area of active litho- and morphodynamics, but a recent study has shown that the easternmost part of the coastal zone suffers from erosion. Within some coastal segments the shoreline recession rate reaches 2 ?C 2.5?m/year. As well as determining the hydrodynamic reasons for recent erosion acceleration, important geological and geomorphic features of coastal zone which influenced the lithodynamics were established. The Kurortny District of St.Petersburg is located along the northern coast of the Gulf of Finland to the west of the St. Petersburg Flood Protection Facility. It has special importance as a unique recreation zone of the North-West of Russia. Coastal erosion is one of the most serious problems of the area. The analysis of historical materials, archive aerial photographs and modern high-resolution satellite images have shown that advancing parts of coast are almost non-existant with most sections of the coast being eroded and further retreating. Field monitoring between 2004 and 2007 showed intense damage to sandy beaches during autumn and winter storms and progressive erosion of the dunes system. Among the most important natural reasons for the erosion processes are that the coastline is open to storm waves induced by westerly and south-westerly winds, the geological structure of coastal area (easily eroded Quaternary deposits) and a sediment deficit. In some areas sediment loss was the result of the submarine coastal slope morphology (a steep slope of a narrow submarine terrace within the area of sediment drift discharge), with erosion of an alongshore submarine sandy terrace and erosion runnels at the depth 8?C12?m. The situation becomes worse due to anthropogenic impact. The southern coastal zone dynamics are also very active. According to an aerial and satellite photos analysis from 1975?C1976 to 1989?C1990, sandy beaches to the west of Lebyazhye village were eroded up to 30?m, and near Bolshaya Izora village up to 70?m. The comparison of coastine GPSsurvey with old nautical and topographic charts published in the 1980s shows the considerable change.  相似文献   

9.
Mangroves forests are facing serious stresses which jeopardize their sustainability and their existence in Pakistan. Theses coastal forests are found in the Indus delta in Sindh and the coastal areas of Sonmiani, Kalmat and Gawatar bay in Balochistan. A significant reduction in the fresh water supply and increased marine water pollution in from industries as well as over harvesting of mangroves and fishes by the local peoples, sedimentation, population stress and coastal erosion are usually considered to be the immediate causes of mangrove loss in Pakistan. Various Projects have been under taken in the past and in current scenario to conserve the resources of mangrove areas. Strong planning with the collaboration of the local institutes at the grass-root levels will be helpful to strengthen their capacity and to achieve the targets easily, and they will also help in achieving the conservation goals in a sustainable manner. It is predictable that large-scale plantation of this mangroves species in these areas would increase the resources in coastal areas, resulting economic benefit to the local people.  相似文献   

10.
城市雨水问题与可持续发展对策   总被引:18,自引:0,他引:18  
城市化的快速发展带来了一系列的雨水问题,如雨水径流污染、水资源严重短缺、洪灾风险加大等,雨水是城市可持续发展的关键问题之一。通过对近年来北京城区雨水水质与水量的监测和分析,根据城市可持续发展的总体要求,提出了解决城市雨水问题的指导思想和对策。  相似文献   

11.
To improve the present national and local sustainable planning capability for the coastal zone a GI application for the Italian Coastal Susceptibility Assessment was planned within an institutional agreement between ENEA and the Land Defence Service of the Italian Ministry of Environment. Taking into account previous European actions a suitable methodology to assess, in a quantitative way, the susceptibility of beaches to be eroded has been set up. The methodology balances the coastline trend as evaluated for a defined time period with the present coastal areas morphology and land use, this in order to derive a value that expresses the evolutionary process in terms of probability of the loss of goods within the ‘Homogeneous Coastal Tracts’. The trend in the movement of the sea-land line has been used asgeo-indicator of a complex dynamic balance that refers both to marine and inland systems, and a vector GI application was built and locally applied in southern Italian coastal areas. The present shoreline position and some other information describing the intrinsic beach morphologies, and having significance for the coastal erosion hazard assessment, have been derived from the national 1∶10.000 ortho-images of the National Cartographic Reference System provided by the Italian Ministry of Environment. The illustrated GI application— CoSTAT—keeps the nominal scale of all data collected or produced. In this analysis the coastal dune presence is analysed as factor limiting coastal erosion susceptibility. Applying a matrix calculation a quantitative evaluation of erosion susceptibility degree was achieved and plans were made to develop new information for a suitable use of Italian coastal areas. The work describes the methodology, the conceptual frame-work and the results of a local application.  相似文献   

12.
Accelerated sea level rise and hurricanes are increasingly influencing human coastal activities. With respect to the projected continuation of accelerated sea level rise and global warming one must count with additional expenses for adaptation strategies along the coasts. On the mountainous island Martinique the majority of settlements are situated along the coast almost at sea level. But potential rises in sea level and its impacts are not addressed in coastal management, even though saltwater intrusion and coastal erosion with increasing offshore loss of sediment are locally already a severe problem. At a sea level rise of 50 cm, one fourth of Martinique’s coastline will be affected by erosion and one fifth of the islands surface will have high probability to get flooded during coastal hazards. This is a growth of 5% of the impact area in comparison to present conditions. This article analyses potential adaptation strategies and argues that the development of a coastal zone management plan considering sea level rise and its impact area is of utmost importance. Empirical assessment models in combination with spatial analysis are useful in obtaining statements about coastal impacts concerning sea level rise. This paper sees itself as recommendation of action not only for Martinique.
Christine SchleupnerEmail:
  相似文献   

13.
Choice experiment surveys are commonly used to assess the general public׳s willingness to pay for different levels of environmental quality. However, respondents need to understand what they are valuing or they will make potentially wrong assumptions based on different experiences and frames of reference. Three-dimensional computer generated models or Virtual Environments (VE) have so far seen little use in economics research, probably due to the complexity and cost of developing and delivering them to study participants. The few studies that have used them find that VE are superior to static image presentations in helping people evaluate complex data. For this study we developed virtual environments for a choice experiment about coastal erosion management using free, easy-to-use software and Google Earth© satellite imagery and presented these to respondents as video tours. Our results indicate that the VE treatment reduced choice error, reduced left-right bias and improved respondent engagement and retention when compared with static images. There were also differences in WTP between the two groups.  相似文献   

14.
Interactions between water and land in The Netherlands   总被引:1,自引:0,他引:1  
The Netherlands are one of the most densely populated coastal countries in the world and there is only limited space for living, working, transport and recreation, while there is also the need to preserve and expand valuable natural habitats. In order to solve many existing and future conflicts of interest, and in order to create ‘added value’, strategies are developed to optimize the use of water-land systems. The principle of ‘building with nature’ is applied in order to integrate land in sea and water in land in such a way that future generations will be able to use coastal resources in a sustainable way, including a minimal effort to maintain the coastline and the promotion of a multiple-use system. The concept of Integrated multifunctional sustainable coastal zone development is introduced. This concept deals with a balanced approach to the lack of space for present and future coastal uses in relation to each other, to the hinterland, and to the sea. Flexible master plans are developed, taking into account many functions of the coastal zone, and facilitating adaptation to future developments—e.g. impacts of climate change and relative sea level rise. In this regard increasing the flexibility of the coastal zone is of vital importance. Large-scale coastal land reclamations in The Netherlands are dealt with, based on two different principles: (1) polder systems (low lying land reclamations surrounded and protected by dikes), (2) systems of ‘building with nature’—land reclamation protected by man-made foreshores, beaches and dunes. In the latter type new flexible dynamic-equilibrium coasts are created for many functions, while coastal vulnerability is reduced and a flexible coast is developed.  相似文献   

15.
Cocos Bay is a barrier beach under threat of marine erosion from the high energy environment of the Atlantic Ocean. This barrier beach borders the Ramsar listed Nariva Swamp, and helps maintain its delicate wetland ecosystem, however, ongoing coastal erosion at this beach threatens the longevity of this freshwater wetland. Due to the geographical location of Cocos Bay being exposed to Atlantic generated storm events and the low relief of the study area, there is a potential threat of storm surges breaching the barrier beach. Owing to the geological setting of the region (located in an active seismic province with earthquakes, volcanicity and landslides), there also exists the threat of tsunamis. This paper is a GIS simulation of the area extent of inundation and the affected infrastructure from such events. It utilizes a DEM and land-use to quantifying inundation areas, and the extent of vulnerability of various elements. The low relief of the barrier beach renders the area extremely vulnerable from events that trigger sea level increases. Simulations revealed that as little as a 1 m storm surge has the potential to disrupt the Nariva Swamp and threaten coastal infrastructure while higher storm surges and tsunamis have the potential to decimate the entire area. The flood-risk model generated indicates a very high vulnerability to storm surges, along the entire length of the coastline. These results have implications for future development and sustainable management of this ecologically sensitive area.  相似文献   

16.
Managing mangroves in Bangladesh: A strategy analysis   总被引:1,自引:0,他引:1  
Bangladesh, favoured by a tropical climate, houses the world’s largest stretch of mangroves forests (Sundarbans Reserved Forest) and plantations. Around half of the forests of the country occur in the coastal zone. People extract various goods and services from the mangroves. Nevertheless the mangrove forests are depleting. Although the extent of the Sundarbans forest has not changed much, its decline is of a qualitative nature. Mangrove plantations are increasing in area but they are losing growing stock. To arrest this, Bangladesh has adopted several strategies. The ‘Sustainable Ecosystem Management’ strategy has now been adopted instead of the ‘Sustained Yield Principle’. Biodiversity conservation and enhancement has been taken as a key management goal. A zoning system is being developed for both production and protection purposes. The government facilitates alternative income for the local people by generating activities for the communities which are dependent on the forest. Different non-governmental organizations collaborate with the government in reducing the local people’s dependence on the forest. Coastal plantations are erected to protect people from cyclones and to make the land more suitable for habitation. Through this greening of the coastal belt tree plantation is encouraged in coastal villages. Coastal embankments are being planted and leased to poor settlers in exchange for routine maintenance of the embankments. Plantations on newly accreted mud flats help in stabilizing the land, which can later on be settled by victims of erosion elsewhere. These adopted management measures do not only contribute to forestry resource management but also to the social, environmental and economic wellbeing of the coastal communities. These efforts are at present being integrated into an Integrated Coastal Zone Management (ICZM) project.  相似文献   

17.
This study reports on the quantification of horizontal erosion by undermining of slopes in the atlantic mesotidal salt marshes of Odiel, SW Spain, and analyses its causes and consequences. Horizontal erosion has produced considerable losses of salt marsh area, including zones of mature salt marsh. Human pressure, such as from water-borne traffic or the exploitation of the slopes for the capture of bait, increases the natural erosion processes. The role of vegetation in protecting the slopes against erosion is studied. Channel banks covered with plants, many of which belong to species with long-living, above-ground creeping stems, were less eroded than those without vegetation cover. The enormous volume of sediments moved (ca. 7000m3 in one year) could contribute to the silting-up of the navigable channels of the estuary, so that continual dredging is necessary to allow access to shipping. These sediments are highly contaminated, and dredging exposes them more directly to the trophic network of the estuary. There is a considerable loss of natural resources. Finally, the integrated management of this coastal ecosystem is discussed.  相似文献   

18.
Coastal features in Ghana's Accra coast reflect both past and present processes that have been undergoing changes. These changes are influenced by a range of morphogenic factors such as geology and climatic conditions. These regimes have shaped the coastal geomorphic features through weathering processes that decompose and disintegrate the coastal rock. Sea level rise due to climate change is expected to increase coastal erosion and thus result in rapid changes in shoreline positions. Historic rate of sea level rise in Accra coast is about 2 mm/yr (Ibe & Quelennec, 1989) which is predicted to reach approximately 6 mm/yr in the next century since it conforms to the global change (Armah et al., 2005). This will result in flooding of vulnerable areas and enable waves to break closer inland. The effectiveness of the erosion process is aided considerably by the type of geology. Accra coastal zone has three types of rock in three identified geomorphic regions. They include unconsolidated and poorly consolidated rock along the western region, the Accraian series occupying the central region and the Dahomeyan series in the eastern region. The geology has thus influenced the extent to which the coastal features have changed and the type of cliff that is formed as a result of erosion within the regions. Generally, soft rock coastal features decay more rapidly than those of hard rock and tend to act as sediment sources. Human activities such as dam construction over the Densu River, engineering interventions to check the spread of erosion and sand mining has created sediment deficit which has exacerbated coastal erosion in Accra. Anthropogenic factors are estimated to account for 70-90% of coastal erosion problems in Accra.  相似文献   

19.
Coastal erosion may be caused by natural causes as well as human factors. Karasu town of the city of Sakarya in Turkey which is a touristic region on the Black Sea coast has been experienced a drastic coastal erosion. In recent years, this erosion reached the threatening dimensions for the structures in the settlement. According to the temporal analyses of Landsat satellite images, the maximum erosion on the coastline was detected 100 m between 1987–2013. The results of the study show that the harbour construct on the Karasu coast has the major impact on this event. The secondary factor is that the amount of the sediment carried by the Sakarya River was decreased in time due to different reasons. To prevent the coastal erosion, a series of offshore breakwaters were planned after the failed application of groins on the coastline. In this study, temporal changes of the coastline are investigated by the Landsat satellite data and land surveys, possible reasons of the erosion are discussed and the solutions are proposed regarding the coastal structures.  相似文献   

20.
The human history of coastal regions around the world has been under assault for decades, from forces that include dam building, coastal modifications, the destruction of wetlands, marine erosion, population growth and rampant development, looting, and other processes. Global warming will exacerbate the destruction of cultural resources in coastal zones through accelerated sea level rise, intensified storm cycles, and related coastal erosion. Although average global sea levels have been rising for ∼20,000 years, they slowed dramatically about 7,000 years ago. Rates of sea level rise now appear to be increasing rapidly due to growing anthropogenic emissions of carbon dioxide and other greenhouse gases. Global warming and rising seas, especially when combined with population growth and the implementation of measures designed to protect endangered coastal properties, threaten the deep maritime history of human migrations, settlement, and adaptations in coastal areas around the world. Ranging in age from the mid-Pleistocene to recent historic times, coastal archaeological sites contain invaluable data on ancient coastal societies, fisheries, and ecosystems. Archaeologists, historians, and other cultural resource managers must do more to anticipate, evaluate, and mitigate the effects of global warming, sea level rise, and coastal erosion on the long history of human maritime cultures.  相似文献   

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