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931.
1996-2005年中国沿海地区土地利用转换时空分析   总被引:14,自引:7,他引:7  
Based on the acquaintance of the regional background of urban-rural transforma- tional development and investigations on the spot, this paper discusses the holistic situation, dominant factors and mechanism of arable land loss and land for construction occupation in the coastal area of China over the last decade, with the aid of GIS technology. Conclusions of the research are summarized as follows: (1) the arable land had been continuously de- creasing from 1996 to 2005, with a loss of 1,708,700 hm2 and an average decrement of 170,900 hm2 per year; (2) land for construction increased 1,373,700 hm2, with an average increment of 153,200 hm2 per year; (3) total area of encroachment on arable land for con- struction between 1996 and 2005 was 1,053,100 hm2, accounting for 34.03% of the arable land loss in the same period, the percentages of which used for industrial land (INL), trans- portation land (TRL), rural construction land (RUL) and town construction land (TOL) are 45.03%, 15.8%, 15.47% and 11.5%, respectively; and (4) the fluctuation of the increase of construction land and encroachment on arable land in the area were deeply influenced by the nation's macroscopic land-use policies and development level of regional economy. The growth of population and advancement of technology promoted the rapid industrialization, construction of transportation infrastructures, rural urbanization and expansion of rural set- tlements in the eastern coastal area, and therefore were the primary driving forces of land-use conversion.  相似文献   
932.
The south coastal plain of Laizhou Bay is one of the typical salt-water intrusion areas in China, the occurrence and development of which was closely related with the palaeoenvironment evolution. Systematic analyses of pollen, foraminifera and grain size composition based on ^14C and luminescence dating from two sediment cores were performed for the purpose of understanding the salt-water intrusion in the coastal plain of Laizhou Bay from the perspective of environmental evolution since late Pleistocene. It could be classified into seven evolution stages since 120 kaBP: 120-85 kaBP was a transition period from cold to warm; 85-76 kaBP was a period with warm and wet climate having swamp lakes developed in the lower reaches of the Weihe River, south coastal plain of Laizhou Bay; 76-50 kaBP was characterized by grassland vegetation and coarse sediments in terrestrial environment, which was the early stage of Dali Ice-Age; 50-24 kaBP was a period with alternate sea deposition in the south coastal plain of Laizhou Bay; 24-10 kaBP was the late stage of Dali Ice-Age with coldest period of Quaternary, the south coastal plain of Laizhou Bay was dry grassland and loess deposition environment; 10-4 kaBP was another warm and wet climate period, sea level was high and regressed at 4 kaBP; and has been the modern sedimentary environment since 4 kaBP. Among the three warm stages, including 85-76 kaBP, 50-24 kaBP and 10-4 kaBP, corresponded to late Yangkou, Guangrao and Kenli seawater transgression respectively. The duration of the latter one in south coastal plain of Laizhou Bay was longer than that in west coast of Bohai Sea and east coast of Laizhou Bay. The three periods of seawater transgression formed the foundation of salt-water intrusion in this area.  相似文献   
933.
Based on the acquaintance of the regional background of urban-rural transforma-tional development and investigations on the spot, this paper discusses the holistic situation, dominant factors and mechanism of arable land loss and land for construction occupation in the coastal area of China over the last decade, with the aid of GIS technology. Conclusions of the research are summarized as follows: (1) the arable land had been continuously de-creasing from 1996 to 2005, with a loss of 1,708,700 hm2 and an average decrement of 170,900 hm2 per year; (2) land for construction increased 1,373,700 hm2, with an average increment of 153,200 hm2 per year; (3) total area of encroachment on arable land for con-struction between 1996 and 2005 was 1,053,100 hm2, accounting for 34.03% of the arable land loss in the same period, the percentages of which used for industrial land (INL), trans-portation land (TRL), rural construction land (RUL) and town construction land (TOL) are 45.03%, 15.8%, 15.47% and 11.5%, respectively; and (4) the fluctuation of the increase of construction land and encroachment on arable land in the area were deeply influenced by the nation’s macroscopic land-use policies and development level of regional economy. The growth of population and advancement of technology promoted the rapid industrialization, construction of transportation infrastructures, rural urbanization and expansion of rural set-tlements in the eastern coastal area, and therefore were the primary driving forces of land-use conversion.  相似文献   
934.
陈曦  倪金  邴智武  赵旭 《地质与资源》2011,20(5):354-357
基于RS和GIS技术,利用多期遥感影像数据,结合地形图、历史海图,定量分析了辽宁省海岸线近百年变迁特征.结果表明,自1909年以来,辽宁省海岸线的构型和长度发生了很大变化,陆地面积也相应增加.在全省范围内,从时序变化看,1909~1932年期间,海岸线变化最大,陆地面积增加最多,年增加速率也较快,1950~1980年期间,海岸线变化速率最小.从空间上看,各地段的岸线变化极不均衡,主要变化区域是辽东湾北部淤泥质海岸,大连附近的基岩岸段变化最小,最大的变化区段是双台子河段、复州湾和大洋河附近.  相似文献   
935.
本文在RS和GIS支持下研究了河北昌黎黄金海岸地区1985年至2000年的土地利用变化格局及其影响因子。该区域的海岸区位对海岸带土地利用变化具有重要影响作用,近岸带变化较剧烈,远岸带变化较小,且具有不同的变化特点。海岸带管理政策对土地利用变化的程度和特征存在重要影响,开发区土地利用变化较剧烈,其变化类型受开发方式及其目标影响;保护区主要是大片沙丘转变为林地和草地。  相似文献   
936.
黄河三角洲海岸剖面类型与演变规律   总被引:3,自引:0,他引:3  
根据1976-2002年黄河三角洲滨海区36个断面的地形实测资料以及利津水文站的水沙资料,运用动力地貌学的方法,对黄河三角洲海岸剖面形态及冲淤演变进行了研究。结果表明,黄河三角洲海岸剖面可分为建设型、破坏型和稳定型三种基本类型。建设型海岸分布于行水河口,等深线向海推进的距离取决于入海泥沙的堆积过程与海洋动力对泥沙的侵蚀过程两者之间的对比;破坏型海岸主要分布于停止行河不久的废弃河口附近,剖面侵蚀深度与海洋动力条件尤其是潮流流速大小密切相关;而稳定型海岸主要分布于长时间不行河的湾湾沟口附近和广利河以南岸段,前者受河海动力因素影响较小,而后者主要与莱州湾潮流流场有关。  相似文献   
937.
利用潮汐模型NAO.99Jb和FES2014确定了山东邻海的深度基准面模型并对其精度进行了评估,结果表明,NAO.99Jb模型确定的深度基准值L10的中误差为23.28 cm,FES2014模型确定的深度基准值L13的中误差为34.37 cm,长周期分潮的相对误差过大导致加入长周期分潮改正项后深度基准值中误差分别增大了11.04 cm和12.38 cm,较其他分潮对深度基准值精度的影响更明显,所以基于潮汐模型构建深度基准面模型时,长周期分潮部分必须加入实测数据改正。进一步采用山东邻海13个长期验潮站实测数据,定量地分析了长周期分潮对深度基准面确定的影响,结果表明,长周期分潮改正项的量值介于13.89~22.39 cm,平均改正值为18.03 cm,在深度基准值中占比达到15.15%。因此,长周期分潮改正对深度基准面的精确确定研究贡献较大,准确的长周期分潮模型是构建高精度深度基准面模型的基础。  相似文献   
938.
Balaena Bay, Wellington Harbour, New Zealand, has a small pocket beach that was covered originally by pebbles and cobbles. In February and October 1982, the beach was nourished with sandy granular gravel, the stability of which was monitored until February 1984. Although isolated from oceanic swell, the new beach readily responded to locally generated wind waves which induced both northwards and southwards longshore drift. The net effect was erosion of the southern beach, aggradation over the central beach, and minor fluctuations at the northern end. Yet despite this mobility nearly all the nourishment sediment was retained in the littoral zone. Beach volumes, calculated for each survey, varied little and sediment distribution patterns revealed negligable transport of nourishment sediment to adjacent beaches and offshore areas. Stability is further confirmed by compositional data which record no preferential loss of the sandstone, argillite, and quartz components. The only compositional changes were the incorporation into the new beach of small (< 10%) quantities of sediment derived from the old beach surface and from biogenic productivity.  相似文献   
939.
香港近岸海域营养盐结构特征及其对浮游植物生长的影响   总被引:5,自引:1,他引:4  
本文利用2000年3月至2001年5月在香港近岸牛尾海海域(Porter Shelter, Hong Kong)14个航次的现场调查数据, 对水体中营养盐组成结构和叶绿素a含量进行了分析研究。结果表明, 该海域表层和底层水体中溶解无机氮(DIN, 包括NO3?-N+NO2?-N, NH4+-N)平均浓度范围分别为1.24—9.72mol/L及1.30—7.49mol/L, 均表现为冬季最高、秋季最低。不同季节表层水体中PO43?-P浓度范围为0.14—0.46mol/L, 夏季平均浓度最底; 底层 PO43?-P浓度变化不大, 但夏季仍低于其他季节。不同季节表层和底层水体中SiO32?-Si的变化趋势基本相似, 平均浓度范围分别为7.80—18.47mol/L 和8.13—16.87mol/L, 均在冬季最高, 其它季节差别不大。叶绿素 a分析结果显示, 表层水体高生物量大多出现在夏末秋初季节(如8月份), 春季(4月份)次之; 底层水体叶绿素 a秋季最高, 夏季次之。进一步分析了该海域营养盐对浮游植物生长的可能限制因子, 结果表明表层水体春季呈现氮–磷协同限制的可能性、夏季磷限制较明显, 秋季表现为显著的氮限制。底层水体春、夏季呈现氮–磷协同限制的趋势, 秋季也表现为明显的氮限制。冬季磷酸盐浓度相对氮、硅的含量较低, 但各种营养盐相对于浮游植物生长的最低阈值都比较丰富, 所以, 冬季表、底层水体中营养盐对浮游植物的生长均不形成限制因素。另外, 除了夏季表层水体外, 其它季节该水域浮游植物生长受溶解无机硅限制的可能性较少。  相似文献   
940.
In this paper, we discuss the validation of water level and current predictions from three coastal hydrodynamic models and document the resource and operational requirements for each modeling system. The ADvanced CIRCulation Model (ADCIRC), the Navy Coastal Ocean Model (NCOM), and Delft3D have been configured and validated for the Chesapeake Bay region during a Navy exercise. Water level predictions are compared with a NOAA/NOS water level gauge at the Chesapeake Bay Bridge Tunnel location while current predictions are validated with Acoustic Doppler Profiler (ADP) measurement records at three locations in the lower Chesapeake Bay. Statistical metrics such as correlation coefficient and root mean square error (RMSE) are computed. Both the vertically-integrated currents and currents at varying water depths are compared as well. The model-data comparisons for surface elevation indicate all three models agreed well with water level gauge data. The two-dimensional version of ADCIRC, ADCIRC2D, and NCOM yield better statistics, in terms of correlation and RMSE, than Delft3D. For vertically-integrated currents, ADCIRC2D has the smallest RMSE at Thimble Shoal and Naval Station locations while NCOM has the smallest RMSE at Cape Henry. For the horizontal currents over the water column, the fully three-dimensional, baroclinic ADCIRC model, ADCIRC3D, and NCOM both showed better agreement with the ADP measurements.  相似文献   
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