高频地波雷达风场数据可用性分析     

何艳丽  敖振浪 《气象科技》2015,43(5):794-798

为了分析高频地波雷达能否应用于海面风场探测,以广东阳江高频地波雷达探测范围内的南鹏岛自动气象站探测的风向风速为参考,将高频地波雷达探测的风场数据与之相比较,通过分析不同季节、风速6~10 m/s及6 m/s以下等各种情况下地波雷达探测风场数据的获取率、标准差及可用性。结果表明,相对而言,地波雷达探测风向数据获取率高、标准差较小,可用性高,而风速获取率在6~10 m/s情况下较好,可用性较高,在低海况（6 m/s以下）时可用性低。  相似文献   

Open for Business but at What Cost? Housing issues in ‘boomtown’ Darwin     

Gretchen Ennis  Matalena Tofa  Mary Finlayson 《The Australian geographer》2014,45(4):447-464

The Greater Darwin area has long experienced high housing costs and high rates of homelessness. Into this already stressed housing context have come large-scale, natural resource development projects, which are predicted to bring thousands of new workers to town, and exciting property investor interest. While many view these developments as positive, there is concern about the impacts upon the most vulnerable members of the population. This paper presents the findings of a qualitative research project exploring current housing issues in the Greater Darwin area. Interviews with housing support service providers and real estate agents reveal that the current population and investment growth have exacerbated longstanding housing issues. Increased housing stress in Darwin, and a myopic focus on rapid economic growth, may disenfranchise current residents and undermine service and support industries. We argue that while there may be some economic benefits from a ‘booming’ Darwin, greater planning and partnership between government, community organisations and corporates is required to ensure the benefits are spread across the population. Unfortunately, the Northern Territory government's dilatory approach to both housing issues and the social costs of the resources boom makes it highly unlikely innovative partnerships will occur.  相似文献   

QZSS对GPS区域性能增强分析     

李作虎  郝金明  李建文  张成军 《武汉大学学报(信息科学版)》2010,(1)

在日本和中国中东部地区,就日本准天顶卫星系统(QZSS)对GPS导航精度增强、完好性增强以及可用性增强进行了仿真计算比较。结果表明,只有3颗卫星组成的QZSS在这些区域内对GPS提供了有效的性能增强,而且随着卫星截止角的增加,这种性能增强显得更为明显;QZSS在战时可有效降低由于部分GPS卫星失效而导致的性能恶化程度。分析结果对于我国在中部地区和东部热点地区有效利用GNSS导航资源具有指导作用。  相似文献   

Simulated long-term changes in river discharge and soil moisture due to global warming / Simulations à long terme de changements d’écoulement fluvial et d’humidité du sol causés par le réchauffement global     

《水文科学杂志》2013,58(4)

Abstract

Abstract By use of a coupled ocean–atmosphere–land model, this study explores the changes of water availability, as measured by river discharge and soil moisture, that could occur by the middle of the 21st century in response to combined increases of greenhouse gases and sulphate aerosols based upon the ?IS92a? scenario. In addition, it presents the simulated change in water availability that might be realized in a few centuries in response to a quadrupling of CO₂ concentration in the atmosphere. Averaging the results over extended periods, the radiatively forced changes, which are very similar between the two sets of experiments, were successfully extracted. The analysis indicates that the discharges from Arctic rivers such as the Mackenzie and Ob’ increase by up to 20% (of the pre-Industrial Period level) by the middle of the 21st century and by up to 40% or more in a few centuries. In the tropics, the discharges from the Amazonas and Ganga-Brahmaputra rivers increase substantially. However, the percentage changes in runoff from other tropical and many mid-latitude rivers are smaller, with both positive and negative signs. For soil moisture, the results of this study indicate reductions during much of the year in many semiarid regions of the world, such as the southwestern region of North America, the northeastern region of China, the Mediterranean coast of Europe, and the grasslands of Australia and Africa. As a percentage, the reduction is particularly large during the dry season. From middle to high latitudes of the Northern Hemisphere, soil moisture decreases in summer but increases in winter.  相似文献   

Diary of forthconing events     

GEORGE H. LEAVESLEY  GREGG C. LUSBY  ROBERT W. LICHTY 《水文科学杂志》2013,58(3):339-344

Abstract

New global models provide the opportunity to generate quantitative information about the world water situation. Here the WaterGAP 2 model is used to compute globally comprehensive estimates about water availability, water withdrawals, and other indicators on the river-basin scale. In applying the model to the current global water situation, it was found that about 24% of world river basin area has a withdrawal to availability ratio greater than 0.4, which some experts consider to be a rough indication of “severe water stress”; the impacts of this stress are expected to be stronger in developing countries than in industrialized ones. Under a “business-as-usual” scenario of continuing demographic, economic and technological trends up to 2025, water withdrawals are expected to stabilize or decrease in 41% of world river basin areas because of the saturation of water needs and improvement in water-use efficiency. Withdrawals grow elsewhere because population and economic growth will lead to rising demand for water, and this outweighs the assumed improvements in water-use efficiency. An uncertainty analysis showed that the uncertainty of these estimates is likely to have a strong geographic variability.  相似文献   

Assessment of hydropower potential using spatial technology and SWAT modelling in the Mat River,southern Mizoram,India     

Ashish Pandey  Daniel Lalrempuia  S.K. Jain 《水文科学杂志》2013,58(10):1651-1665

Abstract

In this study, a hydrological model and spatial technologies have been employed to assess water availability in the Mat River basin, southern Mizoram, India. Furthermore, the results obtained from the SWAT (Soil and Water Assessment Tool) model, satellite data and GIS tools were utilized to identify the hydropower potential in the basin. Thirty three sites with hydropower potential were identified within 147 km² of the Mat River basin. A total of 3039, 1127 and 805 kW can be harnessed with 50, 75 and 90% dependability, respectively. The study revealed that the hydropower potential of a river basin can be correctly assessed by employing a digital elevation model, stream network data and a hydrological model, such as the SWAT model, within a GIS framework.