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1.
The spatial pattern and dynamics of a Sahelian agro-ecosystem 总被引：1，自引：0，他引：1
The spatial pattern and dynamics of a Sahelian agro-ecosystem are analyzed. Approaches and methods suitable for land use systems analysis are discussed. The importance of combining various spatial and temporal scales in a multi-disciplinary framework is stressed. An analytical framework focusing on the land use system at the village level is presented. It pays specific attention to the integration of georelated data with those describing the socio-economic decision-making units (households). It is intended as a basic component in a land use analytical model which meets the requirements of being multidisciplinary as well as hierarchical.Selected results from a case study in northern Burkina Faso, are presented. Mainly issues with a spatial dimension, taking advantage of the georelated observations, are dealt with in this context. They reveal, for instance, that field pattern dynamics appear to be much more complex than generally believed and that the commonly held notion that fields are expanding cannot be confirmed by this case. The land use dynamics constitute a complex pattern, determined by household specific parameters as well as by the natural resource base. Furthermore, the experience from the application of a differential GPS for detailed land use studies in the Sahel is presented and discussed. 相似文献
2.
Continuity and change: Spatiotemporal land use dynamics on Bellona Island, Solomon Islands 总被引：2，自引：2，他引：0
Torben Birch-Thomsen Anette Reenberg Ole Mertz Bjarne Fog 《Singapore journal of tropical geography》2010,31(1):27-40
Traditional agricultural land use systems in the humid tropics of the Southwest Pacific are, as elsewhere, affected by globalization processes. This paper analyzes the directions of change in the land use system of Bellona, a small outer island in the Solomon Islands. We focus on the human–environmental interaction that shapes land use patterns and practices in the context of theoretical lines of thought concerning intensification of agricultural systems in the tropics. Aerial photography from 1966 and satellite imagery from 2006 in conjunction with studies from the 1960s and a contemporary household survey reveal only minor changes in the agricultural system. Land use and land cover dynamics are related to agricultural strategies, demographic factors, institutional actors as well as biophysical drivers or constraints. Local agricultural production still contributes significantly to local subsistence but imported food has also become a major food source. Hence, land use has become partially disconnected from the local population pressure and therefore remains relatively stable while the larger livelihood portfolio has undergone significant diversification. At present, the agricultural system is a supplement to a range of strategies supporting the increasing number of people on the island. This explains why land use patterns continue relatively unchanged while livelihood and food supply strategies have changed. 相似文献
3.
“重庆雾害”课题组 《成都信息工程学院学报》1992,(2)
本模式是为“重庆雾客”课题而设计的,能够通报“雾害”形成的500hPa背景形势场的正压原始方程模式。它从转报、客观分析到数值预报完全自动化。可以投入业务使用。模式提供500hPa环流形势的24小时预报。预报域覆盖整个东亚地区。模式的差分方案采用准拉格朗日平流格式。时间步长取为半小时。通过1990年11月～12月60天的预报试验表明:该模式能够较准确地预报500hPa环流形势。 相似文献
4.
“重庆雾害”课题组 《成都信息工程学院学报》1992,(2)
本文针对重庆市区冬季浓雾的短期预报,分析了雾的气候特点和主要天气形势,并引入多种气象因子,采用模式识别原理,建立浓雾预报规则,进而通过微机自动处理实时气象资料,做出浓雾预报。试验结果表明,预报效果较好。 相似文献
5.
“重庆雾害”课题组 《成都信息工程学院学报》1992,(2)
本文介绍重庆市区雾害潜势预报报警服务系统的显示服务系统。该系统包括资料处理、动力、统计、数值预报、客观推理系统、综合决策(集成)等模式,以及系统简介和显示服务等功能。显示服务系统采用菜单技术,多种语言混合编程,能正确运行各个模式,完成所需功能,具有实用、方便、直观和自动化程度高的特点,在实用中收到良好效果。 相似文献
6.
“重庆雾害”课题组 《成都信息工程学院学报》1992,(2)
本文将所建立的重庆雾一维模式简化移植到微机上,主要进行辐射雾的形成时间和浓雾预报。模式在386机上作12小时预报计需机时25分钟。通过对1990年11月～1991年2月24次的个例计算,预报成功率达70％,雾形成时间平均误差为1.7小时。 相似文献
7.
“重庆雾害”课题组 《成都信息工程学院学报》1992,(2)
本方法从动力、统计相结合的角度出发,利用多年历史资料,采用逐步回归方法并辅以技术处理,求得非线性回归方程为PP模型的预报方程,并且利用正压模式输出的两个月数值预报产品进行了试报,结果表明该模型对重庆雾的24小时预报具有一定的能力。 相似文献
8.
Trepekli Katerina Balstrøm Thomas Friborg Thomas Fog Bjarne Allotey Albert N. Kofie Richard Y. Møller-Jensen Lasse 《Natural Hazards》2022,113(1):423-451
Natural Hazards - In this study, we present the first findings of the potential utility of miniaturized light and detection ranging (LiDAR) scanners mounted on unmanned aerial vehicles (UAVs) for... 相似文献
9.
“重庆雾害”课题组 《成都信息工程学院学报》1992,(2)
本文首先对重庆雾1981～1987年159个例进行500hPa、700hPa、850hPa各气象要素的相关和合成分析,得到了影响重庆雾的主要因子和主要关键区以及雾发生时24小时以前各层要素场的异常特征。在此基础上,对重庆雾进行了分类,用关键区的因子作为自变量,利用逐步回归残差订正和模型集成,建立起重庆雾24小时预报模型,并设计成软件系统,在IBM机上自动预报。 相似文献
10.
The idea of degradation of arid and semi-arid lands, often termed desertification in its irreversible form, due to human impact and/or climatic change has been much debated since the mid-1970s. From the time of the United Nation's Conference On Desertification in Nairobi, 1976, certain areas of northern Burkina Faso have been pointed out as examples of severe desertification. Several studies demonstrated that revitalization of a series of E–W oriented fossille dunes in the Oudalan province was ongoing. The present study includes an analysis of the trends of vegetation development in the region, covering the period 1955 to 1994, with emphasis on the fossile dunes. It is demonstrated that desertification and revitalization of dunes were phenomena associated with the period between the early 1970s and the mid-1980s, and that the decline in vegetation cover on the dunes seems to have been reversed in recent years. The analysis is based upon time series of aerial photos and satellite images, field studies of vegetation, interviews with local people and review of relevant literature. The findings are discussed with reference to the debate concerning desertification and land degradation, as well as to the current revisions of the ‘range management paradigm’. The observations indicate that the environmental history of the region is complex and cannot be boiled down to ‘human-induced irreversible degradation’. Rather they support the idea of semi-arid cultural landscapes undergoing constant change in response to both human impact and climatic trends and fluctuations. 相似文献