Bidirectional winds,barchan dune asymmetry and formation of seif dunes from barchans: a discussion   总被引：1，自引：0，他引：1  

Haim Tsoar  Eric J. R. Parteli 《Environmental Earth Sciences》2016,75(18):1237

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A second look at western Sinai seif dunes and their lateral migration   总被引：1，自引：0，他引：1  

David M. Rubin  Haim Tsoar  Dan G. Blumberg 《Geomorphology》2008,93(3-4):335-342

Tsoar et al. [Tsoar, H., Blumberg, D.G., Stoler, Y., 2004. Elongation and migration of sand dunes. Geomorphology 57, 293–302.] reported that seif dunes in the western Sinai Desert did not migrate laterally between 1973 and 1999. If the planform sinuosities of the dunes are removed by filtering, spatial averaging, or linear regression, however, it is evident that the dunes did, in fact, migrate laterally roughly 13 m during this 26-year period. The measured migration distance is 1–2 orders of magnitude greater than the rms co-registration error Tsoar et al. determined for the first and last air photos that were used to map the dunes. The western Sinai dunes provide another example demonstrating that linear dunes can migrate laterally, and they illustrate some of the difficulties in documenting systematic lateral motion.Lateral migration of a dune can be important geologically or geomorphologically, even where migration is too slow to detect from repeated topographic surveys. This article explains the wind conditions for the lateral migration of seif dunes in western Sinai and the possible wind occurrences that would not lead to such a migration.  相似文献   

The urban geopolitics of neighboring: conflict,encounter and class in Jerusalem’s settlement/neighborhood     

Marik Shtern  Haim Yacobi 《Urban geography》2019,40(4):467-487

This article examines a unique, yet paradigmatic, case study of a colonial neighborhood in East Jerusalem that is undergoing a significant demographic transformation.¹ The French Hill neighborhood, built in 1971, was one of the first settlements in East Jerusalem. Initially, it was populated primarily by upper-middle class secular-Jewish residents. This group has been steadily diminishing as two other distinct new groups moved into the neighborhood: Ultra-Orthodox Jews and Palestinians. This volatile social mix has caused intense inter-ethnic and intra-ethnic collisions. Based on qualitative and quantitative studies, we argue that the juxtaposition of colonial and neoliberal logics of space reveals a shared, yet fragile, middle-class identity. We suggest that this new geopolitical space of neighboring calls for a discussion of political conflict, housing and current colonial conditions that brings class back to our understanding of the production of contested space.  相似文献   

Assessing the impact of climate change on representative field crops in Israeli agriculture: a case study of wheat and cotton     

David Haim  Mordechai Shechter  Pedro Berliner 《Climatic change》2008,86(3-4):425-440

Climate changes, associated with accumulation of greenhouse gases, are expected to have a profound influence on agricultural sustainability in Israel, a semi-arid area characterized by a cold wet winter and a dry warm summer. Accordingly this study explored economic aspects of agricultural production under projected climate-change scenarios by the “production function” approach, as applied to two representative crops: wheat, as the major crop grown in Israel’s dry southern region, and cotton, representing the more humid climate in the north. Adjusting outputs of the global climate model HadCM3 to the specific research locations, we generated projections for 2070–2100 temperatures and precipitations for two climate change scenarios. Results for wheat vary among climate scenarios; net revenues become negative under the severe scenario (change from −145 to −273%), but may increase under the moderate one (−43 to +35%), depending on nitrogen applied to the crop. Distribution of rain events was found to play a major role in determining yields. By contrast, under both scenarios cotton experiences a considerable decrease in yield with significant economic losses (−240 and −173% in A2 and B2 scenarios, respectively). Additional irrigation and nitrogen may reduce farming losses, unlike changes in seeding dates.  相似文献   

Regional and local climatic effects on the Dead-Sea evaporation     

Haim Shafir  Pinhas Alpert 《Climatic change》2011,105(3-4):455-468

The natural evaporation in the Dead-Sea is a very important meteorological parameter to the local industries at Sdom. It was found that the pan evaporation in Sdom has recently increased by 20?C25%. In this paper we explore the reasons for this increase. It is found that both large-scale and local climatic changes have contributed to the evaporation increase in the Dead Sea Valley. The large-scale (global) change potentially associated with the global warming, resulted in changes of the frequencies of some synoptic systems in the region. The local change is a result of the recent Dead-Sea drying, which reduced the local Dead-Sea breeze while intensifying the Mediterranean-Sea breeze penetrating the Dead Sea Valley. It is suggested that while the local effect was the dominant climatic change factor in the Dead-Sea Valley in the 1970?C1990, the global effect becomes the dominant one in the more recent evaporation increase in the Dead-Sea.  相似文献   

Feasibility Study of In-Well Vapor Stripping Using Airlift Pumping     

Haim Gvirtzman  Ori Gonen 《Ground Water Monitoring & Remediation》1995,15(4):155-162

This study tests the feasibility of an aquifer remediation concept proposed by Gvirtzman and Gorelick (1992) that involves the removal of volatile organic compounds (VOCs) dissolved in ground water. The principal is 10 inject air into a well, creating airlift pumping, which is used as a means of in-well vapor stripping. The partially treated water is diverted away from the well and infiltrates back to the water table, thus allowing remediation of a larger aquifer volume.
A remediation well prototype, constructed in a laboratory aquifer model, was used to demonstrate the processes involved. The removal rates of trichloroethylene, toluene, and chloroform were monitored using eight triple-level observation wells. The continuous decrease of VOC concentrations during the short-term experiment has yielded macroscopic evidence that the process offers some promise. It was found that the flow field in the saturated zone. involving the continuous water circulation between the pumping well and the recharging area, caused temporal and spatial variation in remediation efficiency.  相似文献   

Desertification in Northern Sinai in the eighteenth century     

Haim Tsoar 《Climatic change》1995,29(4):429-438

Several natural and anthropogenic phenomena in the northern Sinai sand sea and the northern Negev desert were caused by desiccation of the area during most of the 17^th and the 18^th century. The dry phase had been preceded by a wet period. It appears that the combination of several wet decades followed by a long period of desiccation was the cause of desertification processes in the area which then triggered the destruction of vegetation.There is some congruity between the wet period and the period of maximum sunspot activity, known as theMedieval Maximum, while the desiccation of the area which followed coincided approximately with the period of minimum solar activity, known as theMaunder Minimum.  相似文献   

The distribution of Autumnal Easterly Wind Spells Favoring Rapid spread of forest wildfires on Mount Carmel,Israel     

Haim Kutiel dr.  Pua Kutiel dr. 《GeoJournal》1991,23(2):147-152

Wildfires became a severeecological and financial problem in Israel during the last few years. A significant increase in the incidence of severe wildfires in natural shrublands and planted forests as arson was observed. On 19–20. 9. 89 a large wildfire ignited as an act of terrorism, devastated large parts of Mt. Carmel forests.Weather conditions during a wildfire have an important role in the determination of the rate of spread of the fire. This depends mainly on the availability of dry matter and the wind speed. Two factors that reach their optimum at the end of the summer in September and October during Sharav episodes. The distribution of easterly wind spells associated with Sharav events is considered. The results show that there is no climatic limitation to a spread of a wildfire of the same order of magnitude as the last one, every year.  相似文献   

Temporal segregation in co-existing Acomys species:the possible role of nest site     

A. Haim  F.M. Rozenfeld 《Journal of Arid Environments》1995,29(4)

The co-existence of two species of spiny mouse of the genus Acomys is possible due to temporal segregation. While the common spiny mouse A. cahirinus is nocturnal, the golden spiny mouse A. russatus is diurnal when occurring with the former. An attempt was made to investigate the role of nest site as an environmental resource for competition between these two species. Nine heterospecific pairs of mice of both the same or opposite sexes were tested using an observation pen with two nesting places attached to each side. Each pair tested was observed in the pen over a period of 48h. In eight out of the nine different pairs, A. cahirinus occupied the original nest site of A. russatus. The replacement was found to be not random. The results of this study show that A. cahirinus selects a preferred nest site and its vacated nest sites can be utilized by A. russatus.  相似文献   

Extracting spatial patterns in bicycle routes from crowdsourced data   总被引：1，自引：0，他引：1       下载免费PDF全文

Jody Sultan  Gev Ben‐Haim  Jan‐Henrik Haunert  Sagi Dalyot 《Transactions in GIS》2017,21(6):1321-1340

Much is done nowadays to provide cyclists with safe and sustainable road infrastructure. Its development requires the investigation of road usage and interactions between traffic commuters. This article is focused on exploiting crowdsourced user‐generated data, namely GPS trajectories collected by cyclists and road network infrastructure generated by citizens, to extract and analyze spatial patterns and road‐type use of cyclists in urban environments. Since user‐generated data shows data‐deficiencies, we introduce tailored spatial data‐handling processes for which several algorithms are developed and implemented. These include data filtering and segmentation, map‐matching and spatial arrangement of GPS trajectories with the road network. A spatial analysis and a characterization of road‐type use are then carried out to investigate and identify specific spatial patterns of cycle routes. The proposed analysis was applied to the cities of Amsterdam (The Netherlands) and Osnabrück (Germany), proving its feasibility and reliability in mining road‐type use and extracting pattern information and preferences. This information can help users who wish to explore friendlier and more interesting cycle patterns, based on collective usage, as well as city planners and transportation experts wishing to pinpoint areas most in need of further development and planning.  相似文献