Fog harvesting: An alternative source of water supply on the West Coast of South Africa   总被引：1，自引：0，他引：1  

Jana Olivier 《GeoJournal》2004,61(2):203-214

Experiments conducted during the 1990s investigated the feasibility of using fog water to supplement existing water supplies in the arid west coast region of South Africa. Based on these results, a project was initiated aimed at implementing an operational fog water collection system to provide potable water to a small, water-poor rural community. A 70 m² fog water collector was subsequently erected on the crest of the hill located next to the mission station called Lepelfontein. The volume of water collected was measured by means of a water flow meter and a tipping bucket. An automatic weather station recorded rainfall, wind speed and direction. The data record spans the period September 1999–August 2001. This paper gives a brief overview of the methods used to select the experimental site and describes the design of the fog water collection system. This is followed by a detailed account of the water yields, the contribution of fog and rainfall to the total yield, the characteristics of wet events, the factors associated with water collection and water quality. On average, yields of around 4.6 l of water were collected per square metre of collecting surface per day with maximum daily yields approaching 4000 l. The quality of the water was excellent. It thus appears that fog water collection may have considerable potential as an alternative water source at many other locations on the west coast of South Africa. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Induction vector estimates in the Polish-Czechoslovak part of the Carpathians     

Jerzy Jankowski  Václav Petr  Jana Pečová  Oldřich Praus  Reviewer A. Janáčková 《Studia Geophysica et Geodaetica》1979,23(1):89-93

u¶rt;um ¶rt;a ma ua m u¶rt;uu n mam amu n aum auau ¶rt;a a n -a am anam.  相似文献   

Predictive spectral analysis of short records using maximum entropy     

Jana Konopásková  Reviewer V. Červený 《Studia Geophysica et Geodaetica》1985,29(3):228-237

Summary A method of spectral analysis based on the prediction of the signal by means of AR parameters is proposed. The essence of this method ranks it between the classical methods of spectral analysis and the method of maximum entropy. For sufficiently high SNR its resolution is higher than that of the classical methods. The new method enables power and phase spectra of the signal to be determined, and provides a better determination of the power spectrum amplitude. than the method of maximum entropy. A regularization procedure is presented which abolished the instability of the prediction filter, obtained by the least-squares method.

---

¶rt; n nma aaua, a a n¶rt;aauu uaa n amu naam. mm n m ¶rt;au aumu auu m¶rt; nma aaua nuu u¶rt; u m¶rt;a aua mnuu. n a¶rt;am n aa nm n au auuu m¶rt;au nu aau n ¶rt;mam u mu ua . nm mu ua n¶rt;m a¶rt;, m¶rt; aua mnuu. muu m m¶rt;a aua mnuu n¶rt; n nma aaua nm n¶rt;m m a nm ua. aam n¶rt;aa uma um m¶rt; auu a¶rt;am, m unaa uau ¶rt; ¶rt;u mu am u.

  相似文献   

Sur les variations rapides du champ électrotellurique à Budkov (Tchécoslovaquie)     

Jana Pěčová 《Studia Geophysica et Geodaetica》1960,4(2):158-166

  相似文献   

The impact of cattle pasturing on groundwater quality in bedrock aquifers having minimal overburden     

Jana Levison  Kent Novakowski 《Hydrogeology Journal》2009,17(3):559-569

Widespread agricultural activity may threaten water quality in fractured bedrock aquifers having little overburden protection. A study in Canada improves the understanding of the potential impact of agriculture on water quality in bedrock aquifers, focusing on spatial and temporal variability of nitrate and bacteria. A research site was developed in and adjacent to a hay field where a gneissic aquifer is overlain by a thin veneer of unconsolidated glacial material. Ten wells were installed, hydraulically tested and completed as multilevel piezometers. Results of monthly sampling for nitrate, dissolved organic carbon, and E. coli show significant temporal and spatial variation in concentrations. Intensive 5-day sampling rounds conducted during baseflow and recharge conditions indicate that bacterial concentrations vary daily, with higher concentrations during recharge periods. The location of the impacted monitoring wells is correlated to an upgradient cattle pasture that is used periodically each summer. It is evident that periodic upgradient sources, dilution from recharge, and heterogeneous flow systems lead to varied and unpredictable contaminant concentrations. The temporal and spatial variability of contaminants in bedrock aquifers with minimal overburden must be considered for the protection of human health, as annual or even monthly groundwater monitoring may not capture unsafe concentrations.  相似文献   

Structure and evolution of the volcanic rift zone at Ponta de São Lourenço,eastern Madeira     

Andreas Klügel  Stefanie Schwarz  Paul van den Bogaard  Kaj A. Hoernle  Cora C. Wohlgemuth-Ueberwasser  Jana J. Köster 《Bulletin of Volcanology》2009,71(6):671-685

Ponta de São Lourenço is the deeply eroded eastern end of Madeira’s east–west trending rift zone, located near the geometric intersection of the Madeira rift axis with that of the Desertas Islands to the southeast. It dominantly consists of basaltic pyroclastic deposits from Strombolian and phreatomagmatic eruptions, lava flows, and a dike swarm. Main differences compared to highly productive rift zones such as in Hawai’i are a lower dike intensity (50–60 dikes/km) and the lack of a shallow magma reservoir or summit caldera. ⁴⁰Ar/³⁹Ar age determinations show that volcanic activity at Ponta de São Lourenço lasted from >5.2 to 4 Ma (early Madeira rift phase) and from 2.4 to 0.9 Ma (late Madeira rift phase), with a hiatus dividing the stratigraphy into lower and upper units. Toward the east, the distribution of eruptive centers becomes diffuse, and the rift axis bends to parallel the Desertas ridge. The bending may have resulted from mutual gravitational influence of the Madeira and Desertas volcanic edifices. We propose that Ponta de São Lourenço represents a type example for the interior of a fading rift arm on oceanic volcanoes, with modern analogues being the terminations of the rift zones at La Palma and El Hierro (Canary Islands). There is no evidence for Ponta de São Lourenço representing a former central volcano that interconnected and fed the Madeira and Desertas rifts. Our results suggest a subdivision of volcanic rift zones into (1) a highly productive endmember characterized by a central volcano with a shallow magma chamber feeding one or more rift arms, and (2) a less productive endmember characterized by rifts fed from deep-seated magma reservoirs rather than from a central volcano, as is the case for Ponta de São Lourenço.  相似文献   

Dynamics of Stream Water Quality during Snowmelt and Rainfall – Runoff Events in a Small Agricultural Catchment     

Petr Fučík  Markéta Kaplická  Tomáš Kvítek  Jana Peterková 《洁净——土壤、空气、水》2012,40(2):154-163

Surface water quality can vary a lot with fluctuating discharge during a Rainfall – runoff event. This paper uses a set of hydrological and hydrochemical variables to explain concentration–discharge loops and hysteresis of ${\rm NO}_{3}^{- } $ , ${\rm NH}_{4}^{ + } $ and total suspended solids in a brook dewatering a small upland agricultural catchment in the Czech Republic. Our study is based on data collected by a continuous monitoring approach provided by an automatic ISCO sampler both from snow thawing and rainfall – runoff events. Methods of correlation, regression and principal component analysis (PCA) were employed to reveal possible relationships among the variables. For ${\rm NO}_{3}^{- } $ and ${\rm NH}_{4}^{ + } $ , we found several types of concentration–discharge loops due to the loop rotation direction and also the loop curvature shape, in mutual combinations, no matter which type of a hydrological event it was related to. PCA indicated that ${\rm NO}_{3}^{- } $ loops correlated mostly with the length of a rising hydrograph limb and with the slope of the initial phase of a falling hydrograph limb, 5‐day amount of precipitation and runoff coefficient. In case of ${\rm NH}_{4}^{ + } $ , the concentrations usually increased with elevated discharge, whereas PCA did not detect any closer linkages. For suspended solids, an unambiguous positive monotonic relationship was discovered. Although no definite pattern was found, this study showed the necessity of a continuous water quality monitoring system as an approach for capturing and understanding relationships between solute concentrations and runoff formation for tracing and modelling catchment pollution sources and describing transport processes.  相似文献   

Seismic activity in the Czech Republic in 2009     

Jan Zedník  Jana Pazdírková 《Studia Geophysica et Geodaetica》2012,56(1):299-305

  相似文献   

Influence of glacier advance on the development of the multipart Riffeltal rock glacier,Central Austrian Alps          下载免费PDF全文

Jana‐Marie Dusik  Matthias Leopold  Tobias Heckmann  Florian Haas  Ludwig Hilger  David Morche  Fabian Neugirg  Michael Becht 《地球表面变化过程与地形》2015,40(7):965-980

The multipart Riffeltal rock glacier, located in a tributary valley of the Kaunertal, Tyrol, Austria is investigated to enlarge the knowledge about spatial and temporal development of rock glaciers in and at the margins of pro‐glacial areas and to get a better understanding of glacier–rock glacier interactions. The subject of interest consists of a complex system of two adjacent rock glacier tongues and various superposed lobes with differing ages, origin and root zones, and therefore diverse development. To determine the reasons for their diverging development, the internal structure and permafrost occurrence on and in the surrounding area of the rock glacier were studied by application of geomorphological mapping, geophysical methods and measurement of the basal temperature of the winter snow cover (BTS). Permafrost modelling was performed on the basis of BTS data and land surface parameters derived from a high resolution airborne laser scanning (ALS) digital elevation model (DEM). Additionally, the ALS data were used to measure vertical and horizontal changes of the rock glacier surface between 2006 and 2012. Glacier–rock glacier interactions during and since the Little Ice Age (LIA) are evident for the development of the studied rock glacier. A geomorphic map gives important information about the connection between glacial advance or retreat and permafrost or ground ice occurrence. The combination of all information helps in the analysis of diverse kinematic action of neighbouring rock glacier tongues. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Possibilities and Limitations of Interdisciplinary, User-oriented Research: Experiences from the German Research Network Natural Disasters     

Bruno Merz  Jana Friedrich  Markus Disse  Jochen Schwarz  Johann G. Goldammer  Jochen Wächter 《Natural Hazards》2006,38(1-2):3-20

The German Research Network for Natural Disasters (DFNK) linked 15 partners with scientific expertise in the field of natural hazards. Main objectives were the development and provision of the scientific fundamentals for an advanced risk management of important natural disasters in Germany, i.e., floods, earthquakes, storms and wildland fires. This included risk analyses, the development of information systems for supporting disaster management, and recommendations for risk reduction measures. This paper gives an overview of DFNK and summarises its experiences concerning multidisciplinarity and user-orientation. It illustrates the concept of risk chains, causally linking the different processes from hazard to risk. The step from hazard to risk requires interdisciplinary research teams. The experiences show that integrative concepts allow results not achievable with mono-disciplinary approaches. Integrative approaches pave the way to harmonised safety considerations taking into account the different hazards in a region within a common framework. User-orientation, policy advice and development of operational tools are key issues of disaster research. The experiences of DFNK illustrate the limitations of a research network in bridging the gap between research and application within rather short-term projects. Successful cooperation with users could be established by those activities where, at the beginning of the project, a user was identified who had a strong interest in solving an urgent problem.  相似文献