Showing papers in "Physics and Chemistry of The Earth in 2003"

Selected room temperature magnetic parameters as a function of mineralogy, concentration and grain size

Abstract: A data set of room temperature magnetic parameters for several iron oxides and sulphides was compiled from the available literature. The aim was to propose the most effective methods for assessing mineralogy, concentration and domain state within environmental magnetic studies. Establishing the magnetic mineralogy is essential for a correct interpretation of concentration and grain-size indicative parameters. Hematite and in particular goethite are recognised by their high (remanent) coercivities. The ratio of saturation remanent magnetisation to susceptibility is suited for assessing mineralogy; for low coercivity minerals, high values of the ratio are indicative of pyrrhotite. Greigite and maghemite both have intermediate ratios, while very low values suggest the presence of (titano)magnetite. From the concentration-dependent parameters mass specific susceptibility, saturation remanent magnetisation and susceptibility of anhysteretic remanent magnetisation, susceptibility displayed the least grain-size dependence. Therefore, it is perhaps the best indicator of concentration, under the proviso of uniform mineralogy and when paramagnetic and diamagnetic contributions are taken into consideration. All minerals showed a decrease in coercivity and remanence ratios with increasing grain size for sizes larger than one micrometer. In contrast, the coercivity of goethite showed an increase with grain size. Assessment of domain state was complicated by very small and large grains displaying similar magnetic properties.

Influence of temperature on thermal conductivity, thermal capacity and thermal diffusivity for different types of rock

Abstract: Thermal modeling down to great depth, e.g. down to the Mohorovicic discontinuity, requires representative values of thermal conductivity and thermal capacity at an appropriate depth. Often there is a lack of data, especially concerning temperature and pressure dependence of thermal conductivity and thermal capacity, due to missing or questionable data from boreholes. Studies of the temperature and pressure dependence of thermal conductivity and thermal capacity showed that temperature is dominating. Thus measurements on a set of magmatic, metamorphic and sedimentary rocks sampled from different depth levels of the Eastern Alpine crust were used to obtain an estimate of the temperature dependence of both properties––at least for the area of investigation––and to give a review of the temperature dependence of thermal conductivity ( λ ), thermal capacity ( ρ × c p ) and thermal diffusivity ( κ ) for different types of rock. The temperature dependence of thermal conductivity for crystalline (magmatitic and metamorphic) rocks is different to that of sedimentary rocks. Using the approach that the thermal resistivity (1/ λ ) is a linear function of temperature whose slope increases with λ (0), the conductivity at a temperature of 0 °C, two general equations were determined. The equation for crystalline rocks was verified in the temperature range of 0–500 °C and the equation for sedimentary rocks was tested in the temperature range from 0 to 300 °C. A general equation for the temperature dependence of λ for Eastern Alpine rocks can thus be formulated: λ(T)= λ(0) 0.99+T(a−b/λ(0)) with empirical constants and corresponding uncertainties a =0.0030±0.0015 and b =0.0042±0.0006 for crystalline rocks. The constants for corresponding sedimentary rocks are a =0.0034±0.0006 and b =0.0039±0.0014. λ is given in W m −1 K −1 , T in °C. At ambient conditions thermal diffusivity ( κ ) and thermal conductivity ( λ ) for Eastern Alpine crystalline rocks show the relationship: κ=0.45×λ.

Public participation in integrated water resources management: the case of Tanzania

Abstract: Effective and sustainable management of water resources is vital for ensuring sustainable development. However, efforts of water resource management seem to demonstrate inappropriate practices, especially when compared to water consumption trends in developing countries in general, and sub-Saharan Africa in particular. Being a major and vital ingredient to human kind, water resources influence all sectors. However, there have been increased problems over time that subject water resources to a number of crisis and pressures. Poor water resources management have stimulated and sustained a number of problems related to health, socio-economic and environment, which need to be solved. These problems are accelerated and magnified by the countries’, communities’ and individuals’ struggles for economic and social development as many development initiatives are affected by water availability and vice versa. Integrated water resources management (IWRM), is a process, a change, and an approach that mainstream water resource use and management into the national economic in an equitable manner without compromising the sustainability of vital ecosystems. This paper analyses the importance of community participation in the process of IWRM. The paper describes reasons that justify the need for an IWRM approach and explains the rationale for community participation. Successful cases in community involvement have been cited from different areas to demonstrate the importance of IWRM. The paper concludes that the public/community involvement is crucial for a successful and sustainable water resource management. It has been emphasized that natural resources management related policies including water requires the use of knowledge, experience and opinions of local communities who are the key stakeholders in resource conservation. This could be ensured through public/community participation.

Extremophilic fungi in arctic ice: a relationship between adaptation to low temperature and water activity

Abstract: Little is known about fungal diversity in extremely cold regions. Low temperatures induce the formation of ice crystals and therefore also the creation of low water activity (aw). These are the dominant factors in external chemistry that influence microbial biota in cold regions. Therefore, we have used selective low water activity media plus low incubation temperatures for the isolation of fungi from an Arctic environment. In comparison with the highest values of colony forming units (CFU) obtained on mesophilic media, considerably higher fungal CFU per litre of water were detected on low aw media, ranging from 1000 to 3000 l � 1 in seawater, 6000 to 7000 l � 1 in melted sea ice and up to 13,000 l � 1 in melted glacier ice. The dominant taxa were ascomycetous and basidiomycetous yeasts, melanized fungi, mainly represented by the genera Cladosporium and Aureobasidium plus different species of the genus Penicillium. Preliminary taxonomic analyses revealed several new species and varieties. Further characterisations are needed to determine whether this diversity is due to geographic isolation, ecological conditions or independent evolutionary origin. 2003 Elsevier Ltd. All rights reserved.

Assessment of climate impact on vegetation dynamics by using remote sensing

Abstract: Climate variability has a large impact on the vegetation dynamics. To quantify this impact a study is carried out with Normalized Difference Vegetation Index (NDVI) satellite images and meteorological data over part of Sahelian Africa and Europe over several years. The vegetation dynamics are quantified as the total amount of vegetation (mean NDVI) and the seasonal difference (annual NDVI amplitude) by a time series analysis of NDVI satellite images with the Harmonic ANalysis of Time Series algorithm. A climate indicator (CI) is created from meteorological data (precipitation over net radiation). The relationships between the vegetation dynamics and the CI are determined spatially and temporally. The driest areas prove to be the most sensitive to climate impact. The spatial and temporal patterns of the mean NDVI are the same, while they are partially different for the seasonal difference. The question whether climate impact on vegetation dynamics is the same everywhere on earth in the time and space domain cannot be satisfactorily answered with these limited datasets.

Resilience building and water demand management for drought mitigation

Abstract: Doughts resulting in complete crop failure are common in Eastern and Southern Africa. We are at present experiencing a regional crisis, where crop failures related to drought are threatening the lives of millions of people in several countries in Southern Africa. A major challenge is to seek ways of mitigating and coping with droughts in small-holder farming systems, particularly in semi-arid regions which are most hardly hit by the effects of drought. An entry-point for drought mitigation is to build water resilience of present rainfed farming systems. The water balance is a good starting point to assess the options. As has been argued for decades, the term drought is very debated, and the boundaries between droughts being politically and biophysically defined is not sharp. Often crop failures and social suffering are blamed on drought, while in reality the causes are more complex than only a decline in rainfall. A challenge is to find management strategies to deal with the unreliable and extremely variable rainfall in savannah environments. In this paper examples of small-scale management practices to mitigate drought in semi-arid rainfed farming are presented. Focus is on water harvesting systems for supplemental irrigation. It is shown that with relatively simple and cheap means it is possible to build resilience to deal with water scarcity in semi-arid farming systems. If such measures are combined with efforts of maximising plant water availability and plant water uptake capacity, there are good chances of mitigating certain droughts. Conservation tillage systems have proven to maximise rainfall infiltration and storage of water in the soil, enabling even crops lacking supplemental irrigation to bridge severe dry spells. Interestingly, building resilience in rainfed farming systems is also a means of water demand management. More crop is produced per drop of water in resilient farming systems, which reduces the amount of water needed to produce food. Despite the opportunities to build resilience to mitigate droughts, it is impossible to escape from the severe drought years. This is where coping mechanisms are required, which involve social, economic and institutional preparedness to cope with the social effects of climatic droughts.

Estimation of sensible heat flux using the Surface Energy Balance System (SEBS) and ATSR measurements

Abstract: This paper describes a modified version of the Surface Energy Balance System (SEBS) as regards the use of radiometric data from space and presents the results of a large area validation study on estimated sensible heat flux, extended over several months. The improvements were made possible by the characteristics of the Along Track Scanning Radiometer (ATSR-2) on board the European Remote Sensing satellite (ERS-2) and relate to: (a) the use of bi-angular radiometric data in two thermal infrared channels to estimate column atmospheric water vapor: (b) the use of bi-angular radiometric data in four spectral channels in the 550-1600 nm spectral regions to estimate aerosols optical depth: (c) determination of bottom of atmosphere (BOA) spectral reflectance using column water vapor, aerosols optical depth and a two-stream radiative transfer scheme to relate BOA spectral reflectance to top of atmosphere spectral radiance (d) direct and inverse modeling of radiative transfer in a vegetation canopy to relate BOA spectral reflectance to canopy properties, such as spectrally integrated hemispherical reflectance (albedo). A parameterization of the aerodynamic resistance for heat transfer (in term of kB(-1)) was applied for the first time at large spatial scales. For such large area analyses SEBS requires wind speed, potential temperature and humidity of air at an appropriate reference height. The latter was taken as being the height of the planetary boundary layer (PBL) and the data used were fields generated by an advanced numerical weather prediction model, i.e. regional atmospheric climate model (RACMO), integrated over the PBL. Validation of estimated sensible heat flux H obtained with the ATSR radiometric data was done using long-range, line-averaged measurements of H done with large aperture scintillometers (LAS) located at three sites in Spain and operated continuously between April and September 1999. The root mean square deviation of SEBS H estimates from LAS H measurements was 25.5 W m(-2). (C) 2003 Elsevier Science Ltd. All rights reserved.

Potential of rainwater harvesting in urban Zambia

Abstract: This paper was associated with a WARFSA funded research project “Potential of rainwater harvesting in urban Zambia”. The general objective of the research was to investigate the applicability of rainwater harvesting in urban Zambia. This paper presents the results obtained at the time of writing the paper. Rainwater harvesting was not new to Zambia and there had been installations which were mainly confined to rural areas. Laboratory analysis of water samples from one such system showed that the water was suitable for drinking purposes. Two peri-urban areas of Lusaka were selected mainly based on the water stress in the areas. The socio-cultural survey conducted in the two areas indicated that water ranked among the top two priorities by the Residential Development Committee. Design of the systems was based on the mass curve analysis for storage and rational formula for the gutters. However, a maximum storage of 10 cubic meters was chosen due to budgetary limitation. Construction of five systems was in progress.

Testing water demand management scenarios in a water-stressed basin in South Africa: application of the WEAP model

Abstract: Like many river basins in South Africa, water resources in the Olifants river basin are almost fully allocated. Respecting the so-called “reserve” (water flow reservation for basic human needs and the environment) imposed by the Water Law of 1998 adds a further dimension, if not difficulty, to water resources management in the basin, especially during the dry periods. Decision makers and local stakeholders (i.e. municipalities, water users’ associations, interest groups), who will soon be called upon to work together in a decentralized manner within Catchment Management Agencies (CMAs) and Catchment Management Committees (CMCs), must therefore be able to get a rapid and simple understanding of the water balances at different levels in the basin. This paper seeks to assess the pros and cons of using the Water Evaluation and Planning (WEAP) model for this purpose via its application to the Steelpoort sub-basin of the Olifants river. This model allows the simulation and analysis of various water allocation scenarios and, above all, scenarios of users’ behavior. Water demand management is one of the options discussed in more detail here. Simulations are proposed for diverse climatic situations from dry years to normal years and results are discussed. It is evident that the quality of data (in terms of availability and reliability) is very crucial and must be dealt with carefully and with good judgment. Secondly, credible hypotheses have to be made about water uses (losses, return flow) if the results are to be meaningfully used in support of decision-making. Within the limits of data availability, it appears that some water users are not able to meet all their requirements from the river, and that even the ecological reserve will not be fully met during certain years. But the adoption of water demand management procedures offers opportunities for remedying this situation during normal hydrological years. However, it appears that demand management alone will not suffice during dry years. Nevertheless, the ease of use of the model and its user-friendly interfaces make it particularly useful for discussions and dialogue on water resources management among stakeholders; it can also be used to promote greater awareness and understanding of key issues and concerns among the public.

What is the limit of up-scaling rainwater harvesting in a river basin?

Abstract: The semi-arid savannah environment (SASE) of sub-Saharan Africa are characterized by low erratic rainfall which result to high risk of droughts, intra-seasonal dry spells and frequent food insecurity. The main occupation is subsistence small-scale rainfed agriculture and livestock production, which normally compete for the limited water resources. The main challenges to improving the livelihoods of the small-scale farmers are how to upgrade rainfed agriculture to improve rural livelihoods and conserve nature, and upgrade upstream landuse in balance with water needs for human and ecosystems downstream. There is an increased interest in opportunities of improving rainfed agriculture through adoption of rainwater harvesting (RWH) technologies. However, there is inadequate knowledge on hydrological impacts and limits of up-scaling rainwater harvesting at a river basin scale. Rainwater harvesting has a potential of addressing spatial and temporal water scarcity for domestic, crop production, livestock development, environmental management and overall water resources management is SASE. However, this potential has not been exploited despite the occurrence of persistent low agricultural production and food shortage in sub-Saharan Africa. The need to quantify this perceived potential and related hydrological impacts on a river basin led to the on-going research project titled “hydrological impacts of up-scaling RWH on upper Ewaso Ng’iro river basin water resources management”. It is envisaged that the study will contribute to formulation of sustainable RWH up-scaling strategies to enhance food production and hydro-ecological balance in semi-arid savannahs of Africa. This paper presents the preliminary findings of the study mainly focusing on assessment of the potential of RWH technologies for improving food and water availability especially in semi-arid regions of eastern Africa. This was achieved by evaluating six RWH case studies selected from four countries (Ethiopia, Kenya, Tanzania and Uganda). Despite the success of a number of RWH systems, the rate of adoption is still low, hence making their impacts marginal. Nevertheless, there is a knowledge gap on the limits of up-scaling RWH in a river basin, which the other components of the study will address. The assessment of the hydrological impact of up-scaling RWH technologies is expected to provide answers to the question, what is the limit of up-scaling rainwater harvesting in a river basin ?

Ice cores from Svalbard - useful archives of past climate and pollution history

Abstract: Ice cores from the relatively low-lying ice caps in Svalbard have not been widely exploited in climatic and environmental studies due to uncertainties about the effect of melt water percolation. However, results from two recent Svalbard ice cores, at Lomonosovfonna (1250 m asl) and Austfonna (750 m asl), have shown that with careful site selection, high-resolution sampling and multiple chemical analyses, it is possible to recover ice cores with partly preserved annual signals. These cores are estimated to cover at least the past 600 years and have been dated using a combination of known reference horizons and glacial modeling. The δ18O data from both Lomonosovfonna and Austfonna ice cores suggest that the 20th century was the warmest during the past 600 years. A comparison of the ice core and sea ice records from this period suggests that sea ice extent and Austfonna δ18O are linked over the past 400 years. This may reflect the position of the storm tracks and their direct influence on the relatively low altitude Austfonna. Lomonosovfonna may be less sensitive to such changes and primarily record atmospheric changes due to its higher elevation. The anthropogenic influence on Svalbard environment is illustrated by increased levels of non-sea-salt sulphate, nitrate, acidity, fly-ash and organic contaminants particularly during the second half of 1900s. Decreased concentrations of some components in recent decades most likely reflect emission and use restrictions. However, some current-use organic pesticide compounds show growing concentrations in near surface layers.

Assessing relative soil moisture with remote sensing data: theory, experimental validation, and application to drought monitoring over the North China Plain

Abstract: Based on physical consideration of land surface energy balance, a theory is proposed for assessing relative soil moisture in the rooting depth with remote sensing data. The basis of the theory is the derivation of relative soil moisture in the rooting zone which is theoretically shown to be derivable from relative evaporation. The relationship derived between the relative soil moisture and relative evaporation is confirmed with experimental data collected with lysimeter measurements and in intensive field campaigns. Further it is shown that the proposed theory can be used to define a drought severity index (DSI) for drought monitoring, when the relative evaporation can be determined with remote sensing data. For this purpose, a demonstration in North China is performed. The used remote sensing data are NOAA/AVHRR which is available on a daily basis, the required meteorological data (wind speed, air temperature, humidity and pressure) are obtained from the operational measurement network of the National Meteorological Center of China. Comparisons between the estimated DSI and the actual measurements of soil moisture confirm the validity and robustness of the proposed theory.

One year of particle size distribution and aerosol chemical composition measurements at the Zeppelin Station, Svalbard, March 2000?March 2001

Abstract: One year of aerosol size distribution and chemical composition measurements conducted at the Zeppelin station on Svalbard (78° 58 ′ N and 11° 53 ′ E) is presented. The data, which cover the period March 2000–April 2001, show a very strong seasonal dependence of the number mode particle size. The transition from one seasonal characteristic regime to the other occurs rapidly and takes place over only a few days. As expected, the largest integrated aerosol surface and particle volumes are observed during the Arctic haze period in spring. On a seasonal scale the total number density covariate with the incoming solar radiation, which points to photochemistry as an important component during new particle formation in the Arctic summer. However, maximum number densities are observed during the second part of the summer concurrent with a relative reduction in the incoming radiation. The onset of this period of enhanced particle number densities coincides in time with the surface temperature remaining steadily above the freezing point and the melting of the snow cover. A similar transition occurring over the Siberian tundra is proposed as a potential source of aerosol precursor gases, which could explain the enhanced particle number densities during the second half of the summer. A second maximum of ammonium in particles during late summer and fall, concurrent with a reduction in sea salt and nss-sulfate present in particles would be consistent with continental source without a significant anthropogenic component. The data presented in the study also illustrate the usefulness of measurements that extend over several seasons where phenomenon that occur with in one season, the summer in this case, can be put into context.

Impact of graben-parallel faults on hydrothermal convection--Rhine Graben case study

Abstract: Detailed investigations of the temperature distribution in the Rhine Graben indicate a regular pattern of graben-parallel thermal anomalies following major north–south striking faults. These faults, which might imply north–south convection pattern due to higher permeability, have been ignored in conventional models based on 2D east–west striking sections. The present study investigates small-scale temperature anomalies in the Rhine Graben, focusing on its north–south striking major faults and their important permeability structures. Analytical solutions for convective flow in vertical faults were applied to a clearly observable anomalous temperature pattern. Through these calculations the fault geometry, minimal fault permeability and time to convective onset were derived from observed distances between anomalies. Since analytical solutions are limited to simple model geometries, further improvement was achieved through numerical model simulations, which allow the assumption of more complex initial and boundary conditions. Using the finite volume code TOUGH2 we investigated in detail the convective fluid flow pattern along the Cfault in the Landau region through a 3D model. There, regions of alternatively higher and lower temperatures follow each other at an average distance of 1800 m. Focusing on the predominant north–south permeability structure, our model consists of a vertical north–south striking fault and surrounding matrix with fault geometries based on analytical predictions. The observed temperature could be explained by a numerical model indicating fluid velocities in the fault of � 10 � 9 ms � 1 and an anomaly whose minimal age is 77,000 years. The study proves that the observed small-scale graben-parallel temperature anomalies can be explained only by convection systems within north–south striking fault zones. The regional flow regime is therefore significantly influenced by the convective fluid flux in major north–south striking faults. Investigations of temperature anomalies in the Rhine Graben must take into account this north–south flow. Since the presented results correlate with findings from other geothermal anomalies in the Rhine Graben such as the one at Soultz, we suspect this to be a general feature of the major north–south striking faults there. Moreover, since in most grabenlike structures thermal anomalies are associated with the Graben master faults, the present study may provide common clues for investigating other graben-parallel temperature anomalies. � 2003 Elsevier Science Ltd. All rights reserved.

Forecast of water demand in weinan city in china using wdf-ann model

Abstract: Domestic water use is generally the most important component of urban water consumption.In this paper, the relatively new technique of artificial neural network (ANN) is proposed to model and forecast the water demand in urban areas.Results indicate that the WDF-ANN (water demand forecast using artificial neural network) model offers an effective way to formulate domestic water demand in Weinan City in China.The model evaluation shows that the correlation coefficients are more than 90% both for the training data and the testing data. � 2003 Elsevier Science Ltd.All rights reserved.

Appropriate deflouridation technology for use in flourotic areas in Tanzania

Abstract: High fluoride in drinking water is a problem found in both ground and surface water in various parts of Tanzania. Several defluoridation methods have been tested and detailed studies have been carried on bone-char method, alum/lime method and the combination of the two methods. In bone char method, the bones are charred in special kilns fuelled by wood charcoal. Different sizes of the kiln have been fabricated and tested. Crushing and sieving devices have been developed. The effectiveness of bone char particles sizes in fluoride removal has been studied and the results favoured small particle sizes. However, experimental conditions discouraged the use of very fine particles sizes of bone char due easy clogging. Household and institutional levels bone char defluoridation systems have been developed and tested. Filter columns packed with heat-activated bones are found to be more effective than fill and draw bucket type defluoridator. The bone char media used has the capability of producing water with a residual fluoride concentration of less than 0.1 mg/l from an initial fluoride of 12.0 mg/l. Use of alum and lime in fluoride removal from waters with excessive fluoride has been experimented upon. A plant with an automatic chemical dosing and mixing system for use at institutional levels has been developed and tested. The method was able to treat water with an initial fluoride concentration of 12 mg/l to a residual fluoride concentration ranging from 2 to 3 mg/l. During the study it was established, that the bone char method is appropriate for use in rural areas of Tanzania due its simplicity, local availability of materials and the possibility of processing the material locally.

Air pollution forecasting from regional to urban street scale––implementation and validation for two cities in Denmark

Abstract: An operational air pollution forecast model system, THOR, has been developed. The system is used for 3-days forecasting, monitoring and traffic and/or emission reduction scenarios. The model system includes several models capable of calculating air pollution concentrations at different spatial scales, ranging from European scale over urban background scale down to urban street scale. When coupling models covering such different scales, it is possible to include contributions both from local, near-local and non-local emission sources in order to describe the air quality at a specific location––e.g. in a street canyon. The different air pollution models are driven by a numerical weather forecast model. Operational three days air pollution forecasts are produced four times every day. The system can, in principle, be applied for any city in Europe. Currently the regional model has been implemented for the whole of Europe and the urban models for two major cities in Denmark; Copenhagen and Aalborg. The individual models in the system will be shortly described and typical model results will be shown. The model system has been operational since August 1998 and is continuously being validated against measurements from the Danish urban monitoring network. Results from the evaluation of the system performance for the city of Aalborg and comparisons with results for the city of Copenhagen will be presented. The results show that the street pollution model has quite similar performance for the two cities. However, a difference is seen in the performance of the urban background model for the two cities, which is probably due to the difference in the spatial resolution of the urban emission data.

The European Water Framework Directive and water management research

Abstract: The Water Framework Directive (WFD) is the most important EU directive in the water field over the past decades The WFD requires “good water status” for all European waters by 2015, to be achieved through a system of participatory river basin management planning and supported by several assessments and extensive monitoring A lot of research is required to implement the WFD This research should be inter- or multidisciplinary, participatory and pragmatic

Hyperspectral remote sensing of salt marsh vegetation, morphology and soil topography

Abstract: The present paper deals with the relationship between vegetation patterns and salt marsh morphology in the Venice lagoon and with the use of remote sensing to infer salt marsh morphologic characteristics from vegetation mapping. Field measurements indicate that salt marsh vegetation species (halophytes) are reliable indicators of ground elevation and live within typical elevation ranges characterised by standard deviations of less than 5 cm. A model is then developed which uses vegetation as a morphological indicator of soil topography to estimate ground elevation from fractional cover values of each vegetation type. The use of data from an airborne remote hyperspectral sensor is presented as a means of discriminating between different salt marsh vegetation communities. Vegetation maps obtained from unmixing techniques have then been used to produce digital elevation maps (DEM) of salt marsh areas. The DEM based on halophytes cover estimates and extracted from high spatial and spectral resolution data allows a high estimation accuracy, with an error standard deviation of a few centimetres in the considered study area within the Venice lagoon. The accuracy and resolution attainable through this method are comparable and often superior to those obtained through state of the art laser altimetry.

Web-based modelling of energy, water and matter fluxes to support decision making in mesoscale catchments - the integrative perspective of GLOWA-Danube

Abstract: The GLOWA-initiative (Global Change of the water cycle), funded by the German Ministry of Research and Education (BMBF), has been established to address the manifold consequences of Global Change on regional water resources in a variety of catchment areas with different natural and cultural characteristics. Within this framework, the GLOWA-Danube project is dealing with the Upper Danube watershed as a representative mesoscale test site (∼75.000 km2) for mountain-foreland regions in the temperate mid-latitudes. The principle objective is to identify, examine and develop new techniques of coupled distributed modelling for the integration of natural and socio-economic sciences. The transdisciplinary research in GLOWA-Danube develops an integrated decision support system, called DANUBIA, to investigate the sustainability of future water use. GLOWA-Danube, which is scheduled for a total run-time of eight years to operationally implement and establish DANUBIA, comprises a university-based network of experts with water-related competence in the fields of engineering, natural and social sciences. Co-operation with a network of stakeholders in water resources management of the Upper Danube catchment ensures that practical issues and future problems in the water sector of the region can be addressed. In order to synthesize a common understanding between the project partners, a standardized notation of parameters and functions and a platform-independent structure of computational methods and interfaces has been established, by making use of the unified modelling language, an industry standard for the structuring and co-ordination of large projects in software development [Booch et al., The Unified Modelling Language User Guide, Addison-Wesley, Reading, 1999]. DANUBIA is object-oriented, spatially distributed and raster-based at its core. It applies the concept of “proxels” (process pixels) as its basic objects, which have different dimensions depending on the viewing scale and connect to their environment through fluxes. The presented paper excerpts the hydrological view point of GLOWA-Danube, its approach of model coupling and network-based communication, and object-oriented techniques to simulate physical processes and interactions at the land surface. The mechanisms and technologies applied to communicate data and model parameters across the typical discipline borders are demonstrated from the perspective of the Landsurface object. It comprises the capabilities of interdependent expert models for energy exchange at various surface types, snowmelt, soil water movement, runoff formation and plant growth in a distributed Java-based modelling environment using the remote method invocation [Pitt et al., Java.rmi: The Remote Method Invocation Guide, Addison Wesley Professional, Reading, 2001, p. 320]. The presented text summarizes the GLOWA-Danube concept and shows the state of an implemented DANUBIA prototype after completion of the first project-year (2001).

The influence of historic land use changes and future planned land use scenarios on floods in the Oder catchment

Abstract: In July 1997, dramatic flooding occurred in the Oder Basin, covering parts of the Czech Republic, Poland, and Germany. In August 2001, Poland again suffered from flooding, but more in the Vistula River than in the Oder River. To investigate the causes of the flooding and the influence of land use, soil characteristics and antecedent catchment moisture conditions, the distributed catchment model LISFLOOD has been developed. LISFLOOD simulates runoff in large river basins. In close cooperation with the water authorities of Germany, Poland, and the Czech Republic, the model has been set up, calibrated, and validated for the flood events of 1977, 1985, and 1997. Several scenarios have been evaluated with LISFLOOD, such as the effects of flood defence measures and also of expected future trends of climate and land use change. The study has demonstrated that the proposed measures for flood control by the International Oder Commission lead to a significant improvement and reduction of flood risk in the Oder catchment, especially for downstream reaches. Historic land use changes show an increase in forested and urban areas between 1780 and 1995, which hydrologically are balancing out each other in terms of discharge. It has been shown that the use of flood forecasting in reservoir management can also reduce flood risk downstream. Finally, it is expected that urban growth will slightly increase flood risk in the next 30 years.

Towards the identification of siderite, rhodochrosite, and vivianite in sediments by their low-temperature magnetic properties

Abstract: Siderite (FeCO3), rhodochrosite (MnCO3), and vivianite ((Fe3(PO4)2) � 8H 2O) are well-known authigenic minerals in a number of sedimentary settings. Here, we explore the potential of low-temperature mineral magnetic techniques for their identification at low concentration in bulk samples thus expanding mineral magnetic proxies for environmental purposes. The basic rock magnetic properties of these minerals, which are paramagnetic at ambient temperature, were determined with aMagnetic Properties Mea- surement System'. Well-crystalline chemically analyzed material of natural origin was used to gather these data. The diagnostic value of the observed specific magnetic properties was tested on two mid-Eocene sediment samples from the Norwegian Sea (ODP Leg 104, Site 643) known to contain these minerals. The observed Ntemperatures of siderite (37 K) and rhodochrosite (34 K) conform with literature data. Both carbonates show a fairly strong spin-canted remanence (� 0.4 Am 2 /kg) from cooling in a 5 T magnetic field. Different ratios of field-cooled and zero- field-cooled remanences, however, allow a discrimination between the two minerals. A characteristic of rhodochrosite is its ex- tremely high magnetic susceptibility just below the Ne temperature. An almost vertical slope in very low fields of the hysteresis loop also testifies to this high susceptibility. It is assigned to a weak anisotropic ferromagnetism confined to the basal plane in which the spontaneous magnetization can almost freely rotate. A prominent magnetic property of siderite is its metamagnetism, resulting in a progressively upward bending of the hysteresis curve in magnetic fields above 5 T. Vivianite also shows an onset of meta- magnetic transition below 5 K in 5 T fields and atwo-stage' increase in susceptibility between 2 and 12 K attributed to successive short- and long-range magnetic ordering. The magnetic properties of the two authigenic marine sediments could be largely explained by combining characteristics of rhodochrosite and manganosiderite. Shifting of the Npoints to lower temperatures and less well pronounced magnetic phenomena are attributed to element substitution and non-stoichiometry which occur commonly in sedi- mentary environments. � 2003 Elsevier Ltd. All rights reserved.

A new model for a magnetoreceptor in homing pigeons based on interacting clusters of superparamagnetic magnetite

Abstract: We present a new model of magnetic-field reception in magnetite-containing nerve terminals, which have recently been identified in the upper-beak skin of homing pigeons. The potentially magnetoreceptive nerve cells comprise chain-like aggregates with up to 20 closely spaced clusters of superparamagnetic (SP) magnetite. We designed experiments on superparamagnetic model systems to simulate the behaviour of the aggregates in varying magnetic fields. Magnetic-field induced interactions between the clusters in an aggregate gives rise to attractive and repulsive forces between the clusters. The resulting stress on the surrounding cellular structures varies with field direction and intensity. Our model is able to explain the principal features of the magnetic sense in homing pigeons as derived from behavioural experiments.

Managing the water quality of the Kafue River

Abstract: Most vital surface water bodies in developing countries are under serious threat of degradation resulting from constant discharge of polluted effluents stemming from industrial, agricultural, mining and domestic/sewage activities. The most affected river systems are those traversing cities and towns in urban areas. The Kafue River in Zambia is one such river system that is threatened with serious degradation and probable loss of biodiversity. Kafue River cuts across the country in a North–South direction, stretches for about 1576 km before draining into the Zambezi River. It covers an area of 152,000 km 2 and generates a mean annual runoff of 350 m 3 /s which represents about 12% of the Zambezi’s mean annual runoff at the confluence [Water Resources Development and Vector-borne Diseases in Zambia: Report of a National Seminar held at Kafue Gorge, Zambia, WHO, Geneva, 1995]. The area coverage of the Kafue River Basin (KRB) is approximately 20% of Zambia’s land area (743,000 km 2 ) and approximately 17% of the Zambezi Basin [Water Resources Use in the Zambezi Basin: Proceedings of a Workshop held at Kasane, Botswana, IUCN, 1993]. More than half of Zambia’s population live in the KRB, of which about 65% are in urban while 35% are in rural areas. Over the years, however, the Kafue River has been receiving all sorts of pollutant and effluents from all sectors of economical development in Zambia that include mining, industrial and agricultural. The continuous discharge of pollutants into the Kafue river has led to the deterioration of the river water quality. The consequences have been heightened eutrophic conditions, increased heavy metal concentration in the river sediments and aquatic life, increased suspended solids, etc. leading to proliferation of Salvinia molesta in some sections of the river, decreased fish catch and fish size and objectionable taste of the Kafue River water. Fishermen along the Chanyanya–Kafue Gorge stretch of the Kafue River have complained about the alleged loss of taste and the decrease in both the fish catch and size in these areas of the Kafue River. The communities along the same stretch have also complained about the objectionable taste of the river water [Report of the Proceedings of the First Multi-sectoral Workshop on the Effects of Environmental Pollution and Degradation on the Kafue River Basin (KRB) on the Community in the Kafue Town Area, AREZ, 2001]. This paper reviews the water quality of the Kafue River resulting from anthropogenic activities and proposes the framework for the sustainable management of river water quality.

Extremely high heat flow anomaly in the middle part of the Nankai Trough

Abstract: Detailed heat flow measurements were carried out in the central part of the Nankai Trough off eastern Shikoku, where the fossil spreading center of the Shikoku Basin is subducting beneath the southwest Japan arc. The quality of temperature gradient values was examined for all the existing and new heat flow data and the average of new thermal conductivity data was used at all the stations. Reliable heat flow on the floor of the trough was found to be very high and rather uniform, with an average of about 200 ± 20 mW/m 2 . Taking account of the effect of recent rapid sedimentation on the surface heat flow, the heat flow from the deeper part is estimated to be even higher by 20–30%, almost twice as high as the value expected from the age of the subducting Shikoku Basin, about 15 m.y. Such a large heat flow anomaly cannot be attributed solely to advective heat transfer by pore fluid flows associated with subduction and accretion of the sediments brought into the trough, suggesting that the underlying Shikoku Basin lithosphere is anomalously warm in the study area. A possible cause of the anomaly is reheating of the lithosphere by post-spreading thermal activities along the fossil spreading center, which produced the Kinan Seamount Chain and continued until about 7 Ma. However, such reheating even at 6 Ma cannot produce a heat flow high enough to explain the observed values. A steep landward decrease in the heat flow is observed at the toe of the accretionary prism. The scale of this decrease indicates that its origin is not deep seated, and thus a part of the anomalous heat flow on the trough floor may result from some processes in relatively shallow layers. The thermal structure of the Shikoku Basin is a critical boundary condition for thermal models of the Nankai subduction zone and its seismogenic zone for large thrust earthquakes. More heat flow measurements need to be made around the study area in order to clarify the extent and origin of the high heat flow anomaly.

Water reform in Sub-Saharan Africa: what is the difference?

Abstract: Since the early 1990s African governments took an active part in the global movement of water reform towards Integrated Water Resources Management (IWRM). The first step consisted primarily of assimilating the generic principles of IWRM. At this generic level, water reform in Sub-Saharan Africa seems quite similar to water reform elsewhere in the developed and developing world. However, in taking the second step of operationalizing generic principles into concrete actions on the ground, at least three salient differences between Sub-Saharan Africa and elsewhere emerged: (a) Africa’s relative abundance of water resources but its scarcity of economic means to harness available water resources; (b) the importance of agriculture and agricultural water development for economic growth and poverty eradication; and (c) the need for systems of water rights and financial resource mobilization that are separated and suit the African reality in which large water users are relatively few, while the bulk of water users are scattered smallholders. This paper discusses the early operationalization with regard to these three unique features and identifies lessons learnt.

Experimental procedure to detect multidomain remanence during Thellier–Thellier experiments

Abstract: Reliability checks in Thellier-type experiments usually focus on the detection of chemical alteration of the magnetic mineral component or the formation of new magnetic phases during the heating process. However, a major problem in Thellier-type experiments is the presence of multidomain (MD) particles which can lead either to complete failure of palaeointensity determinations or to serious misinterpretation. We present a modification of the Thellier–Thellier experiment that detects the presence of MD particles by verifying the law of additivity of pTRMs. The law of additivity is valid for regular pTRMs (i.e. the upper temperature of pTRM acquisition is reached by cooling from the Curie temperature) for both SD and MD particles, whereas it is not valid for pTRM* (the upper temperature of pTRM acquisition is reached by heating from room temperature) in the case of MD particles. As the partial thermoremanences imparted in Thellier–Thellier experiments are of the pTRM* type, additivity as a prerequisite for the validity of the obtained result is not given if the remanence is carried predominantly by MD particles. The proposed method is applied to seven synthetic samples covering a grain size range of 23 nm to 12.1 μm. The obtained palaeointensity estimates show a significant error for all samples with grain sizes >0.7 μm due to the failure of the law of additivity. Our experiment is able to detect this failure.

On measuring and remote sensing surface energy partitioning over the Tibetan Plateau––from GAME/Tibet to CAMP/Tibet

Abstract: The energy and water cycle over the Tibetan Plateau play an important role in the Asian monsoon system, which in turn is a major component of both the energy and water cycles of the global climate system. The intensive observation period and long-term observation of the GEWEX (global energy and water cycle experiment) Asian monsoon experiment on the Tibetan Plateau (GAME/Tibet) and CEOP (coordinated enhanced observing period) Asia–Australia monsoon project (CAMP) on the Tibetan Plateau (CAMP/Tibet) have been done successfully in the past five years. A large amount of data has been collected, which is the best data set so far for the study of energy and water cycle over the Tibetan Plateau. The field experiments of GAME/Tibet and CAMP/Tibet are introduced and some results on the local surface energy partitioning (imbalance, diurnal variation, inter-monthly variation and inter-yearly variation etc.) are presented by using the field observational data in this study. The study on the regional surface energy partitioning is of paramount importance over heterogeneous landscape of the Tibetan Plateau and it is also one of the main scientific objectives of GAME/Tibet and CAMP/Tibet. Therefore, the regional distributions of surface variables (surface reflectance and surface temperature), vegetation variables (NDVI, MSAVI, vegetation coverage and LAI) and surface heat fluxes (net radiation flux, soil heat flux, sensible and latent heat flux) are also derived by combining NOAA-14 AVHRR data with field observations in this study.

Towards an integrated water resource management in Tanzania: the role of appropriate institutional framework in Rufiji Basin

Abstract: Over the past 50 years, changes in the intersectoral water use in the Rufiji Basin have been enormous. A growing human population, migration and increasing demands in the basin have culminated this change. The basin, however, still lack an appropriate integrated management approach. This has resulted into inter-institutional conflicts, ineffectiveness, gaps in management imperatives and duplication of efforts. This paper reviews the existing institutional linkages identifies the gap and proposes an appropriate institutional framework which involve questions of institutional arrangements and the assignment of responsibilities among various levels of development, ensures stakeholders participation, accommodates adaptive change and remain self sustainable. The basic argument of this paper is that water management issue is both a question of developing stakeholders’ participation and transferring state’s competence to water user associations. Such an endeavour requires a complete and complex institutional framework, which would define clearly the role and rule of each stakeholder in water resource management. The paper further argues that; in Tanzania, the institutions that are involved in water management are loosely connected and lack basic coordination and are often at the periphery of the water management agenda––divorced from the water management programs; the predominance of isolated institutions locked up in narrowly defined activities with no interactive learning process will continue to hamper national aspirations to manage water; and that to change this situation will require innovative reforms in national institutions and institutional learning.

A trajectory climatology for Svalbard; investigating how atmospheric flow patterns influence observed tracer concentrations

Abstract: A 10-year climatology of long-range atmospheric transport to Ny-Alesund, Svalbard (78.9°N, 11.9°E) is developed using three-dimensional 5-day back-trajectories. We calculate trajectories arriving twice daily at 950, 850 and 750 hPa during 1992–2001, using European Centre for Medium-Range Weather Forecasts (ECMWF) analyzed wind fields. Cluster analysis is used to classify the trajectories into distinct transport patterns. The clustering procedure is performed on the whole 10-year set of trajectories, to study both year-to-year and month-to-month variability in the synoptic-scale atmospheric circulation. We identify eight major transport patterns to Ny-Alesund, which we find to be consistent with mean-pressure charts of the Arctic region. The distribution of trajectories between these flows is similar for all years during the 10-year period. However, there are seasonal differences in when different clusters are most prevalent. The calculated clusters provide an indication of source regions and transport pathways influencing Svalbard at different times of the year. Such information is valuable for interpreting measured time-series of trace gases and aerosols and could serve as guidance for formulating sampling strategies. We compare the trajectory clusters to CO2 measurements to study to what degree different atmospheric flow patterns influence the variability of the atmospheric CO2. Overall we see a linkage between CO2 concentration and the large-scale circulation. For instance, in connection with transport over Europe and Siberia during winter, high CO2 mixing ratios are observed, whereas trajectories originating from the Atlantic are associated with low CO2 concentrations. However, during some periods and for some individual trajectories we see no conclusive linkage between variability in atmospheric CO2 and transport. This can be due to a combination of the complex structure of CO2 sources and sinks and its relatively long atmospheric turn-over time. CO2 and 222Rn mixing ratios are calculated using the three-dimensional transport model MATCH to further illustrate these characteristics of CO2.