bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glacier mass balance reconstruction by sublimation induced enrichment of chemical species on Cerro Tapado (Chilean Andes)
Authors: Ginot P. , Kull C. , Schotterer U. , Schwikowski M. , Gäggeler H. W. 
Published: April 2010

Abstract. A 36 m long ice core down to bedrock from the Cerro Tapado glacier (5536 m a.s.l., 30°08' S, 69°55' W) was analyzed to reconstruct past climatic conditions for Northern Chile. Because of the marked seasonality in the precipitation (short wet winter and extended dry summer periods) in this region, major snow ablation and related post-depositional processes occur on the glacier surface during summer periods. They include predominantly sublimation and dry deposition. Under certain assumptions the chemical record along the ice core may be applied to reconstruct the history of such secondary processes. For the time period 1962–1999, a mean annual net accumulation of 316 mm water equivalent (weq) and 327 mm weq loss by sublimation was deduced by this method. This corresponds to an initial total annual accumulation of 539 mm weq. The annual variability of the accumulation and sublimation may exhibit a correlation with the Southern Oscillation Index (SOI). The deepest part of the ice record shows a time discontinuity; its age is unknown.
Millennial temperature reconstruction intercomparison and evaluation
Authors: Juckes M. N. , Allen M. R. , Briffa K. R. , Esper J. , Hegerl G. C. , Moberg A. , Osborn T. J. , Weber S. L. , Zorita E. 
Published: April 2010

Abstract. There has been considerable recent interest in paleoclimate reconstructions of the temperature history of the last millennium. A wide variety of techniques have been used. The interrelation between the techniques is sometimes unclear, as different studies often use distinct data sources as well as distinct methodologies. Recent work is reviewed with an aim to clarifying the import of the different approaches. A range of proxy data collections used by different authors are passed through two reconstruction algorithms: firstly, inverse regression and, secondly, compositing followed by variance matching. It is found that the first method tends to give large weighting to a small number of proxies and that the second approach is more robust to varying proxy input. A reconstruction using 18 proxy records extending back to AD 1000 shows a maximum pre-industrial temperature of 0.25 K (relative to the 1866 to 1970 mean). The standard error on this estimate, based on the residual in the calibration period is 0.149 K. Two recent years (1998 and 2005) have exceeded the estimated pre-industrial maximum by more than 4 standard errors.
Agricultural sustainability in the semi-arid Near East
Authors: Hole F. 
Published: April 2010

Abstract. Agriculture began in the eastern Mediterranean Levantine Corridor about 11 000 years ago toward the end of the Younger Dryas when aridity had diminished wild food resources. During the subsequent Climatic Optimum, agricultural villages spread rapidly but subsequent climatic changes on centennial to millennial scales resulted in striking oscillations in settlement, especially in marginal areas. Natural climate change thus alternately enhanced and diminished the agricultural potential of the land. Growing populations and more intensive land use, both for agriculture and livestock, have led to changes in the structure of vegetation, hydrology, and land quality. Over the millennia, political and economic interventions, warfare and incursions by nomadic herding tribes all impacted sustainability of agriculture and the ability of the land to support its populations. In much of the region today, agricultural land use is not sustainable given existing technology and national priorities. The Near Eastern case is instructive because of the quality of information, the length of the record, and the pace of modern change.
Climate-human-environment interactions: resolving our past
Authors: Dearing J. A. 
Published: April 2010

Abstract. The paper reviews how we can learn from the past about climate-human-interactions at the present time, and in the future. It focuses on data sources for environmental change at local and regional/global spatial scales, and shows the scope and limitations of each. The use of parallel histories in local case-studies is described in a case-study from China, where independent records help unravel the complexity of interactions and provide a basis for assessing the resilience and sustainability of the landscape system. Holocene global records for Natural Forcings (e.g. climate and tectonics), Human Society and Ecosystems are reviewed, and the problems of reconstructing global records of processes that are only recorded at local scales examined. Existing regional/global records are used to speculate about the veracity of anthropogenic forcing of global climate. The paper concludes that a full understanding of causes of earth system change through (at least) the Holocene can come only through the most rigorous reconstructions of climate, human activities and earth processes, and importantly their interactions, at all locations and at all scales. It follows that we need to promote inter-scale learning: regionalisation and generalisation of existing data would be useful first steps. There is now a need to develop long-term simulation models that can help anticipate complex ecosystem behaviour and environmental processes in the face of global environmental change – and resolving our past is an essential element in that endeavour.
The Dutch secret: how to provide safe drinking water without chlorine in the Netherlands
Authors: Smeets P. W. M. H. , Medema G. J. , van Dijk J. C. 
Published: April 2010

Abstract. The Netherlands is one of the few countries where chlorine is not used at all, neither for primary disinfection nor to maintain a residual disinfectant in the distribution network. The Dutch approach that allows production and distribution of drinking water without the use of chlorine while not compromising microbial safety at the tap, can be summarized as follows: 1. Use the best source available, in order of preference: – microbiologically safe groundwater, – surface water with soil passage such as artificial recharge or bank filtration, – direct treatment of surface water in a multiple barrier treatment; 2. Use a preferred physical process treatment such as sedimentation, filtration and UV-disinfection. If absolutely necessary, also oxidation by means of ozone or peroxide can be used, but chlorine is avoided; 3. Prevent ingress of contamination during distribution; 4. Prevent microbial growth in the distribution system by production and distribution of biologically stable (biostable) water and the use of biostable materials; 5. Monitor for timely detection of any failure of the system to prevent significant health consequences. New developments in safe drinking water in the Netherlands include the adaptation of the Dutch drinking water decree, implementation of quantitative microbial risk assessment (QMRA) by water companies and research into source water quality, drinking water treatment efficacy, safe distribution and biostability of drinking water during distribution and Legionella. This paper summarizes how the Dutch water companies warrant the safety of the drinking water without chlorine.
Water discharge and sediment flux changes over the past decades in the Lower Mekong River: possible impacts of the Chinese dams
Authors: Lu X. X. , Siew R. Y. 
Published: April 2010

Abstract. The Lower Mekong River has witnessed extremely low water levels over the past few years. There is speculation that the changes are a consequence of the construction and operation of the Chinese cascade dams in the upper part of the Mekong main stream, the Lancang River. Dam construction on upper streams can produce a series of induced effects downstream, particularly in terms of water, sediment, channel and ecological changes. Analyses of discharge and sediment flux at various gauging stations on the Lower Mekong River have indicated a disruption in water discharge, water fluctuations and sediment transport downstream of the first Chinese dam among the 8 cascades (i.e. the Manwan Dam), after its reservoir was infilled in 1992. Dry season flows showed a declining trend, and water level fluctuations in the dry season increased considerably in the post-dam (1993–2000) period. Monthly suspended sediment concentration (SSC) has also decreased significantly in several gauging stations in the post-dam period. The estimation of sediment flux is challenging since the measurements of SSC were sporadic. Our estimation based on the available data indicated that the areas along the upper-middle and lowermost reaches of the Mekong River have experienced a decline in sediment flux, possibly due to sedimentation in the Manwan Dam. However, the decrease is only statistically significant at the nearest gauging station below the Dam (i.e. Chiang Saen). Areas located in the mid-length of the river show less sensitivity to the operation of the Manwan Dam, as sediment fluxes have remained stable or even increased in the post-dam period.
On the asymptotic behavior of flood peak distributions
Authors: Gaume E. 
Published: April 2010

Abstract. This paper presents some analytical results and numerical illustrations on the asymptotic properties of flood peak distributions obtained through derived flood frequency approaches. It confirms and extends the results of previous works: i.e. the shape of the flood peak distributions are asymptotically controlled by the rainfall statistical properties, given limited and reasonable assumptions concerning the rainfall-runoff process. This result is partial so far: the impact of the rainfall spatial heterogeneity has not been studied for instance. From a practical point of view, it provides a general framework for analysis of the outcomes of previous works based on derived flood frequency approaches and leads to some proposals for the estimation of very large return-period flood quantiles. This paper, focussed on asymptotic distribution properties, does not propose any new approach for the extrapolation of flood frequency distribution to estimate intermediate return period flood quantiles. Nevertheless, the large distance between frequent flood peak values and the asymptotic values as well as the simulations conducted in this paper help quantifying the ill condition of the problem of flood frequency distribution extrapolation: it illustrates how large the range of possibilities for the shapes of flood peak distributions is.
Multi-criteria assessment of the Representative Elementary Watershed approach on the Donga catchment (Benin) using a downward approach of model complexity
Authors: Varado N. , Braud I. , Galle S. , Le Lay M. , Séguis L. , Kamagate B. , Depraetere C. 
Published: April 2010

Abstract. This study is part of the AMMA - African Multidisciplinary Monsoon Analysis- project and aims at a better understanding and modelling of the Donga catchment (580 km2, Benin) behaviour in order to determine its spatially distributed water balance. For this purpose, we applied the REW concept proposed by Reggiani et al. (1998, 1999), which allows the description of the main local processes at the sub-watershed scale. Such distributed hydrological models, which represent hydrological processes at various scales, should be evaluated not only on the discharge at the outlet but also on each of the represented processes and in several points of the catchment. This multi-criteria approach is required in order to assess the global behaviour of hydrological models. We applied such multi-criteria strategy to the Donga catchment (586 km2), in Benin. The work was supported by an observation set up, undertaken since 1998 consisting in a network of 20 rain gauges, an automatic meteorological station, 6 discharge stations and 18 wells. The main goal of this study was to assess the model's ability to reproduce the discharge at the outlet, the water table dynamics in several points of the catchment and the vadose zone dynamics at the sub-catchment scale. We tested two spatial discretisations of increasing resolution. To test the internal structure of the model, we looked at its ability to represent also the discharge at intermediate stations. After adjustment of soil parameters, the model is shown to accurately represent discharge down to a drainage area of 100 km2, whereas poorer simulation is achieved on smaller catchments. We introduced the spatial variability of rainfall by distributing the daily rainfall over the REW and obtained a very low sensitivity of the model response to this variability. Simulation of groundwater levels was poor and our results, in conjunction with new data available at the local scale, suggest that the representation of the processes in the unsaturated zone should first be improved, in order to better simulate soil water dynamics and represent perched water tables which were not included in this first modelling study.
Detecting the influence of land use changes on discharges and floods in the Meuse River Basin – the predictive power of a ninety-year rainfall-runoff relation?
Authors: Ashagrie A. G. , de Laat P. J. , de Wit M. J. , Tu M. , Uhlenbrook S. 
Published: April 2010

Abstract. Quantifying how changes in land use affect the hydrological response at the river basin scale is a current challenge in hydrological science. A daily discharge record (1911–2000) of the river Meuse (21 000 km2; Western Europe) has been simulated with a semi-distributed conceptual model (HBV). The model has been calibrated and validated with a data set for the period 1968–1998. In this study the performance of the model for the period prior to 1968 has been analysed. The observed and simulated discharge records are compared in terms of annual average discharge, summer and winter average discharge, annual maximum daily discharge, and annual maximum 10-day average discharge. The results are discussed with reference to land use change (i.e. forest type change) and shortcomings of the available precipitation and discharge records. The general agreement between the observed and simulated discharge records is good (Nash-Sutcliffe efficiency: 0.89–0.93), in particular flood volumes and the highest flood peaks are simulated well but the model has problems with the medium floods (shape and peak value). However, there are some systematic deviations between the observed and simulated discharges during specific periods. The simulation result could somewhat be improved by taking the historical land use into consideration. But the systematic overestimation of the discharge for the period 1933–1968 could not be attributed to observed changes in land use. It is concluded that the overall impact of land use changes in the Meuse basin is too small to be detected given the uncertainties in the available records.
Inverse distributed hydrological modelling of alpine catchments
Authors: Kunstmann H. , Krause J. , Mayr S. 
Published: April 2010

Abstract. Even in physically based distributed hydrological models, various remaining parameters must be estimated for each sub-catchment. This can involve tremendous effort, especially when the number of sub-catchments is large and the applied hydrological model is computationally expensive. Automatic parameter estimation tools can significantly facilitate the calibration process. Hence, we combined the nonlinear parameter estimation tool PEST with the distributed hydrological model WaSiM. PEST is based on the Gauss-Marquardt-Levenberg method, a gradient-based nonlinear parameter estimation algorithm. WaSiM is a fully distributed hydrological model using physically based algorithms for most of the process descriptions. WaSiM was applied to the alpine/prealpine Ammer River catchment (southern Germany, 710 km2) in a 100×100 m2 horizontal resolution. The catchment is heterogeneous in terms of geology, pedology and land use and shows a complex orography (the difference of elevation is around 1600 m). Using the developed PEST-WaSiM interface, the hydrological model was calibrated by comparing simulated and observed runoff at eight gauges for the hydrologic year 1997 and validated for the hydrologic year 1993. For each sub-catchment four parameters had to be calibrated: the recession constants of direct runoff and interflow, the drainage density, and the hydraulic conductivity of the uppermost aquifer. Additionally, five snowmelt specific parameters were adjusted for the entire catchment. Altogether, 37 parameters had to be calibrated. Additional a priori information (e.g. from flood hydrograph analysis) narrowed the parameter space of the solutions and improved the non-uniqueness of the fitted values. A reasonable quality of fit was achieved. Discrepancies between modelled and observed runoff were also due to the small number of meteorological stations and corresponding interpolation artefacts in the orographically complex terrain. A detailed covariance analysis was performed allowing to derive confidence bounds for all estimated parameters. The correlation between the estimated parameters was in most cases negligible, showing that parameters were estimated independently from each other.
Using the MESH modelling system for hydrological ensemble forecasting of the Laurentian Great Lakes at the regional scale
Authors: Pietroniro A. , Fortin V. , Kouwen N. , Neal C. , Turcotte R. , Davison B. , Verseghy D. , Soulis E. D. , Caldwell R. , Evora N. , Pellerin P. 
Published: April 2010

Abstract. Environment Canada has been developing a community environmental modelling system (Modélisation Environmentale Communautaire – MEC), which is designed to facilitate coupling between models focusing on different components of the earth system. The ultimate objective of MEC is to use the coupled models to produce operational forecasts. MESH (MEC – Surface and Hydrology), a configuration of MEC currently under development, is specialized for coupled land-surface and hydrological models. To determine the specific requirements for MESH, its different components were implemented on the Laurentian Great Lakes watershed, situated on the Canada–U.S. border. This experiment showed that MESH can help us better understand the behaviour of different land-surface models, test different schemes for producing ensemble streamflow forecasts, and provide a means of sharing the data, the models and the results with collaborators and end-users. This modelling framework is at the heart of a testbed proposal for the Hydrologic Ensemble Prediction Experiment (HEPEX) which should allow us to make use of the North American Ensemble Forecasting System (NAEFS) to improve streamflow forecasts of the Great Lakes tributaries, and demonstrate how MESH can contribute to a Community Hydrologic Prediction System (CHPS).
Biotic pump of atmospheric moisture as driver of the hydrological cycle on land
Authors: Makarieva A. M. , Gorshkov V. G. 
Published: April 2010

Abstract. In this paper the basic geophysical and ecological principles are jointly analyzed that allow the landmasses of Earth to remain moistened sufficiently for terrestrial life to be possible. 1. Under gravity, land inevitably loses water to the ocean. To keep land moistened, the gravitational water runoff must be continuously compensated by the atmospheric ocean-to-land moisture transport. Using data for five terrestrial transects of the International Geosphere Biosphere Program we show that the mean distance to which the passive geophysical air fluxes can transport moisture over non-forested areas, does not exceed several hundred kilometers; precipitation decreases exponentially with distance from the ocean. 2. In contrast, precipitation over extensive natural forests does not depend on the distance from the ocean along several thousand kilometers, as illustrated for the Amazon and Yenisey river basins and Equatorial Africa. This points to the existence of an active biotic pump transporting atmospheric moisture inland from the ocean. 3. Physical principles of the biotic moisture pump are investigated based on the previously unstudied properties of atmospheric water vapor, which can be either in or out of hydrostatic equilibrium depending on the lapse rate of air temperature. A novel physical principle is formulated according to which the low-level air moves from areas with weak evaporation to areas with more intensive evaporation. Due to the high leaf area index, natural forests maintain high transpiration fluxes, which support the ascending air motion over the forest and "suck in" moist air from the ocean, which is the essence of the biotic pump of atmospheric moisture. In the result, the gravitational runoff water losses from the optimally moistened forest soil can be fully compensated by the biotically enhanced precipitation at any distance from the ocean. 4. It is discussed how a continent-scale biotic water pump mechanism could be produced by natural selection acting on individual trees. 5. Replacement of the natural forest cover by a low leaf index vegetation leads to an up to tenfold reduction in mean continental precipitation and runoff, in contrast to the previously available estimates made without accounting for the biotic moisture pump. The analyzed body of evidence testifies that the long-term stability of an intense terrestrial water cycle is unachievable without the recovery of natural, self-sustaining forests on continent-wide areas.