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  • 1
    Language: English
    In: PLoS ONE, 01 January 2017, Vol.12(5), p.e0178165
    Description: Citizen science opens new pathways that can complement traditional scientific practice. Intuition and reasoning often make humans more effective than computer algorithms in various realms of problem solving. In particular, a simple visual comparison of spatial patterns is a task where humans are often considered to be more reliable than computer algorithms. However, in practice, science still largely depends on computer based solutions, which inevitably gives benefits such as speed and the possibility to automatize processes. However, the human vision can be harnessed to evaluate the reliability of algorithms which are tailored to quantify similarity in spatial patterns. We established a citizen science project to employ the human perception to rate similarity and dissimilarity between simulated spatial patterns of several scenarios of a hydrological catchment model. In total, the turnout counts more than 2500 volunteers that provided over 43000 classifications of 1095 individual subjects. We investigate the capability of a set of advanced statistical performance metrics to mimic the human perception to distinguish between similarity and dissimilarity. Results suggest that more complex metrics are not necessarily better at emulating the human perception, but clearly provide auxiliary information that is valuable for model diagnostics. The metrics clearly differ in their ability to unambiguously distinguish between similar and dissimilar patterns which is regarded a key feature of a reliable metric. The obtained dataset can provide an insightful benchmark to the community to test novel spatial metrics.
    Keywords: Sciences (General)
    E-ISSN: 1932-6203
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  • 2
    Language: English
    In: Journal of Hydrology, October 2015, Vol.529, pp.1754-1767
    Description: Soil moisture plays a key role in the water and energy balance in soil, vegetation and atmosphere systems. According to Wood et al. (2011) there is a grand need to increase global-scale hyper-resolution water–energy–biogeochemistry land surface modelling capabilities. These modelling capabilities should also recognize epistemic uncertainties, as well as the nonlinearity and hysteresis in its dynamics. Unfortunately, it is not clear how to parameterize hydrological processes as a function of scale, and how to test deterministic models with regard to epistemic uncertainties. In this study, high resolution long-term simulations were conducted in the highly instrumented TERENO hydrological observatory of the Wüstebach catchment. Soil hydraulic parameters were derived using inverse modelling with the Hydrus-1D model using the global optimization scheme SCE-UA and soil moisture data from a wireless soil moisture sensor network. The estimated parameters were then used for 3D simulations of water transport using the integrated parallel simulation platform ParFlow-CLM. The simulated soil moisture dynamics, as well as evapotranspiration (ET) and runoff, were compared with long-term field observations to illustrate how well the model was able to reproduce the water budget dynamics. We investigated different anisotropies of hydraulic conductivity to analyze how fast lateral flow processes above the underlying bedrock affect the simulation results. For a detail investigation of the model results we applied the empirical orthogonal function (EOF) and wavelet coherence methods. The EOF analysis of temporal–spatial patterns of simulated and observed soil moisture revealed that introduction of heterogeneity in the soil porosity effectively improves estimates of soil moisture patterns. Our wavelet coherence analysis indicates that wet and dry seasons have significant effect on temporal correlation between observed and simulated soil moisture and ET. Our study demonstrates the usefulness of the EOF and wavelet coherence methods for a more in-depth validation of spatially highly resolved hydrological 3D models.
    Keywords: 3d Hydrological Simulation ; Soil Moisture ; Eof Analysis ; Wavelet Coherence Analysis ; Geography
    ISSN: 0022-1694
    E-ISSN: 1879-2707
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  • 3
    Language: English
    In: Journal of Hydrology, February 2016, Vol.533, pp.234-249
    Description: The objective of this study is to inter-compare three spatially distributed hydrological models (HydroGeoSphere, MIKE SHE and ParFlow-CLM) by means of their ability to simulate soil moisture patterns. This study pools the catchment modeling efforts which have been undertaken at the Wüstebach catchment; one of TERENO’s hydrological observatories. The catchment is densely instrumented with a wireless sensor network (SoilNET) which allows continuous measurements of the spatio-temporal soil moisture dynamics. This unique dataset is ideal to benchmark hydrological models as it poses distinct challenges like seasonality and spatial heterogeneity. Two scenarios of soil parametrization assess the modeling implications of moving from homogeneous to heterogeneous porosity. The three given models perform well in terms of discharge and accumulated water balance components. However, their ability to predict soil moisture is found to be more diverging. Interpretations are ambiguous and depend on what performance metric and what level of spatial aggregation is chosen. In comparison to the other models, ParFlow-CLM performs more accurate at predicting the temporal dynamics and the heterogeneity aggregated to catchment scale. Nevertheless, at local scale HydroGeoSphere and MIKE SHE provide more detailed soil moisture predictions. Overall, a clear increase in performance can be attested to the scenario that includes heterogeneous porosity. Next to soil parametrization, topography is among the main drivers of soil moisture variability which was found to have an overemphasized feedback in ParFlow-CLM compared to the other models. This study stresses that further efforts toward spatially distributed input data need to emerge alongside a more suitable soil parametrization that can account for the observed heterogeneity and seasonality of soil moisture.
    Keywords: Distributed Hydrological Modeling ; Model Inter-Comparison ; Soil Moisture ; Spatial Patterns ; Soil Parametrization ; Spatial Model Evaluation ; Geography
    ISSN: 0022-1694
    E-ISSN: 1879-2707
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  • 4
    In: German Life and Letters, October 2018, Vol.71(4), pp.434-451
    Description: This article explores Paul Celan's poetics of the image. Beginning with a close analysis of his text ‘Edgar Jené. Der Traum vom Traume’, the article seeks to demonstrate that Celan's conception of the image is informed by a long theological and philosophical tradition of thinking about the image as constituted by ‘Urbild’ and ‘Abbild’. The article then traces attenuated elements of this discourse, as reformed by Celan's translation of the painter Jean Bazaine's writing on painting, and his own readings of Edmund Husserl's phenomenology, in his later poetological writings on the image surrounding his ‘Meridian’ speech. Dieser Beitrag untersucht den Bildbegriff in Paul Celans Poetik. Beginnend mit einer detaillierten Analyse seines Aufsatzes ‘Edgar Jené. Der Traum vom Traume’ demonstriert dieser Artikel, dass Celans Bildbegriff von einer langen theologischen und philosophischen Denktradition beeinflusst ist, welche das Bild zwischen Urbild und Abbild verhandelt. Im Anschluss weist der Artikel diesen Bilddiskurs in abgeschwächter Form in Celans späteren poetologischen Schriften im Umfeld der ‘Meridian’‐Rede nach, deren Bildbegriff zusätzlich durch Celans Übersetzung von Jean Bazaines Text zur Malerei und seine Lektüre von Edmund Husserls Phänomenologie beeinflusst ist.
    Keywords: Celan, Paul (1920-1970) ; Poetics ; Poetry ; Translations ; Image;
    ISSN: 0016-8777
    E-ISSN: 1468-0483
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  • 5
    In: Haseltonia, 2014, Vol.19(〈issue/〉), p.38-45
    Description: Abstract: Several studies have shown the interesting properties of Opuntia spp. (prickly pears), although most of this knowledge is based on O. ficus-indica. O. sulphurea is a species that is largely distributed in the Monte region of Argentina, where it has been used as an edible resource, especially in periods of food shortage. This is the first report evaluating the chemical composition of O. sulphurea cladodes. Our results show that cladodes are composed primarily of water, as with most other prickly pears that have been studied, which is consistent with their expected role as water reservoir in desert communities. Ash and protein content in O. sulphurea are consistent with values found for other species of the genus, whereas carbohydrates are well below levels of other Opuntia spp. Finally, the percentage of lipids in O. sulphurea cladodes is larger than in other studied species and fatty acid composition is quite different from observations made in similar studies. These earlier studies showed that linoleic acid is the major constituent of fatty acid fractions, followed by palmitic and oleic acids. Our analyses showed that these fatty acids are also principal constituents of O. sulphurea cladodes, although linolenic acid proved to be the most abundant. Curiously, the previous works found relatively low quantities of this fatty acid. Other minor fatty acids were also detected in cladodes of O. sulphurea, although the percentages are larger than in other studies of prickly pears. We discuss our results in the context of the potential nutraceutical and economic utility of O. sulphurea cladodes as a new source of essential fatty acids, especially in semi-arid areas as the Monte region where this species represents an abundant edible resource which is available even in periods of scarcity.
    Keywords: Prickly Pear ; Opuntia ; Nopal ; Nutritional Value ; Fatty Acids
    ISSN: 1070-0048
    E-ISSN: 19382898
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  • 6
    Language: English
    In: Cancer Research, 05/01/2015, Vol.75(9 Supplement), pp.P4-01-16-P4-01-16
    Keywords: Medicine;
    ISSN: 0008-5472
    E-ISSN: 1538-7445
    Source: CrossRef
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  • 7
    In: Advanced Functional Materials, February 2017, Vol.27(8), pp.n/a-n/a
    Description: A variety of new ternary and quaternary metal–semiconductor inorganic nanostructures with unprecedented structural morphologies is achieved by the decoration of five monolayer‐thick CdSe/CdS core/crown nanoplatelets with Au and Pt domains. Significant differences in metal growth behavior are observed by varying the CdSe core and the CdS crown dimensions. Depending on the core size, Au growth can be directed only to the CdS edges, or both at the edges and at the center of the nanoplatelets. In contrast, the nucleation of Pt domains always happens at the CdS edges independently of the core and crown dimensions. Furthermore, quaternary structures are obtained by additional Au growth on Pt‐decorated CdSe/CdS nanoplatelets, where the effect of steric hindrance of the existing Pt domains results in the Au nucleation to occur only at the CdSe core. Instead, a change in the order of growth of the two noble metals results in Pt‐Au alloys present only at the surrounding edges of the nanoplatelets. Additionally, the metal‐decorated nanoplatelets are found to be efficient catalysts for H fuel generation under white light irradiation. The highest apparent quantum efficiency measured is 19.3% ± 1.4% with a turnover frequency of ≈10 molecules of H per hour per nanoplatelet. are synthesized by growing Au and/or Pt domains on CdSe/CdS nanoplatelets of variable core and crown dimensions. The nanoplatelets are phase transferred to water and found to be an efficient catalyst for H fuel generation with compelling apparent quantum efficiency as high as ≈19.3% under white light illumination.
    Keywords: Charge Carrier Separation ; Core/Crown Nanoplatelets ; Metal–Semiconductor Inorganic Nanoplatelets ; Nanoheteroplatelets ; Photocatalytic Hydrogen Generation
    ISSN: 1616-301X
    E-ISSN: 1616-3028
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  • 8
    Language: English
    In: Hydrology and Earth System Sciences, Nov 30, 2017, Vol.21(12), p.5987
    Description: Distributed hydrological models are traditionally evaluated against discharge stations, emphasizing the temporal and neglecting the spatial component of a model. The present study widens the traditional paradigm by highlighting spatial patterns of evapotranspiration (ET), a key variable at the land-atmosphere interface, obtained from two different approaches at the national scale of Denmark. The first approach is based on a national water resources model (DK-model), using the MIKE-SHE model code, and the second approach utilizes a two-source energy balance model (TSEB) driven mainly by satellite remote sensing data. Ideally, the hydrological model simulation and remote-sensing-based approach should present similar spatial patterns and driving mechanisms of ET. However, the spatial comparison showed that the differences are significant and indicate insufficient spatial pattern performance of the hydrological model.The differences in spatial patterns can partly be explained by the fact that the hydrological model is configured to run in six domains that are calibrated independently from each other, as it is often the case for large-scale multi-basin calibrations. Furthermore, the model incorporates predefined temporal dynamics of leaf area index (LAI), root depth (RD) and crop coefficient (Kc) for each land cover type. This zonal approach of model parameterization ignores the spatiotemporal complexity of the natural system. To overcome this limitation, this study features a modified version of the DK-model in which LAI, RD and Kc are empirically derived using remote sensing data and detailed soil property maps in order to generate a higher degree of spatiotemporal variability and spatial consistency between the six domains. The effects of these changes are analyzed by using empirical orthogonal function (EOF) analysis to evaluate spatial patterns. The EOF analysis shows that including remote-sensing-derived LAI, RD and Kc in the distributed hydrological model adds spatial features found in the spatial pattern of remote-sensing-based ET.
    Keywords: Satellite Remote Sensing – Methods ; Pattern Recognition (Computers) – Methods ; Climate Models – Testing
    ISSN: 1027-5606
    ISSN: 16077938
    E-ISSN: 16077938
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  • 9
    Language: English
    In: Journal of Hydrometeorology, 04/2017, Vol.18(4), pp.1121-1142
    Description: Distributed hydrological models simulate states and fluxes of water and energy in the terrestrial hydrosphere at each cell. The predicted spatial patterns result from complex nonlinear relationships and feedbacks. Spatial patterns are often neglected during the modeling process, and therefore a spatial sensitivity analysis framework that highlights their importance is proposed. This study features a comprehensive analysis of spatial patterns of actual evapotranspiration (ET) and land surface temperature (LST), with the aim of quantifying the extent to which forcing data and model parameters drive these patterns. This framework is applied on a distributed model [MIKE Système Hydrologique Européen (MIKE SHE)] coupled to a land surface model [Shuttleworth and Wallace-Evapotranspiration (SW-ET)] of a catchment in Denmark. Twenty-two scenarios are defined, each having a simplified representation of a potential driver of spatial variability. A baseline model that incorporates full spatial detail is used to assess sensitivity. High sensitivity can be attested in scenarios where the simulated spatial patterns differ significantly from the baseline. The core novelty of this study is that the analysis is based on a set of innovative spatial performance metrics that enable a reliable spatial pattern comparison. Overall, LST is very sensitive to air temperature and wind speed whereas ET is rather driven by vegetation. Both are sensitive to groundwater coupling and precipitation. The conclusions may be limited to the selected catchment and to the applied modeling system, but the suggested framework is generically relevant for the modeling community. While the applied metrics focus on specific spatial information, they partly exhibit redundant information. Thus, a combination of metrics is the ideal approach to evaluate spatial patterns in models outputs.
    Keywords: Denmark ; Precipitation ; Spatial Analysis ; Precipitation ; Air Temperature ; Remote Sensing ; Business Metrics ; Sensitivity Analysis ; Groundwater ; Studies ; Vegetation ; Evapotranspiration ; Hydrology ; Hydrosphere ; Algorithms ; Terrestrial Environments ; Groundwater ; Climate Change ; Catchment Areas ; Catchments ; Sensitivity Analysis ; Bias ; Geology ; Analysis ; Tides ; Spatial Variations ; Sensitivity Analysis ; Air Temperature ; Catchment Models ; Groundwater ; Computer Simulation ; Spatial Data ; Framework ; Evapotranspiration ; Wind Speed ; Ground Water ; Land Surface Temperature ; Evapotranspiration ; Modelling ; Spatial Discrimination ; Modelling ; Performance Measurement ; Evapotranspiration ; Catchment Area ; Groundwater ; Fluxes ; Air Temperature ; Hydrologic Models ; Air Temperature ; Hydrosphere ; Surface Temperature ; Hydrology ; Wind Velocity ; Surface Temperature ; Sensitivity Analysis ; Precipitation ; Hydrosphere ; Wind Speed ; Evapotranspiration ; Land Surface Models ; Hydrologic Models ; Spatial Variability ; Atmosphere-Land Interaction ; Remote Sensing ; Sensitivity Studies ; Hydrologic Models ; Land Surface Model ; Model Output Statistics;
    ISSN: 1525-755X
    E-ISSN: 1525-7541
    Source: CrossRef
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  • 10
    Language: English
    In: Geoscientific Model Development Discussions, 11/23/2017, pp.1-25
    Description: The process of model evaluation is not only an integral part of model development and calibration but also of paramount importance when communicating modelling results to the scientific community and stakeholders. The modelling community has a large and well tested toolbox of metrics to evaluate temporal model performance. On the contrary, spatial performance evaluation is not corresponding to the grand availability of spatial observations readily available and to the sophisticate model codes simulating the spatial variability of complex earth system processes. This study makes a contribution towards advancing spatial pattern oriented model calibration by rigorously testing a multiple-component performance metric. The promoted SPAtial EFficiency (SPAEF) metric reflects three equally weighted components: correlation, coefficient of variation and histogram overlap. This multiple-component approach is found to be advantageous in order to achieve the complex task of comparing spatial patterns. SPAEF, its three components individually and two alternative spatial performance metrics, i.e. connectivity analysis and fractions skill score, are applied in a spatial pattern oriented model calibration of a catchment model in Denmark. Results suggest the importance of multiple-component metrics, because stand-alone metrics tend to fail to provide holistic pattern information to the optimizer. The three SPAEF components are found to be independent which allows them to complement each other in a meaningful way. In order to optimally exploit spatial observations made available by remote sensing platforms this study suggests applying bias insensitive metrics which further allow comparing variables which are related but may differ in unit. This study applies SPAEF in the hydrological context using the mesoscale Hydrologic Model (mHM; version 5.6), but we see great potential across disciplines related to spatial distributed earth system modelling.
    Keywords: Geology;
    ISSN: Geoscientific Model Development Discussions
    E-ISSN: 1991-962X
    Source: CrossRef
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