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Large earthquakes initiate chains of surface processes that last much longer than the brief moments of strong shaking. Most moderate‐ and large‐magnitude earthquakes trigger landslides, ranging from small failures in the soil cover to massive, devastating rock avalanches. Some landslides dam rivers and impound lakes, which can collapse days to centuries later, and flood mountain valleys for hundreds of kilometers downstream. Landslide deposits on slopes can remobilize during heavy rainfall and evolve into debris flows. Cracks and fractures can form and widen on mountain crests and flanks, promoting increased frequency of landslides that lasts for decades. More gradual impacts involve the flushing of excess debris downstream by rivers, which can generate bank erosion and floodplain accretion as well as channel avulsions that affect flooding frequency, settlements, ecosystems, and infrastructure. Ultimately, earthquake sequences and their geomorphic consequences alter mountain landscapes over both human and geologic time scales. Two recent events have attracted intense research into earthquake‐induced landslides and their consequences: the magnitude M 7.6 Chi‐Chi, Taiwan earthquake of 1999, and the M 7.9 Wenchuan, China earthquake of 2008. Using data and insights from these and several other earthquakes, we analyze how such events initiate processes that change mountain landscapes, highlight research gaps, and suggest pathways toward a more complete understanding of the seismic effects on the Earth's surface.
Speleothems, secondary cave carbonates, are important tools for climate reconstruction, especially as they often can be very precisely dated with the UTh method. If the U-Th method fails, dating becomes difficult, and often results in abandonment of samples and study sites. Radiocarbon dating is the only other radiometric dating technique applicable to the last similar to 50 ka, but presents complexities related to temporal variability of the reservoir effect in speleothems. Thus, radiocarbon dating of speleothems is not straightforward, and there are currently no publicly available tools to define proper age-depth relationships with this method. Here, we present an improved version of a previously published radiocarbon based age-depth modelling approach (star, Lechleitner et al., 2016b), which is now made freely available. The software is easy to use and provides the possibility to obtain reliable age-depth relationships, without prior knowledge of reservoir effects and their variability. In addition, star is able to detect and handle growth stops and phases with different growth rates. We test star on artificially constructed data sets and illustrate steps to improve the model performance. Furthermore, we apply the new approach to published radiocarbon data of U-Th dated stalagmites. This offers the possibility to investigate the strengths and weaknesses of the new approach with respect to potentially significant long term trends in the radiocarbon reservoir effect, which might otherwise remain undetected. In summary, we have produced a valuable software, which easily enables to construct age-depth relationships on the basis of reservoir effect disturbed radiocarbon measurements.
During the earliest Triassic microbial mats flourished in the photic zones of marginal seas, generating widespread microbialites. It has been suggested that anoxic conditions in shallow marine environments, linked to the end-Permian mass extinction, limited mat-inhibiting metazoans allowing for this microbialite expansion. The presence of a diverse suite of proxies indicating oxygenated shallow sea-water conditions (metazoan fossils, biomarkers and redox proxies) from microbialite successions have, however, challenged the inference of anoxic conditions. Here, the distribution and faunal composition of Griesbachian microbialites from China, Iran, Turkey, Armenia, Slovenia and Hungary are investigated to determine the factors that allowed microbialite-forming microbial mats to flourish following the end-Permian crisis. The results presented here show that Neotethyan microbial buildups record a unique faunal association due to the presence of keratose sponges, while the Palaeotethyan buildups have a higher proportion of molluscs and the foraminifera Earlandia. The distribution of the faunal components within the microbial fabrics suggests that, except for the keratose sponges and some microconchids, most of the metazoans were transported into the microbial framework via wave currents. The presence of both microbialites and metazoan associations were limited to oxygenated settings, suggesting that a factor other than anoxia resulted in a relaxation of ecological constraints following the mass extinction event. It is inferred that the end-Permian mass extinction event decreased the diversity and abundance of metazoans to the point of significantly reducing competition, allowing photosynthesis-based microbial mats to flourish in shallow water settings and resulting in the formation of widespread microbialites.
Influence of the Main Border Faults on the 3D Hydraulic Field of the Central Upper Rhine Graben
(2019)
The Upper Rhine Graben (URG) is an active rift with a high geothermal potential. Despite being a well-studied area, the three-dimensional interaction of the main controlling factors of the thermal and hydraulic regime is still not fully understood. Therefore, we have used a data-based 3D structural model of the lithological configuration of the central URG for some conceptual numerical experiments of 3D coupled simulations of fluid and heat transport. To assess the influence of the main faults bordering the graben on the hydraulic and the deep thermal field, we carried out a sensitivity analysis on fault width and permeability. Depending on the assigned width and permeability of the main border faults, fluid velocity and temperatures are affected only in the direct proximity of the respective border faults. Hence, the hydraulic characteristics of these major faults do not significantly influence the graben-wide groundwater flow patterns. Instead, the different scenarios tested provide a consistent image of the main characteristics of fluid and heat transport as they have in common: (1) a topography-driven basin-wide fluid flow perpendicular to the rift axis from the graben shoulders to the rift center, (2) a N/NE-directed flow parallel to the rift axis in the center of the rift and, (3) a pronounced upflow of hot fluids along the rift central axis, where the streams from both sides of the rift merge. This upflow axis is predicted to occur predominantly in the center of the URG (northern and southern model area) and shifted towards the eastern boundary fault (central model area).
Southern Patagonia is a prime example of ongoing oceanic ridge collision and slab-window formation sustained over several million years. The impact of these phenomena on the thermal structure and exhumation of the crust have been mainly assessed with low-temperature thermochronology of bedrock samples. Here, we infer thermal histories from new and existing thermochronological data from the region of most recent ridge collision. In particular, we evaluate the potential far-reaching thermal effects of the evolving slab window, which have previously been considered responsible for patterns of late Miocene reheating associated with back-arc alkaline volcanism. Our model results define protracted cooling since similar to 15 Ma and stepwise exhumation since the late Miocene. The pattern of stepwise exhumation closely matches the onset of Patagonian glaciation at 7 Ma and the successive pulse of glacial incision coeval with neotectonic activity since 3-4 Ma that are also documented by independent geological and geomorphological evidence in the region. Importantly, our findings challenge the recently suggested lack of glacial erosion and incision since 5 Ma in this region. Furthermore, in contrast to previous modelling studies, we find that the available data do not evidence a previously proposed northward-propagating heating event associated with alkaline volcanism. We hypothesize that the anomalous alkaline volcanism in the Patagonian back-arc might be related to trench-orthogonal tears aligned with transform faults in the subducting plate. The substantial differences from the previous modelling procedure on some of the same samples is demonstrated to result from an important lack of convergence in model runs. (C) 2019 Elsevier B.V. All rights reserved.
Geophysical data acquisition in oceanic domains is challenging, implying measurements with low and/or nonhomogeneous spatial resolution. The evolution of satellite gravimetry and altimetry techniques allows testing 3-D density models of the lithosphere, taking advantage of the high spatial resolution and homogeneous coverage of satellites. However, it is not trivial to discretise the source of the gravity field at different depths. Here, we propose a new method for inferring tectonic boundaries at the crustal level. As a novelty, instead of modeling the gravity anomalies and assuming a flat Earth approximation, we model the vertical gravity gradients (VGG) in spherical coordinates, which are especially sensitive to density contrasts in the upper layers of the Earth. To validate the methodology, the complex oceanic domain of the Caribbean region is studied, which includes different crustal domains with a tectonic history since Late Jurassic time. After defining a lithospheric starting model constrained by up-to-date geophysical data sets, we tested several a-priory density distributions and selected the model with the minimum misfits with respect to the VGG calculated from the EIGEN-6C4 data set. Additionally, the density of the crystalline crust was inferred by inverting the VGG field. Our methodology enabled us not only to refine, confirm, and/or propose tectonic boundaries in the study area but also to identify a new anomalous buoyant body, located in the South Lesser Antilles subduction zone, and high-density bodies along the Greater, Lesser, and Leeward Antilles forearcs.
Core Ideas
3D MRI relaxation time maps reflect water mobility in root, rhizosphere, and soil.
3D NCT water content maps of the same plant complement relaxation time maps.
The relaxation time T1 decreases from soil to root, whereas water content increases.
Parameters together indicate modification of rhizosphere pore space by gel phase.
The zone of reduced T1 corresponds to the zone remaining dry after rewetting.
In situ investigations of the rhizosphere require high‐resolution imaging techniques, which allow a look into the optically opaque soil compartment. We present the novel combination of magnetic resonance imaging (MRI) and neutron computed tomography (NCT) to achieve synergistic information such as water mobility in terms of three‐dimensional (3D) relaxation time maps and total water content maps. Besides a stationary MRI scanner for relaxation time mapping, we used a transportable MRI system on site in the NCT facility to capture rhizosphere properties before desiccation and after subsequent rewetting. First, we addressed two questions using water‐filled test capillaries between 0.1 and 5 mm: which root diameters can still be detected by both methods, and to what extent are defined interfaces blurred by these imaging techniques? Going to real root system architecture, we demonstrated the sensitivity of the transportable MRI device by co‐registration with NCT and additional validation using X‐ray computed tomography. Under saturated conditions, we observed for the rhizosphere in situ a zone with shorter T1 relaxation time across a distance of about 1 mm that was not caused by reduced water content, as proven by successive NCT measurements. We conclude that the effective pore size in the pore network had changed, induced by a gel phase. After rewetting, NCT images showed a dry zone persisting while the MRI intensity inside the root increased considerably, indicating water uptake from the surrounding bulk soil through the still hydrophobic rhizosphere. Overall, combining NCT and MRI allows a more detailed analysis of the rhizosphere's functioning.
Auf dem Gelände der Landesgartenschau 2018 in Würzburg untersuchte unsere Forschungsgruppe das Anpassungsverhalten der BesucherInnen an Hitze. Ziel war es herauszufinden, wie BesucherInnen von Großveranstaltungen Hitzetage erleben und wie sie sich während unterschiedlicher Wetterbedingungen verhalten. Auf Grundlage der Ergebnisse sollen Empfehlungen zur Förderung individuellen Anpassungsverhaltens bei Hitzebelastung an Veranstalter ausgesprochen werden. An sechs aufeinanderfolgenden Wochenenden im Juli und August führten wir Temperaturmessungen, Verhaltensbeobachtungen und Befragungen unter den BesucherInnen durch. Die Wetterlage an den zwölf Erhebungstagen fiel unterschiedlich aus: Es gab sechs Hitzetage mit Temperaturen über 30 °C, vier warme Sommertage und zwei kühle Regentage.
Es ließen sich unterschiedliche Anpassungsmaßnahmen bei den 2741 beobachteten BesucherInnen identifizieren. Hierzu gehören das Tragen von leichter oder kurzer Kleidung und von Kopfbedeckungen, das Mitführen von Getränken oder Schirmen sowie das Aufhalten im Schatten oder Abkühlen in einer Wasserfläche. Dabei fanden sich Unterschiede zwischen den verschiedenen Altersgruppen: Jüngere und Ältere hatten unterschiedliche Präferenzen für einzelne Anpassungsmaßnahmen. So suchten BesucherInnen über 60 Jahren bevorzugt Sitzplätze im Schatten auf, wohingegen sich Kinder zum Abkühlen in Wasserflächen aufhielten.
Die Befragung von 306 BesucherInnen ergab, dass Hitzetage als stärker belastend wahrgenommen wurden als Sommer- oder Regentage. Die Mehrheit zeigte zudem ein hohes Bewusstsein für die Thematik Hitzebelastung und Anpassung. Dies spiegelte sich aber nur bei einem Teil der Befragten in ihrem tatsächlich gezeigten Anpassungsmaßnahmen wider. Offizielle Hitzewarnungen des DWD waren den meisten BesucherInnen an Tagen mit ebendiesen nicht bekannt.
Auf Grundlage unserer Untersuchungsergebnisse empfehlen wir eine verbesserte Risikokommunikation in Bezug auf Hitze. Veranstalter und Behörden müssen zielgruppenspezifisch denken, wenn es um die Förderung von Hitzeanpassung geht. Angeraten werden u. a. die Schaffung von schattigen Sitzplätzen besonders für ältere BesucherInnen und Wasserstellen, an denen Kinder und Jugendliche spielen und sich erfrischen können. Da sich Hitzewellen in Zukunft häufen werden, dienen die Erkenntnisse dieser Untersuchung der Planung und Durchführung weiterer Open-Air-Veranstaltungen.
Meteoroids largely disintegrate during their entry into the atmosphere, contributing significantly to the input of cosmic material to Earth. Yet, their atmospheric entry is not well understood. Experimental studies on meteoroid material degradation in high-enthalpy facilities are scarce and when the material is recovered after testing, it rarely provides sufficient quantitative data for the validation of simulation tools. In this work, we investigate the thermochemical degradation mechanism of a meteorite in a high-enthalpy ground facility able to reproduce atmospheric entry conditions. A testing methodology involving measurement techniques previously used for the characterization of thermal protection systems for spacecraft is adapted for the investigation of ablation of alkali basalt (employed here as meteorite analog) and ordinary chondrite samples. Both materials are exposed to a cold-wall stagnation point heat flux of 1.2 MW m(-2). Numerous local pockets that formed on the surface of the samples by the emergence of gas bubbles reveal the frothing phenomenon characteristic of material degradation. Time-resolved optical emission spectroscopy data of ablated species allow us to identify the main radiating atoms and ions of potassium, calcium, magnesium, and iron. Surface temperature measurements provide maximum values of 2280 K for the basalt and 2360 K for the chondrite samples. We also develop a material response model by solving the heat conduction equation and accounting for evaporation and oxidation reaction processes in a 1D Cartesian domain. The simulation results are in good agreement with the data collected during the experiments, highlighting the importance of iron oxidation to the material degradation.
Humus forms are a distinctive morphological indicator of soil organic matter decomposition. The spatial distribution of humus forms depends on environmental factors such as topography, climate and vegetation. In montane and subalpine forests, environmental influences show a high spatial heterogeneity, which is reflected by a high spatial variability of humus forms. This study aims at examining spatial patterns of humus forms and their dependence on the spatial scale in a high mountain forest environment (Val di Sole/Val di Rabbi, Trentino, Italian Alps). On the basis of the distributions of environmental covariates across the study area, we described humus forms at the local scale (six sampling sites), slope scale (60 sampling sites) and landscape scale (30 additional sampling sites). The local variability of humus forms was analyzed with regard to the ground cover type. At the slope and landscape scale, spatial patterns of humus forms were modeled applying random forests and ordinary kriging of the model residuals. The results indicate that the occurrence of the humus form classes Mull, Mullmoder, Moder, Amphi and Eroded Moder generally depends on the topographical position. Local-scale patterns are mostly related to micro-topography (local accumulation and erosion sites) and ground cover, whereas slope-scale patterns are mainly connected with slope exposure and elevation. Patterns at the landscape scale show a rather irregular distribution, as spatial models at this scale do not account for local to slope-scale variations of humus forms. Moreover, models at the slope scale perform distinctly better than at the landscape scale. In conclusion, the results of this study highlight that landscape-scale predictions of humus forms should be accompanied by local- and slope-scale studies in order to enhance the general understanding of humus form patterns.
Land cover change is a dynamic phenomenon driven by synergetic biophysical and socioeconomic effects. It involves massive transitions from natural to less natural habitats and thereby threatens ecosystems and the services they provide. To retain intact ecosystems and reduce land cover change to a minimum of natural transition processes, a dense network of protected areas has been established across Europe. However, even protected areas and in particular the zones around protected areas have been shown to undergo land cover changes. The aim of our study was to compare land cover changes in protected areas, non-protected areas, and 1 km buffer zones around protected areas and analyse their relationship to climatic and socioeconomic factors across Europe between 2000 and 2012 based on earth observation data. We investigated land cover flows describing major change processes: urbanisation, afforestation, deforestation, intensification of agriculture, extensification of agriculture, and formation of water bodies. Based on boosted regression trees, we modelled correlations between land cover flows and climatic and socioeconomic factors. The results show that land cover changes were most frequent in 1 km buffer zones around protected areas (3.0% of all buffer areas affected). Overall, land cover changes within protected areas were less frequent than outside, although they still amounted to 18,800 km2 (1.5% of all protected areas) from 2000 to 2012. In some parts of Europe, urbanisation and intensification of agriculture still accounted for up to 25% of land cover changes within protected areas. Modelling revealed meaningful relationships between land cover changes and a combination of influencing factors. Demographic factors (accessibility to cities and population density) were most important for coarse-scale patterns of land cover changes, whereas fine-scale patterns were most related to longitude (representing the general east/west economic gradient) and latitude (representing the north/south climatic gradient).
Land cover change is a dynamic phenomenon driven by synergetic biophysical and socioeconomic effects. It involves massive transitions from natural to less natural habitats and thereby threatens ecosystems and the services they provide. To retain intact ecosystems and reduce land cover change to a minimum of natural transition processes, a dense network of protected areas has been established across Europe. However, even protected areas and in particular the zones around protected areas have been shown to undergo land cover changes. The aim of our study was to compare land cover changes in protected areas, non-protected areas, and 1 km buffer zones around protected areas and analyse their relationship to climatic and socioeconomic factors across Europe between 2000 and 2012 based on earth observation data. We investigated land cover flows describing major change processes: urbanisation, afforestation, deforestation, intensification of agriculture, extensification of agriculture, and formation of water bodies. Based on boosted regression trees, we modelled correlations between land cover flows and climatic and socioeconomic factors. The results show that land cover changes were most frequent in 1 km buffer zones around protected areas (3.0% of all buffer areas affected). Overall, land cover changes within protected areas were less frequent than outside, although they still amounted to 18,800 km2 (1.5% of all protected areas) from 2000 to 2012. In some parts of Europe, urbanisation and intensification of agriculture still accounted for up to 25% of land cover changes within protected areas. Modelling revealed meaningful relationships between land cover changes and a combination of influencing factors. Demographic factors (accessibility to cities and population density) were most important for coarse-scale patterns of land cover changes, whereas fine-scale patterns were most related to longitude (representing the general east/west economic gradient) and latitude (representing the north/south climatic gradient).
Most epiphytic bromeliads, especially those in the genus Tillandsia, lack functional roots and rely on the absorption of water and nutrients by large, multicellular trichomes on the epidermal surfaces of leaves and stems. Another important function of these structures is the spread of water over the epidermal surface by capillary action between trichome "wings" and epidermal surface. Although critical for the ultimate absorption by these plants, understanding of this function of trichomes is primarily based on light microscope observations. To better understand this phenomenon, the distribution of water was followed by its attenuation of cold neutrons following application of H2O to the cut end of Tillandsia usneoides shoots. Experiments confirmed the spread of added water on the external surfaces of this "atmospheric" epiphyte. In a morphologically and physiologically similar plant lacking epidermal trichomes, water added to the cut end of a shoot clearly moved via its internal xylem and not on its epidermis. Thus, in T. usneoides, water moves primarily by capillarity among the overlapping trichomes forming a dense indumentum on shoot surfaces, while internal vascular water movement is less likely. T. usneoides, occupying xeric microhabitats, benefits from reduction of water losses by low-shoot xylem hydraulic conductivities.
Proxy-based reconstructions and modeling of Holocene spatiotemporal precipitation patterns for China and Mongolia have hitherto yielded contradictory results indicating that the basic mechanisms behind the East Asian Summer Monsoon and its interaction with the westerly jet stream remain poorly understood. We present quantitative reconstructions of Holocene precipitation derived from 101 fossil pollen records and analyse them with the help of a minimal empirical model. We show that the westerly jet-stream axis shifted gradually southward and became less tilted since the middle Holocene. This was tracked by the summer monsoon rain band resulting in an early-Holocene precipitation maximum over most of western China, a mid-Holocene maximum in north-central and northeastern China, and a late-Holocene maximum in southeastern China. Our results suggest that a correct simulation of the orientation and position of the westerly jet stream is crucial to the reliable prediction of precipitation patterns in China and Mongolia.
Carbonate rocks, widely used for paleomagnetically quantifying the drift history of the Gondwana derived continental blocks of the Tibetan Plateau and evolution of the Paleo/Meso/Neo-Tethys Oceans, are prone to pervasive remagnetization. Identifying remagnetization is difficult because it is commonly undetectable through the classic paleomagnetic field tests. Here we apply comprehensive paleomagnetic, rock magnetic, and petrographic studies to upper Triassic limestones in the eastern Qiangtang block. Our results reveal that detrital/biogenic magnetite, which may carry the primary natural remanent magnetization (NRM), is rarely preserved in these rocks. In contrast, authigenic magnetite and hematite pseudomorphs after pyrite, and monoclinic pyrrhotite record three episodes of remagnetization. The earliest remagnetization was induced by oxidation of early diagenetic pyrite to magnetite, probably related to the collision between the northeastern Tibetan Plateau and the Qiangtang block after closure of the Paleo-Tethys Ocean in the Late Triassic. The second remagnetization, residing in hematite and minor goethite, which is the further subsurface oxidation product of pyrite/magnetite, is possibly related to the development of the localized Cenozoic basins soon after India-Asia collision in the Paleocene. The youngest remagnetization is a combination of thermoviscous and chemical remanent magnetization carried by authigenic magnetite and pyrrhotite, respectively. Our analyses suggest that a high supply of organic carbon during carbonate deposition, prevailing sulfate reducing conditions during early diagenesis, and widespread orogenic fluid migration related to crustal shortening during later diagenesis, have altered the primary remanence of the shallow-water Tethyan carbonate rocks of the Tibetan Plateau. We emphasize that all paleomagnetic results from these rocks must be carefully examined for remagnetization before being used for paleogeographic reconstructions. Future paleomagnetic investigations of the carbonate rocks in orogenic belts should be accompanied by thorough rock magnetic and petrographic studies to determine the origin of the NRM. (C) 2019 Elsevier B.V. All rights reserved.
Yukon’s Beaufort coast, Canada, is a highly dynamic landscape. Cultural sites, infrastructure, and travel routes used by the local population are particularly vulnerable to coastal erosion. To assess threats to these phenomena, rates of shoreline change for a 210 km length of the coast were analyzed and combined with socioeconomic and cultural information. Rates of shoreline change were derived from aerial and satellite imagery from the 1950s, 1970s, 1990s, and 2011. Using these data, conservative (S1) and dynamic (S2) shoreline projections were constructed to predict shoreline positions for the year 2100. The locations of cultural features in the archives of a Parks Canada database, the Yukon Archaeological Program, and as reported in other literature were combined with projected shoreline position changes. Between 2011 and 2100, approximately 850 ha (S1) and 2660 ha (S2) may erode, resulting in a loss of 45% (S1) to 61% (S2) of all cultural features by 2100. The last large, actively used camp area and two nearshore landing strips will likely be threatened by future coastal processes. Future coastal erosion and sedimentation processes are expected to increasingly threaten cultural sites and influence travelling and living along the Yukon coast.
Groundwater travel time distributions (TTDs) provide a robust description of the subsurface mixing behavior and hydrological response of a subsurface system. Lagrangian particle tracking is often used to derive the groundwater TTDs. The reliability of this approach is subjected to the uncertainty of external forcings, internal hydraulic properties, and the interplay between them. Here, we evaluate the uncertainty of catchment groundwater TTDs in an agricultural catchment using a 3-D groundwater model with an overall focus on revealing the relationship between external forcing, internal hydraulic properties, and TTD predictions. Eight recharge realizations are sampled from a high-resolution dataset of land surface fluxes and states. Calibration-constrained hydraulic conductivity fields (Ks fields) are stochastically generated using the null-space Monte Carlo (NSMC) method for each recharge realization. The random walk particle tracking (RWPT) method is used to track the pathways of particles and compute travel times. Moreover, an analytical model under the random sampling (RS) assumption is fit against the numerical solutions, serving as a reference for the mixing behavior of the model domain. The StorAge Selection (SAS) function is used to interpret the results in terms of quantifying the systematic preference for discharging young/old water. The simulation results reveal the primary effect of recharge on the predicted mean travel time (MTT). The different realizations of calibration-constrained Ks fields moderately magnify or attenuate the predicted MTTs. The analytical model does not properly replicate the numerical solution, and it underestimates the mean travel time. Simulated SAS functions indicate an overall preference for young water for all realizations. The spatial pattern of recharge controls the shape and breadth of simulated TTDs and SAS functions by changing the spatial distribution of particles' pathways. In conclusion, overlooking the spatial nonuniformity and uncertainty of input (forcing) will result in biased travel time predictions. We also highlight the worth of reliable observations in reducing predictive uncertainty and the good interpretability of SAS functions in terms of understanding catchment transport processes.
Cash vs. in-kind transfers
(2019)
Historically, India has relied on subsidizing staple food as a major instrument in improving food security. Recently, however, cash transfers have entered the debate as an alternative, as they are associated with lower market distortions, leakages and fiscal costs. This study contributes to this debate by analyzing India’s Targeted Public Distribution System (TPDS). Our main objective was to explain the under-purchase, or low take-up, from the TPDS, which is typically attributed to ‘leakage’, i.e. the diversion of food grains from eligible consumers. We provide an alternative solution based on self-targeting; while poorer households increase their consumption from the TPDS, wealthier households restrain from consuming subsidized commodities. Using a large household dataset, we estimated that such a voluntary opt-out system, based on income, would save a minimum of 6.5% of grains released through the TPDS. Besides these demand-driven aspects, our analysis indicates that poor regions perform better at lowering the diversion of grains and that large targeting errors exist among female-led households. Finally, we find substantial regional price differences that would benefit the poor and rural population under a uniform cash-transfer system that does not correct for regional price levels.