Mapping the vulnerability of European summer tourism under 2 °C global warming

Summer tourism is one of the most important contributors to the European GDP especially for the southern countries and is highly dependent on the climatic conditions. Changes in average climatic conditions, along with the potential subsequent changes in the physical environment, will pose stress on the favorability of the climate of European destinations for tourism and recreational activities. Here, we study the vulnerability of summer-oriented tourism due to a global temperature increase by 2 °C relative to the preindustrial era. We use a well-defined framework of exposure, sensitivity, and adaptive capacity indicators for a set of plausible climate (RCPs) and socioeconomic (SSPs) combinations. Our result shows that a 2 °C global warming will pose substantial changes to the vulnerability of the European tourism sector. Despite the general increase in exposure, the vulnerability of summer tourism is highly depended on the socioeconomic developments (SSPs). Although exposure is higher for most of the popular southern European destinations like Spain, France, South Italy, southernmost Greece, and Cyprus, they are expected to be less vulnerable than others, under specific SSPs, due to their higher capacity to adapt to a different climate. The capacity to adapt is lower for higher emission scenarios. Substantial changes are also apparent at the subnational level. Countries like France are foreseen to experience very diverse impacts and vulnerabilities within their own territories that will have consequences in terms of domestic tourism. The dynamics of these changes are expected to alter the state of the current European tourism regime.     

The simulation of European heat waves from an ensemble of regional climate models within the EURO-CORDEX project

The ability of a large ensemble of regional climate models to accurately simulate heat waves at the regional scale of Europe was evaluated. Within the EURO-CORDEX project, several state-of-the art models, including non-hydrostatic meso-scale models, were run for an extended time period (20 years) at high resolution (12 km), over a large domain allowing for the first time the simultaneous representation of atmospheric phenomena over a large range of spatial scales. Eight models were run in this configuration, and thirteen models were run at a classical resolution of 50 km. The models were driven with the same boundary conditions, the ERA-Interim re-analysis, and except for one simulation, no observations were assimilated in the inner domain. Results, which are compared with daily temperature and precipitation observations (ECA&D and E-OBS data sets) show that, even forced by the same re-analysis, the ensemble exhibits a large spread. A preliminary analysis of the sources of spread, using in particular simulations of the same model with different parameterizations, shows that the simulation of hot temperature is primarily sensitive to the convection and the microphysics schemes, which affect incoming energy and the Bowen ratio. Further, most models exhibit an overestimation of summertime temperature extremes in Mediterranean regions and an underestimation over Scandinavia. Even after bias removal, the simulated heat wave events were found to be too persistent, but a higher resolution reduced this deficiency. The amplitude of events as well as the variability beyond the 90th percentile threshold were found to be too strong in almost all simulations and increasing resolution did not generally improve this deficiency. Resolution increase was also shown to induce large-scale 90th percentile warming or cooling for some models, with beneficial or detrimental effects on the overall biases. Even though full causality cannot be established on the basis of this evaluation work, the drivers of such regional differences were shown to be linked to changes in precipitation due to resolution changes, affecting the energy partitioning. Finally, the inter-annual sequence of hot summers over central/southern Europe was found to be fairly well simulated in most experiments despite an overestimation of the number of hot days and of the variability. The accurate simulation of inter-annual variability for a few models is independent of the model bias. This indicates that internal variability of high summer temperatures should not play a major role in controlling inter-annual variability. Despite some improvements, especially along coastlines, the analyses conducted here did not allow us to generally conclude that a higher resolution is clearly beneficial for a correct representation of heat waves by regional climate models. Even though local-scale feedbacks should be better represented at high resolution, combinations of parameterizations have to be improved or adapted accordingly.     

Submarine channel initiation,filling and maintenance from sea‐floor geomorphology and morphodynamic modelling of cyclic steps

Advances in acoustic imaging of submarine canyons and channels have provided accurate renderings of sea‐floor geomorphology. Still, a fundamental understanding of channel inception, evolution, sediment transport and the nature of the currents traversing these channels remains elusive. Herein, Autonomous Underwater Vehicle technology developed by the Monterey Bay Aquarium Research Institute provides high‐resolution perspectives of the geomorphology and shallow stratigraphy of the San Mateo canyon‐channel system, which is located on a tectonically active slope offshore of southern California. The channel comprises a series of crescent‐shaped bedforms in its thalweg. Numerical modelling is combined with interpretations of sea‐floor and shallow subsurface stratigraphic imagery to demonstrate that these bedforms are likely to be cyclic steps. Submarine cyclic steps compose a morphodynamic feature characterized by a cyclic series of long‐wave, upstream‐migrating bedforms. The bedforms are cyclic steps if each bedform in the series is bounded by a hydraulic jump in an overriding turbidity current, which is Froude‐supercritical over the lee side of the bedform and Froude‐subcritical over the stoss side. Numerical modelling and seismic‐reflection imagery support an interpretation of weakly asymmetrical to near‐symmetrical aggradation of predominantly fine‐grained net‐depositional cyclic steps. The dominant mode of San Mateo channel maintenance during the Holocene is interpreted to be thalweg reworking into aggrading cyclic steps by dilute turbidity currents. Numerical modelling also suggests that an incipient, proto‐San Mateo channel comprises a series of relatively coarse‐grained net‐erosional cyclic steps, which nucleated out of sea‐floor perturbations across the tectonically active lower slope. Thus, the interaction between turbidity‐current processes and sea‐floor perturbations appears to be fundamentally important to channel initiation, particularly in high‐gradient systems. Offshore of southern California, and in analogous deep‐water basins, channel inception, filling and maintenance are hypothesized to be strongly linked to the development of morphodynamic instability manifested as cyclic steps.     

Application of a hydrometeorological model chain to investigate the effect of global boundaries and downscaling on simulated river discharge

In the current study, two regional climate models (MM5 and REMO) driven by different global boundary conditions (the ERA40 reanalysis and the ECHAM5 model) are one-way coupled to the uncalibrated hydrological process model PROMET to analyze the impact of global boundary conditions, dynamical regionalization and subsequent statistical downscaling (bilinear interpolation, correction of subgrid-scale variability and combined correction of subgrid-scale variability and bias) on river discharge simulation. The results of 12 one-way coupled model runs, set up for the catchment of the Upper Danube (Central Europe) over the historical period 1971–2000, prove the expectation that the global boundaries applied to force the RCMs strongly influence the accuracy of simulated river discharge. It is, however, noteworthy that all efficiency criteria in case of bias corrected MM5 simulations indicate better performance under ERA40 boundaries, whereas REMO-driven hydrological simulations better correspond to measured discharge under ECHAM5 boundaries. Comparing the hydrological results achievable with MM5 and REMO, the application of bias-corrected MM5 simulations turned out to allow for a more accurate simulation of discharge, while the variance in simulated discharge in most cases was better reflected in case of REMO forcings. The correction of subgrid-scale variability within the downscaling of RCM simulations compared to a bilinear interpolation allows for a more accurate simulation of discharge for all model configurations and all discharge criteria considered (mean monthly discharge, mean monthly low-flow and peak-flow discharge). Further improvements in the hydrological simulations could be achieved by eliminating the biases (in terms of deviations from observed meteorological conditions) inherent in the driving RCM simulations, regardless of the global boundary conditions or the RCM applied. In spite of all downscaling and bias correction efforts described, the RCM-driven hydrological simulations remain less accurate than those achievable with spatially distributed meteorological observations.     

Constraining input and output fluxes of the southern-central Chile subduction zone: water,chlorine and sulfur

In this paper, we constrain the input and output fluxes of H₂O, Cl and S into the southern-central Chilean subduction zone (31°S–46°S). We determine the input flux by calculating the amounts of water, chlorine and sulfur that are carried into the subduction zone in subducted sediments, igneous crust and hydrated lithospheric mantle. The applied models take into account that latitudinal variations in the subducting Nazca plate impact the crustal porosity and the degree of upper mantle serpentinization and thus water storage in the crust and mantle. In another step, we constrain the output fluxes of the subduction zone both to the subcontinental lithospheric mantle and to the atmosphere–geosphere–ocean by the combined use of gas flux determinations at the volcanic arc, volume calculations of volcanic rocks and the combination of mineralogical and geothermal models of the subduction zone. The calculations indicate that about 68 Tg/m/Ma of water enters the subduction zone, as averaged over its total length of 1,480 km. The volcanic output on the other hand accounts for 2 Tg/m/Ma or 3 % of that input. We presume that a large fraction of the volatiles that are captured within the subducting sediments (which accounts for roughly one-third of the input) are cycled back into the ocean through the forearc. This assumption is however questioned by the present lack of evidence for major venting systems of the submarine forearc. The largest part of the water that is carried into the subduction zone in the crust and hydrated mantle (accounting for two-thirds of the input) appears to be transported beyond the volcanic arc.     

Calcmylonites and solution transfer in a Devonian reef at Warstein,Germany

Massive limestone complexes of Late Palaeozoic age are scattered across the allochthonous foreland of the Hercynides in Germany. One of these complexes is situated at Warstein. Stratigraphic facies studies have represented the Warstein complex as a reef in a coastal shelf. Our study emphasizes that at least part of the reef consists of a pile of calcmylonites.The calcmylonites have a strong foliation (S_m) and lineation (L_m) and a structural asymmetry indicating non-coaxial deformation. X-ray textures and calcite microstructures show that the mylonitization involved intracrystalline deformation and dynamic recrystallization. These processes competed with solution transfer, as the mylonites are corroded at S_m-parallel stylolites and contain carbonate veins. Cathodoluminescopy shows that some veins are parallel to S_m and have been recrystallized, whereas others are normal to S_m and retain a fibrous crackseal microstructure. The latter type created limestones showing a pair of preferred grain boundary orientations; one normal to S_m, one in S_m. This orthogonal boundary fabric is distinct from crystalplastic fabrics: the latter show only one preferred grain boundary orientation (in S_m).

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Zusammenfassung Massenkalkkomplexe spätpaläozoischen Alters liegen verstreut über das allochthone Vorland des Variszischen Gebirges in Deutschland. Einer dieser Komplexe liegt bei Warstein. Stratigraphische Faziesstudien haben den Warsteiner Komplex als ein Riff in einem küstennahen Schelf dargestellt. Die vorliegende Arbeit betont, daß wenigstens ein Teil des Riffes aus einer Stapelung von Kalkmyloniten besteht.Die Kalkmylonite haben eine starke Foliation (S_m) und Lineation (L_m), und eine strukturelle Asymmetrie die auf nicht-koaxiale Verformung hinweist. Röntgentexturen und Calcitmikrostrukturen zeigen, daß die Mylonitisierung intrakristalline Verformung und dynamische Rekristallisation beinhaltet. Diese Prozesse müssen mit Lösungstransport konkurriert haben, da die Mylonite an S_m-parallelen Styloliten korrodiert sind und Karbonatgänge erhalten. Kathodolumineskopie zeigt, daß einige Gänge (parallel zu S_m) rekristallisiert sind, während andere (senkrecht zu S_m) eine faserige crack-seal Mikro-Struktur enthalten. Der letzte Typ ist verbunden mit Konformgefügen. Diese unterscheiden sich von kristallplastischen Kornformgefügen, da sie eine zweite bevorzugte Korngrenzorientierung aufweisen, die senkrecht zur ersten (in S_m) einfällt.

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Résumé Les complexes de calcaires massifs de l'Âge paléozoîque supérieure sont repandus sur l'avantpays allochthone des Hercynides en Allemagne. Un de ces complexes est situé à Warstein. Les Études de faciès stratigraphiques ont répresenté le complexe à Warstein comme un Récif littoral. Notre étude montre que au moins partie de ce «Récif» consiste en un empilement des calcmylonites.Les calcmylonites ont une foliation (S_m) et linéation (L_m) fort, et une asymmetrie structurale indiquant de la déformation non-coaxiale. Les textures röntgenographiques et les microstructures calcitiques montrent que la mylonitization était incluse de déformation intracristalline et récristallisation dynamique. Ces processus auront été en compétition avec dissolution-cristallization («solution transfer»), car les mylonites sont corrodées aux stylolites parallel à S_m et contient des veines carbonatiques. La cathodoluminescopie montre que quelques veines (parallel à S_m) sont récristallisées, pendant que les autres (perpendiculaire à S_m) ont retenu une microstructure fibreuse («crack-seal»). Le dernier type est lié avec des fabriques de forme des grains. Ils se sont distingués des fabriques de plasticité cristalline par la présence d'une deuxième orientation préférentielle des bordures des grains, perpendiculaire à la première (dans S_m).

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. Warstein'a. , . , , , »« . (S_m) (L_m), , . , - , . , .. , S_m, . , , S_m, , , S_m, = »crack-seal«. : , S_m.

     

GIS and Field‐Based Spatiotemporal Analysis for Evaluation of Paleo–Ice Sheet Simulations*

Reconstructing paleo–ice sheets is significant for paleoclimate reconstructions and evaluations of sea level low stands. Accurate reconstructions of paleo–ice sheet dimensions and dynamics necessitate the combination of field evidence and process modeling. In this study, a GIS‐based technique was developed to quantitatively assess model output against geomorphic data. However, implementation of this technique is not straightforward and requires consideration of time‐space relationships, data representation, resolution, and analytical design. Combined use of two software tools holds considerable promise for the use, application, and interpretation of refined ice sheet models.     

A new look at the Rockall region, offshore Ireland

A 700 km wide-angle reflection/refraction profile carried out in the central North Atlantic west of Ireland crossed the Erris Trough, Rockall Trough and Rockall Bank, and terminated in the western Hatton-Rockall Basin. The results reveal the presence of a number of sedimentary basins separated by basement highs. The Rockall Trough, with a sedimentary pile up to 5 km thick, is underlain by thinned continental crust 8–10 km thick. Some major fault block structures are identified, especially on the eastern margin of the Rockall Trough and in the adjacent Erris Trough. The Hatton-Rockall Basin is underlain by westward-thinning continental crust 22–10 km thick. Sedimentary strata are up to 5 km thick. The strata in the Rockall Trough and Hatton-Rockall Basin probably range in age from Late Palaeozoic to Cenozoic. However, the basins have different sedimentation histories and differ in structural style. The geometry of the crust and sediments suggests that the Rockall Trough originated by pure shear crustal stretching, associated with rift deposits and Cenozoic thermal sag strata. In contrast, the development of the Erris Trough, located on unthinned continental crust, was facilitated by shallow, brittle extension with little deep crustal attenuation. A two-layered crust occurs throughout the region. The lower crustal velocity in the Hatton-Rockall Basin is higher than that in the Rockall Trough. The velocity structure shows no indication of crustal underplating by upper mantle material in the region.     

On wave motions in a tropical spectral experiment

An attempt is made to use the barotropic vorticity equation in spectral form in order to study barotropic instability when the basic current has east-west quasi-stationary asymmetries on the scale of long waves. This is done by expressing the spectral equations in three different ways. In the first experiment a 9-component system is integrated and the long waves are allowed to propagate freely. In the second experiment the long waves are constrained to propagate slowly and in the third experiment, they are removed altogether.The motivation behind the present investigation is due to observations made in the motion fields of the tropics. These are characterized by quasi-stationary long waves and very energetically active and propagating short waves.The presence of quasi-stationary long waves seems to enhance the energy exchanges between the short waves and the mean zonal current and also allow for larger energy values for the short waves. Long term integration (90 days) shows a 6-day mode in thev time spectra at latitude 10°N and a 15-day mode in theu time spectra at individual grid points in the equatorial latitudes. Any possible connection between this peak and the observed peak of 15 days in the completely different physics of Kelvin waves is left as a conjecture.     

Low-cost water-lifting from groundwater sources: a comparison of the EMAS Pump with the Rope Pump

In sub-Saharan Africa, low-cost groundwater supply systems offer great opportunities for the current unserved population of >300 million to access drinking water. A comparative study was performed in Uganda of the EMAS Pump (designed by Escuela Móvil Aguas y Saneamiento Básico) with the trade-named Rope Pump, two low-cost manual water-lifting devices appropriate to pumping from shallow groundwater sources. Pumping rates, energy expended, material costs, and construction requirements were analyzed. Focus was on low-cost application for use in shallow groundwater systems at the household level in developing countries, particularly in sub-Saharan Africa. The study site was northern Uganda, with testing performed at several drilled boreholes. Two variants of each pump were tested by a male and female user, pumping from multiple static water-level depths ranging from 5 to 28 m. Results demonstrated the most common version of the EMAS Pump to perform similarly to the comparable version of the Rope Pump in terms of average pumping rate at depth range 5 to 18 m (93–111%), but less so at deeper depths (63–85%). Normalized pumping rates (considering energy expended) accentuated differences between these versions of the EMAS Pump and Rope Pump (47–97%). Cost of materials to construct the EMAS Pump were 21–60% those of the Rope Pump, and EMAS Pump construction requirements were also less. Based on the assessed factors, it is concluded that the EMAS Pump has potential for success in “self-supply” groundwater systems in sub-Saharan Africa and is particularly appropriate to link with low-cost shallow groundwater sources.