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Risk-based approaches have been increasingly accepted and operationalized in flood risk management during recent decades. For instance, commercial flood risk models are used by the insurance industry to assess potential losses, establish the pricing of policies and determine reinsurance needs. Despite considerable progress in the development of loss estimation tools since the 1980s, loss estimates still reflect high uncertainties and disparities that often lead to questioning their quality. This requires an assessment of the validity and robustness of loss models as it affects prioritization and investment decision in flood risk management as well as regulatory requirements and business decisions in the insurance industry. Hence, more effort is needed to quantify uncertainties and undertake validations. Due to a lack of detailed and reliable flood loss data, first order validations are difficult to accomplish, so that model comparisons in terms of benchmarking are essential. It is checked if the models are informed by existing data and knowledge and if the assumptions made in the models are aligned with the existing knowledge. When this alignment is confirmed through validation or benchmarking exercises, the user gains confidence in the models. Before these benchmarking exercises are feasible, however, a cohesive survey of existing knowledge needs to be undertaken. With that aim, this work presents a review of flood loss-or flood vulnerability-relationships collected from the public domain and some professional sources. Our survey analyses 61 sources consisting of publications or software packages, of which 47 are reviewed in detail. This exercise results in probably the most complete review of flood loss models to date containing nearly a thousand vulnerability functions. These functions are highly heterogeneous and only about half of the loss models are found to be accompanied by explicit validation at the time of their proposal. This paper exemplarily presents an approach for a quantitative comparison of disparate models via the reduction to the joint input variables of all models. Harmonization of models for benchmarking and comparison requires profound insight into the model structures, mechanisms and underlying assumptions. Possibilities and challenges are discussed that exist in model harmonization and the application of the inventory in a benchmarking framework.

Intergranular oxidation (IGO) of the Ni-based superalloy Inconel 718 was studied at 650 °C, 700 °C and 900 °C. The oxidized samples were characterized by X -ray diffraction and scanning electron microscopy. For all the studied temperatures, the external scale was mainly composed of Cr 2 O 3 , while the oxides along the grain boundaries were rich in Al and, to a minor extent, Ti. This was consistent with thermodynamic computations. The time evolution of the maximum depth of IGO was found to be parabolic with an apparent activation energy of 164 kJ/mol. The results of this study confirm with three temperatures that IGO kinetics can be described using an extension of the Wagner’s theory of internal oxidation, as recently suggested in the literature at 850 °C. According to this description, the mechanisms controlling the IGO kinetics of Inconel 718 are the aluminum diffusion in the alloy matrix and the oxygen diffusion along the interface between the alloy matrix and the oxidized grain boundary.

In order to construct physically based models of the mechanical response of metastable austenitic steels, one must know the load partitioning between the austenite and the strain-induced martensitic phases. While diffraction-based techniques have become common for such measurements, they often require access to large facilities. In this work, we have explored a simple magnetic technique capable of providing a measure of the stresses in an embedded ferromagnetic phase. This technique makes use of the coupling between the elastic strain and the magnetic response of the -martensite in an austenitic stainless steel undergoing straining. The magnetic technique proposed here is compared to neutron diffraction measurements made on the same material and is shown to give nearly identical results. The resulting predictions of the load partitioning to the -martensite phase suggest that deforms in a complex fashion, reflecting the fact that the microstructure is progressively transformed from austenite to martensite with straining. In particular, it is shown that the apparent hardening of the -martensite suggests elastic deformation as an important source of high macroscopic work-hardening rate in this material.

The latent heat flux over snow near Ny-Ålesund, Spitsbergen, was investigated for the 1999 snowmelt season to assess different methods of modelling the flux. Snow evaporation had hitherto been estimated as the residual of plot water balance calculations and was subject to measurement errors: hence a modelling solution was sought to make use of existing data. Precipitation, snow depth and albedo were measured daily. Runoff from the plots was recorded continuously. Wind speed, relative humidity and air temperature were measured at two levels (2 and 10 m) every 10 minutes; wind direction was noted hourly. Three models which simulate latent heat were assessed against evaporation and condensation measured by weighing several snow-filled containers each day. Two employ the bulk profile method (within the SNTHERM and CROCUS snowmelt models), while the third is the aerodynamic profile method (APM). Each follows the measured evaporation until snow-free patches develop after which the APM predicts evaporation whereas the snowmelt models predict condensation. The effect of wind is also noted. A major conclusion of this work is that the complexity of the land surface/atmosphere interactions, particularly when the snow cover breaks up, precludes the use of simple models for determining latent heat.

Hydrological models are powerful tools for the investigation of many hydrological issues. The historical approach for the development of rainfall-runoff models, with regard to the choice of model structure and the calibration of the free parameters, has been to focus on gauged catchments where sufficient data, in particular stream flow data, are available. Applications of models were then extended to the case of ungauged catchments. In recent years, it has become apparent that this approach did not lead to satisfying results in ungauged catchments, and that the main focus should instead be on ungauged catchments for the implementation of new modelling strategies. This thesis demonstrates the potential of a new conceptual, catchment-scale, semi-distributed, integrated rainfall-runoff model as a modelling tool in both ungauged and gauged catchments for the assessment of water resources management, land use change or climate changes at the catchment scale. The review of existing model structures and regionalisation methods has lead to the development of the Catchment Resources and Soil Hydrology (CRASH) model following the top-down modelling strategy. The free parameters of the model are directly related to controlling factors of the hydrological processes in the United Kingdom, i.e. soil and land use. The classification of the soils according to their hydrological behaviour is based on the Hydrology Of Soil Types (HOST) system. CRASH also incorporates a novel rainfall disaggregation scheme for the derivation of infiltration excess surface runoff. A regional set of model parameters has been derived from the calibration of CRASH in 32 catchments throughout England and Wales covering contrasting climatic, soil, geological, and land use conditions. The single-site and regional CRASH models performed satisfactorily according to reviewed performance criteria for gauged catchments and to a scoring system proposed for ungauged catchments. However the quality of stream flow data in the UK which was used for the calculation of the regional parameter set, in particular the widespread unavailability of naturalised flow data, tends to limit the performance of the regional CRASH model for low flows.

End-of-winter snow accumulation has been measured over large areas on Spitsbergen, Svalbard, using Ground Penetrating Radar (GPR) in the years of 1997, 1998, and 1999. Measuring transects following different latitudes reveal west-to-east and south-to-north gradients of snow accumulation. Generally, the east coast receives over 40% more snow (in water equivalent) than the west coast. A continental effect with lower accumulation rates can be seen in central parts of Spitsbergen at middle and northern latitudes. In the southern part of Spitsbergen accumulation rates are approximately twice as high as in the north. Elevation gradients of snow accumulation vary considerably, from –9 mm per 100 metre increase of elevation in the north-east to 258 mm/100 m in the central south. In average, the accumulation increases with 97 mm/100 m. Finally, accumulation rates close to the summit of Austfonna ice cap range from about 200 mm to 800 mm, i.e., with a factor of 4, over a few tens of kilometres. The average snow accumulation for all glacier localities measured on Spitsbergen (i.e., Austfonna excluded) for all three years is 590 mm.

End-of-winter snow accumulation has been measured over large areas on Spitsbergen, Svalbard, using Ground Penetrating Radar (GPR) in the years of 1997, 1998, and 1999. Measuring transects following different latitudes reveal west-to-east and south-to-north gradients of snow accumulation. Generally, the east coast receives over 40% more snow (in water equivalent) than the west coast. A continental effect with lower accumulation rates can be seen in central parts of Spitsbergen at middle and northern latitudes. In the southern part of Spitsbergen accumulation rates are approximately twice as high as in the north. Elevation gradients of snow accumulation vary considerably, from –9 mm per 100 metre increase of elevation in the north-east to 258 mm/100 m in the central south. In average, the accumulation increases with 97 mm/100 m. Finally, accumulation rates close to the summit of Austfonna ice cap range from about 200 mm to 800 mm, i.e., with a factor of 4, over a few tens of kilometres. The average snow accumulation for all glacier localities measured on Spitsbergen (i.e., Austfonna excluded) for all three years is 590 mm.

The mechanisms regulating myelin repair in the adult central nervous system (CNS) are unclear. Here, we identify DNA hydroxymethylation, catalyzed by the Ten-Eleven-Translocation (TET) enzyme TET1, as necessary for myelin repair in young adults and defective in old mice. Constitutive and inducible oligodendrocyte lineage-specific ablation of Tet1 (but not of Tet2 ), recapitulate this age-related decline in repair of demyelinated lesions. DNA hydroxymethylation and transcriptomic analyses identify TET1-target in adult oligodendrocytes, as genes regulating neuro-glial communication, including the solute carrier ( Slc ) gene family. Among them, we show that the expression levels of the Na + /K + /Cl − transporter, SLC12A2, are higher in Tet1 overexpressing cells and lower in old or Tet1 knockout. Both aged mice and Tet1 mutants also present inefficient myelin repair and axo-myelinic swellings. Zebrafish mutants for slc12a2b also display swellings of CNS myelinated axons. Our findings suggest that TET1 is required for adult myelin repair and regulation of the axon-myelin interface. Myelin formation is regulated by epigenetic mechanisms and ensures proper neuronal function during development and after demyelination. Here, the authors show that TET1, a DNA hydroxymethylase, regulates myelin repair in adult mice, but is defective with aging.