50 research outputs found

    Downscaling of Precipitation in the Upper Danube Catchment Area

    Get PDF
    This work has been carried out in the framework of the project GLOWA-Danube (GLObal WAter cycle) where a joint effort is made by several groups to model the interaction of the water cycle and society in the Upper Danube catchment area. In particular regional climate models are used to simulate and eventually predict precipitation in this research area, while other groups convert this information into river runoff estimates and groundwater fluxes. It has been agreed in the project that precipitation data and other meteorological data must be handed over to the hydrological groups with a spatial resolution of 1 km. Long term runs with regional climate models are, however, not feasible at 1 km resolution, because they would exceed available computer resources by far. Therefore, a pragmatic downscaling method for precipitation must be implemented which provides data of 1 km resolution on the basis of model results of fairly coarse resolution. This downscaling uses extensively climatological precipitation observations where such downscaling relations can be derived. These observed rates are then adapted to the model results. The data are provided by the German Weather Service (DWD) and the Austrian Weather Service (ZAMG). The years 1991-2000 have been chosen as a reference period for the analysis. The climate simulation is carried out by the mesoscale model MM5 at a resolution of 45 km. The model MM5 offers a wide range of parameterizations with respect to convective processes, the boundary layer, cloud microphysics, and the radiation balance, all directly or indirectly responsible for generating precipitation. Sensitivity studies are performed to find the best configuration for the research area and reference period. A variety of methods is tested to generate observed and simulated climatological time series of precipitation. In particular, a linear average, a running average, a Fourier analysis, and spline interpolation are intercompared. In the end, spline interpolation between monthly values showed the best results for both time series and is used as a basis for the downscaling method. The downscaling method has to correct two major discrepancies between the observed precipitation distribution at the 1 km resolution and the simulated distribution at the 45 km resolution. First, these are small scale details related to topography in the rainfall distribution at the 1 km resolution, which lack in the 45 km resolution. Second, there is an unrealistic southward shift of the rainfall maximum at the northern rim of the Alps in the simulations, which needs to be corrected. A specific correction factor is introduced for each problem. The correlation between the spatial distribution of observed and simulated distributions increases after using the correction factors. Due to the climatological relationships, the results time periods of 10 days and longer are superior to those for periods shorter than 10 days. The precipitation distribution depends, of course, on the wind direction in particular so near the Alps. Wind direction and wind speed are simulated by the MM5 model and combined with the correction factors described above. The correlation between the spatial distribution of observed and simulated precipitation increases more if the wind direction dependent correction factors are introduced. These improved correction factors depend less on climatological relationships and perform therefore better for shorter time periods. Additionally, they will be able to respond better on changes in the weather regime in future climates. Altogether, this investigation provides a new pragmatic method to downscale model simulations on the basis of observations. This method will be used in the project GLOWA-Danube

    UTCI climatology and its future change in Germany – an RCM ensemble approach

    Get PDF
    n the present study, the quantity, duration and intensity of heat stress events in Germany as well as their future change and relation with weather types were investigated. A small ensemble of regional climate simulations with the regional climate model (RCM) COSMO-CLM driven by four general circulation models (GCMs) was used to calculate the Universal Thermal Climate Index (UTCI); the UTCI is a well-accepted thermal comfort index which we use here to quantify thermal stress. The variables entering the UTCI were bias corrected with a method that preserves their interdependencies. The projected climate changes cause a significant increase of both the mean UTCI and the number, duration and intensity of heat stress events between the control period (1981–2000) and the projection period (2031–2050). The projected future hourly frequency distribution of the UTCI at a location can be described by a shift to higher UTCI values with an almost constant shape of distribution. The investigations of the projected changes in weather types show no significant changes between the periods covered, with a few exceptions. An exception concerning heat stress events is the increase of summer anticyclonic weather types. Although more anticyclonic weather types in summer lead to an increase in heat stress events, they are not the primary cause of the projected increases. Rather, it turns out that the characteristics of the air masses associated with the weather types change towards warmer and more humid conditions

    Added Value of High-resolution Regional Climate Simulations for Regional Impact Studies

    Get PDF
    We present a comparison of results from the regional climate model COSMO-CLM at a horizontal resolution of 2.8 km with observations and assess the added value of such higher resolution compared to a coarser resolution of 7 km. Such an added value is expected to result from a better resolution of orography and land use as well as from direct simulation of deep convection.The simulations are driven by ERA40 reanalyses for the years 1971 to 2000 and cover southwestern Germany and parts of eastern France. We show that 2.8 km horizontal resolution simulations yield in many, but not all, cases a better agreement of temperature, precipitation, humidity, and global radiation with observation data than simulations with 7 km resolution, especially during the summer half year. At 2.8 km resolution, the model also is well able to capture the mechanisms generating small-scale features, e.g. wind systems. However, the added value is highly dependent on region and altitude. In general, we conclude that high-resolution climate modeling allows studying the impact of climatological parameters on regional scales. It produces encouraging results and has a high potential for applications and direct use in regional and local impact models and impact studies

    Factors of subjective heat stress of urban citizens in contexts of everyday life

    Get PDF
    Heat waves and the consequent heat stress of urban populations have a growing relevance in urban risk management and strategies of urban adaptation to climate change. In this context, social science studies on subjective experiencing of heat as stress by urban citizens are a new emerging field. To contribute to the understanding of selfreported subjective heat stress and its major determinants in a daily life perspective, we conducted a questionnaire survey with 323 respondents in Karlsruhe, Germany, after heat waves in July and August 2013. Statistical data analysis showed that subjective heat stress is an issue permeating everyday activities. Subjective heat stress at home was lower than at work and in general. Subjective heat stress in general, at home, and at work was determined by the health impairments experienced during the heat and the feeling of being helplessly exposed to the heat. For subjective heat stress at home, characteristics of the residential building and the built environment additionally played a role. Although the rate of implemented coping measures was rather high, coping measures showed no uniform effect for the subjective heat stress. We conclude that in terms of urban adaptation strategies, further research is needed to understand how various processes of daily social (work) life enable or limit individual coping and that communication strategies are important for building capacities to better cope with future heat waves

    Factors of subjective heat stress of urban citizens in contexts of everyday life

    Get PDF
    Heat waves and the consequent heat stress of urban populations have a growing relevance in urban risk management and strategies of urban adaptation to climate change. In this context, social science studies on subjective experiencing of heat as stress by urban citizens are a new emerging field. To contribute to the understanding of selfreported subjective heat stress and its major determinants in a daily life perspective, we conducted a questionnaire survey with 323 respondents in Karlsruhe, Germany, after heat waves in July and August 2013. Statistical data analysis showed that subjective heat stress is an issue permeating everyday activities. Subjective heat stress at home was lower than at work and in general. Subjective heat stress in general, at home, and at work was determined by the health impairments experienced during the heat and the feeling of being helplessly exposed to the heat. For subjective heat stress at home, characteristics of the residential building and the built environment additionally played a role. Although the rate of implemented coping measures was rather high, coping measures showed no uniform effect for the subjective heat stress. We conclude that in terms of urban adaptation strategies, further research is needed to understand how various processes of daily social (work) life enable or limit individual coping and that communication strategies are important for building capacities to better cope with future heat waves

    Tailoring Climate Parameters to Information Needs for Local Adaptation to Climate Change

    Get PDF
    Municipalities are important actors in the field of local climate change adaptation. Stakeholders need scientifically sound information tailored to their needs to make local assessment of climate change effects. To provide tailored data to support municipal decision-making, climate scientists must know the state of municipal climate change adaptation, and the climate parameters relevant to decisions about such adaptation. The results of an empirical study in municipalities in the state of Baden-Wuerttemberg in Southwestern Germany showed that adaptation is a relatively new topic, but one of increasing importance. Therefore, past weather events that caused problems in a municipality can be a starting point in adaptation considerations. Deduction of tailored climate parameters has shown that, for decisions on the implementation of specific adaptation measures, it also is necessary to have information on specific parameters not yet evaluated in climate model simulations. We recommend intensifying the professional exchange between climate scientists and stakeholders in collaborative projects with the dual goals of making practical adaptation experience and knowledge accessible to climate science, and providing municipalities with tailored information about climate change and its effects. View Full-Tex

    Cerebral near-infrared spectroscopy monitoring (NIRS) in children and adults: a systematic review with meta-analysis

    Full text link
    Background: Cerebral oxygenation monitoring utilising near-infrared spectroscopy (NIRS) is increasingly used to guide interventions in clinical care. The objective of this systematic review with meta-analysis and Trial Sequential Analysis is to evaluate the effects of clinical care with access to cerebral NIRS monitoring in children and adults versus care without. Methods: This review conforms to PRISMA guidelines and was registered in PROSPERO (CRD42020202986). Methods are outlined in our protocol (doi: 10.1186/s13643-021-01660-2). Results: Twenty-five randomised clinical trials were included (2606 participants). All trials were at a high risk of bias. Two trials assessed the effects of NIRS during neonatal intensive care, 13 during cardiac surgery, 9 during non-cardiac surgery and 1 during neurocritical care. Meta-analyses showed no significant difference for all-cause mortality (RR 0.75, 95% CI 0.51-1.10; 1489 participants; I2 = 0; 11 trials; very low certainty of evidence); moderate or severe, persistent cognitive or neurological deficit (RR 0.74, 95% CI 0.42-1.32; 1135 participants; I2 = 39.6; 9 trials; very low certainty of evidence); and serious adverse events (RR 0.82; 95% CI 0.67-1.01; 2132 participants; I2 = 68.4; 17 trials; very low certainty of evidence). Conclusion: The evidence on the effects of clinical care with access to cerebral NIRS monitoring is very uncertain. Impact: The evidence of the effects of cerebral NIRS versus no NIRS monitoring are very uncertain for mortality, neuroprotection, and serious adverse events. Additional trials to obtain sufficient information size, focusing on lowering bias risk, are required. The first attempt to systematically review randomised clinical trials with meta-analysis to evaluate the effects of cerebral NIRS monitoring by pooling data across various clinical settings. Despite pooling data across clinical settings, study interpretation was not substantially impacted by heterogeneity. We have insufficient evidence to support or reject the clinical use of cerebral NIRS monitoring

    Establishing a protocol for building a pan-Canadian population-based monitoring system for early childhood development for children with health disorders: Canadian Children's Health in Context Study (CCHICS)

    Get PDF
    Introduction Health disorders early in life have tremendous impact on children's developmental trajectories. Almost 80% of children with health disorders lack the developmental skills to take full advantage of school-based education relative to 27% of children without a health disorder. In Canada, there is currently a dearth of nationally representative data on the social determinants of early childhood development for children with health disorders. Evidence from Canada and other countries indicate t

    Alzheimer disease models and human neuropathology: similarities and differences

    Get PDF
    Animal models aim to replicate the symptoms, the lesions or the cause(s) of Alzheimer disease. Numerous mouse transgenic lines have now succeeded in partially reproducing its lesions: the extracellular deposits of Aβ peptide and the intracellular accumulation of tau protein. Mutated human APP transgenes result in the deposition of Aβ peptide, similar but not identical to the Aβ peptide of human senile plaque. Amyloid angiopathy is common. Besides the deposition of Aβ, axon dystrophy and alteration of dendrites have been observed. All of the mutations cause an increase in Aβ 42 levels, except for the Arctic mutation, which alters the Aβ sequence itself. Overexpressing wild-type APP alone (as in the murine models of human trisomy 21) causes no Aβ deposition in most mouse lines. Doubly (APP × mutated PS1) transgenic mice develop the lesions earlier. Transgenic mice in which BACE1 has been knocked out or overexpressed have been produced, as well as lines with altered expression of neprilysin, the main degrading enzyme of Aβ. The APP transgenic mice have raised new questions concerning the mechanisms of neuronal loss, the accumulation of Aβ in the cell body of the neurons, inflammation and gliosis, and the dendritic alterations. They have allowed some insight to be gained into the kinetics of the changes. The connection between the symptoms, the lesions and the increase in Aβ oligomers has been found to be difficult to unravel. Neurofibrillary tangles are only found in mouse lines that overexpress mutated tau or human tau on a murine tau −/− background. A triply transgenic model (mutated APP, PS1 and tau) recapitulates the alterations seen in AD but its physiological relevance may be discussed. A number of modulators of Aβ or of tau accumulation have been tested. A transgenic model may be analyzed at three levels at least (symptoms, lesions, cause of the disease), and a reading key is proposed to summarize this analysis
    corecore