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The diurnal cycle of both air temperature and wind speed is characterized by considerable differences, when comparing open site conditions to forests. In the course of this article, a new two-hourly, open-source dataset, covering a high spatial and temporal variability, is presented and analyzed. It contains air temperature measurements (128 station pairs (open/forest); six winter seasons; six study sites), wind speed measurements (64 station pairs; three winter seasons, four study sites) and related metadata in central Europe. Daily cycles of air temperature and wind speed, as well as further dependencies of the effective Leaf Area Index (effective LAI), the exposure in the context of forest effects, and the distance to the forest edge, are illustrated in this paper. The forest effects on air temperature can be seen particularly with increasing canopy density, in southern exposures, and in the late winter season, while wind speed depends on multiple factors such as effective LAI or the distance to the forest edge. New transfer functions, developed using linear and non-linear regression analysis, in a leave-one-out cross-validation, improve certain efficiency criteria (NSME; r2; RMSE; MAE) compared to existing transfer functions. The dataset enables multiple purposes and capabilities due to its diversity and sample size.
Michael Klein; Jakob Garvelmann; Kristian Förster. Revisiting Forest Effects on Winter Air Temperature and Wind Speed—New Open Data and Transfer Functions. Atmosphere 2021, 12, 710 .
AMA StyleMichael Klein, Jakob Garvelmann, Kristian Förster. Revisiting Forest Effects on Winter Air Temperature and Wind Speed—New Open Data and Transfer Functions. Atmosphere. 2021; 12 (6):710.
Chicago/Turabian StyleMichael Klein; Jakob Garvelmann; Kristian Förster. 2021. "Revisiting Forest Effects on Winter Air Temperature and Wind Speed—New Open Data and Transfer Functions." Atmosphere 12, no. 6: 710.
Glaciers fulfil several important roles in the earth system, including being clear indicators of climate change and providing essential freshwater storage and downstream runoff to 22% of the global population. In addition, they are the main contributors to sea level rise and are expected to remain so throughout the 21st Century. In order to monitor glacier development, observing and predicting glacier mass balance on different spatial and temporal scales is essential. The current study aims to improve the understanding of glacier mass balance prediction on the decadal scale (5-15 years), a rarely studied time scale in the context of glaciers, but if reliable, highly applicable for glacier related water resource management and sea level rise predictions. This is achieved through the use of CMIP5 decadal climate prediction multi-model ensembles (reforecasts) to force the mass balance component of the Open Global Glacier Model (OGGM). This method is applied to 254 reference glaciers, distributed throughout 17 of the 19 Randolph Glacier Inventory (RGI) regions. The reforecasts are initialized in 1960 and 1980 and bias corrected to the glacier scale. The following statistical analysis then gives a good indication of the skill of climate reforecasts in mass balance modelling on this glacier atypical time scale.
Larissa van der Laan; Kristian Förster; Fabien Maussion; Adam Scaife. Using a CMIP5 multi-model ensemble to model glacier mass balance on decadal scales. 2021, 1 .
AMA StyleLarissa van der Laan, Kristian Förster, Fabien Maussion, Adam Scaife. Using a CMIP5 multi-model ensemble to model glacier mass balance on decadal scales. . 2021; ():1.
Chicago/Turabian StyleLarissa van der Laan; Kristian Förster; Fabien Maussion; Adam Scaife. 2021. "Using a CMIP5 multi-model ensemble to model glacier mass balance on decadal scales." , no. : 1.
Hydro-morphodynamic models are increasingly popular for predicting sedimentation processes in reservoirs. To leverage the accuracy of such models, their boundary conditions have to be defined as precise as possible. While hydrological models provide efficient routines to establish inflow hydrographs at the model boundaries, the determination of the sediment input is challenging and involves large uncertainties. This study identifies prominent parameters that influence the sediment input into a reservoir, and therefore, expected sedimentation rates. For this purpose, erosion and transport processes in the catchment area of the Banja Reservoir (Albania) are analyzed.
The Banja Reservoir is located on the Devoll River in the Southeast of Albania and has a storage capacity of 400 Million m³. The catchment area has a size of 2,900 km² and lies in a mountainous region. The climate is characterized by dry and hot summers and humid winters. There are significant differences in precipitation patterns in the catchment due to topographical conditions and with increasing distance from the coast in the West of the reservoir. Because snowfall is frequent in winter, the runoff regime of the Devoll River and its tributaries is driven by precipitation and snowmelt.
To calculate the sediment input at the inflow boundaries of the reservoir, a comprehensive analysis in combination with hydrological modelling of the catchment is indispensable. This study applies the Revised Universal Soil Loss Equation (RUSLE) model coupled with the SEdiment Delivery Distributed (SEDD) model, as an integrated approach that bridges interdisciplinary expertise in geomorphology and hydrology. Since measured precipitation data neither fulfils minimum requirements in terms of spatio-temporal resolution nor in terms of time series length, the ERA5 reanalysis dataset is used as input data. The coupled model is calibrated with suspended sediment data measured at a monitoring station upstream of the reservoir over a 2–years period. The model enables to approximate the monthly or annual sediment load for any point in the river network. Thus, the sediment load into the reservoir can be assessed for every major tributary, even in areas with limited data availability. In addition, a high spatial resolution (25 m x 25 m) of the model enables the identification of areas that cause particularly high sediment loads.
The optimized coupled model predicts sediment loads that are in good agreement with sediment loads measured at the monitoring station (Nash-Sutcliffe efficiency: NSEannual = 0.96; NSEmonthly = 0.81). Consequently, climate reanalysis datasets are a viable alternative in regions with data scarcity. Furthermore, the spatial representation of the results suggests that the sediment load into the reservoir mainly originates from steep and sparsely vegetated or agricultural areas close to the river network. Intensive rainfall additionally fosters erosion, which is why erosion rates are higher in the Western part of the catchment area.
Kilian Mouris; Sebastian Schwindt; Stefan Haun; Maria Herminia Pesci; Kristian Förster; Nils Rüther; Kordula Schwarzwälder; Silke Wieprecht. Climate reanalysis data with global coverage enable sediment load prediction in the absence of systematic field data. 2021, 1 .
AMA StyleKilian Mouris, Sebastian Schwindt, Stefan Haun, Maria Herminia Pesci, Kristian Förster, Nils Rüther, Kordula Schwarzwälder, Silke Wieprecht. Climate reanalysis data with global coverage enable sediment load prediction in the absence of systematic field data. . 2021; ():1.
Chicago/Turabian StyleKilian Mouris; Sebastian Schwindt; Stefan Haun; Maria Herminia Pesci; Kristian Förster; Nils Rüther; Kordula Schwarzwälder; Silke Wieprecht. 2021. "Climate reanalysis data with global coverage enable sediment load prediction in the absence of systematic field data." , no. : 1.
In increasingly expanding cities, roofs are still largely unused areas to counteract the negative impacts of urbanization on the water balance and to reduce flooding. To estimate the effect of green roofs as a sustainable low impact development (LID) technique on the building scale, different approaches to predict the runoff are carried out. In hydrological modelling, representing vegetation feedback on evapotranspiration (ET) is still considered challenging. In this research article, the focus is on improving the representation of the coupled soil–vegetation system of green roofs. Relevant data to calibrate and validate model representations were obtained from an existing field campaign comprising several green roof test plots with different characteristics. A coupled model, utilizing both the Penman–Monteith equation to estimate ET and the software EPA stormwater management model (SWMM) to calculate the runoff, was set up. Through the application of an automatic calibration procedure, we demonstrate that this coupled modelling approach (Kling–Gupta efficiency KGE = 0.88) outperforms the standard ET representation in EPA SWMM (KGE = −0.35), whilst providing a consistent and robust parameter set across all green roof configurations. Moreover, through a global sensitivity analysis, the impact of changes in model parameters was quantified in order to aid modelers in simplifying their parameterization of EPA SWMM. Finally, an improved model using the Penman–Monteith equation and various recommendations are presented.
Ronja Iffland; Kristian Förster; Daniel Westerholt; María Pesci; Gilbert Lösken. Robust Vegetation Parameterization for Green Roofs in the EPA Stormwater Management Model (SWMM). Hydrology 2021, 8, 12 .
AMA StyleRonja Iffland, Kristian Förster, Daniel Westerholt, María Pesci, Gilbert Lösken. Robust Vegetation Parameterization for Green Roofs in the EPA Stormwater Management Model (SWMM). Hydrology. 2021; 8 (1):12.
Chicago/Turabian StyleRonja Iffland; Kristian Förster; Daniel Westerholt; María Pesci; Gilbert Lösken. 2021. "Robust Vegetation Parameterization for Green Roofs in the EPA Stormwater Management Model (SWMM)." Hydrology 8, no. 1: 12.
Glacio-hydrological models combine both glacier and catchment hydrology modeling and are used to assess the hydrological response of high-mountain glacierized catchments to climate change. To capture the uncertainties from these model combinations, it is essential to compare the outcomes of several model entities forced with the same climate projections. For the first time, we compare the results of two completely independent glacio-hydrological models: (i) HQsim-GEM and (ii) AMUNDSEN. In contrast to prevailing studies, we use distinct glacier models and glacier initialization times. At first glance, the results achieved for future glacier states and hydrological characteristics in the Rofenache catchment in Ötztal Alps (Austria) appear to be similar and consistent, but a closer look reveals clear differences. What can be learned from this study is that low-complexity models can achieve higher accuracy in the calibration period. This is advantageous especially when data availability is weak, and priority is given to efficient computation time. Furthermore, the time and method of glacier initialization play an important role due to different data requirements. In essence, it is not possible to make conclusions about the model performance outside of the calibration period or more specifically in the future. Hence, similar to climate modeling, we suggest considering different modeling approaches when assessing future catchment discharge or glacier evolution. Especially when transferring the results to stakeholders, it is vital to transparently communicate the bandwidth of future states that come with all model results.
Elena Stoll; Florian Hanzer; Felix Oesterle; Johanna Nemec; Johannes Schöber; Matthias Huttenlau; Kristian Förster. What Can We Learn from Comparing Glacio-Hydrological Models? Atmosphere 2020, 11, 981 .
AMA StyleElena Stoll, Florian Hanzer, Felix Oesterle, Johanna Nemec, Johannes Schöber, Matthias Huttenlau, Kristian Förster. What Can We Learn from Comparing Glacio-Hydrological Models? Atmosphere. 2020; 11 (9):981.
Chicago/Turabian StyleElena Stoll; Florian Hanzer; Felix Oesterle; Johanna Nemec; Johannes Schöber; Matthias Huttenlau; Kristian Förster. 2020. "What Can We Learn from Comparing Glacio-Hydrological Models?" Atmosphere 11, no. 9: 981.
Flood risk assessment is an important prerequisite for risk management decisions. To estimate the risk, i.e. the probability of damage, flood damage needs to be either systematically recorded over a long period or modelled for a series of synthetically generated flood events. Since damage records are typically rare, time series of plausible, spatially coherent event precipitation or peak discharges need to be generated to drive the chain of process models. In the present study, synthetic flood events are generated by two different approaches to modelling flood risk in a meso-scale alpine study area (Vorarlberg, Austria). The first approach is based on the semi-conditional multi-variate dependence model applied to discharge series. The second approach relies on the continuous hydrological modelling of synthetic meteorological fields generated by a multi-site weather generator and using an hourly disaggregation scheme. The results of the two approaches are compared in terms of simulated spatial patterns of peak discharges and overall flood risk estimates. It could be demonstrated that both methods are valid approaches for risk assessment with specific advantages and disadvantages. Both methods are superior to the traditional assumption of a uniform return period, where risk is computed by assuming a homogeneous return period (e.g. 100-year flood) across the entire study area.
Benjamin Winter; Klaus Schneeberger; Kristian Förster; Sergiy Vorogushyn. Event generation for probabilistic flood risk modelling: multi-site peak flow dependence model vs. weather-generator-based approach. Natural Hazards and Earth System Sciences 2020, 20, 1689 -1703.
AMA StyleBenjamin Winter, Klaus Schneeberger, Kristian Förster, Sergiy Vorogushyn. Event generation for probabilistic flood risk modelling: multi-site peak flow dependence model vs. weather-generator-based approach. Natural Hazards and Earth System Sciences. 2020; 20 (6):1689-1703.
Chicago/Turabian StyleBenjamin Winter; Klaus Schneeberger; Kristian Förster; Sergiy Vorogushyn. 2020. "Event generation for probabilistic flood risk modelling: multi-site peak flow dependence model vs. weather-generator-based approach." Natural Hazards and Earth System Sciences 20, no. 6: 1689-1703.
Due to data availability long-term variations in precipitation rates are mostly studied based on daily precipitation recordings. Recent research suggests, however, that variations in sub-daily precipitation are subject to higher dynamics compared to daily precipitation and a more rapid intensification is likely. Here we show that both observational data with at least 58 years of sub-daily precipitation records and a dynamical downscaling approach with low spatial resolution based on atmospheric re-analysis data confirm these expectations with consistent results. High percentiles of precipitation are subject to multi-decadal oscillations and increased during the last 150 years. We found an increase of 4% K−1 (daily), 12% K−1 (hourly), and 13% K−1 (10 min), which is consistent with Clausius–Clapeyron- (CC) and super CC-scaling, respectively. These findings highlight that dynamical downscaling can help to reliably shed light on sub-daily precipitation variations if small timescales are considered in the experiments.
Kristian Förster; Luisa-Bianca Thiele. Variations in sub-daily precipitation at centennial scale. npj Climate and Atmospheric Science 2020, 3, 1 .
AMA StyleKristian Förster, Luisa-Bianca Thiele. Variations in sub-daily precipitation at centennial scale. npj Climate and Atmospheric Science. 2020; 3 (1):1.
Chicago/Turabian StyleKristian Förster; Luisa-Bianca Thiele. 2020. "Variations in sub-daily precipitation at centennial scale." npj Climate and Atmospheric Science 3, no. 1: 1.
In order to assess glacier mass balance on large temporal and/or spatial scales, numerical modelling is an essential tool, complementing ground observations and remote sensing methods. For a reliable simulation of a glacier’s development over time, knowledge of its initial state is fundamental. Attaining this information entirely through empirical evidence is impossible due to a lack of data, hence the need for alternative, numerical methods. In this study, three methods of varying complexity are applied to initialize the Open Global Glacier Model (OGGM) for 254 glaciers. These glaciers have a minimum of 5 years of in-situ mass balance observations, allowing for direct comparison with modelled values. The initialization methods comprise, in brief, i) a basic spin-up, starting from present-day conditions, running the model for 200 years with a random climate, representative of the period 1900-2000 ii) a cold climate spin-up, allowing the glacier to grow and create a more representative initial condition for e.g. the year 1901 and iii) a synthetic experiment based on present day glacier observations and past climate information, used to generate a large set of physically plausible initial states, which are then evaluated. Using each method, we reconstruct the glaciers’ initial states and set up a forward run from which to extract mass balance values over the time period 1970-2014, used for validation purposes. The overall aim is to identify an initialization approach that can be successfully applied to our current set of 254 glaciers, as well as areas with even sparser data available, expanding the range of scale for glacier modelling.
Larissa Van Der Laan; Julia Eis; Kristian Förster; Ben Marzeion. Comparison of methods for initialization of the Open Global Glacier Model (OGGM). 2020, 1 .
AMA StyleLarissa Van Der Laan, Julia Eis, Kristian Förster, Ben Marzeion. Comparison of methods for initialization of the Open Global Glacier Model (OGGM). . 2020; ():1.
Chicago/Turabian StyleLarissa Van Der Laan; Julia Eis; Kristian Förster; Ben Marzeion. 2020. "Comparison of methods for initialization of the Open Global Glacier Model (OGGM)." , no. : 1.
The need for effective water resources management has turned into a major challenge, especially in the face of climate change. Meteorological data is not always readily available and thus the task of predicting the response of hydrological systems becomes complicated. For this reason, climate reanalysis datasets are used as a viable alternative. They combine models with data from satellites and ground sensors and provide consistent long-term meteorological conditions with high temporal resolution. The ERA5 reanalysis dataset was produced and is continuously updated by the European Centre for Medium-Range Weather Forecasts (ECMWF). Within this framework, the ERA5 reanalysis dataset has been applied to predict the hydrological response of the Devoll River catchment in Albania. Due to its location, Albania belongs to the Mediterranean climatic belt, which is characterized by hot dry summers and mild rainy winters. The Devoll River catchment is situated south from the capital city Tirana and covers a surface of around 3140 km2. The flow regime of this catchment consists mainly of snowmelt in the upstream mountainous part, whereas precipitation dominates the lower regions. The simulation of the different flow components was carried out with the latest version of the Water Balance and Simulation Model (WaSiM) on a daily time step. The performance of the simulation was evaluated with the Nash-Sutcliffe (NSE) and the Kling-Gupta (KGE) efficiencies, yielding values of 0.66 and 0.80, respectively. Although the model performance suggests some deficiencies, it is considered satisfactory given that ERA5 is a reanalysis dataset with modelled precipitation fields. From the resulting hydrographs, it is possible to infer that observed and simulated runoff follow the same dynamics and a close correspondence between flow peaks can be achieved. These results finally reinforce the idea of applying ERA5 datasets in cases where meteorological input data availability is low or even absent.
María Herminia Pesci; Fenja Voges; Nils Rüther; Kristian Förster. A first look at ERA5 for physically based water balance modelling of the Devoll Catchment, Albania. 2020, 1 .
AMA StyleMaría Herminia Pesci, Fenja Voges, Nils Rüther, Kristian Förster. A first look at ERA5 for physically based water balance modelling of the Devoll Catchment, Albania. . 2020; ():1.
Chicago/Turabian StyleMaría Herminia Pesci; Fenja Voges; Nils Rüther; Kristian Förster. 2020. "A first look at ERA5 for physically based water balance modelling of the Devoll Catchment, Albania." , no. : 1.
Green infrastructure plays a key role in contemporary concepts to mitigate flooding in urban environments. Concepts like water sensitive cities, sponge cities, and water sensitive urban design aim to mimic features of the natural water cycle even in highly urbanized districts. For instance, green roofs – as a key element of green infrastructure – reduce runoff due to their storage capacity. Hence, evapotranspiration is also increased at the expense of runoff, which better matches the characteristics of the natural water cycle. In this presentation, we demonstrate the added value of green roofs for stormwater mitigation. First, a green roof test plot with a slope of zero degrees and dimensions of 20 m in length and 1 m in width is built under laboratory conditions. The vertical extent is 0.08 m filled with a homogeneous substrate layer with a 300 g m-2 drainage mat below. The runoff leaving the green roof at one of the 1 m edges is collected in tanks, which allows to continuously monitor the outflow. The water level in the green roof is observed using cameras. In this physical experiment, a sprinkler system is set up in order to generate an artificial rainfall event that mimics a design storm with a rainfall volume of 27 l m-2 in total falling within 15 minutes. This corresponds to a return period of 100 years at the experimental site in Hanover, Germany. A numerical model utilizing the open source Catchment Modelling Framework (CMF) is developed to represent the green roof in a physically based model representation, which solves the Darcy flow along a 1D numerical grid with a grid spacing of 0.2 m. The model captures the dynamics of the green roof’s hydrological response very well. The comparison of observed and modelled runoff time series, each with a temporal resolution of 1 minute, suggest a Nash-Sutcliffe model efficiency of 0.64. The root mean square error (RMSE) of modelled water levels in the green roof amounts to 1.2 cm. Both the physical experiment and the model suggest a runoff coefficient of 9% after 15 minutes. At present, we also focus on analyzing other configurations of green roofs with altered dimensions and slope (50 experiments in total with up to three repetitions each). These results highlight that (i) CMF represents the hydrology of the green roof with high accuracy, and (ii) green roofs are a very efficient measure of green infrastructure that helps to reduce runoff even for design storms well beyond return periods usually considered in urban drainage planning. This is especially relevant in the process of transforming grey to green infrastructure in the light of climate change adaptation.
Kristian Förster; Daniel Westerholt; Lukas Bargel; Philipp Kraft; Gilbert Lösken. Set storage to the rain – Experimental and model-based evidence in mitigating extreme rainfall excess with green roofs. 2020, 1 .
AMA StyleKristian Förster, Daniel Westerholt, Lukas Bargel, Philipp Kraft, Gilbert Lösken. Set storage to the rain – Experimental and model-based evidence in mitigating extreme rainfall excess with green roofs. . 2020; ():1.
Chicago/Turabian StyleKristian Förster; Daniel Westerholt; Lukas Bargel; Philipp Kraft; Gilbert Lösken. 2020. "Set storage to the rain – Experimental and model-based evidence in mitigating extreme rainfall excess with green roofs." , no. : 1.
Kristian Förster; Luisa-Bianca Thiele. Variations in sub-daily precipitation at centennial scale. 2019, 1 .
AMA StyleKristian Förster, Luisa-Bianca Thiele. Variations in sub-daily precipitation at centennial scale. . 2019; ():1.
Chicago/Turabian StyleKristian Förster; Luisa-Bianca Thiele. 2019. "Variations in sub-daily precipitation at centennial scale." , no. : 1.
Kristian Förster. Review. 2019, 1 .
AMA StyleKristian Förster. Review. . 2019; ():1.
Chicago/Turabian StyleKristian Förster. 2019. "Review." , no. : 1.
In this paper, the hydrological impacts of future socio-economic and climatic development are assessed for a regional-scale Alpine catchment (Brixental, Tyrol, Austria). Therefore, coupled storylines of future land use and climate scenarios were developed in a transdisciplinary stakeholder process by means of questionnaire analyses and interviews with local experts from various relevant societal sectors. Resulting future land use maps for each decade were used as spatial input in the hydrological model WaSiM, to which a new module for the consideration of snow-canopy interaction processes has been added. Simulation results for three developed storylines, each combined with a moderate (A1B) and an extreme (RCP8.5) climate future, show that in a warmer and dryer climate the amount of annual simulated streamflow at the gauge of the catchment undergoes a significant reduction. The (mainly natural) reforestation of the catchment – caused by abandonment of previously cultivated areas – leads to additional losses of water by enhanced interception and evapotranspiration processes. Further cultivation of the current mountain pasture areas has a certain potential to attenuate undesirable long-term impacts of climate change on the catchment water balance.
Ulrich Strasser; Kristian Förster; Herbert Formayer; Florentin Hofmeister; Thomas Marke; Gertraud Meißl; Imran Nadeem; Rike Stotten; Markus Schermer. Storylines of combined future land use and climate scenarios and their hydrological impacts in an Alpine catchment (Brixental/Austria). Science of The Total Environment 2018, 657, 746 -763.
AMA StyleUlrich Strasser, Kristian Förster, Herbert Formayer, Florentin Hofmeister, Thomas Marke, Gertraud Meißl, Imran Nadeem, Rike Stotten, Markus Schermer. Storylines of combined future land use and climate scenarios and their hydrological impacts in an Alpine catchment (Brixental/Austria). Science of The Total Environment. 2018; 657 ():746-763.
Chicago/Turabian StyleUlrich Strasser; Kristian Förster; Herbert Formayer; Florentin Hofmeister; Thomas Marke; Gertraud Meißl; Imran Nadeem; Rike Stotten; Markus Schermer. 2018. "Storylines of combined future land use and climate scenarios and their hydrological impacts in an Alpine catchment (Brixental/Austria)." Science of The Total Environment 657, no. : 746-763.
While science widely acknowledges the necessity of climate change adaptation (CCA), concrete strategies for CCA by major land-use actor groups at a local level are largely missing. Immediate economic challenges often prevent the establishment of long-term collective strategies. However, collective decisions on a communal level regarding land use are crucial for CCA strategies, given the interdependencies of farming with forestry, tourism, and other economic sectors, especially in mountain areas. This paper presents inter- and trans-disciplinary learning processes, which have evolved into a project modelling the hydrological effects of combined future climate and land-use changes based on the combined scenarios of climate and socio-economic change in an Alpine valley (Brixental in Tyrol/Austria). Locally adapted scenarios illustrate future land-use changes as a result of both climate change and different socio-economic developments. The hydrological results show how an increase in the forested area reduces streamflow (as a measure of water availability) in the long term. For local stakeholders, the process demonstrated clearly the interdependence of different economic sectors and the necessity for collective action at a regional level to influence socio-economic development. Moreover, it made them aware that local decisions on future land use may influence the effects of climate change. Consistent storylines helped stakeholders to visualize a desired future and to see their scope of influence. The transdisciplinary research process allowed local stakeholders to translate the hydrological modelling results into a concrete local CCA strategy.
Markus Schermer; Rike Stotten; Ulrich Strasser; Gertraud Meißl; Thomas Marke; Kristian Förster; Herbert Formayer. The Role of Transdisciplinary Research for Agricultural Climate Change Adaptation Strategies. Agronomy 2018, 8, 237 .
AMA StyleMarkus Schermer, Rike Stotten, Ulrich Strasser, Gertraud Meißl, Thomas Marke, Kristian Förster, Herbert Formayer. The Role of Transdisciplinary Research for Agricultural Climate Change Adaptation Strategies. Agronomy. 2018; 8 (11):237.
Chicago/Turabian StyleMarkus Schermer; Rike Stotten; Ulrich Strasser; Gertraud Meißl; Thomas Marke; Kristian Förster; Herbert Formayer. 2018. "The Role of Transdisciplinary Research for Agricultural Climate Change Adaptation Strategies." Agronomy 8, no. 11: 237.
In this study, the influence of disaggregated rainfall products with different degrees of spatial consistence on rainfall–runoff modeling results is analyzed for three mesoscale catchments in Lower Saxony, Germany. For the disaggregation of daily rainfall time series into hourly values, a multiplicative random cascade model is applied. The disaggregation is applied on a station by station basis without consideration of surrounding stations; hence subsequent steps are then required to implement spatial consistence. Spatial consistence is represented here by three bivariate spatial rainfall characteristics that complement each other. A resampling algorithm and a parallelization approach are evaluated against the disaggregated time series without any subsequent steps. With respect to rainfall, clear differences between these three approaches can be identified regarding bivariate spatial rainfall characteristics, areal rainfall intensities and extreme values. The resampled time series lead to the best agreement with the observed ones. Using these different rainfall products as input to hydrological modeling, we hypothesize that derived runoff statistics – with emphasis on seasonal extreme values – are subject to similar differences as well. However, an impact on the extreme values' statistics of the hydrological simulations forced by different rainfall approaches cannot be detected. Several modifications of the study design using rainfall–runoff models with and without parameter calibration or using different rain gauge densities lead to similar results in runoff statistics. Only if the spatially highly resolved rainfall–runoff WaSiM model is applied instead of the semi-distributed HBV-IWW model can slight differences regarding the seasonal peak flows be identified. Hence, the hypothesis formulated before is rejected in this case study. These findings suggest that (i) simple model structures might compensate for deficiencies in spatial representativeness through parameterization and (ii) highly resolved hydrological models benefit from improved spatial modeling of rainfall.
Hannes Müller-Thomy; Markus Wallner; Kristian Förster. Rainfall disaggregation for hydrological modeling: is there a need for spatial consistence? Hydrology and Earth System Sciences 2018, 22, 5259 -5280.
AMA StyleHannes Müller-Thomy, Markus Wallner, Kristian Förster. Rainfall disaggregation for hydrological modeling: is there a need for spatial consistence? Hydrology and Earth System Sciences. 2018; 22 (10):5259-5280.
Chicago/Turabian StyleHannes Müller-Thomy; Markus Wallner; Kristian Förster. 2018. "Rainfall disaggregation for hydrological modeling: is there a need for spatial consistence?" Hydrology and Earth System Sciences 22, no. 10: 5259-5280.
Kristian Förster; Jakob Garvelmann; Gertraud Meißl; Ulrich Strasser. Modelling forest snow processes with a new version of WaSiM. Hydrological Sciences Journal 2018, 63, 1540 -1557.
AMA StyleKristian Förster, Jakob Garvelmann, Gertraud Meißl, Ulrich Strasser. Modelling forest snow processes with a new version of WaSiM. Hydrological Sciences Journal. 2018; 63 (10):1540-1557.
Chicago/Turabian StyleKristian Förster; Jakob Garvelmann; Gertraud Meißl; Ulrich Strasser. 2018. "Modelling forest snow processes with a new version of WaSiM." Hydrological Sciences Journal 63, no. 10: 1540-1557.
A physically based hydroclimatological model (AMUNDSEN) is used to assess future climate change impacts on the cryosphere and hydrology of the Ötztal Alps (Austria) until 2100. The model is run in 100 m spatial and 3 h temporal resolution using in total 31 downscaled, bias-corrected, and temporally disaggregated EURO-CORDEX climate projections for the representative concentration pathways (RCPs) 2.6, 4.5, and 8.5 scenarios as forcing data, making this – to date – the most detailed study for this region in terms of process representation and range of considered climate projections. Changes in snow coverage, glacierization, and hydrological regimes are discussed both for a larger area encompassing the Ötztal Alps (1850 km2, 862–3770 m a.s.l.) as well as for seven catchments in the area with varying size (11–165 km2) and glacierization (24–77 %). Results show generally declining snow amounts with moderate decreases (0–20 % depending on the emission scenario) of mean annual snow water equivalent in high elevations (> 2500 m a.s.l.) until the end of the century. The largest decreases, amounting to up to 25–80 %, are projected to occur in elevations below 1500 m a.s.l. Glaciers in the region will continue to retreat strongly, leaving only 4–20 % of the initial (as of 2006) ice volume left by 2100. Total and summer (JJA) runoff will change little during the early 21st century (2011–2040) with simulated decreases (compared to 1997–2006) of up to 11 % (total) and 13 % (summer) depending on catchment and scenario, whereas runoff volumes decrease by up to 39 % (total) and 47 % (summer) towards the end of the century (2071–2100), accompanied by a shift in peak flows from July towards June.
Florian Hanzer; Kristian Förster; Johanna Nemec; Ulrich Strasser. Projected cryospheric and hydrological impacts of 21st century climate change in the Ötztal Alps (Austria) simulated using a physically based approach. Hydrology and Earth System Sciences 2018, 22, 1593 -1614.
AMA StyleFlorian Hanzer, Kristian Förster, Johanna Nemec, Ulrich Strasser. Projected cryospheric and hydrological impacts of 21st century climate change in the Ötztal Alps (Austria) simulated using a physically based approach. Hydrology and Earth System Sciences. 2018; 22 (2):1593-1614.
Chicago/Turabian StyleFlorian Hanzer; Kristian Förster; Johanna Nemec; Ulrich Strasser. 2018. "Projected cryospheric and hydrological impacts of 21st century climate change in the Ötztal Alps (Austria) simulated using a physically based approach." Hydrology and Earth System Sciences 22, no. 2: 1593-1614.
Kristian Förster. Review. 2018, 1 .
AMA StyleKristian Förster. Review. . 2018; ():1.
Chicago/Turabian StyleKristian Förster. 2018. "Review." , no. : 1.
This article presents analyses of retrospective seasonal forecasts of snow accumulation. Re-forecasts with 4 months' lead time from two coupled atmosphere–ocean general circulation models (NCEP CFSv2 and MetOffice GloSea5) drive the Alpine Water balance and Runoff Estimation model (AWARE) in order to predict mid-winter snow accumulation in the Inn headwaters. As snowpack is hydrological storage that evolves during the winter season, it is strongly dependent on precipitation totals of the previous months. Climate model (CM) predictions of precipitation totals integrated from November to February (NDJF) compare reasonably well with observations. Even though predictions for precipitation may not be significantly more skilful than for temperature, the predictive skill achieved for precipitation is retained in subsequent water balance simulations when snow water equivalent (SWE) in February is considered. Given the AWARE simulations driven by observed meteorological fields as a benchmark for SWE analyses, the correlation achieved using GloSea5-AWARE SWE predictions is r = 0.57. The tendency of SWE anomalies (i.e. the sign of anomalies) is correctly predicted in 11 of 13 years. For CFSv2-AWARE, the corresponding values are r = 0.28 and 7 of 13 years. The results suggest that some seasonal prediction of hydrological model storage tendencies in parts of Europe is possible.
Kristian Förster; Florian Hanzer; Elena Stoll; Adam A. Scaife; Craig MacLachlan; Johannes Schöber; Matthias Huttenlau; Stefan Achleitner; Ulrich Strasser. Retrospective forecasts of the upcoming winter season snow accumulation in the Inn headwaters (European Alps). Hydrology and Earth System Sciences 2018, 22, 1157 -1173.
AMA StyleKristian Förster, Florian Hanzer, Elena Stoll, Adam A. Scaife, Craig MacLachlan, Johannes Schöber, Matthias Huttenlau, Stefan Achleitner, Ulrich Strasser. Retrospective forecasts of the upcoming winter season snow accumulation in the Inn headwaters (European Alps). Hydrology and Earth System Sciences. 2018; 22 (2):1157-1173.
Chicago/Turabian StyleKristian Förster; Florian Hanzer; Elena Stoll; Adam A. Scaife; Craig MacLachlan; Johannes Schöber; Matthias Huttenlau; Stefan Achleitner; Ulrich Strasser. 2018. "Retrospective forecasts of the upcoming winter season snow accumulation in the Inn headwaters (European Alps)." Hydrology and Earth System Sciences 22, no. 2: 1157-1173.
In this investigation, the influence of disaggregated rainfall data sets with different degrees of spatial consistence on rainfall runoff modeling results is analyzed for three meso-scale catchments in Lower Saxony, Germany. For the disaggregation of daily rainfall time series into hourly values a multiplicative random cascade model is applied. The disaggregation is applied on a per station basis without consideration of surrounding stations, hence subsequent steps are then required to implement spatial consistence. Spatial consistence is here represented by three bivariate spatial rainfall characteristics, complementing each other. A resampling algorithm and a parallelization approach are evaluated against the disaggregated time series without any subsequent steps. With respect to rainfall, clear differences between these three approaches can be identified regarding bivariate spatial rainfall characteristics, areal rainfall intensities and extreme values. The resampled time series lead to the best agreement with the observed ones. Using these different rainfall data sets as input to hydrological modeling, we hypothesize that derived runoff statistics are subject to similar differences as well. However, an impact on the runoff statistics summer and winter peak flows, monthly average discharge and flow duration curve of the simulated runoff time series cannot be detected. Several modifications of the investigation using rainfall runoff models with and without parameter calibration or using different rain gauge densities lead to similar results in runoff statistics. Only if the spatially highly resolved rainfall-runoff WaSiM-model is applied instead of the semi-distributed HBV-IWW-model, slight differences regarding the seasonal peak flows can be identified. Hence, the hypothesis formulated before is rejected in this case study. These findings suggest that (i) simple model structures might compensate for deficiencies in spatial representativeness through parameterization and (ii) highly resolved hydrological models benefit from improved spatial modeling of rainfall.
Hannes Müller; Markus Wallner; Kristian Förster. Rainfall disaggregation for hydrological modeling: Is there a need for spatial consistence? 2017, 1 -43.
AMA StyleHannes Müller, Markus Wallner, Kristian Förster. Rainfall disaggregation for hydrological modeling: Is there a need for spatial consistence? . 2017; ():1-43.
Chicago/Turabian StyleHannes Müller; Markus Wallner; Kristian Förster. 2017. "Rainfall disaggregation for hydrological modeling: Is there a need for spatial consistence?" , no. : 1-43.