7 research outputs found
Rainfall disaggregation for hydrological modeling: is there a need for spatial consistence?
In this study, the influence of disaggregated rainfall products with
different degrees of spatial consistence on rainfallârunoff 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 â with emphasis on seasonal
extreme values â 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 rainfallârunoff 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
rainfallârunoff 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)Â simple model structures might
compensate for deficiencies in spatial representativeness through
parameterization and (ii)Â highly resolved hydrological models benefit from
improved spatial modeling of rainfall.</p
Does the complexity in temporal precipitation disaggregation matter for a lumped hydrological model?
Flood peaks and volumes are essential design variables and can be simulated by precipitationârunoff (PâR) modelling. The high-resolution precipitation time series that are often required for this purpose can be generated by various temporal disaggregation methods. Here, we compare a simple method (M1, one parameter), focusing on the effective precipitation duration for flood simulations, with a multiplicative cascade model (M2, 32/36 parameters). While M2 aims at generating realistic characteristics of precipitation time series, M1 aims only at accurately reproducing flood variables by PâR modelling. Both disaggregation methods were tested on precipitation time series of nine Swiss mesoscale catchments. The generated high-resolution time series served as input for PâR modelling using a lumped HBV model. The results indicate that differences identified in precipitation characteristics of disaggregated time series vanish when introduced into the lumped hydrological model. Moreover, flood peaks were more sensitive than flood volumes to the choice of disaggregation method. © 2019, © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group
Twenty-three unsolved problems in hydrology (UPH) â a community perspective
This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through on-line media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focussed on process-based understanding of hydrological variability and causality at all space and time scales.
Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come
Twenty-three unsolved problems in hydrology (UPH)âa community perspective
This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through online media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focused on the process-based understanding of hydrological variability and causality at all space and time scales. Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come
Twenty-three unsolved problems in hydrology (UPH)âa community perspective
This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through online media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focused on the process-based understanding of hydrological variability and causality at all space and time scales. Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come