A5063300829- Hydrology and Watershed Management Studies
- Water resources management and optimization
- Hydrology and Drought Analysis
- Climate variability and models
- Flood Risk Assessment and Management
- Groundwater flow and contamination studies
- Hydrological Forecasting Using AI
- Reservoir Engineering and Simulation Methods
- Meteorological Phenomena and Simulations
- Water-Energy-Food Nexus Studies
- Geophysical and Geoelectrical Methods
- Water Systems and Optimization
- Geophysics and Gravity Measurements
- Fish Ecology and Management Studies
- Financial Risk and Volatility Modeling
- Precipitation Measurement and Analysis
- Oceanographic and Atmospheric Processes
- Climate change and permafrost
- Tropical and Extratropical Cyclones Research
- Cryospheric studies and observations
- Plant Water Relations and Carbon Dynamics
- Environmental Changes in China
- Groundwater and Isotope Geochemistry
- Remote Sensing and Land Use
- Soil Geostatistics and Mapping
Technical University of Denmark
2013-2025
Environmental and Water Resources Engineering
1993-2015
Care Resource
2008-2011
DHI
2011
Norsk Hydro (Norway)
2007-2008
Lund University
1999
National Institute of Water and Atmospheric Research
1997
Two different models for analyzing extreme hydrologic events, based on, respectively, partial duration series (PDS) and annual maximum (AMS), are compared. The PDS model assumes a generalized Pareto distribution modeling threshold exceedances corresponding to value maxima. performance of the two in terms uncertainty T ‐year event estimator is evaluated cases estimation with, likelihood (ML) method, method moments (MOM), probability weighted (PWM). In case ML estimation, provides most...
As a common approach to reservoir operating policies, water levels at the end of each time interval should be kept or above rule curve. In this study, policy is captured using rationing target yield reduce intensity severe shortages. For purpose, hybrid model developed optimize simultaneously both conventional curve and hedging rule. compound model, simple genetic algorithm coupled with simulation program, including an inner linear programming algorithm. way, operational policies are imposed...
Abstract Definitions and estimators of water resources system reliability (the probability that the will remain in a non-failure state), resilience ability to return state after failure has occurred) vulnerability likely damage event) have been thoroughly investigated. A behaviour analysis addressing monotonic behaviour, overlap correlation between was carried out by routing time series monthly runoff through reservoir with specified storage volume is operated according fixed operation...
Two regional estimation schemes, based on, respectively, partial duration series (PDS) and annual maximum (AMS), are compared. The PDS model assumes a generalized Pareto (GP) distribution for modeling threshold exceedances corresponding to extreme value (GEV) maxima. First, the accuracy of PDS/GP AMS/GEV index‐flood T ‐year event estimators compared using Monte Carlo simulations. For in typical regions assuming realistic degree heterogeneity, is more efficient. AMS procedures subsequently...
As a generalization of the common assumption exponential distribution exceedances in partial duration series generalized Pareto has been adopted. Estimators for parameters are presented using estimation by both method moments and probability‐weighted moments. The corresponding estimators T ‐year event given approximate expressions bias variance derived cases. Using mean square error estimator as performance index it is shown that preferable to Maintaining parent exceedance estimated assuming...
A general framework for regional analysis and modeling of extreme rainfall characteristics is presented. The model based on the partial duration series (PDS) method that includes in all events above a threshold level. In PDS average annual number exceedances, mean value exceedance magnitudes, coefficient L variation (LCV) are considered as variables. generalized least squares (GLS) regression explicitly accounts intersite correlation sampling uncertainties applied evaluating heterogenity...
We explore how to address the challenges of adaptation water resources systems under changing conditions by supporting flexible, resilient and low-regret solutions, coupled with on-going monitoring evaluation. This will require improved understanding linkages between biophysical social aspects in order better anticipate possible future co-evolution society. also present a call enhance dialogue foster actions governments, international scientific community, research funding agencies...
A regional estimation procedure that combines the index‐flood concept with an empirical Bayes method for inferring information is introduced. The model based on partial duration series approach generalized Pareto (GP) distributed exceedances. prior of parameters inferred from data using least squares (GLS) regression. Two different Bayesian T ‐year event estimators are introduced: a linear estimator requires only some moments distributions to be specified and parametric families...
Four different methods of parameterizing spatially varying log transmissivities in an inverse approach are compared with respect to prediction accuracy simulated flow and transport. Transport parameter estimation is included by two‐stage feedback optimization. In stage one the estimated fitting both head concentration data, given initial values source dispersivities. two, dispersivities data. With updated transport parameters, final estimates obtained repeating optimization one. The...
A regional partial duration series (PDS) model is applied for estimation of intensity frequency relationships extreme rainfalls in Denmark. The uses generalised least squares regression to relate the PDS parameters gridded rainfall statistics from a dense network rain gauges with daily measurements. Poisson rate positively correlated mean annual precipitation all durations considered (1 min 48 hours). can be assumed constant over Denmark up 1 hour. For larger than hour, significantly...
ABSTRACT The use of socio-economic methods for designing urban drainage expansion to account climate change is gradually coming into praxis and has recently become mandatory in Denmark. A few different return periods damaging rainfall must be selected, the one that leads greatest net present value considering expenses as well savings should chosen. Here, a method suggested addresses continuum instead selecting only comparison. Based on log-linear relations damage costs caused by cost...
The lumped conceptual rainfall-runoff model NAM was published in Nordic Hydrology (now Research) 1973 the same issue of journal as Swedish HBV model. It developed at Technical University Denmark (DTU), but its worldwide applications can be ascribed primarily to DHI. DHI adopted and implemented it their river modelling software, has been used numerous consulting projects further become an element distributed hydrological models.Like HBV, is a soil-moisture accounting overall structure will...
Flowmeter‐measured hydraulic conductivities from the heterogeneous MADE site have been used predictively in advection‐dispersion models. Resulting simulated concentrations failed to reproduce even major plume characteristics and some concluded that other mechanisms, such as dual porosity, are important. Here an alternative possibility is investigated: small‐scale flowmeter measurements too noisy possibly biased use so directly site‐scale models head transport data more suitable for...
The estimation of hydrological model parameters by calibration to field data is a critical step in the modeling process. However, often fails because parameter correlation. Here it shown that time‐lapse gravity can be combined with hydraulic head coupled hydrogeophysical inversion decrease correlation groundwater models. This demonstrated for riverbank infiltration where successfully constrains conductivity and specific yield both an analytical numerical model. A sensitivity study shows are...
Water scarcity and rapid economic growth have increased the pressure on water resources environment in Northern China, causing decreased groundwater tables, ecosystem degradation, direct losses due to insufficient supply. The authors applied value method, a variant of stochastic dynamic programming, optimize management Ziya River basin. Natural runoff from upper basin was estimated with rainfall-runoff model autocalibrated using situ measured discharge. serial correlation described by Markov...
Changes in extreme precipitation are expected to be one of the most important impacts climate change cities. Urban floods mainly caused by short duration events. Hence, robust information on changes at high-temporal resolution is required for design adaptation measures. However, quantification these challenging and subject numerous uncertainties. This study assesses uncertainties hourly scale over Denmark. It explores three statistical downscaling approaches: a delta method events, weather...
Key Points A model of spatial and temporal changes in the frequency extreme rainfall Explanatory variables two dimensions correlation among observations Trend is correlated to summer temperature