Thomas Skaugen - Profile on Academia.edu (original) (raw)
Papers by Thomas Skaugen
Snow is an important and complicated element in hydrological modelling. The traditional catchment... more Snow is an important and complicated element in hydrological modelling. The traditional catchment hydrological model with its many free calibration parameters, also in snow sub-models, is not a wellsuited tool for predicting conditions for which it has not been calibrated. Such conditions include prediction in ungauged basins and assessing hydrological effects of climate change. In this study, a new model for the spatial distribution of snow water equivalent (SWE), parameterized solely from observed spatial variability of precipitation (SD_G), is compared with the current snow distribution model used in the operational flood forecasting models in Norway. The latter model (SD_LN) has a fixed, calibrated coefficient of variation, which parameterizes a log-normal model for snow distribution. The two models are implemented in the already parameter parsimonious rainfall runoff model Distance Distribution Dynamics (DDD) and their capability for predicting runoff, SWE and snow covered area (SCA) are tested and compared for 71 Norwegian catchments. Results show that SD_G better simulates SCA when compared with MODIS satellite derived snow cover. In addition, SWE is simulated more realistically in that seasonal snow is melted out and the building up of "snow towers" and giving spurious positive trends in SWE, typical for SD_LN, is prevented. The precision of runoff simulations using SD_G is slightly inferior, with a reduction in Nash-Sutcliffe and Kling Gupta Criterion of 0.01, but it is shown that high precision in runoff prediction using SD_LN is accompanied with erroneous simulations of SWE.
Annals of Glaciology, 2004
Snow-courses data have been collected in order to investigate the temporal variability of snow di... more Snow-courses data have been collected in order to investigate the temporal variability of snow distribution in two catchments in southern Norway during the 2002 melt season. The profiles represent different elevations, aspects and terrain types. At snow maximum the spatial distribution of snow above the tree line was positively skewed (long tail in the positive direction), whereas the spatial distribution below the tree line followed a more normal distribution. During the snowmelt season the spatial distribution of snow became increasingly skewed. By separating the datasets into two terrain classes, alpine and forest, the snow distribution could be described by a time-variant gamma distribution function, one for each terrain class. The results of the study will be used to formulate a new snow routine in the Swedish rainfall^runoff model HBV, which is used for flood forecasting in Norway.
Annals of Glaciology, 2004
A model is put forward which focuses on the dynamical evolution of the spatial distribution of sn... more A model is put forward which focuses on the dynamical evolution of the spatial distribution of snow water equivalent (SWE). We make use of the fact that when the accumulation and ablation process of the snow reservoir is modelled as a summation of a gamma-distributed variable, both skewed distributions, typical of alpine areas, and more normal distributions, typical of forested areas, can be accounted for. A particular problem is to represent fractional snow-covered area (SCA) within the distribution framework. The change in SCA as a response to a melting event is explicitly linked to the shape of the distribution of SWE and is estimated as the probability of non-exceedance of the melted amount from a scaled version of the spatial distribution of SWE. An extensive snow-measuring programme, where several snow courses have been measured repeatedly throughout the melting season, justifies the dynamical aspects of the snow distribution in the modelling approach. The modelling approach has been tested with the Swedish rain-fall^runoff model, HBV, and estimated values of SWE and SCA are compared with results obtained using the statistical distribution (log-normal) traditionally used in the model.
In this study we propose a new formulation of subsurface water storage dynamics for use in rainfa... more In this study we propose a new formulation of subsurface water storage dynamics for use in rainfall-runoff models. Under the assumption of a strong relationship between storage and runoff, the temporal distribution of storage is considered to have the same shape as the distribution of observed recessions (measured as the difference between HESSD
Evaluering av flomvarslingas modellverktøy
Resultater fra 98 nedbørfelt simulert med HBV, ODM og DDD modellen er vurdert. DDD har noe bedre ... more Resultater fra 98 nedbørfelt simulert med HBV, ODM og DDD modellen er vurdert. DDD har noe bedre treff og færre falske alarmer enn HBV og ODM for alternativene der det ikke tillates en tidsforskyvning mellom observerte og simulerte flomtopper. Generelt scorer modellene bedre når man tillater en tidsforskjell i flomtoppen på et døgn, og i dette tilfellet er resultatene fra HBV litt bedre enn de to andre modellsystemene. Analysene indikerer også at det er rom for forbedringer når det gjelder modellenes evne til å treffe flomtoppene
Metoder for å måle vannføring i umålte felt
Forbedring av flomvarslingas verktøy
Denne sluttrapporten oppsummerer resultater og leveranser fra prosjektet 81057. Prosjektet har ha... more Denne sluttrapporten oppsummerer resultater og leveranser fra prosjektet 81057. Prosjektet har hatt som fokus å videreutvikle flomvarslingens modellrammeverk og forbedre de hydrologiske modellprognosene så treffsikkerheten øker og presisjonen kan angis. Prosjektet har også vært opptatt av at det store og mangeartede datamaterialet som tilflyter flomvarslingstjenesten skal tilgjengeliggjøres og tas i bruk, slik at prognosegrunnlaget blir bredest muli
Treffsikkerhet og presisjon i hydrologiske prognoser
NVE, 2019
Denne sluttrapporten oppsummerer resultater og leveranser fra det interne FoU-prosjektet 80103, T... more Denne sluttrapporten oppsummerer resultater og leveranser fra det interne FoU-prosjektet 80103, Treffsikkerhet og presisjon i hydrologiske prognoser, som ble gjennomført i perioden 2015 til 2018. Målsettingen med prosjektet var å forbedre våre operasjonelle metoder med hensyn til metodikk og tilgjengelige data, for å forbedre treffsikkerhet og presisjon i våre hydrologiske prognose
Forbedring av flomvarslingas verktøy
Denne sluttrapporten oppsummerer resultater og leveranser fra prosjektet 81057. Prosjektet har ha... more Denne sluttrapporten oppsummerer resultater og leveranser fra prosjektet 81057. Prosjektet har hatt som fokus å videreutvikle flomvarslingens modellrammeverk og forbedre de hydrologiske modellprognosene så treffsikkerheten øker og presisjonen kan angis. Prosjektet har også vært opptatt av at det store og mangeartede datamaterialet som tilflyter flomvarslingstjenesten skal tilgjengeliggjøres og tas i bruk, slik at prognosegrunnlaget blir bredest muli
Evaluering av flomvarslingas modellverktøy
Resultater fra 98 nedbørfelt simulert med HBV, ODM og DDD modellen er vurdert. DDD har noe bedre ... more Resultater fra 98 nedbørfelt simulert med HBV, ODM og DDD modellen er vurdert. DDD har noe bedre treff og færre falske alarmer enn HBV og ODM for alternativene der det ikke tillates en tidsforskyvning mellom observerte og simulerte flomtopper. Generelt scorer modellene bedre når man tillater en tidsforskjell i flomtoppen på et døgn, og i dette tilfellet er resultatene fra HBV litt bedre enn de to andre modellsystemene. Analysene indikerer også at det er rom for forbedringer når det gjelder modellenes evne til å treffe flomtoppene
The Cryosphere Discussions, 2016
Snow is an important and complicated element in hydrological modelling. The traditional catchment... more Snow is an important and complicated element in hydrological modelling. The traditional catchment hydrological model with its many free calibration parameters, also in snow sub-models, is not a well-suited tool for predicting conditions for which it has not been calibrated. Such conditions include prediction in ungauged basins and assessing hydrological effects of climate change. In this study, a new model for the spatial distribution of snow water equivalent (SWE), parameterized solely from observed spatial variability of precipitation (SD_G), is compared with the current snow distribution model used in the operational flood forecasting models in Norway. The latter model (SD_LN) has a fixed, calibrated coefficient of variation, which parameterizes a log-normal model for snow distribution. The two models are implemented in the already parameter parsimonious rainfall runoff model Distance Distribution Dynamics (DDD) and their capability for predicting runoff, SWE and snow covered are...
Hydrology and Earth System Sciences Discussions, 2015
In this study we propose a new formulation of subsurface water storage dynamics for use in rainfa... more In this study we propose a new formulation of subsurface water storage dynamics for use in rainfall–runoff models. Under the assumption of a strong relationship between storage and runoff, the temporal distribution of storage is considered to have the same shape as the distribution of observed recessions (measured as the difference between the log of runoff values). The mean subsurface storage is estimated as the storage at steady-state, where moisture input equals the mean annual runoff. An important contribution of the new formulation is that its parameters are derived directly from observed recession data and the mean annual runoff and hence estimated prior to calibration. Key principles guiding the evaluation of the new subsurface storage routine have been (a) to minimize the number of parameters to be estimated through the, often arbitrary fitting to optimize runoff predictions (calibration) and (b) maximize the range of testing conditions (i.e. large-sample hydrology). The new...
Annals of Glaciology, 2004
A model is put forward which focuses on the dynamical evolution of the spatial distribution of sn... more A model is put forward which focuses on the dynamical evolution of the spatial distribution of snow water equivalent (SWE). We make use of the fact that when the accumulation and ablation process of the snow reservoir is modelled as a summation of a gamma-distributed variable, both skewed distributions, typical of alpine areas, and more normal distributions, typical of forested areas, can be accounted for. A particular problem is to represent fractional snow-covered area (SCA) within the distribution framework. The change in SCA as a response to a melting event is explicitly linked to the shape of the distribution of SWE and is estimated as the probability of non-exceedance of the melted amount from a scaled version of the spatial distribution of SWE. An extensive snow-measuring programme, where several snow courses have been measured repeatedly throughout the melting season, justifies the dynamical aspects of the snow distribution in the modelling approach. The modelling approach h...
Journal of Geophysical Research, Nov 1, 1996
The analysis and modeling of extreme areal precipitation is carried out focusing the attention on... more The analysis and modeling of extreme areal precipitation is carried out focusing the attention on extreme areal precipitation events rather than extreme point precipitation. The data is daily precipitation values from southern Norway. By investigating the spatial coverage of the fractional area (fraction of the considered catchment) where it rains over a certain intensity threshold, it was found, for a range of rain intensities, that the ratio between two fractional areas of consecutive thresholds is independent of the actual value of the rain intensity and the size of the considered catchment. The mean areal precipitation is seen as the sum of the fractional thresholded rainy areas for all intensity thresholds. By the properties of independence of the consecutive area ratios, it is possible to simulate fractional thresholded rainy areas, and thus compute the mean areal rainfall. The mean and the standard deviation of simulated series of extreme areal precipitation for five catchments of different size (from 48000 to 468 km 2) are in very good agreement with those of the observed. This is also the case for the observed and simulated values of the fractional thresholded rainy areas. The mean values of the spatial coverage of thresholded areas for mesoscale convective complexes in the United States are found to be well modeled by the proposed method. 1.
Updating snow reservoir in hydrological models from satellite-observed snow covered areas
… Water Resources and …, 2005
... Editor: Authors: Eli Alfnes, Elin Langsholt, Thomas Skaugen and Hans-Christian Udnæs Print: N... more ... Editor: Authors: Eli Alfnes, Elin Langsholt, Thomas Skaugen and Hans-Christian Udnæs Print: NVE's printing office Number printed: 40 ... Oslo, January 2005 Svein Taksdal Acting director of the Hydrology Department Liss M. Andreassen Project leader Page 7. 6 Summary ...
Journal of Hydrology X, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Journal of Hydrology X, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Geostatistical regionalization of daily runoff forecasts in Norway
International Journal of River Basin Management, 2011
The national flood forecasting service in Norway applies the conceptual HBV model in 117 catchmen... more The national flood forecasting service in Norway applies the conceptual HBV model in 117 catchments of different scales. Daily runoff forecasts from these 117 catchments are regionalized for nationwide qualitative flood risk regionalization displayed in a map. The regionalization is performed without considering scale dependency in runoff response in different-sized catchments. We developed a simple catchment classification approach that allows
Scenarios of extreme daily precipitation for Norway under climate change
Hydrology Research
Based on downscaled daily precipitation values from the global climate model of the Max Planck In... more Based on downscaled daily precipitation values from the global climate model of the Max Planck Institute in Hamburg, time series of 20 years have been generated to describe the current climate of 1980- 1999 (control data) and the future climate of 2030-2049 (scenario data) for Norway. These time series serve as training data for the Randomised Bartlett-Lewis Rectangular Pulse Model (RBLRPM), a precipitation simulation model, and time series of 1000 years length have been generated to assess possible changes in the extreme precipitation regime due to climate change. The analysis of changes in extreme value patterns for annual and seasonal values in the scenario and control data sets shows tendencies towards increased extreme values and seasonal shifts for the scenario period. A general increase in mean and standard deviation of the extreme value sample and for values of 10 and 100 years return period is found, although the regional variability is significant. For some regions the inc...
A first version of an energy balance (EB) based snow melt model is formulated, based on previous ... more A first version of an energy balance (EB) based snow melt model is formulated, based on previous published work from several authors. The EB model uses only precipitation and air temperature as input, and the timeresolution is flexible (from hourly to daily). The algorithms of the EB model are presented in this technical research note, together with some evaluation results, where simulated and observed snow amounts and melt rates are compared. Comparison is also made between the EB approach and the basic degreeday approach to snow melt modelling.
Snow is an important and complicated element in hydrological modelling. The traditional catchment... more Snow is an important and complicated element in hydrological modelling. The traditional catchment hydrological model with its many free calibration parameters, also in snow sub-models, is not a wellsuited tool for predicting conditions for which it has not been calibrated. Such conditions include prediction in ungauged basins and assessing hydrological effects of climate change. In this study, a new model for the spatial distribution of snow water equivalent (SWE), parameterized solely from observed spatial variability of precipitation (SD_G), is compared with the current snow distribution model used in the operational flood forecasting models in Norway. The latter model (SD_LN) has a fixed, calibrated coefficient of variation, which parameterizes a log-normal model for snow distribution. The two models are implemented in the already parameter parsimonious rainfall runoff model Distance Distribution Dynamics (DDD) and their capability for predicting runoff, SWE and snow covered area (SCA) are tested and compared for 71 Norwegian catchments. Results show that SD_G better simulates SCA when compared with MODIS satellite derived snow cover. In addition, SWE is simulated more realistically in that seasonal snow is melted out and the building up of "snow towers" and giving spurious positive trends in SWE, typical for SD_LN, is prevented. The precision of runoff simulations using SD_G is slightly inferior, with a reduction in Nash-Sutcliffe and Kling Gupta Criterion of 0.01, but it is shown that high precision in runoff prediction using SD_LN is accompanied with erroneous simulations of SWE.
Annals of Glaciology, 2004
Snow-courses data have been collected in order to investigate the temporal variability of snow di... more Snow-courses data have been collected in order to investigate the temporal variability of snow distribution in two catchments in southern Norway during the 2002 melt season. The profiles represent different elevations, aspects and terrain types. At snow maximum the spatial distribution of snow above the tree line was positively skewed (long tail in the positive direction), whereas the spatial distribution below the tree line followed a more normal distribution. During the snowmelt season the spatial distribution of snow became increasingly skewed. By separating the datasets into two terrain classes, alpine and forest, the snow distribution could be described by a time-variant gamma distribution function, one for each terrain class. The results of the study will be used to formulate a new snow routine in the Swedish rainfall^runoff model HBV, which is used for flood forecasting in Norway.
Annals of Glaciology, 2004
A model is put forward which focuses on the dynamical evolution of the spatial distribution of sn... more A model is put forward which focuses on the dynamical evolution of the spatial distribution of snow water equivalent (SWE). We make use of the fact that when the accumulation and ablation process of the snow reservoir is modelled as a summation of a gamma-distributed variable, both skewed distributions, typical of alpine areas, and more normal distributions, typical of forested areas, can be accounted for. A particular problem is to represent fractional snow-covered area (SCA) within the distribution framework. The change in SCA as a response to a melting event is explicitly linked to the shape of the distribution of SWE and is estimated as the probability of non-exceedance of the melted amount from a scaled version of the spatial distribution of SWE. An extensive snow-measuring programme, where several snow courses have been measured repeatedly throughout the melting season, justifies the dynamical aspects of the snow distribution in the modelling approach. The modelling approach has been tested with the Swedish rain-fall^runoff model, HBV, and estimated values of SWE and SCA are compared with results obtained using the statistical distribution (log-normal) traditionally used in the model.
In this study we propose a new formulation of subsurface water storage dynamics for use in rainfa... more In this study we propose a new formulation of subsurface water storage dynamics for use in rainfall-runoff models. Under the assumption of a strong relationship between storage and runoff, the temporal distribution of storage is considered to have the same shape as the distribution of observed recessions (measured as the difference between HESSD
Evaluering av flomvarslingas modellverktøy
Resultater fra 98 nedbørfelt simulert med HBV, ODM og DDD modellen er vurdert. DDD har noe bedre ... more Resultater fra 98 nedbørfelt simulert med HBV, ODM og DDD modellen er vurdert. DDD har noe bedre treff og færre falske alarmer enn HBV og ODM for alternativene der det ikke tillates en tidsforskyvning mellom observerte og simulerte flomtopper. Generelt scorer modellene bedre når man tillater en tidsforskjell i flomtoppen på et døgn, og i dette tilfellet er resultatene fra HBV litt bedre enn de to andre modellsystemene. Analysene indikerer også at det er rom for forbedringer når det gjelder modellenes evne til å treffe flomtoppene
Metoder for å måle vannføring i umålte felt
Forbedring av flomvarslingas verktøy
Denne sluttrapporten oppsummerer resultater og leveranser fra prosjektet 81057. Prosjektet har ha... more Denne sluttrapporten oppsummerer resultater og leveranser fra prosjektet 81057. Prosjektet har hatt som fokus å videreutvikle flomvarslingens modellrammeverk og forbedre de hydrologiske modellprognosene så treffsikkerheten øker og presisjonen kan angis. Prosjektet har også vært opptatt av at det store og mangeartede datamaterialet som tilflyter flomvarslingstjenesten skal tilgjengeliggjøres og tas i bruk, slik at prognosegrunnlaget blir bredest muli
Treffsikkerhet og presisjon i hydrologiske prognoser
NVE, 2019
Denne sluttrapporten oppsummerer resultater og leveranser fra det interne FoU-prosjektet 80103, T... more Denne sluttrapporten oppsummerer resultater og leveranser fra det interne FoU-prosjektet 80103, Treffsikkerhet og presisjon i hydrologiske prognoser, som ble gjennomført i perioden 2015 til 2018. Målsettingen med prosjektet var å forbedre våre operasjonelle metoder med hensyn til metodikk og tilgjengelige data, for å forbedre treffsikkerhet og presisjon i våre hydrologiske prognose
Forbedring av flomvarslingas verktøy
Denne sluttrapporten oppsummerer resultater og leveranser fra prosjektet 81057. Prosjektet har ha... more Denne sluttrapporten oppsummerer resultater og leveranser fra prosjektet 81057. Prosjektet har hatt som fokus å videreutvikle flomvarslingens modellrammeverk og forbedre de hydrologiske modellprognosene så treffsikkerheten øker og presisjonen kan angis. Prosjektet har også vært opptatt av at det store og mangeartede datamaterialet som tilflyter flomvarslingstjenesten skal tilgjengeliggjøres og tas i bruk, slik at prognosegrunnlaget blir bredest muli
Evaluering av flomvarslingas modellverktøy
Resultater fra 98 nedbørfelt simulert med HBV, ODM og DDD modellen er vurdert. DDD har noe bedre ... more Resultater fra 98 nedbørfelt simulert med HBV, ODM og DDD modellen er vurdert. DDD har noe bedre treff og færre falske alarmer enn HBV og ODM for alternativene der det ikke tillates en tidsforskyvning mellom observerte og simulerte flomtopper. Generelt scorer modellene bedre når man tillater en tidsforskjell i flomtoppen på et døgn, og i dette tilfellet er resultatene fra HBV litt bedre enn de to andre modellsystemene. Analysene indikerer også at det er rom for forbedringer når det gjelder modellenes evne til å treffe flomtoppene
The Cryosphere Discussions, 2016
Snow is an important and complicated element in hydrological modelling. The traditional catchment... more Snow is an important and complicated element in hydrological modelling. The traditional catchment hydrological model with its many free calibration parameters, also in snow sub-models, is not a well-suited tool for predicting conditions for which it has not been calibrated. Such conditions include prediction in ungauged basins and assessing hydrological effects of climate change. In this study, a new model for the spatial distribution of snow water equivalent (SWE), parameterized solely from observed spatial variability of precipitation (SD_G), is compared with the current snow distribution model used in the operational flood forecasting models in Norway. The latter model (SD_LN) has a fixed, calibrated coefficient of variation, which parameterizes a log-normal model for snow distribution. The two models are implemented in the already parameter parsimonious rainfall runoff model Distance Distribution Dynamics (DDD) and their capability for predicting runoff, SWE and snow covered are...
Hydrology and Earth System Sciences Discussions, 2015
In this study we propose a new formulation of subsurface water storage dynamics for use in rainfa... more In this study we propose a new formulation of subsurface water storage dynamics for use in rainfall–runoff models. Under the assumption of a strong relationship between storage and runoff, the temporal distribution of storage is considered to have the same shape as the distribution of observed recessions (measured as the difference between the log of runoff values). The mean subsurface storage is estimated as the storage at steady-state, where moisture input equals the mean annual runoff. An important contribution of the new formulation is that its parameters are derived directly from observed recession data and the mean annual runoff and hence estimated prior to calibration. Key principles guiding the evaluation of the new subsurface storage routine have been (a) to minimize the number of parameters to be estimated through the, often arbitrary fitting to optimize runoff predictions (calibration) and (b) maximize the range of testing conditions (i.e. large-sample hydrology). The new...
Annals of Glaciology, 2004
A model is put forward which focuses on the dynamical evolution of the spatial distribution of sn... more A model is put forward which focuses on the dynamical evolution of the spatial distribution of snow water equivalent (SWE). We make use of the fact that when the accumulation and ablation process of the snow reservoir is modelled as a summation of a gamma-distributed variable, both skewed distributions, typical of alpine areas, and more normal distributions, typical of forested areas, can be accounted for. A particular problem is to represent fractional snow-covered area (SCA) within the distribution framework. The change in SCA as a response to a melting event is explicitly linked to the shape of the distribution of SWE and is estimated as the probability of non-exceedance of the melted amount from a scaled version of the spatial distribution of SWE. An extensive snow-measuring programme, where several snow courses have been measured repeatedly throughout the melting season, justifies the dynamical aspects of the snow distribution in the modelling approach. The modelling approach h...
Journal of Geophysical Research, Nov 1, 1996
The analysis and modeling of extreme areal precipitation is carried out focusing the attention on... more The analysis and modeling of extreme areal precipitation is carried out focusing the attention on extreme areal precipitation events rather than extreme point precipitation. The data is daily precipitation values from southern Norway. By investigating the spatial coverage of the fractional area (fraction of the considered catchment) where it rains over a certain intensity threshold, it was found, for a range of rain intensities, that the ratio between two fractional areas of consecutive thresholds is independent of the actual value of the rain intensity and the size of the considered catchment. The mean areal precipitation is seen as the sum of the fractional thresholded rainy areas for all intensity thresholds. By the properties of independence of the consecutive area ratios, it is possible to simulate fractional thresholded rainy areas, and thus compute the mean areal rainfall. The mean and the standard deviation of simulated series of extreme areal precipitation for five catchments of different size (from 48000 to 468 km 2) are in very good agreement with those of the observed. This is also the case for the observed and simulated values of the fractional thresholded rainy areas. The mean values of the spatial coverage of thresholded areas for mesoscale convective complexes in the United States are found to be well modeled by the proposed method. 1.
Updating snow reservoir in hydrological models from satellite-observed snow covered areas
… Water Resources and …, 2005
... Editor: Authors: Eli Alfnes, Elin Langsholt, Thomas Skaugen and Hans-Christian Udnæs Print: N... more ... Editor: Authors: Eli Alfnes, Elin Langsholt, Thomas Skaugen and Hans-Christian Udnæs Print: NVE's printing office Number printed: 40 ... Oslo, January 2005 Svein Taksdal Acting director of the Hydrology Department Liss M. Andreassen Project leader Page 7. 6 Summary ...
Journal of Hydrology X, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Journal of Hydrology X, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Geostatistical regionalization of daily runoff forecasts in Norway
International Journal of River Basin Management, 2011
The national flood forecasting service in Norway applies the conceptual HBV model in 117 catchmen... more The national flood forecasting service in Norway applies the conceptual HBV model in 117 catchments of different scales. Daily runoff forecasts from these 117 catchments are regionalized for nationwide qualitative flood risk regionalization displayed in a map. The regionalization is performed without considering scale dependency in runoff response in different-sized catchments. We developed a simple catchment classification approach that allows
Scenarios of extreme daily precipitation for Norway under climate change
Hydrology Research
Based on downscaled daily precipitation values from the global climate model of the Max Planck In... more Based on downscaled daily precipitation values from the global climate model of the Max Planck Institute in Hamburg, time series of 20 years have been generated to describe the current climate of 1980- 1999 (control data) and the future climate of 2030-2049 (scenario data) for Norway. These time series serve as training data for the Randomised Bartlett-Lewis Rectangular Pulse Model (RBLRPM), a precipitation simulation model, and time series of 1000 years length have been generated to assess possible changes in the extreme precipitation regime due to climate change. The analysis of changes in extreme value patterns for annual and seasonal values in the scenario and control data sets shows tendencies towards increased extreme values and seasonal shifts for the scenario period. A general increase in mean and standard deviation of the extreme value sample and for values of 10 and 100 years return period is found, although the regional variability is significant. For some regions the inc...
A first version of an energy balance (EB) based snow melt model is formulated, based on previous ... more A first version of an energy balance (EB) based snow melt model is formulated, based on previous published work from several authors. The EB model uses only precipitation and air temperature as input, and the timeresolution is flexible (from hourly to daily). The algorithms of the EB model are presented in this technical research note, together with some evaluation results, where simulated and observed snow amounts and melt rates are compared. Comparison is also made between the EB approach and the basic degreeday approach to snow melt modelling.