
Berit ArheimerSwedish Meteorological and Hydrological Institute | SMHI · Research and Development
Berit Arheimer
PhD (Docent)
About
180
Publications
82,243
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Introduction
My main contribution is on putting science into practice. My research group develop, test and implement numerical methods in operational computational systems to derive water information of various resolution in time and space. This information is then used in practice by warning services, water-management authorities and companies, by consultancies, or for design variables and public information. The model systems are also used for research, environmental assessments and scenario estimates.
Additional affiliations
January 1997 - present
September 1991 - December 1996
Publications
Publications (180)
Historical drainage to improve forestry practices has resulted in 0.6–0.7 million hectares drained forested peatland in Sweden. This has reduced the storage of water in the landscape and may impact greenhouse gas emissions, biodiversity and the damping of extreme water flows. National restoration actions therefore aim at rewetting 0.1 million hecta...
Megafloods that far exceed previously observed records often take citizens and experts by surprise, resulting in extremely severe damage and loss of life. Existing methods based on local and regional information rarely go beyond national borders and cannot predict these floods well because of limited data on megafloods, and because flood generation...
Although many potential evapotranspiration (PET) formulas are available, there is still a lack of knowledge on when and where to use them in catchment modeling world‐wide. Here we experimented with three different formulas in a global hydrological model (the World‐wide HYPE), using 15 years of observations from 5,338 streamflow gauges and global ev...
Conceptual hydrological models can move towards process‐oriented modelling when addressing broader issues than discharge modelling alone. For instance, water quality modelling generally requires understanding of both pathways and travel times which might not be easily identified because observations at the outlet aggregate all processes at the catc...
A climatic anomaly can potentially affect the hydrological behaviour of a catchment for several years. This article presents a new approach to quantifying this multi-year hydrological memory, using exclusively streamflow and climate data. Rather than providing a single value of catchment memory, we aim to describe how this memory fades over time. T...
Streamflow simulation across the tropics is limited by the lack of data to calibrate and validate large-scale hydrological models. Here, we applied the process-based, conceptual HYPE (Hydrological Predictions for the Environment) model to quantitatively assess Costa Rica's water resources at a national scale. Data scarcity was compensated for by us...
This paper presents an evaluation of the parameter sensitivity of a process-based model at the global scale using large-sample data. The analysis was carried out using the HYdrological Prediction of the Environment (HYPE) model, for which soil and snow parameters were evaluated using 187 river flow gauges spread worldwide. As a result, 6 out of 12...
Streamflow simulation across the tropics is limited by the lack of data to calibrate and validate large-scale hydrological models. Here, we applied the process-based, conceptual HYPE (Hydrological Predictions for the Environment) model to quantitively assess Costa Rica’s water resources at a national scale. Data scarcity was compensated using adjus...
Study Region
Our study region is the Baltic Sea Drainage Basin (BSDB), which covers an area of 1.8 Mio km2 distributed over 14 countries in northern Europe.
Study Focus
We use a large-scale hydrological and nutrient transport model (E-HYPE) to model basin-wide impacts of measure scenarios on the Baltic Sea, where eutrophication is a critical issue...
This article presents a new approach to quantifying pluriannual hydrological memory, using exclusively streamflow and climate data. The rainfall--runoff relationship is analyzed through the concept of elasticity, focusing on the relation between the annual anomalies of runoff yield and humidity index. We identify Catchment Forgetting Curves (CFC) t...
Continental and global dynamic hydrological models have emerged recently as tools for large-scale analyses. One such tool is a dynamic process-based rainfall-runoff and water quality model called Hydrological Predictions for Environment (HYPE). This study presents and compares historical simulations of runoff and sediment concentrations for three n...
The next generation of climate services needs not only tailoring to specific user needs but to provide, in addition, access to key information in a usable way that satisfies the needs of different users’ profiles; especially web-based services. Here, we present the outcomes from developing such a new interactive prototype. The service provides data...
The effect of model calibration on the projection of climate change impact on hydrological indicators was assessed by employing variants of a pan-European hydrological model driven by forcing data from an ensemble of climate models. The hydrological model was calibrated using three approaches: calibration at the outlets of major river basins, regio...
The largest forest wildfire in Swedish modern history burnt 14,000 ha of Boreal forest in the Västmanland County (south-central Sweden) during the summer of 2014. Here, we assess the impacts of this wildfire on the hydrological regime during the three years after it happened. In the empirical experiment carried out, four catchments (two burnt and t...
This study details the enhancement and calibration of the Arctic implementation of the HYdrological Predictions for the Environment (HYPE) hydrological model established for the BaySys group of projects to produce freshwater discharge scenarios for the Hudson Bay Drainage Basin (HBDB). The challenge in producing estimates of freshwater discharge fo...
Recent advancements in catchment hydrology (such as understanding catchment similarity, accessing new data sources, and refining methods for parameter constraints) make it possible to apply catchment models for ungauged basins over large domains. Here we present a cutting-edge case study applying catchment-modelling techniques with evaluation again...
Changes in river flow may appear from shifts in land cover, constructions in the river channel, and climatic change, but currently there is a lack of understanding of the relative importance of these drivers. Therefore, we collected gauged river flow time series from 1961 to 2018 from across Sweden for 34 disturbed catchments to quantify how the va...
The Baltic Sea is suffering from eutrophication caused by nutrient discharges from land to sea, and these loads might change in a changing climate. We show that the impact from climate change by mid-century is probably less than the direct impact of changing socioeconomic factors such as land use, agricultural practices, atmospheric deposition, and...
Advances in open data science serve large-scale model developments and, subsequently, hydroclimate services. Local river flow observations are key in hydrology but data sharing remains limited due to unclear quality, or to political, economic or infrastructure reasons. This paper provides methods for quality checking openly accessible river-flow ti...
Climate change has led to concerns about increasing river floods resulting from the greater water-holding capacity of a warmer atmosphere¹. These concerns are reinforced by evidence of increasing economic losses associated with flooding in many parts of the world, including Europe². Any changes in river floods would have lasting implications for th...
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, p...
Accepted Manuscript at https://engrxiv.org/9gf82/
Long term time series of variable renewable energy (VRE) generation and electricity demand (load) provide important insights into the feasibility of fully renewable power systems. The coverage of energy statistics is usually too short or the temporal resolution too low to study effects related to i...
The current landscape of climate services represents a highly diverse and still growing range of programs, projects, and portals involved in developing and/or providing climate services at different administrative levels and spatial-temporal scales. The diversity of service producers, users, and policy arenas has created a highly heterogeneous data...
The current landscape of climate services represents a highly diverse and still growing range of programs, projects, and portals involved in developing and/or providing climate services at different administrative levels and spatial-temporal scales. The diversity of service producers, users, and policy arenas has created a highly heterogeneous data...
Recent advancements in catchment hydrology (such as understanding hydrological processes, accessing new data sources, and refining methods for parameter constraints) make it possible to apply catchment models for ungauged basins over large domains. Here we present a cutting-edge case study applying catchment-modelling techniques at the global scale...
The geophysical and hydrological processes governing river flow formation exhibit persistence at several timescales, which may manifest itself with the presence of positive seasonal correlation of streamflow at several different time lags. We investigate here how persistence propagates along subsequent seasons and affects low and high flows. We def...
Climate change poses a significant challenge to dairy farming systems. Adaptation to predicted changes will be enhanced with improved modelling of regional changes in climate indicators. In this study, we use a Multi-Model Ensemble (MME) approach, using output from a suite of eighteen global climate models to predict impacts of climate change on ra...
Future energy systems with high shares of intermittent renewables will be stressed by climatic extreme events. We assess the frequency, duration, and magnitude of such extreme residual load events with a share of VRE generation of about 50% for the case of Sweden. For our analysis, we use 29 years of river runoff and of wind power and PV generation...
The calibration of hydrological models without streamflow observations is problematic, and the simultaneous, combined use of remotely sensed products for this purpose has not been exhaustively tested thus far. Our hypothesis is that the combined use of products can 1) reduce the parameter search space and 2) improve the representation of internal m...
Global change is affecting agroforestry and its inherent ecosystems in Sweden. Here we examine the benefits of ecologically adjusted dam regulations to conserve biodiversity under climate change in floodplain habitats, including meadows and riparian mixed forests. The natural flood regime in snow-dominated regions has changed significantly during t...
Our study develops and tests a geostatistical technique for locally enhancing macro-scale rainfall–runoff simulations on the basis of observed streamflow data that were not used in calibration. We consider Tyrol (Austria and Italy) and two different types of daily streamflow data: macro-scale rainfall–runoff simulations at 11 prediction nodes and o...
Land cover changes at watershed scale constitute key issues in general hydrology. Wildfires are one of the drivers of the changes in vegetation, which might affect hydrological fluxes and the water balance. The Västmanland fire in central Sweden burned 14000 hectares and removed the Boreal forest in this area during the summer 2014. In here, we hav...
Discharge projections into the Hudson Bay Complex to 2070 are investigated for global mean temperature warming levels of 1.5 and 2.0 °C. Median precipitation increases from 1986–2005, ranging from 2% during summer to 19% during winter, are projected to increase discharge in all seasons except summer. The rise in discharge is greatest furthest north...
Given the current proliferation of climate change services, how should a user judge which one is most relevant for a specific case? In this study, climate researchers and users compare continental, national and locally tailored climate change services for two case studies in Sweden with clear adaptation needs. The case studies addressed the organis...
The geophysical and hydrological processes governing river flow formation exhibit persistence at several timescales, which may manifest itself with the presence of positive seasonal correlation of streamflow at several different time lags. We investigate here how persistence propagates along subsequent seasons and affects low and high flows. We def...
Two approaches can be distinguished in studies of climate change impacts on water resources when accounting for issues related to impact model performance: (1) using a multi-model ensemble disregarding model performance, and (2) using models after their evaluation and considering model performance. We discuss the implications of both approaches in...
During the last 6 decades, forest biomass has increased in Sweden mainly due to forest management, with a possible increasing effect on evapotranspiration. However, increasing global CO2 concentrations may also trigger physiological water-saving responses in broadleaf tree species, and to a lesser degree in some needleleaf conifer species, inducing...
Global characterization of streamflow patterns based on climatic and physiographic characteristics is important for advancing understanding of large-scale hydrology, assessment of macro-scale hydrological models, and detection of global hydrological changes, among other applications. Here, based on large and open global datasets of streamflow obser...
Every catchment has a memory defining how long a water drop may remain in this catchment and how long one given hydrological state will have repercussions on following states. Catchment memory depends partly on the storage capacity of this catchment. This storage can for example be a groundwater aquifer, a lake or reservoir, or simply snow-pack dur...
Traditionally, catchment modelling mainly focused on simulating the lumped hydrological cycle at local to regional scales with high precision in a specific point of a river. However, recent advancement in understanding hydrological processes, accessing new data sources, and refining methods for parameter constraints, should make it possible to appl...
River flow is mainly controlled by climate, physiography and regulations, but their relative importance over large landmasses is poorly understood. Here we show from computational modelling that hydropower regulation is a key driver of flow regime change in snow-dominated regions and is more important than future climate changes. This implies that...
Our study develops and tests a geostatistical technique for locally enhancing macro-scale rainfall-runoff simulations on the basis of observed streamflow data that were not used in calibration. We consider Tyrol (Austria and Italy) and two different types of daily streamflow data: macro-scale rainfall-runoff simulations at 11 prediction nodes and o...
An intercomparison of climate change impacts projected by nine regional‐scale hydrological models for 12 large river basins on all continents was performed, and sources of uncertainty quantified in the framework of the ISIMIP project. The models ECOMAG, HBV, HYMOD, HYPE, mHM, SWAT, SWIM, VIC and WaterGAP3 were applied in the following basins: Rhine...
This study examines a method to improve a process-oriented hydrological model concept applied to another region than it was first developed for. In principle, we propose to analyse and refine each major hydrological process separately, sequentially, and iteratively. To test the method, the HYPE model concept (HYdrological Predictions for the Enviro...
Arctic deltas, such as the Mackenzie Delta, are expected to face major climate change and increased human influence in the near future. Deltas are characterised by highly dynamic fluvial processes and changing climate will cause considerable evolution of the riverine environment. The changes are difficult to predict with existing knowledge and data...
A warming climate is expected to have an impact on the magnitude and timing of river floods; however, no consistent large-scale climate change signal in observed flood magnitudes has been identified so far. We analyzed the timing of river floods in Europe over the past five decades, using a pan-European database from 4262 observational hydrometric...
During the last six decades, forest biomass has expanded in the Northern basins, mainly due to forest management. This expansion should imply an increasing effect on evapotranspiration. However, increasing global CO2 emissions also trigger physiological plant water saving responses that induce an opposite effect on evapotranspiration. The dominant...
This study contributes to better understanding the physical controls on spatial patterns of pan-European flow signatures – taking advantage of large open datasets for catchment classification and comparative hydrology. Similarities in 16 flow signatures and 35 catchment descriptors were explored for 35 215 catchments and 1366 river gauges across Eu...
This policy brief illustrates how the SWITCH-ON project has provided proof-of-concept of how product development based on Open Innovation and Open Data can foster environmental and economic benefits in the European Union. This was achieved by transforming Open Databased hydrological science outputs into useful products and services for water manage...
The ECOlogical Model for Applied Geophysics (ECOMAG) and the HYdrological Predictions for the Environment (HYPE) process-based hydrological models were set up to assess possible impacts of climate change on the hydrological regime of two pan-Arctic great drainage basins of the Lena and the Mackenzie Rivers. We firstly assessed the reliability of th...
We investigate simulated hydrological extremes (i.e., high and low flows) under the present and future climatic conditions for five river basins worldwide: the Ganges, Lena, Niger, Rhine, and Tagus. Future projections are based on five GCMs and four emission scenarios. We analyse results from the HYPE, mHM, SWIM, VIC and WaterGAP3 hydrological mode...
We present one of the first climate change impact assessments on river runoff that utilises an ensemble of global hydrological models (Glob-HMs) and an ensemble of catchment-scale hydrological models (Cat-HMs), across multiple catchments: the upper Amazon, Darling, Ganges, Lena, upper Mississippi, upper Niger, Rhine and Tagus. Relative changes in s...
While seasonal outlooks have been operational for many years, until recently the extended-range timescale referred to as subseasonal-to-seasonal (S2S) has received little attention. S2S prediction fills the gap between short-range weather prediction and long-range seasonal outlooks. Decisions in a range of sectors are made in this extended-range le...
In this article we reply to a comment made on our previous commentary (Hutton et al [2016]) regarding reproducibility in computational hydrology. Re-executing someone else's code and workflow to derive a set of published results does not by itself constitute reproducibility. However, it forms a key part of the process: it demonstrates that all the...
In this article we reply to a comment made on our previous commentary (Hutton et al [2016]) regarding reproducibility in computational hydrology. Software licensing and version control of code are important technical aspects of making code and workflows of scientific experiments open and reproducible. However, in our view it is the cultural change...