Malte Müller

1. Müller, M., Knol-Kauffman, M., Jeuring, J. (2023). Arctic shipping trends during hazardous weather and sea-ice conditions and the Polar Code’s effectiveness. npj Ocean Sustainability 2, 12.

2. Palerme, C., Lavergne, T., Rusin, J., Melsom, A., Brajard, J., Kvanum, A. F., Macdonald Sørensen, A., Bertino, L., & Müller, M. (2024). Improving short-term sea ice concentration forecasts using deep learning. The Cryosphere 18, 2161–2176.

3. Müller, M., Batrak, Y., Dinesen, F., Grote, R., & Wang, K. (2023). Challenges in the description of sea ice for a kilometer-scale weather forecasting system. Weather and Forecasting 38, 1157–1171.

4. Batrak, Y. & Müller, M. (2019). On the warm bias in atmospheric reanalyses induced by the missing snow over Arctic sea ice. Nature Communications 10, 4170.

5. Müller, M., Batrak, Y., Kristiansen, J., Køltzow, M., Noer, G., & Korosov, A. (2017). Characteristics of a convective-scale weather forecasting system for the European Arctic. Monthly Weather Review 145, 4771–4787.

6. Müller, M. et al. (2017). AROME-MetCoOp: a Nordic convective-scale operational weather prediction model. Weather and Forecasting 32, 609–627.

• Collins, Clarence O.; Amador, Andre; Babanin, Alexander; Behrens, James; Benetazzo, Alvise & Bergamasco, Filippo [Show all 51 contributors for this article] (2026). Measuring Ocean Surface Waves. Reviews of Geophysics. ISSN 8755-1209. 64(3), p. 1–128. doi: 10.1029/2025rg000888. Full text in Research Archive Show summary

  Abstract Propagating waves on the ocean surface can be represented as a stochastic process whose statistics are characterized by a spectrum. This paper reviews methods for measuring the wave spectrum and related quantities. Observations begin by sensing fluid dynamical properties of the sea surface over space and/or time. Visual observations, collected routinely since the mid‐18th century, comprise the longest‐running wave record. Nearshore measurement methods continue to advance, including traditional pressure and acoustic sensing as well as newer technologies like distributed acoustic sensing and LiDAR. Detailed small‐scale wave physics can now be explored with measurement techniques using light, including stereo‐imaging and polarimetry. Reductions in the size, cost, and power consumption of microelectronics have propagated through ocean wave instrumentation, most notably in wave buoys. Global networks of freely drifting miniature wave buoys offer novel observational capabilities. Remote sensing techniques based on radar and LiDAR continue to evolve and are widely deployed from land, ships, aircraft, autonomous vehicles, and satellites. Spaceborne altimeters form one of the most important records of wave height, and new spaceborne sensors now observe directional spectra globally with sampling akin to traditional altimetry. Aircraft and autonomous systems provide strategic sampling capabilities for detailed process studies and access to extreme storm environments. The quality and quantity of ocean wave measurements have never been greater. This review aims to help make sense of it all.

• Schroth, E.; Forbriger, T.; Westerhaus, M.; Müller, Malte; Saynisch-Wagner, J. & Arbic, B. K. [Show all 11 contributors for this article] (2026). The annual variation of the M2 gravimetric tidal parameters investigated with nonlinear, time-stepping ocean models. Journal of Geodesy. ISSN 0949-7714. 100(1), p. 1–22. doi: 10.1007/s00190-025-02013-w. Full text in Research Archive Show summary

  Temporal variations of the M2 tidal parameters in gravity are observed at all superconducting gravimeter stations. We specifically investigate the annual variation of M2 tidal parameters. A similar variation is observed for the parameters from sea surface heights which is larger than expected from astronomical forcing alone. This leads to the hypothesis that the variations of the gravimetric tidal parameters are caused by the loading of the annual variation of M2 in the oceans. Only nonlinear, time-stepping ocean models are able to describe such variations. We use sea surface heights from three global and two regional models of this kind to calculate the loading. The loading time series is then added to synthetic body tides and analyzed by a moving window tidal analysis with ETERNA in the same way as the measured data. We compare the resulting variations of the M2 tidal parameters for synthetic gravity with those observed from measurements. Three of the five ocean models show an annual variation of a similar order of magnitude which supports our hypothesis. The other two ocean models produce smaller or no clear annual variation of the M2 tidal parameters. In the ocean the annual variation of M2 has large amplitudes in shelf areas and small amplitudes in the open ocean. Large areas with small amplitude might contribute to the gravity loading as much as small areas with large amplitudes do. We investigate this with the global Hycom model at three SG stations. The investigation shows that not only close shelf areas but also distant ocean regions, including open ocean areas, contribute significantly to the annual variation of the M2 tidal parameters at the superconducting gravimeter stations.

• Åsmund, Bakketun; Blyverket, Jostein & Müller, Malte (2026). Ensemble-based snow depth data assimilation for a multi-layer snow scheme over the European Arctic. The Cryosphere. ISSN 1994-0416. 20(1), p. 737–756. doi: 10.5194/tc-20-737-2026. Full text in Research Archive Show summary

  Reliable estimates of Earth system conditions are important for weather forecasting, hydrological modelling and their downstream applications. Both real-time prediction systems and historical reanalyses use a combination of observations and physical laws embedded in numerical models to generate gapless and accurate estimates of weather, climate and hydrological conditions. Data assimilation systems merge information from model estimates and observations in an objective way, accounting for their respective uncertainties. In this work we present a regional reanalysis system, focusing on the land surface component. The system uses a multi-layer snow model together with the ensemble-based Local Ensemble Transform Kalman Filter (LETKF) data assimilation scheme. The system is run for a 4 year period over the European Arctic, assimilating in situ snow depth observations. Evaluation of the new snow depth analysis showed reduced errors compared to existing products and positive impact of the data assimilation over the domain. Furthermore, a significant difference in total accumulated snow water was seen over the domain, implying a potential impact on downstream hydrological applications. The ensemble correlations between the total snow depth and the multivariate control vector indicated that the ensemble was able to represent snow compaction processes. The LETKF is thus able to account for processes which are often neglected in snow depth data assimilation. The system presented in this study allows for future extensions, including other types of observations and analyses beyond snow variables.

• Palerme, Cyril; Röhrs, Johannes; Lavergne, Thomas; Rusin, Jozef; Kvanum, Are Frode & Sørensen, John Atle Macdonald [Show all 11 contributors for this article] (2025). MET-AICE v1.0: an operational data-driven sea ice prediction system for the European Arctic. Geoscientific Model Development. ISSN 1991-959X. 18, p. 9751–9766. doi: 10.5194/gmd-18-9751-2025. Full text in Research Archive Show summary

  Abstract. There is an increasing need for reliable short-term sea ice forecasts that can support maritime operations in polar regions. While numerous studies have shown the potential of machine learning for sea ice forecasting, there are currently only a few operational data-driven sea ice prediction systems. Here, we introduce MET-AICE, a prediction system providing sea ice concentration forecasts for the next 10 days in the European Arctic. To our knowledge, it is the first operational data-driven prediction system designed for short-term sea ice forecasting. MET-AICE has been trained to predict sea ice concentration observations from the Advanced Microwave Scanning Radiometer 2 (AMSR2) at 5 km resolution. After one year of operation, we show that MET-AICE considerably outperforms persistence of AMSR2 observations (root mean square error about 31 % lower on average) and forecasts from the Barents-2.5km physically-based model (root mean square error about 50 % lower on average).

• Kvanum, Are Frode; Palerme, Cyril; Müller, Malte; Rabault, Jean & Hughes, Nick (2025). Developing a deep learning forecasting system for short-term and high-resolution prediction of sea ice concentration. The Cryosphere. ISSN 1994-0416. 19(10), p. 4149–4166. doi: 10.5194/tc-19-4149-2025. Full text in Research Archive Show summary

  Abstract. There has been a steady increase in marine activity throughout the Arctic Ocean during the last few decades, and maritime end users are requesting skilful high-resolution sea ice forecasts to ensure operational safety. Different studies have demonstrated the effectiveness of utilizing computationally lightweight deep learning models to predict sea ice properties in the Arctic. In this study, we utilize operational atmospheric forecasts, ice charts, and sea ice concentration passive microwave observations as predictors to train a deep learning model with future ice charts as ground truth. The developed deep learning forecasting system predicts regional ice charts covering parts of the East Greenland and Barents seas at 1 km resolution for 1–3 d lead time. We validate the deep learning system performance by evaluating the position of forecasted sea ice concentration contours at different concentration thresholds. It is shown that the deep learning forecasting system achieves a lower error for several sea ice concentration contours when compared against baseline forecasts (persistence forecasts, sea ice free drift, and a linear trend) and two state-of-the-art dynamical sea ice forecasting systems (neXtSIM and Barents-2.5) for all considered lead times and seasons.

• Rabault, Jean; Halsne, Trygve; Carrasco, Ana; Korosov, Anton; Voermans, Joey & Bohlinger, Patrik [Show all 28 contributors for this article] (2025). Buoy measurements of strong waves in ice amplitude modulation: a signature of the impact of sea ice closedness on waves in ice attenuation. The Cryosphere. ISSN 1994-0416. 19(11), p. 6229–6260. doi: 10.5194/tc-19-6229-2025. Full text in Research Archive Show summary

  The Marginal Ice Zone (MIZ) forms a critical transition region between the ocean and sea ice cover, as it protects the close ice further in from the effect of the steepest and most energetic open ocean waves. As waves propagate through the MIZ, they become exponentially attenuated. Unfortunately, the associated attenuation coefficient is difficult to accurately estimate and model, and there are still large uncertainties around which attenuation mechanisms dominate depending on the conditions. This makes it difficult to predict waves in ice attenuation, as well as sea ice breakup and dynamics. Here, we report in situ observations of strongly modulated waves in ice amplitude, with a modulation period of around 12 h. We show that simple explanations, such as changes in the incoming open water waves or the direct effect of tides and currents and bathymetry on the propagating waves, cannot explain the observed modulation. Therefore, the wave height modulation observed in the ice comes from a modulation of the waves in ice attenuation coefficient. We gather evidence that sea ice convergence and divergence is likely the factor driving this modulation in the attenuation coefficient, through its influence on the ice “closedness”. This implies that the level of sea ice “closedness” needs to be taken into account by future dissipation parameterizations.

• Müller, Malte; Rabault, Jean; Geeter, Chiara de; Palerme, Cyril; Bhattarai, Bikas Chandra & Collard, Fabrice [Show all 14 contributors for this article] (2025). Svalbard Marginal Ice Zone 2024: A distributed network of temperature, waves, and sea ice drift observations. Scientific Data. 12. doi: 10.1038/s41597-025-05889-7. Full text in Research Archive Show summary

  The coupling of weather, sea-ice, ocean, and wave forecasting systems has been a research priority for improving Arctic prediction capabilities. However, the complexity of the underlying physical processes and the difficulty of obtaining observations on representative spatial and temporal scales present significant challenges, particularly in the Marginal Ice Zone (MIZ). The primary objective of the Svalbard Marginal Ice Zone Campaign 2024 (SvalMIZ-24) was to establish a network of observations with a spatial distribution that enables a representative comparison between in situ measurements and gridded model data. The key variables that were measured are air and surface temperatures, sea-ice drift, and wave energy spectra. Within the main observation period, a persistent cold air outbreak as well as a warm air intrusion event, coinciding with the formation of an intense wave system propagating into the MIZ was captured. This dataset provides valuable insights into atmosphere-ice-ocean interactions in the MIZ and serves as a resource for future studies, model validation, and intercomparison efforts aimed at improving Arctic forecasting systems.

• Müller, Malte; Rabault, Jean; Abdel-Fattah, Dina Tarek & Sutherland, Graig (2025). Distributed observation networks in the Arctic Marginal Ice Zone to advance forecasting systems. Bulletin of The American Meteorological Society - (BAMS). ISSN 0003-0007. 106(6), p. E1204–E1210. doi: 10.1175/BAMS-D-25-0082.1. Full text in Research Archive Show summary

  More than 40 researchers from various disciplines related to the modeling and observation of weather, sea ice, and wave dynamics met to discuss challenges in coupled forecasting systems to represent processes in the Arctic marginal ice zone.

• Jeuring, Jelmer; Samuelsen, Eirik Mikal; Lamers, Machiel; Müller, Malte; Hjøllo, Bjørn Åge & Bertino, Laurent [Show all 7 contributors for this article] (2024). Map-Based Ensemble Forecasts for Maritime Operations: An Interactive Usability Assessment with Decision Scenarios. Weather, Climate, and Society. ISSN 1948-8327. 16(1), p. 235–256. doi: 10.1175/WCAS-D-23-0076.1. Full text in Research Archive
• Palerme, Cyril; Lavergne, Thomas; Rusin, Jozef; Melsom, Arne; Brajard, Julien & Kvanum, Are Frode Helvig [Show all 9 contributors for this article] (2024). Improving short-term sea ice concentration forecasts using deep learning. The Cryosphere. ISSN 1994-0416. 18(4), p. 2161–2176. doi: 10.5194/tc-18-2161-2024. Full text in Research Archive Show summary

  Reliable short-term sea ice forecasts are needed to support maritime operations in polar regions. While sea ice forecasts produced by physically based models still have limited accuracy, statistical post-processing techniques can be applied to reduce forecast errors. In this study, post-processing methods based on supervised machine learning have been developed for improving the skill of sea ice concentration forecasts from the TOPAZ4 prediction system for lead times from 1 to 10 d. The deep learning models use predictors from TOPAZ4 sea ice forecasts, weather forecasts, and sea ice concentration observations. Predicting the sea ice concentration for the next 10 d takes about 4 min (including data preparation), which is reasonable in an operational context. On average, the forecasts from the deep learning models have a root mean square error 41 % lower than TOPAZ4 forecasts and 29 % lower than forecasts based on persistence of sea ice concentration observations. They also significantly improve the forecasts for the location of the ice edges, with similar improvements as for the root mean square error. Furthermore, the impact of different types of predictors (observations, sea ice, and weather forecasts) on the predictions has been evaluated. Sea ice observations are the most important type of predictors, and the weather forecasts have a much stronger impact on the predictions than sea ice forecasts.

• Rabault, Jean; Taelman, Catherine Cecilia A; Idzanovic, Martina; Hope, Gaute; Nose, Takehiko & Kristoffersen, Yngve [Show all 31 contributors for this article] (2024). A position and wave spectra dataset of Marginal Ice Zone dynamics collected around Svalbard in 2022 and 2023. Scientific Data. 11, p. 1–10. doi: 10.1038/s41597-024-04281-1. Full text in Research Archive Show summary

  Sea ice is a key element of the global Earth system, with a major impact on global climate and regional weather. Unfortunately, accurate sea ice modeling is challenging due to the diversity and complexity of underlying physics happening there, and a relative lack of ground truth observations. This is especially true for the Marginal Ice Zone (MIZ), which is the area where sea ice is affected by incoming ocean waves. Waves contribute to making the area dynamic, and due to the low survival time of the buoys deployed there, the MIZ is challenging to monitor. In 2022-2023, we released 79 OpenMetBuoys (OMBs) around Svalbard, both in the MIZ and the ocean immediately outside of it. OMBs are affordable enough to be deployed in large number, and gather information about drift (GNSS position) and waves (1-dimensional elevation spectrum). This provides data focusing on the area around Svalbard with unprecedented spatial and temporal resolution. We expect that this will allow to perform validation and calibration of ice models and remote sensing algorithms.

• Bakketun, Åsmund; Blyverket, Jostein & Müller, Malte (2023). Using a reanalysis driven land surface model for initialization of a numerical weather prediction system. Weather and forecasting. ISSN 0882-8156. 38(11), p. 2155–2168. doi: 10.1175/WAF-D-22-0184.1. Full text in Research Archive Show summary

  Abstract Realistic initialization of the land surface is important to produce accurate NWP forecasts. Therefore, making use of available observations is essential when estimating the surface state. In this work, sequential land surface data assimilation of soil variables is replaced with an offline cycling method. To obtain the best possible initial state for the lower boundary of the NWP system, the land surface model is rerun between forecasts with an analyzed atmospheric forcing. We found a relative reduction of 2-m temperature root-mean-square errors and mean errors of 6% and 12%, respectively, and 4.5% and 11% for 2-m specific humidity. During a convective event, the system was able to produce useful (fractions skill score greater than the uniform forecast) forecasts [above 30 mm (12 h) −1 ] down to a 100-km length scale where the reference failed to do so below 200 km. The different precipitation forcing caused differences in soil moisture fields that persisted for several weeks and consequently impacted the surface fluxes of heat and moisture and the forecasts of screen level parameters. The experiments also indicate diurnal- and weather-dependent variations of the forecast errors that give valuable insight on the role of initial land surface conditions and the land–atmosphere interactions in southern Scandinavia.

• Müller, Malte; Batrak, Yurii; Dinessen, Frode; Grote, Johannes Rafael & Wang, Keguang (2023). Challenges in the Description of Sea Ice for a Kilometer-Scale Weather Forecasting System. Weather and forecasting. ISSN 0882-8156. 38(7), p. 1157–1171. doi: 10.1175/WAF-D-22-0134.1. Full text in Research Archive
• Müller, Malte; Knol-Kauffman, Maaike; Jeuring, Jelmer & Palerme, Cyril (2023). Arctic shipping trends during hazardous weather and sea-ice conditions and the Polar Code’s effectiveness. npj Ocean Sustainability. 2(1). doi: 10.1038/s44183-023-00021-x. Full text in Research Archive Show summary

  The Arctic’s extreme environmental conditions and remoteness make it a complex and dynamic environment for maritime operators. We find that Arctic shipping has grown by 7% per year over the past decade, despite the hazardous weather and sea-ice conditions that pose risks to vessels operating in the region. As a result of a strong increase in winter sailing, the time ships operate in these extreme conditions has even tripled. To mitigate maritime risks, the Polar Code has been introduced. Among other things, it regulates Arctic shipping by specifying hazardous conditions with a sea-ice classification scheme and design temperature threshold. However, we argue that the Polar Code needs refinement through the integration of maritime warning systems and a broader description of hazardous conditions. This is supported by an analysis of shipping activity patterns in severe sea-spray icing conditions and a discussion of a recent sea-ice induced incident along the Northern Sea Route.

• Ødemark, Karianne; Müller, Malte; Palerme, Cyril & Tveito, Ole Einar Ellingbø (2023). Recent changes in circulation patterns and their opposing impact on extreme precipitation at the west coast of Norway. Weather and Climate Extremes. ISSN 2212-0947. 39. doi: 10.1016/j.wace.2022.100530. Full text in Research Archive Show summary

  Understanding recent and future changes of extreme precipitation is essential for climate change adaptation. Here, we use 3800 extreme precipitation events produced by an ensemble seasonal prediction system. The ensemble represents the climate from 1981 to 2018 and we analyse 3-day maximum precipitation events in September–October–November for the west coast of Norway. Two dominant atmospheric patterns, described by an empirical orthogonal function (EOF) analysis, are related to the results of the extreme value statistics. The principal components of the second and third mode of EOFs have significant trends over the last 40 years, but with an opposing impact on the return values of extreme precipitation. This explains the observed stationarity of extreme precipitation over recent decades at the west coast of Norway, which was also found in previous studies. The second mode of EOFs also shows a relation to the sea-ice coverage in the Barents and Kara Seas, which suggests a connection between the decline of sea-ice to the changes in the atmospheric pattern.

• Gerland, Sebastian; Ingvaldsen, Randi Brunvær; Reigstad, Marit; Sundfjord, Arild; Bogstad, Bjarte & Chierici, Melissa [Show all 41 contributors for this article] (2023). Still Arctic? — The changing Barents Sea. Elementa: Science of the Anthropocene. 11(1), p. 1–62. doi: 10.1525/elementa.2022.00088. Full text in Research Archive Show summary

  The Barents Sea is one of the Polar regions where current climate and ecosystem change is most pronounced. Here we review the current state of knowledge of the physical, chemical and biological systems in the Barents Sea. Physical conditions in this area are characterized by large seasonal contrasts between partial sea-ice cover in winter and spring versus predominantly open water in summer and autumn. Observations over recent decades show that surface air and ocean temperatures have increased, sea-ice extent has decreased, ocean stratification has weakened, and water chemistry and ecosystem components have changed, the latter in a direction often described as “Atlantification” or “borealisation,” with a less “Arctic” appearance. Temporal and spatial changes in the Barents Sea have a wider relevance, both in the context of large-scale climatic (air, water mass and sea-ice) transport processes and in comparison to other Arctic regions. These observed changes also have socioeconomic consequences, including for fisheries and other human activities. While several of the ongoing changes are monitored and quantified, observation and knowledge gaps remain, especially for winter months when field observations and sample collections are still sparse. Knowledge of the interplay of physical and biogeochemical drivers and ecosystem responses, including complex feedback processes, needs further development.

• Herrmannsdörfer, Lia F; Müller, Malte; Shupe, Matthew D. & Rostosky, Philip (2023). Surface temperature comparison of the Arctic winter MOSAiC observations, ERA5 reanalysis, and MODIS satellite retrieval. Elementa: Science of the Anthropocene. 11(1). doi: 10.1525/elementa.2022.00085. Full text in Research Archive
• Rabault, Jean; Müller, Malte; Voermans, Joey; Brazhnikov, Dmitry; Turnbull, Ian & Marchenko, Aleksey [Show all 28 contributors for this article] (2023). A dataset of direct observations of sea ice drift and waves in ice. Scientific Data. 10. doi: 10.1038/s41597-023-02160-9. Full text in Research Archive Show summary

  Variability in sea ice conditions, combined with strong couplings to the atmosphere and the ocean, lead to a broad range of complex sea ice dynamics. More in-situ measurements are needed to better identify the phenomena and mechanisms that govern sea ice growth, drift, and breakup. To this end, we have gathered a dataset of in-situ observations of sea ice drift and waves in ice. A total of 15 deployments were performed over a period of 5 years in both the Arctic and Antarctic, involving 72 instruments. These provide both GPS drift tracks, and measurements of waves in ice. The data can, in turn, be used for tuning sea ice drift models, investigating waves damping by sea ice, and helping calibrate other sea ice measurement techniques, such as satellite based observations.

• Thomas, Erin E. & Müller, Malte (2022). Characterizing vertical upper ocean temperature structures in the European Arctic through unsupervised machine learning. Ocean Modelling. ISSN 1463-5003. 177. doi: 10.1016/j.ocemod.2022.102092. Full text in Research Archive Show summary

  In-situ observations of subsurface ocean temperatures are, in many regions, inconsistently distributed in time and space. These spatio-temporal inconsistencies in the observational network lead to difficulties in utilizing those observations effectively for ocean model evaluation or understanding larger-scale ocean characteristics. Model accuracy of subsurface ocean characteristics is especially important within regions that contain complex ocean structures. One such region is the European Arctic which not only contains several types of water masses with unique characteristics, but also wintertime sea ice coverage and complex bathymetry. This study presents an unsupervised neural networking technique that can be used in combination with traditional ocean model evaluation techniques to provide additional information on the accuracy of modeled vertical ocean temperature profiles. Self-organizing maps is an unsupervised machine learning technique that we apply to approximately twenty thousand Argo and CTD temperature profiles from 2012 to 2020 in the European Arctic to categorize the observed vertical ocean temperature structures in the top 150 m. The observed ocean profile categories, or neurons, defined by the self-organizing map show strong spatial and temporal dependencies. We then use the neuron weights, or the learned temperature profile structure of each neuron, to validate the spatial and temporal variability of modeled vertical temperature structures. This analysis gives us new insights about the model’s capabilities to reproduce specific vertical structures of the top-most ocean layer within different regions and seasons. Mapping modeled ocean temperature profiles onto the neuron-space of the observationally-defined self organized map highlights the potential of this method to advance our understanding of model deficiencies in that region.

• Müller, Malte; Kelder, Timo & Palerme, Cyril (2022). Decline of sea-ice in the Greenland Sea intensifies extreme precipitation over Svalbard. Weather and Climate Extremes. ISSN 2212-0947. 36. doi: 10.1016/j.wace.2022.100437. Full text in Research Archive Show summary

  Extreme precipitation over the Svalbard Archipelago in the Arctic can have severe consequences for the ecosystem and society. In recent years several extreme precipitation events have been observed at Ny Ålesund, a weather station in the north-western part of the Svalbard Archipelago. The most recent observed events in the years 2012, 2016, and 2018 were the strongest events in the entire precipitation record from 1974 till today. The key question of our study is whether those recently observed extremes are part of a climate change signal or are a random accumulation of extremes. With a novel approach based on a large ensemble of model simulations, we show that the likelihood of occurrence for extreme precipitation over Svalbard has increased over the last four decades. We find that the likelihood of occurrence is connected to the sea ice extent east of Greenland because the presence of sea ice shields the west coast of Svalbard from the incoming southerly moist air. Our analysis suggests, that in the future with a further decline of the sea ice coverage east of Greenland, the recently observed precipitation extremes will become even more frequent.

• Blair, Berill; Müller, Malte; Palerme, Cyril; Blair, Rayne; Crookall, David & Knol-Kauffman, Maaike [Show all 7 contributors for this article] (2022). Coproducing Sea Ice Predictions with Stakeholders Using Simulation. Weather, Climate, and Society. ISSN 1948-8327. 14(2), p. 399–413. doi: 10.1175/WCAS-D-21-0048.1. Full text in Research Archive Show summary

  Forecasts of sea ice evolution in the Arctic region for several months ahead can be of considerable socioeconomic value for a diverse range of marine sectors and for local community supply logistics. However, subseasonal-to-seasonal (S2S) forecasts represent a significant technical challenge, and translating user needs into scientifically manageable procedures and robust user confidence requires collaboration among a range of stakeholders. We developed and tested a novel, transdisciplinary coproduction approach that combined socioeconomic scenarios and participatory, research-driven simulation gaming to test a new S2S sea ice forecast system with experienced mariners in the cruise tourism sector. Our custom-developed computerized simulation game known as “ICEWISE” integrated sea ice parameters, forecast technology, and human factors as a participatory environment for stakeholder engagement. We explored the value of applications-relevant S2S sea ice prediction and linked uncertainty information. Results suggest that the usefulness of S2S services is currently most evident in schedule-dependent sectors but is expected to increase as a result of anticipated changes in the physical environment and continued growth in Arctic operations. Reliable communication of uncertainty information in sea ice forecasts must be demonstrated and trialed before users gain confidence in emerging services and technologies. Mariners’ own intuition, experience, and familiarity with forecast service provider reputation impact the extent to which sea ice information may reduce uncertainties and risks for Arctic mariners. Our insights into the performance of the combined foresight/simulation coproduction model in brokering knowledge across a range of domains demonstrates promise. We conclude with an overview of the potential contributions from S2S sea ice predictions and from experiential coproduction models to the development of decision-driven and science-informed climate services.

• Rabault, Jean; Nose, Takehiko; Hope, Gaute; Müller, Malte; Breivik, Øyvind & Voermans, Joey [Show all 20 contributors for this article] (2022). OpenMetBuoy-v2021: An Easy-to-Build, Affordable, Customizable, Open-Source Instrument for Oceanographic Measurements of Drift and Waves in Sea Ice and the Open Ocean. Geosciences. 12(3). doi: 10.3390/geosciences12030110. Full text in Research Archive Show summary

  There is a wide consensus within the polar science, meteorology, and oceanography communities that more in situ observations of the ocean, atmosphere, and sea ice are required to further improve operational forecasting model skills. Traditionally, the volume of such measurements has been limited by the high cost of commercially available instruments. An increasingly attractive solution to this cost issue is to use instruments produced in-house from open-source hardware, firmware, and postprocessing building blocks. In the present work, we release the next iteration of the open-source drifter and wave-monitoring instrument of Rabault et al. (see “An open source, versatile, affordable waves in ice instrument for scientific measurements in the Polar Regions”, Cold Regions Science and Technology, 2020), which follows these solution aspects. The new design is significantly less expensive (typically by a factor of 5 compared with our previous, already cost-effective instrument), much easier to build and assemble for people without specific microelectronics and programming competence, more easily extendable and customizable, and two orders of magnitude more power-efficient (to the point where solar panels are no longer needed even for long-term deployments). Improving performance and reducing noise levels and costs compared with our previous generation of instruments is possible in large part thanks to progress from the electronics component industry. As a result, we believe that this will allow scientists in geosciences to increase by an order of magnitude the amount of in situ data they can collect under a constant instrumentation budget. In the following, we offer (1) a detailed overview of our hardware and software solution, (2) in situ validation and benchmarking of our instrument, (3) a fully open-source release of both hardware and software blueprints. We hope that this work, and the associated open-source release, will be a milestone that will allow our scientific fields to transition towards open-source, community-driven instrumentation. We believe that this could have a considerable impact on many fields by making in situ instrumentation at least an order of magnitude less expensive and more customizable than it has been for the last 50 years, marking the start of a new paradigm in oceanography and polar science, where instrumentation is an inexpensive commodity and in situ data are easier and less expensive to collect.

• Daher, Houraa; Arbic, Brian K.; Williams, James G.; Ansong, Joseph K.; Boggs, Dale H. & Müller, Malte [Show all 18 contributors for this article] (2021). Long-Term Earth-Moon Evolution With High-Level Orbit and Ocean Tide Models. Journal of Geophysical Research (JGR): Planets. ISSN 2169-9097. 126(12), p. 1–39. doi: 10.1029/2021JE006875. Full text in Research Archive
• Schuckmann, Karina von; Traon, Pierre-Yves; Smith, Neville; Pascual, Ananda; Djavidnia, Samuel & Gattuso, Jean-Pierre [Show all 22 contributors for this article] (2021). Copernicus Marine Service Ocean State Report, Issue 5. Journal of operational oceanography. Publisher: The Institute of Marine Engineering, Science & Technology. ISSN 1755-876X. 14(S1). doi: 10.1080/1755876X.2021.1946240. Full text in Research Archive
• Thomas, Erin E.; Müller, Malte; Bohlinger, Patrik; Batrak, Yurii & Szapiro, Nicholas (2021). A Kilometer-Scale Coupled Atmosphere-Wave Forecasting System for the European Arctic. Weather and forecasting. ISSN 0882-8156. 36(6), p. 2087–2099. doi: 10.1175/WAF-D-21-0065.1. Full text in Research Archive Show summary

  Abstract Accurately simulating the interactions between the components of a coupled Earth modelling system (atmosphere, sea-ice, and wave) on a kilometer-scale resolution is a new challenge in operational numerical weather prediction. It is difficult due to the complexity of interactive mechanisms, the limited accuracy of model components and scarcity of observations available for assessing relevant coupled processes. This study presents a newly developed convective-scale atmosphere-wave coupled forecasting system for the European Arctic. The HARMONIE-AROME configuration of the ALADIN-HIRLAM numerical weather prediction system is coupled to the spectral wave model WAVEWATCH III using the OASIS3 model coupling toolkit. We analyze the impact of representing the kilometer-scale atmosphere-wave interactions through coupled and uncoupled forecasts on a model domain with 2.5 km spatial resolution. In order to assess the coupled model’s accuracy and uncertainties we compare 48-hour model forecasts against satellite observational products such as Advanced Scatterometer 10 m wind speed, and altimeter based significant wave height. The fully coupled atmosphere-wave model results closely match both satellite-based wind speed and significant wave height observations as well as surface pressure and wind speed measurements from selected coastal station observation sites. Furthermore, the coupled model contains smaller standard deviation of errors in both 10m wind speed and significant wave height parameters when compared to the uncoupled model forecasts. Atmosphere and wave coupling reduces the short term forecast error variability of 10 m wind speed and significant wave height with the greatest benefit occurring for high wind and wave conditions.

• Palerme, Cyril & Müller, Malte (2021). Calibration of sea ice drift forecasts using random forest algorithms. The Cryosphere. ISSN 1994-0416. 15(8), p. 3989–4004. doi: 10.5194/tc-15-3989-2021. Full text in Research Archive
• Løken, Trygve Kvåle; Rabault, Jean; Thomas, Erin E.; Müller, Malte; Christensen, Kai Håkon & Sutherland, Graig [Show all 7 contributors for this article] (2020). A comparison of wave observations in the Arctic marginal ice zone with spectral models. Proceedings of the IAHR International Symposium on Ice. p. 499–508. Full text in Research Archive
• Kelder, Timo; Müller, Malte; Slater, L.J.; Marjoribanks, T.I.; Wilby, R.L. & Prudhomme, Christel [Show all 9 contributors for this article] (2020). Using UNSEEN trends to detect decadal changes in 100-year precipitation extremes. npj Climate and Atmospheric Science. 3. doi: 10.1038/s41612-020-00149-4. Full text in Research Archive Show summary

  Abstract Sample sizes of observed climate extremes are typically too small to reliably constrain return period estimates when there is non-stationary behaviour. To increase the historical record 100-fold, we apply the UNprecedented Simulated Extreme ENsemble (UNSEEN) approach, by pooling ensemble members and lead times from the ECMWF seasonal prediction system SEAS5. We fit the GEV distribution to the UNSEEN ensemble with a time covariate to facilitate detection of changes in 100-year precipitation values over a period of 35 years (1981–2015). Applying UNSEEN trends to 3-day precipitation extremes over Western Norway substantially reduces uncertainties compared to estimates based on the observed record and returns no significant linear trend over time. For Svalbard, UNSEEN trends suggests there is a significant rise in precipitation extremes, such that the 100-year event estimated in 1981 occurs with a return period of around 40 years in 2015. We propose a suite of methods to evaluate UNSEEN and highlight paths for further developing UNSEEN trends to investigate non-stationarities in climate extremes.

• Løken, Trygve Kvåle; Rabault, Jean; Jensen, Atle; Sutherland, Graig; Christensen, Kai Håkon & Müller, Malte (2020). Wave measurements from ship mounted sensors in the Arctic marginal ice zone. Cold Regions Science and Technology. ISSN 0165-232X. 182. doi: 10.1016/j.coldregions.2020.103207. Full text in Research Archive Show summary

  This study presents wave measurements in the Marginal Ice Zone (MIZ) obtained from ship mounted sensors. The system combines altimeter readings from the ship bow with ship motion correction data to provide estimated single point ocean surface elevation. Significant wave height and mean wave period, as well as one-dimensional wave spectra are derived from the combined measurements. The results are compared with integrated parameters from two spectral wave models over a period of eight days in the open ocean, and with spectra and integrated parameters derived from motion detecting instruments placed on ice floes inside the MIZ. Mean absolute errors of the integrated parameters are in the range 13.4-29.9% when comparing with the spectral wave models and 1.0-9.6% when comparing with valid motion detecting instruments. The spatial wave damping coefficient is estimated by looking at the change in spectral wave amplitude found at discrete frequency values as the ship was moving along the longitudinal direction of the MIZ within time intervals where the wave field is found to be approximately constant in time. As expected from theory, high frequency waves are effectively dampened by the presence of sea ice. The observed wave attenuation rates compare favourably with a two-layer dissipation model. Our methodology can be regarded as a simple and reliable way to collect more waves-in-ice data as it can be easily added to any ship participating to ice expeditions, at little extra cost.

• Schuckmann, K. von; Traon, Pierre-Yves Le; Smith, Neville; Pascual, Ananda; Djavidnia, Samuel & Gattuso, Jean-Pierre [Show all 13 contributors for this article] (2020). Copernicus Marine Service Ocean State Report, issue 4. Journal of operational oceanography. Publisher: The Institute of Marine Engineering, Science & Technology. ISSN 1755-876X. 13(1), p. 1–172. doi: 10.1080/1755876X.2020.1785097. Full text in Research Archive
• Ødemark, Karianne; Müller, Malte & Tveito, Ole Einar Ellingbø (2020). Changing lateral boundary conditions for probable maximum precipitation studies: A physically consistent approach. Journal of Hydrometeorology. ISSN 1525-755X. 22(1), p. 113–123. doi: 10.1175/JHM-D-20-0070.1. Full text in Research Archive Show summary

  Abstract This article presents a conceptual study toward establishing a new method for altering lateral boundary conditions in numerical model based estimates for probable maximum precipitation (PMP). We altered an extreme event in a physically and dynamically consistent way in a regional convective-scale weather prediction model (AROME-MetCoOp) by applying fields from a global ensemble climate model approach based on EC-EARTH. Ten ensemble members are downscaled with the regional model, which results in 10 different realizations of an extreme precipitation event for the west coast of Norway. We show how the position and orientation of the moisture flow is different between the individual ensemble members, which leads to relatively large changes in precipitation values for a selected catchment. For example, the modification of the moisture transport on scales of several hundred kilometers impacts the extreme precipitation amount by about 75% among the model members. Compared with historical rainfall records, precipitation changes of 62% and 71% are found for two selected catchments. Although the present study is restricted to one particular extreme event that is modified 10 times with the ensemble approach, there is a considerable spread of the moisture transport compared to the spread of the moisture transport of extreme precipitation events of the past 40 years. We conclude that the described approach is a step toward a new method to derive PMP values for a given catchment; however, a larger amount of events and larger ensembles would have to be considered to estimate PMP values.

• Haigh, Ivan D.; Pickering, Mark D.; Green, J.A. Mattias; Arbic, Brian K.; Arns, Arne & Dangendorf, Sönke [Show all 18 contributors for this article] (2020). The tides they are a-changin': A comprehensive review of past and future nonastronomical changes in tides, their driving mechanisms, and future implications. Reviews of Geophysics. ISSN 8755-1209. 58:e2018RG000636(1), p. 1–39. doi: 10.1029/2018RG000636. Full text in Research Archive
• Schaller, Nathalie; Sillmann, Jana; Müller, Malte; Haarsma, Reindert; Hazeleger, Wilco & Hegdahl, Trine Jahr [Show all 10 contributors for this article] (2020). The role of spatial and temporal model resolution in a flood event storyline approach in western Norway. Weather and Climate Extremes. ISSN 2212-0947. 29, p. 100259–100259. doi: 10.1016/j.wace.2020.100259. Full text in Research Archive Show summary

  We apply a physical climate storyline approach to an autumn flood event in the West Coast of Norway caused by an atmospheric river to demonstrate the value and challenges of higher spatial and temporal resolution in simulating flood impacts. We use a modelling chain whose outputs are familiar and used operationally, for example to issue flood warnings. With two different versions of a hydrological model, we show that (1) the higher spatial resolution between the global and regional climate model is necessary to realistically simulate the high spatial variability of precipitation in this mountainous region and (2) only with hourly data are we able to capture the fast flood-generating processes leading to the peak streamflow. The higher resolution regional atmospheric model captures the fact that with the passage of an atmospheric river, some valleys receive high amounts of precipitation and others not, while the coarser resolution global model shows uniform precipitation in the whole region. Translating the event into the future leads to similar results: while in some catchments, a future flood might be much larger than a present one, in others no event occurs as the atmospheric river simply does not hit that catchment. The use of an operational flood warning system for future events is expected to facilitate stakeholder engagement.

• Bohlinger, Patrik; Breivik, Øyvind; Economou, Theodoros & Müller, Malte (2019). A novel approach to computing super observations for probabilistic wave model validation. Ocean Modelling. ISSN 1463-5003. 139:101404, p. 1–10. doi: 10.1016/j.ocemod.2019.101404. Full text in Research Archive Show summary

  In the field of wave model validation, the use of super observations is a common strategy to smooth satellite observations and match the simulated spatiotemporal scales. An approach based on averaging along track is widely applied because it is straightforward to implement and adjustable. However, the choice of an appropriate length scale for obtaining the averages can be ambiguous, affecting subsequent analyses. Despite this dilemma, no uncertainty for the validation metric is provided when proceeding with wave model validation. We show that super observations computed from averaging data points applying an inappropriate length scale can lead to a misrepresentation of the wave field which can introduce errors into the wave model validation. Modelling the mean of observations as a Gaussian Process mitigates those errors and reliably identifies outliers by exploiting information hidden in the observational time series. Moreover, the uncertainty accompanying the validation statistic is readily accessible in the Gaussian Process framework. The flexibility of a Gaussian process makes it an attractive candidate for the probabilistic validation of wave models with steadily increasing horizontal resolution. Moreover, this approach can be applied to measurements from other platforms (e.g. buoys) and other variables (e.g. wind).

• Palerme, Cyril; Müller, Malte & Melsom, Arne (2019). An intercomparison of verification scores for evaluating the sea ice edge position in seasonal forecasts. Geophysical Research Letters. ISSN 0094-8276. 46(9), p. 4757–4763. doi: 10.1029/2019GL082482. Full text in Research Archive
• Melsom, Arne; Palerme, Cyril & Müller, Malte (2019). Validation metrics for ice edge position forecasts. Ocean Science. ISSN 1812-0784. 15(3), p. 615–630. doi: 10.5194/os-15-615-2019. Full text in Research Archive Show summary

  Retreating sea ice in the Arctic Ocean gives rise to increased naval traffic with shorter navigation distances. Hence, information about the position of the sea ice edge is crucial for safe navigation. In the present study we explore methods for examining the quality of sea ice edge forecasts. We conclude that the forecast quality can be monitored with results from a set of four quantities. We also recommend the use of maps which display discrepancies in the positions of the sea ice edge.

• Batrak, Yurii & Müller, Malte (2019). On the warm bias in atmospheric reanalyses induced by the missing snow over Arctic sea-ice. Nature Communications. 10(1), p. 4170–4170. doi: 10.1038/s41467-019-11975-3. Full text in Research Archive
• Howe, Bruce M.; Arbic, Brian K.; Aucan, Jérome; Barnes, Chris; Bayliff, Nigel & Becker, Nathan [Show all 25 contributors for this article] (2019). Smart cables for observing the global ocean: Science and implementation. Frontiers in Marine Science. 6. doi: 10.3389/fmars.2019.00424. Full text in Research Archive
• Aaboe, Signe; Aguiar, Eva; Fanjul, Enrique Álvarez; Alvera-Azcárate, Aida; Aouf, Lotfi & Barciela, Rosa [Show all 113 contributors for this article] (2019). Copernicus Marine Service Ocean State Report, Issue 3. Journal of operational oceanography. Publisher: The Institute of Marine Engineering, Science & Technology. ISSN 1755-876X. 12, p. 1–123. doi: 10.1080/1755876X.2019.1633075. Full text in Research Archive
• Sérazin, Guillaume; Penduff, Thierry; Barnier, Bernard; Molines, Jean-Marc; Arbic, Brian K. & Müller, Malte [Show all 7 contributors for this article] (2018). Inverse cascades of kinetic energy as a source of intrinsic variability: A global OGCM study. Journal of Physical Oceanography. ISSN 0022-3670. 48(6), p. 1385–1408. doi: 10.1175/JPO-D-17-0136.1. Full text in Research Archive
• Batrak, Yurii & Müller, Malte (2018). Atmospheric response to kilometer‐scale changes in sea‐ice concentration within the Marginal Ice Zone. Geophysical Research Letters. ISSN 0094-8276. 45(13), p. 6702–6709. doi: 10.1029/2018GL078295. Full text in Research Archive
• Müller, Malte; Homleid, Mariken; Ivarsson, Karl-Ivar; Køltzow, Morten Andreas Ødegaard; Lindskog, Magnus & Midtbø, Knut Helge [Show all 15 contributors for this article] (2017). AROME-MetCoOp: A Nordic Convective-Scale Operational Weather Prediction Model. Weather and forecasting. ISSN 0882-8156. 32(2), p. 609–627. doi: 10.1175/WAF-D-16-0099.1. Full text in Research Archive
• Li, Zhuhua; Storch, Jin-Song von & Müller, Malte (2017). The K1 internal tide simulated by a 1/10° OGCM. Ocean Modelling. ISSN 1463-5003. 113, p. 145–156. doi: 10.1016/j.ocemod.2017.04.002. Full text in Research Archive
• Müller, Malte; Batrak, Yurii; Kristiansen, Jørn; Køltzow, Morten Andreas Ødegaard; Noer, Gunnar & Korosov, Anton (2017). Characteristics of a convective-scale weather forecasting system for the European Arctic. Monthly Weather Review. ISSN 0027-0644. 145(12), p. 4771–4787. doi: 10.1175/MWR-D-17-0194.1. Full text in Research Archive
• Li, Zhuhua; Storch, Jin-Song von & Müller, Malte (2015). The M2 Internal Tide Simulated by a 1/10° OGCM. Journal of Physical Oceanography. ISSN 0022-3670. 45(12), p. 3119–3135. doi: 10.1175/JPO-D-14-0228.1. Full text in Research Archive
• Müller, Malte; Arbic, Brian K.; Richman, James G.; Shriver, Jay F.; Kunze, Eric & Scott, Robert [Show all 8 contributors for this article] (2015). Toward an internal gravity wave spectrum in global ocean models. Geophysical Research Letters. ISSN 0094-8276. 42(9), p. 3474–3481. doi: 10.1002/2015GL063365. Full text in Research Archive
• Fer, Ilker; Müller, Malte & Peterson, Algot Kristoffer (2015). Tidal forcing, energetics, and mixing near the Yermak Plateau. Ocean Science. ISSN 1812-0784. 11(2), p. 287–304. doi: 10.5194/os-11-287-2015. Full text in Research Archive Show summary

  The Yermak Plateau (YP), located northwest of Svalbard in Fram Strait, is the final passage for the inflow of warm Atlantic Water into the Arctic Ocean. The region is characterized by the largest barotropic tidal velocities in the Arctic Ocean. Internal response to the tidal flow over this topographic feature locally contributes to mixing that removes heat from the Atlantic Water. Here, we investigate the tidal forcing, barotropic-to-baroclinic energy conversion rates, and dissipation rates in the region using observations of oceanic currents, hydrography, and microstructure collected on the southern flanks of the plateau in summer 2007, together with results from a global high-resolution ocean circulation and tide model simulation. The energetics (depth-integrated conversion rates, baroclinic energy fluxes and dissipation rates) show large spatial variability over the plateau and are dominated by the luni-solar diurnal (K1) and the principal lunar semidiurnal (M2) constituents. The volume-integrated conversion rate over the region enclosing the topographic feature is approximately 1 GW and accounts for about 50% of the M2 and approximately all of the K1 conversion in a larger domain covering the entire Fram Strait extended to the North Pole. Despite the substantial energy conversion, internal tides are trapped along the topography, implying large local dissipation rates. An approximate local conversion–dissipation balance is found over shallows and also in the deep part of the sloping flanks. The baroclinic energy radiated away from the upper slope is dissipated over the deeper isobaths. From the microstructure observations, we inferred lower and upper bounds on the total dissipation rate of about 0.5 and 1.1 GW, respectively, where about 0.4–0.6 GW can be attributed to the contribution of hot spots of energetic turbulence. The domain-integrated dissipation from the model is close to the upper bound of the observed dissipation, and implies that almost the entire dissipation in the region can be attributed to the dissipation of baroclinic tidal energy.

• Müller, Malte; Cherniawsky, Josef Y.; Foreman, Michael G.G. & Storch, Jin-Song von (2014). Seasonal variation of the M 2 tide. Ocean Dynamics. ISSN 1616-7341. 64(2), p. 159–177. doi: 10.1007/s10236-013-0679-0. Full text in Research Archive
• Arbic, Brian K.; Müller, Malte; Richman, James G.; Shriver, Jay F.; Morten, Andrew J. & Scott, Robert B. [Show all 8 contributors for this article] (2014). Geostrophic turbulence in the frequency-wavenumber domain: Eddy-driven low-frequency variability. Journal of Physical Oceanography. ISSN 0022-3670. 44(8), p. 2050–2069. doi: 10.1175/JPO-D-13-054.1. Full text in Research Archive
• Gräwe, Ulf; Burchard, Hans; Müller, Malte & Schuttelaars, Henk M. (2014). Seasonal variability in M<sub>2</sub> and M<sub>4</sub> tidal constituents and its implications for the coastal residual sediment transport. Geophysical Research Letters. ISSN 0094-8276. 41(15), p. 5563–5570. doi: 10.1002/2014GL060517. Full text in Research Archive
• Stammer, Detlef; Ray, Richard D.; Andersen, Ole Baltazar; Arbic, Brian K.; Bösch, Wolfgang & Carrère, Loren [Show all 27 contributors for this article] (2014). Accuracy assessment of global barotropic ocean tide models. Reviews of Geophysics. ISSN 8755-1209. 52(3), p. 243–282. doi: 10.1002/2014RG000450. Full text in Research Archive
• Müller, Malte (2013). On the space- and time-dependence of barotropic-to-baroclinic tidal energy conversion. Ocean Modelling. ISSN 1463-5003. 72, p. 242–252. doi: 10.1016/j.ocemod.2013.09.007. Full text in Research Archive
• Skiba, Aaron W.; Zeng, Libo; Arbic, Brian K.; Müller, Malte & Godwin, William J. (2013). On the Resonance and Shelf/Open-Ocean Coupling of the Global Diurnal Tides. Journal of Physical Oceanography. ISSN 0022-3670. 43(7), p. 1301–1324. doi: 10.1175/JPO-D-12-054.1. Full text in Research Archive

View all works in NVA

• Trubbach, Saskia; Sander, Gunnar; Knol-Kauffman, Maaike; Jeuring, Jelmer & Müller, Malte (2024). Navigating the waves of maritime safety regulations in the Norwegian Arctic. Fram Forum. ISSN 1893-5532. p. 1–10. Full text in Research Archive
• Müller, Malte & Knol-Kauffman, Maaike (2024). Forbedret bruk av prognoser kan øke sikkerheten for arktisk shipping. Skipsrevyen. ISSN 0800-2282. Full text in Research Archive
• Carrasco, Ana; Rabault, Jean; Halsne, Trygve; Debernard, Jens Boldingh; Breivik, Øyvind & Müller, Malte [Show all 8 contributors for this article] (2023). Understanding the physical drivers behind observations of hs with a 12-hr modulation in the Arctic Marginal Ice Zone. Full text in Research Archive
• Müller, Malte; Batrak, Yurii; Dinessen, Frode; Grote, Johannes Rafael & Wang, Keguang (2023). Challenges in the description of sea-ice for a kilometer-scale weather forecasting system. Full text in Research Archive
• Müller, Malte (2023). Importance of Sea - Ice - Atmosphere Interactions for Kilometer-Scale Weather Prediction. Full text in Research Archive
• Rabault, Jean; Müller, Malte; Hope, Gaute; Breivik, Øyvind; Nose, Takehiko & Voermans, Joey [Show all 16 contributors for this article] (2023). Collecting Marginal Ice Zone ground truth observations: recent deployments, data use, and outstanding questions. Full text in Research Archive
• Müller, Malte; Kelder, Timo & Palerme, Cyril (2023). Extreme precipitation over Svalbard and its relation to the recent decline of sea-ice in the Greenland Sea. Full text in Research Archive
• Müller, Malte & Knol-Kauffman, Maaike (2023). Improved use of forecasts can increase the safety of Arctic shipping. The Circle. ISSN 2073-980X. p. 20–21. Full text in Research Archive
• Knol-Kauffman, Maaike; Arbo, Peter; Jeuring, Jelmer; Müller, Malte; Palerme, Cyril & Sydnes, Maria [Show all 8 contributors for this article] (2023). Arctic risk paradoxes: Understanding activity trends and safety in Svalbard waters. Full text in Research Archive
• Müller, Malte; Batrak, Yurii; Hermannsdörfer, Lia Francisca; Shupe, Matthew D. & Rostosky, Philip (2023). Analysis of the representation of sea ice surface temperature and radiative states in atmospheric reanalyses. Full text in Research Archive
• Müller, Malte; Batrak, Yurii; Thomas, Erin E.; Dinessen, Frode; Wang, Keguang & Williams, Timothy (2023). Towards an Arctic coupled kilometer-scale atmosphere, snow/sea-ice, ocean, and wave forecasting system. Full text in Research Archive
• Thomas, Erin E. & Müller, Malte (2022). Characterizing Upper Ocean Temperature Structures in the European Arctic: Self-organizing Mapping for Model Validation. Full text in Research Archive
• Müller, Malte (2022). Atmosphere, sea-ice, ocean, and wave interactions in a coupled kilometer-scale Arctic forecasting system. Full text in Research Archive
• Seuthe, Lena; Bluhm, Bodil Annikki Ulla Barbro; Reigstad, Marit; Steer, Adam; Lundesgaard, Øyvind & Gerland, Sebastian [Show all 8 contributors for this article] (2022). Beyond satellite observations of sea ice. Fram Forum. ISSN 1893-5532. Full text in Research Archive
• Müller, Malte; Kelder, Timo & Palerme, Cyril (2021). Extreme precipitation over Svalbard and its relation to the recent decline of sea-ice. Full text in Research Archive
• Müller, Malte; Jeuring, Jelmer; Thomas, Erin E.; Palerme, Cyril; Hjøllo, Bjørn Åge & Høylandskjær, Ståle [Show all 8 contributors for this article] (2021). Tailored probabilistic weather and sea ice forecasting services for Arctic marine operators. Full text in Research Archive
• Thomas, Erin E.; Müller, Malte; Szapiro, Nicholas; Bohlinger, Patrik; Batrak, Yurii & Palerme, Cyril (2021). An Arctic coupled kilometer-scale atmosphere, sea-ice, and wave forecasting system. Full text in Research Archive
• Müller, Malte; Sundfjord, Arild & Årthun, Marius (2021). Rekordlite is og økt skipstrafikk i Arktis: Hvordan forbereder vi oss på framtiden? Full text in Research Archive
• Løken, Trygve Kvåle; Rabault, Jean; Thomas, Erin E.; Müller, Malte; Christensen, Kai Håkon & Sutherland, Graig [Show all 7 contributors for this article] (2020). A comparison of wave observations in the Arctic marginal ice zone with spectral models. Full text in Research Archive
• Müller, Malte; Stige, Leif Christian; Gabrielsen, Geir W.; Rinaldo, Øyvind; Knudsen, Stig Morten & Rødven, Rolf [Show all 8 contributors for this article] (2020). Arctic Frontiers side event FROM NANSEN LEGACY SCIENCE TO USEFUL KNOWLEDGE FOR SOCIETY. Full text in Research Archive
• Hegdahl, Trine J.; Engeland, Kolbjørn; Müller, Malte & Sillmann, Jana (2020). An Event-Based Approach to Explore Selected Present and Future Atmospheric River – Induced Floods in Western Norway. Journal of Hydrometeorology. ISSN 1525-755X. 21(9), p. 2003–2021. doi: 10.1175/JHM-D-19-0071.1. Full text in Research Archive Show summary

  The aim of this study is to investigate extreme precipitation events caused by atmospheric rivers and compare their flood impact in a warmer climate to current climate using an event-based storyline approach. The study was set up by selecting four high-precipitation events from 30 years of present and future climate simulations of the high-resolution global climate model EC-Earth. The two most extreme precipitation events within the selection area for the present and future climate were identified, and EC-Earth was rerun creating 10 perturbed realizations for each event. All realizations were further downscaled with the regional weather prediction model, AROME-MetCoOp. The events were thereafter used as input to the operational Norwegian flood-forecasting model for 37 selected catchments in western Norway, and the magnitude and the spatial pattern of floods were analyzed. The role of the hydrological initial conditions, which are important for the total flooding, were analyzed with a special emphasis on snow and soil moisture excess. The results show that the selected future extreme precipitation events affected more catchments with larger floods, compared to the events from present climate. In addition, multiple realizations of the meteorological forcing and four different hydrological initial conditions, for example, soil saturation and snow storage, were important for the estimation of the maximum flood level. The meteorological forcing (e.g., the internal variability/perturbed output) accounts for the highest contribution to the spread in flood magnitude; however, for some events and catchments the hydrological initial conditions affected the magnitudes of floods more than the meteorological forcing.

• Breivik, Øyvind; Rabault, Jean; Hole, Lars R; Christensen, Kai Håkon; Müller, Malte & Jensen, Atle [Show all 7 contributors for this article] (2019). Bølger i isen påvirker Arktis. Å forstå isdønningene kan forbedre værvarsler og klimamodeller. Forskning.no. ISSN 1891-635X. Full text in Research Archive
• Løken, Trygve Kvåle; Rabault, Jean; Jensen, Atle; Sutherland, Graig; Christensen, Kai Håkon & Müller, Malte (2019). Wave measurements from ship mounted sensors in the Arctic marginal ice zone. Full text in Research Archive
• Müller, Malte (2019). On the warm bias of atmospheric reanalysis over sea-ice in Arctic winter. Full text in Research Archive
• Thomas, Erin E.; Batrak, Yurii; Müller, Malte; Carrasco, Ana & Sætra, Øyvind (2019). Atmosphere-Wave Coupling in a NWP System. Full text in Research Archive
• Thomas, Erin E.; Batrak, Yurii; Müller, Malte; Carrasco, Ana & Sætra, Øyvind (2019). Atmosphere-Wave Coupling in an Arctic NWP System. Full text in Research Archive
• Evans, Anna Kathinka Dalland; Batrak, Yurii & Müller, Malte (2019). Ny metode for varsling av vær i arktisk. Forskning.no. ISSN 1891-635X. Full text in Research Archive
• Evans, Anna Kathinka Dalland; Batrak, Yurii & Müller, Malte (2019). New method for weather forecasting in the arctic. sciencenorway.no. Full text in Research Archive
• Løken, Trygve Kvåle; Rabault, Jean; Jensen, Atle; Christensen, Kai Håkon & Müller, Malte (2019). Wave statistics from ship mounted sensors in the marginal ice zone. Full text in Research Archive
• Schaller, Nathalie; Sillmann, Jana; Müller, Malte; Bjørge, Dag; Kelder, Timo & Oord, Gjis van den [Show all 8 contributors for this article] (2018). Translating the October 2014 flood event in western Norway into the future. Full text in Research Archive
• Schaller, Nathalie; Sillmann, Jana; Müller, Malte; Bjørge, Dag; Kelder, Timo & Oort, Gijs van den [Show all 8 contributors for this article] (2018). Translating the October 2014 flood event in western Norway into the future. Geophysical Research Abstracts. ISSN 1029-7006. 20. Full text in Research Archive
• Müller, Malte & Batrak, Yurii (2018). On the warm bias of atmospheric reanalysis over sea-ice in Arctic winter. Full text in Research Archive
• Arbic, Brian K.; Alford, Matthew H.; Ansong, Joseph K.; Buijsman, Maarten C.; Ciotti, Robert B. & Farrar, J. Thomas [Show all 27 contributors for this article] (2018). A Primer on Global Internal Tide and Internal Gravity Wave Continuum Modeling n HYCOM and MITgcm. In Chassignet, Eric P. (Eds.), New Frontiers in Operational Oceanography. GODAE OceanView. ISSN 9781720549970. p. 307–392. Full text in Research Archive
• Schaller, Nathalie; Sillmann, Jana; Müller, Malte; Bjørge, Dag; Kelder, Timo & Oord, Gjis van den [Show all 8 contributors for this article] (2018). Translating the October 2014 flood event in western Norway into the future. Full text in Research Archive
• Müller, Malte & Sivle, Anders Doksæter (2018). Maritimt forskning - SALIENSEAS. Skipsrevyen. ISSN 0800-2282. 5. Full text in Research Archive
• Müller, Malte & Batrak, Yurii (2018). Convective-scale atmospheric modelling in the Arctic: Model characteristics and sensitivity to the sea-ice representation. Full text in Research Archive
• Schaller, Nathalie; Sillmann, Jana; Müller, Malte; Haarsma, Reindert J.; Hazeleger, Wilco & Amundsen, Helene [Show all 7 contributors for this article] (2017). Translating weather extremes into the future - A case for Norway. Full text in Research Archive
• Schaller, Nathalie; Sillmann, Jana; Müller, Malte; Haarsma, Reindert J.; Amundsen, Helene & Whan, Kirien (2017). Translating weather extremes into the future - A case for Norway. Full text in Research Archive
• Schaller, Nathalie; Sillmann, Jana; Müller, Malte & Bjørge, Dag (2017). First results from the West Coast event. Full text in Research Archive
• Nilsen, Frank; Fer, Ilker; Baumann, Till Martin; Breivik, Øyvind; Czyz, Ceslav & Frank, Lukas [Show all 14 contributors for this article] (2021). PC-2 Winter Process Cruise (WPC). Septentrio Academic Publishing. doi: 10.7557/nlrs.6324. Full text in Research Archive
• Fer, Ilker; Nilsen, Frank; Bosse, Anthony; Falck, Eva; Fossum, Trygve Olav & Hole, Lars Robert [Show all 18 contributors for this article] (2020). Physical Process Cruise 2018: Cruise Report. Septentrio Academic Publishing. Full text in Research Archive
• Lamers, Machiel; Knol, Maaike; Müller, Malte; Blair, Berill; Jeuring, Jelmer & Rasmussen, Till Andreas Soya [Show all 7 contributors for this article] (2018). Enhancing the saliency of climate services for marine mobility sectors in European Arctic seas (SALIENSEAS): Stakeholder Advisory Group Workshop Report. Wageningen University. Full text in Research Archive Show summary

  This report provides an overview of the activities and discussions that took place during the first SALIENSEAS Stakeholder Advisory Group workshop, held on 25 January at UiT The Arctic University of Norway in Tromsø, Norway. The workshop was inspired by a participatory approach, in order to give prominence to the perspectives and needs of the various stakeholders involved in maritime activities in the European Arctic. The core purpose of the workshop was twofold: 1) to identify the most pressing issues around metocean information availability and access, in terms of sector-specific needs to increase safety and efficiency of operations; and 2) to formulate a plan for efficient and relevant data collection from end-users. Invited stakeholder representatives have extensive expertise in Arctic marine operations, and their knowledge will be considered in the assessment of service needs throughout the project. Each participant brought a unique perspective to the workshop, which contributed to gaining a comprehensive view of marine mobile sectors’ metocean information needs in the European Arctic. Though two stakeholder representatives were not able to join workshop activities, they were consulted separately. Their insights are also included in this report. The structure of the report follows the agenda of the workshop. Each section of the report covers one agenda point and ends with a short summary of key insights. The final section connects these insights in an overall reflection and summarizes potential avenues for further collaboration.

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