Evaluation of a sub-kilometre NWP system in an Arctic fjord-valley system in winter

Valkonen, Teresa; Stoll, Patrick; Batrak, Yurii; Køltzow, Morten; Schneider, Thea; Stigter, Emmy E.; Aashamar, Ola Bakke; Støylen, Eivind; Jonassen, Marius O.

doi:10.1080/16000870.2020.1838181

Cited by 10 publications

(8 citation statements)

References 31 publications

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“…A general improvement by applying higher spatial resolution is not surprising and agrees with other related studies in the same areas (e.g. Køltzow et al, 2019;Valkonen et al, 2020).…”

Section: Objective Added Value For Near Surface Variablessupporting

confidence: 91%

“…Also the EPS members have a cold bias for these days, but the EPS mean is more consistent and the uncertainty is instead reflected in the ensemble spread. These drops in forecasted temperature can be related to a model specific deficiency which occasionally is seen in the operational forecasts for Svalbard and include an unrealistic sudden drop in temperature during cold and calm conditions (Valkonen et al, 2020) However, the substantial temperature drop seen on 18 March in the forecasts is accompanied by little ensemble spread and is also observed, but with a slightly shifted timing. The results presented here confirm that the EPS mean is an efficient way to improve some verification scores since unpredictable small scales are filtered out (e.g.…”

Section: Objective Added Value For Near Surface Variablesmentioning

confidence: 88%

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On the configuration of a regional Arctic Numerical Weather Prediction system to maximize predictive capacity

Køltzow

Grote

Singleton

2021

Tellus A: Dynamic Meteorology and Oceanography

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Limitations to operational weather forecasts exist in terms of availability of computer (and human) resources combined with operational deadlines. For operational weather services it is therefore important to utilize their resources to maximize the predictive capability. This study shows how forecast quality in a state-of-theart high-resolution regional Arctic Numerical Weather Prediction (NWP) system changes with varying configuration choices; (1) Ensemble Prediction System (EPS), (2) higher spatial resolution, (3) atmospheric initialization by assimilation of observations, (4) surface initialization by assimilation of observations and by (5) changing the regional domain and location. Results from such inter-comparisons are useful guidance for (Arctic) weather forecast systems, and can together with information on e.g. user-needs and post-processing capabilities be used to maximize the operational predictive capacity. All configuration choices have a significant impact on the forecast quality of near-surface parameters, but the impact varies with parameter, region, weather type, lead time and part of the forecast evaluated (e.g. average errors or rare events). Higher spatial resolution and EPS are expensive, but are still promising to further improve state-of-the-art regional Arctic high-resolution NWP systems. In particular when forecasting rare events regional EPS shows huge benefits. Assimilation of observations in the initialization process of the regional NWP system has also a positive impact on forecast quality. Finally, although less pronounced, the choice of the domain size and location also has a significant impact and should therefore be chosen carefully.

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“…A general improvement by applying higher spatial resolution is not surprising and agrees with other related studies in the same areas (e.g. Køltzow et al, 2019;Valkonen et al, 2020).…”

Section: Objective Added Value For Near Surface Variablessupporting

confidence: 91%

Section: Objective Added Value For Near Surface Variablesmentioning

confidence: 88%

On the configuration of a regional Arctic Numerical Weather Prediction system to maximize predictive capacity

Køltzow

Grote

Singleton

2021

Tellus A: Dynamic Meteorology and Oceanography

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“…However, CARRA's horizontal grid spacing of 2.5 km is still not sufficient to properly capture the effect of the smaller valleys and fjords on the flow fields. Valkonen et al (2020) indicate how a sub-kilometer NWP system can improve weather forecasting in the complex terrain of Svalbard. In the same way, a sub-kilometer reanalysis would allow to statistically investigate features in the flow fields on scales similar to the characteristic dimensions of the topography in the Isfjorden region.…”

Section: Discussionmentioning

confidence: 99%

“…Valkonen et al. (2020) indicate how a sub‐kilometer NWP system can improve weather forecasting in the complex terrain of Svalbard. In the same way, a sub‐kilometer reanalysis would allow to statistically investigate features in the flow fields on scales similar to the characteristic dimensions of the topography in the Isfjorden region.…”

Section: Discussionmentioning

confidence: 99%

Atmospheric Climatologies Over Isfjorden, Svalbard

Frank,

Jonassen,

Skogseth

et al. 2023

JGR Atmospheres

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The Isfjorden region at the west coast of Spitsbergen is the most easily accessible area in the Svalbard Archipelago, making it a perfect outdoor laboratory for Arctic research. Due to its location in the high Arctic together with its complex terrain, the climatic conditions vary substantially both in time and space. Based on a new high‐resolution reanalysis, we present climatologies of five major atmospheric variables over the Isfjorden region during 2011–2021 with special focus on local effects. For example, we find that topographic channeling effects often lead to differences in near‐surface wind speeds of several m s−1 over small horizontal distances. During winter, the fjord acts as a heat and moisture island, ultimately impacting the adjacent low‐elevation land areas. These land–sea gradients reverse during summer. High mountain areas surrounding the fjord experience substantially different climatic conditions, with for example, seasonal precipitation doubling from sea level to approximately 700 m. The spatial variability over the Isfjorden region is in general found to be smaller than its temporal counterpart but larger than the diurnal cycle. Besides these findings, this study furthermore demonstrates the importance of high‐resolution regional atmospheric reanalyses compared to global products for the characterization of the local micro‐climate over Arctic fjords and the interaction with surrounding land areas.

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“…APPLICATE additionally explored the impact of model resolution on process-representation and forecast quality. Increasing the model resolution in the AROME-Arctic NWP system from 2.5 to 1.25 km and from 65 to 90 vertical showed overall added value in forecast accuracy of near-surface variables, especially during winter (Køltzow et al 2021). Valkonen et al (2020 additionally showed that regional NWP configurations with kilometer and subkilometer grid spacing can outperform state-of-the-art Arctic operational systems over complex terrain areas thanks to a better representation of topographic wind effects.…”

Section: Model Development To Enhance Process Representationmentioning

confidence: 99%

Improving Arctic Weather and Seasonal Climate Prediction: Recommendations for Future Forecast Systems Evolution from the European Project APPLICATE

Ortega

Blockley

Køltzow

et al. 2022

Bulletin of the American Meteorological Society

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The Arctic environment is changing, increasing the vulnerability of local communities and ecosystems, and impacting its socio-economic landscape. In this context, weather and climate prediction systems can be powerful tools to support strategic planning and decision-making at different time horizons. This article presents several success stories from the H2020 project APPLICATE on how to advance Arctic weather and seasonal climate prediction, synthesizing the key lessons learned throughout the project and providing recommendations for future model and forecast system development.

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Evaluation of a sub-kilometre NWP system in an Arctic fjord-valley system in winter

Cited by 10 publications

References 31 publications

On the configuration of a regional Arctic Numerical Weather Prediction system to maximize predictive capacity

On the configuration of a regional Arctic Numerical Weather Prediction system to maximize predictive capacity

Atmospheric Climatologies Over Isfjorden, Svalbard

Improving Arctic Weather and Seasonal Climate Prediction: Recommendations for Future Forecast Systems Evolution from the European Project APPLICATE

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