Downslope windstorms and associated extreme wind speed statistics evaluation according to the COSMO-CLM Russian Arctic hindcast, ASR reanalysis and observations

Platonov, V.; Shestakova, A.

Авторы: Platonov Vladimir, Shestakova Anna
Сборник: EMS Annual Meeting Abstracts
Том: 18
Тезисы
Год издания: 2021
Издательство: Copernicus Group
Местоположение издательства: Germany
Номер статьи: 300
DOI: 10.5194/ems2021-300
Аннотация: The number of severe weather events at the Arctic region increased significantly. Its formationrelated generally to the mesoscale processes including downslope windstorms over Novaya Zemlya,Svalbard, Tiksi bay accompanied by strong winds. Therefore, its investigation required detailedhydrometeorological and climatic information with a horizontal resolution of at least severalkilometers. This work aims to investigate extreme wind speeds statistics associated with downslopewindstorms and evaluate it according to the COSMO-CLM Russian Arctic hindcast, ASR reanalysis,stations and satellite data.COSMO-CLM Russian Arctic hindcast created in 2020 covers the 1980–2016 period with grid size~12 km and 1-hour output step, containing approximately a hundred hydrometeorologicalcharacteristics, as well at surface, as on the 50 model levels. The primary assessments of thesurface wind speed and temperature fields showed good agreement with ERA-Interim reanalysis inlarge-scale patterns and many added values in the regional mesoscale features reproductionaccording to the coastlines, mountains, large lakes, and other surface properties.Mean values, absolute and daily maxima of wind speed, high wind speed frequencies were estimatedfor the COSMO-CLM Russian Arctic hindcast and the well-known Arctic System Reanalysis (ASRv2)for a 2000-2016 period. COSMO-CLM showed higher mean and daily maximal wind speed areasconcerned to coastal regions of Svalbard and Scandinavia, over the northern areas of Taymyrpeninsula. At the same time, the absolute wind speed maxima are significantly higher according toASRv2, specially over the Barents Sea, near the Novaya Zemlya coast (differences are up to 15-20m/s). The same pattern observed by a number of days with wind speed above the 30 m/s threshold.Compared with station data, the ASRv2 reproduced mean wind speeds better at most coastal andinland station, MAE are within 3 m/s. For absolute wind speed maxima differences between twodatasets get lower, the COSMO-CLM hindcast is quite better for inland stations.Model capability to reproduce strong downslope windstorms evaluated according to the observationstimeseries over Novaya Zemlya, Svalbard and Tiksi stations during bora conditions. Generally, theASRv2 reproduced the wind direction closer to observations and the wind speed worser than COSMOCLM.The extreme wind speed frequencies during bora cases have less errors according to COSMOCLMhindcast (up to ~5%) compared to the ASRv2 data (up to 10%). At the same time, moderatewind speed frequencies are reproduced by ASRv2 better.Five specific Novaya Zemlya bora cases were evaluated according to SAR satellite wind speed data.Both ASRv2 and COSMO-CLM overestimated mean wind speed (MAE 0.5-6 m/s), maximal windspeed bias has different signs, however, the COSMO-CLM is better in most cases. Extremepercentiles biases (99 and 99.9%), correlation, structure and amplitude (according to the SALmethod) are closer to observations by the COSMO-CLM hindcast.Powered by TCPDF (www.tcpdf.org)
Добавил в систему: Платонов Владимир Сергеевич

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Downslope windstorms and associated extreme wind speed statistics evaluation according to the COSMO-CLM Russian Arctic hindcast, ASR reanalysis and observationsтезисы доклада

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