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High-resolution wind speed and waves modeling, and an assessment of mesoscale peculiarities caused by coastline parameters and relief at near-shore Kara Sea regionsстатья
- Авторы: Platonov V.S., Kislov A.V., Myslenkov S.A.
- Сборник: Международная конференция и школа молодых ученых по измерениям, моделированию и информационным системам для изучения окружающей среды ENVIROMIS-2020. Избранные труды
- Год издания: 2020
- Место издания: Издательство Томского ЦНТИ Томск
- Первая страница: 373
- Последняя страница: 374
- Аннотация: Complex shorelines and coastal relief influence strongly on the wind speed and, including bathymetry, on the wave regime of seas. Forecast of severe hydrometeorological events in Arctic coastal zones is crucial for port infrastructures, marine operations, icing conditions, etc. These extreme events have in most cases a mesoscale nature, that limits its predictability significantly. Since the Arctic is poorly covered by ground observations, one of the most reasonable approaches to investigate these events is hydrodynamical high-resolution modeling. In this work we are applying the COSMO-CLM [Rockel, 2008] and WaveWatchIII [Tolman, 2014] models to reproduce of wind and waves fields and characteristics in different rugged shore conditions. Some model experiments designed with the regional climate non-hydrostatic atmospheric model COSMO-CLM investigated the best configuration to reproduce mesoscale circulations in the Arctic coastal zones considering different relief conditions. A good testbed for such experiments is the Kara Sea, because there are different conditions of coastline, relief peculiarities, islands of various scales, etc. Some mid-term experiments (three months timespan: Aug-Oct 2012 and Jul-Sep 2014) were conducted over the Arctic domain and specially over the Kara Sea region using the downscaling approach with ~12 and ~3 km horizontal resolutions. After that, the WaveWatchIII model was applied to reproduce wave conditions in the Kara Sea using different wind forcing – global NCEP-CFSv2 reanalysis data (0.20 res.) and COSMO-CLM of 12 and 3 km res. Considering periods were characterized by some storm events. The main focus of these experiments was to reproduce surface wind and wave characteristics the best way, especially near the shorelines during storm events. Different experiments' options were applied to reveal the best COSMO-CLM model configuration, e.g. “spectral nudging technique”, changing time step, nested domain area. Special unstructured high-resolution grid was prepared in WaveWatchIII model for Kara Sea (from 10 km in open sea to 0.7 km in coastal areas). Verification of wind speed was performed on 12 coastal meteorological stations of Kara Sea and surroundings based on the near-neighbor method and showed the best configuration of COSMO-CLM with the “spectral nudging” technique and reducing the model time step. Compared with global reanalysis data this configuration didn’t show any significant improvement having RMSE ~2 m/s and bias ~0.2 m/s. However, verification and detailed investigation of model runs raise a question about the quality of this verification, and how relevant are wind station data in different coastline and relief conditions. Therefore, an additional scale analysis of case studies carried out from synoptic overview to influence of coastline configuration on different mesoscales and for different regions. Malye Karmakuly (Novaya Zemlya island), Belyi island, Dikson island, Marresale and some other sites were considered as different examples to study wind and waves regime. Experiments with different resolutions, options were compared and analyzed for mesoscale atmospheric circulations and waves characteristics dynamics. Wind shadows, channel winds, atmospheric waves propagation were revealed using spatial coastlines scale analysis, vorticity analysis. Quantitative estimations of mesoscale circulations features compared to theoretical relations showed significant influence of shore, relief and bathymetry conditions on mesoscale wind and wave characteristics near the coastline. This analysis demonstrated also an important open question about reliability of coastal wind observations depending on local geographical conditions, shown a need to investigate these circulations using numerical modelling to predict it and following waves better.
- Добавил в систему: Платонов Владимир Сергеевич