Мезомасштабное моделирование экстремальных скоростей ветра с высоким разрешением над западными акваториями Российской Арктики

Платонов, В.С.; Кислов, А.В.

Авторы: Платонов В.С., Кислов А.В.
Сборник: Избранные труды Международной конференции и школы молодых ученых по измерениям, моделированию и информационным системам для изучения окружающей среды ENVIROMIS 2016
Серия: IOP Conference Series: Earth and Environmental Science
Том: 48
Тезисы
Год издания: 2016
Место издания: Томское ЦНТИ Томск
Первая страница: 105
Последняя страница: 110
Аннотация: Wind velocity at the boundary layer has strong spatio-temporal variability, therefore its correct simulation is still associated with significant errors. It is especially relevant to Arctic seashores with complicate surface and to poor data areas. One of the ways to reduce errors is the mesoscale modeling. Many studies [6, 4, 5, 8] has shown definite advantage of mesoscale atmospheric models in the reproduction of wind velocity pattern against the most modern reanalyses. In [11] many interesting features of wind velocity statistical distribution were revealed. Wind velocity extremes are belonging to different general samples, each described by Weibull distribution. These sets of extremes were called as ‘black swans’ and ‘dragons’ [8, 9], at that ‘dragons’ exceeds ‘swans’ 10 – 30 % (by the same quantile 0,99). These extremes and specifications could be reproduced by the mesoscale modeling only. In this study, the climate version of COSMO model (COSMO-CLM) was used. It is well-known non-hydrostatic regional atmospheric model developed by German Weather Service (DWD) and CLM-Community [1]. The COSMO-CLM model was applied for many case-studies simulation of the most extreme winds observed over the Russian Arctic basin during the last 15 years. Many cases were presented for further modeling: 15 – 17.12.1997, 29 – 30.10.2000, 26.01.2002, 05.02.2003, 12.12.2013. Model runs were performed for the unified ‘large’ domain with spatial resolution of 0.120, covered the Barents Sea, part of Kara Sea, northern European territory of Russia and the surrounding water areas. Driving conditions came from ERA-Interim reanalysis (~0.750 resolution). After that, the downscaling technology was performed for the different ‘small’ domains (resolution of ~2.8 km), inside the ‘large’ domain. Standard configuration of COSMO-CLM model (version 5.0) was applied: Runge-Kutta integration scheme with 5th advection order; 40 vertical levels; prognostic TKE-based scheme for turbulence, etc. [2]. Runs continued for a week for the most cases including extreme situations observed near the middle of the period. Analyze has shown that model reproduces the synoptic-scale dynamics and general synoptic-scale wind velocity patterns well as both with the 0.120 km, and 2 – 3 km resolutions. Model with 2.8 km resolution succeed to reproduce detailed spotty wind pattern, caused by local orography or/and dynamic factors. On the one hand, the model underestimates observed mean values and wind gusts over seashores up to 4 – 5 m/s systematically. On the other hand, it could be interpreted as follow: such extreme speeds of air particles (15 – 20 m/s and more) does not make much physical sense to focus on wind velocity at a certain point. Therefore, we can consider wind velocity values for some surrounding area, according to the distance, corresponding to wind velocities. Taking into account these reasons, we can ascertain, that COSMO-CLM model reproduces wind velocity pattern quite adequately, but using the resolution 5 km and less, only. With respect to revealing many differences between ‘swans’ and ‘dragons’ situatons, there were found out no clear distinctions. It could be associated with a poor sample of cases. We can assume it caused by the rare overlay of large-scale synoptic factors and many local meso- and microscale factors (surface, coastline configuration etc.). In the future, further studies of the extreme wind speeds genesis in the Arctic, such as the ‘black swans’ and ‘dragons’, necessary to focus on nonhydrostatic high-resolution modeling using downscaling techniques.
Добавил в систему: Платонов Владимир Сергеевич

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