Evaluation of downscaled wind speeds and parameterised gusts for recent and historical windstorms in Switzerland
Assessments of local-scale windstorm hazard require highly resolved spatial information on wind speeds and gusts. In this study, maximum (peak) sustained wind speeds on a 3-km horizontal grid over Switzerland are obtained by dynamical downscaling from the Twentieth Century Reanalysis (20CR) employin...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Stockholm University Press
2016-08-01
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| Series: | Tellus: Series A, Dynamic Meteorology and Oceanography |
| Subjects: | |
| Online Access: | http://www.tellusa.net/index.php/tellusa/article/view/31820/48315 |
| _version_ | 1818008823587143680 |
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| author | Peter Stucki Silke Dierer Christoph Welker Juan José Gómez-Navarro Christoph C. Raible Olivia Martius Stefan Brönnimann |
| author_facet | Peter Stucki Silke Dierer Christoph Welker Juan José Gómez-Navarro Christoph C. Raible Olivia Martius Stefan Brönnimann |
| author_sort | Peter Stucki |
| collection | DOAJ |
| description | Assessments of local-scale windstorm hazard require highly resolved spatial information on wind speeds and gusts. In this study, maximum (peak) sustained wind speeds on a 3-km horizontal grid over Switzerland are obtained by dynamical downscaling from the Twentieth Century Reanalysis (20CR) employing the Weather Research and Forecasting (WRF) model. Subsequently, simulated peak gusts are derived using four wind gust parameterizations (WGPs). Evaluations against observations at 63 locations in complex terrain include four high-impact windstorms (occurring in 1919, 1935, 1990, and 1999) and 14 recent windstorms (occurring between 1993 and 2011). Peak sustained wind speeds and directions are generally well simulated, although wind speeds are mostly overestimated. In general, performance and skill measures are best for locations on the Swiss Plateau and inferior for Alpine mountain and valley locations. An independent ERA-Interim WRF downscaling configuration produces overall comparable results, implying that the 20CR ensemble mean is a reliable data set in dynamical downscaling exercises. The four evaluated WGPs largely reproduce the observed gustiness, although the timing and magnitude of the peak gusts are not regularly captured. None of the WGPs stands out as single best for the complex topography of Switzerland. Differences among the WGPs are small compared to the biases inherited from the sustained-wind part in the WGP formulations. All WGPs transform overestimated peak sustained winds into underestimated peak gusts, which points to an underrepresentation of the turbulent part in the WGP formulations. The range of simulated peak gusts from downscaling all 20CR ensemble members does not reliably include the observed peak gust, indicating limited benefit in applying an ensemble approach. Despite the limitations, we infer that with spatial optimisations of the simulation (e.g. by bias correction or adaptation of the WGP schemes), downscaling of 20CR input is an efficient option for high-resolution assessments of windstorm hazard and risk in Switzerland. |
| first_indexed | 2024-04-14T05:34:00Z |
| format | Article |
| id | doaj.art-b58ecdfc4e5b44b188d85fc0fe885e46 |
| institution | Directory Open Access Journal |
| issn | 1600-0870 |
| language | English |
| last_indexed | 2024-04-14T05:34:00Z |
| publishDate | 2016-08-01 |
| publisher | Stockholm University Press |
| record_format | Article |
| series | Tellus: Series A, Dynamic Meteorology and Oceanography |
| spelling | doaj.art-b58ecdfc4e5b44b188d85fc0fe885e462022-12-22T02:09:42ZengStockholm University PressTellus: Series A, Dynamic Meteorology and Oceanography1600-08702016-08-0168011810.3402/tellusa.v68.3182031820Evaluation of downscaled wind speeds and parameterised gusts for recent and historical windstorms in SwitzerlandPeter Stucki0Silke Dierer1Christoph Welker2Juan José Gómez-Navarro3Christoph C. Raible4Olivia Martius5Stefan Brönnimann6 Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland Meteotest, Bern, Switzerland Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland Oeschger Centre for Climate Change Research, University of Bern, Bern, SwitzerlandAssessments of local-scale windstorm hazard require highly resolved spatial information on wind speeds and gusts. In this study, maximum (peak) sustained wind speeds on a 3-km horizontal grid over Switzerland are obtained by dynamical downscaling from the Twentieth Century Reanalysis (20CR) employing the Weather Research and Forecasting (WRF) model. Subsequently, simulated peak gusts are derived using four wind gust parameterizations (WGPs). Evaluations against observations at 63 locations in complex terrain include four high-impact windstorms (occurring in 1919, 1935, 1990, and 1999) and 14 recent windstorms (occurring between 1993 and 2011). Peak sustained wind speeds and directions are generally well simulated, although wind speeds are mostly overestimated. In general, performance and skill measures are best for locations on the Swiss Plateau and inferior for Alpine mountain and valley locations. An independent ERA-Interim WRF downscaling configuration produces overall comparable results, implying that the 20CR ensemble mean is a reliable data set in dynamical downscaling exercises. The four evaluated WGPs largely reproduce the observed gustiness, although the timing and magnitude of the peak gusts are not regularly captured. None of the WGPs stands out as single best for the complex topography of Switzerland. Differences among the WGPs are small compared to the biases inherited from the sustained-wind part in the WGP formulations. All WGPs transform overestimated peak sustained winds into underestimated peak gusts, which points to an underrepresentation of the turbulent part in the WGP formulations. The range of simulated peak gusts from downscaling all 20CR ensemble members does not reliably include the observed peak gust, indicating limited benefit in applying an ensemble approach. Despite the limitations, we infer that with spatial optimisations of the simulation (e.g. by bias correction or adaptation of the WGP schemes), downscaling of 20CR input is an efficient option for high-resolution assessments of windstorm hazard and risk in Switzerland.http://www.tellusa.net/index.php/tellusa/article/view/31820/48315dynamical downscaling20CR, ERA-Interimwind speedwind gust estimationextreme eventhazard mapAlpsgust factorriskWRF wind evaluation |
| spellingShingle | Peter Stucki Silke Dierer Christoph Welker Juan José Gómez-Navarro Christoph C. Raible Olivia Martius Stefan Brönnimann Evaluation of downscaled wind speeds and parameterised gusts for recent and historical windstorms in Switzerland Tellus: Series A, Dynamic Meteorology and Oceanography dynamical downscaling 20CR, ERA-Interim wind speed wind gust estimation extreme event hazard map Alps gust factor risk WRF wind evaluation |
| title | Evaluation of downscaled wind speeds and parameterised gusts for recent and historical windstorms in Switzerland |
| title_full | Evaluation of downscaled wind speeds and parameterised gusts for recent and historical windstorms in Switzerland |
| title_fullStr | Evaluation of downscaled wind speeds and parameterised gusts for recent and historical windstorms in Switzerland |
| title_full_unstemmed | Evaluation of downscaled wind speeds and parameterised gusts for recent and historical windstorms in Switzerland |
| title_short | Evaluation of downscaled wind speeds and parameterised gusts for recent and historical windstorms in Switzerland |
| title_sort | evaluation of downscaled wind speeds and parameterised gusts for recent and historical windstorms in switzerland |
| topic | dynamical downscaling 20CR, ERA-Interim wind speed wind gust estimation extreme event hazard map Alps gust factor risk WRF wind evaluation |
| url | http://www.tellusa.net/index.php/tellusa/article/view/31820/48315 |
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