Development of a model-based high-resolution extreme surface wind climatology for Switzerland

Goyette, Stéphane

doi:10.1007/s11069-007-9130-5

Cited by 11 publications

(13 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Inclusion of further information such as meteorological variables (temperature, turbulence, stability, etc.) would lead to the refinement of climate models (Goyette et al 2001;Goyette 2008), which could better represent the numerous atmospheric interactions and complex physical description of wind flows.…”

Section: Discussionmentioning

confidence: 99%

Spatial Predictions of Extreme Wind Speeds over Switzerland Using Generalized Additive Models

Etienne

Lehmann

Goyette

et al. 2010

Journal of Applied Meteorology and Climatology

Self Cite

View full text Add to dashboard Cite

The purpose of this work is to present a methodology aimed at predicting extreme wind speeds over Switzerland. Generalized additive models are used to regionalize wind statistics for Swiss weather stations using a number of variables that describe the main physiographical features of the country. This procedure enables one to present the results for Switzerland in the form of a map that provides the 98th percentiles of daily maximum wind speeds (W98) at a 10-m anemometer height for cells with a 50-m grid interval. This investigation comprises three major steps. First, meteorological data recorded by the weather stations was gathered to build local wind statistics at each station. Then, data describing the topographic and landscape characteristics of the country were prepared using geographic information systems (GIS). Third, appropriate regression models were selected to make spatially explicit predictions of extreme wind speeds in Switzerland. The predictions undertaken in this study provide realistic values of the W98. The effects of topography on the results are particularly conspicuous. Wind speeds increase with altitude and are greatest on mountain peaks in the Alps, as would be intuitively expected. Relative errors between observations and model results calculated for the meteorological stations do not exceed 30%, and only 12 out of 70 stations exhibit errors that exceed 20%. The combination of GIS techniques and statistical models used to predict a highly uncertain variable, such as extreme wind speed, yields interesting results that can be extended to other fields, such as the assessment of storm damage on infrastructures.

show abstract

Section: Discussionmentioning

confidence: 99%

Spatial Predictions of Extreme Wind Speeds over Switzerland Using Generalized Additive Models

Etienne

Lehmann

Goyette

et al. 2010

Journal of Applied Meteorology and Climatology

Self Cite

View full text Add to dashboard Cite

show abstract

“…Schär et al, 2004;Kjellström et al, 2007;Rajczak et al, 2013). For example, in areas of complex terrain like Switzerland, the main focus of high-resolution simulations with respect to wind is on case studies (Goyette, 2008;Etienne et al, 2013). Recently, simulations of about 90 storms over Switzerland were combined into a storm climatology (Stucki et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Sensitivity of the WRF model to PBL parametrisations and nesting techniques: evaluation of wind storms over complex terrain

Gómez-Navarro

Raible

Dierer³

2015

Geosci. Model Dev.

View full text Add to dashboard Cite

Abstract. Simulating surface wind over complex terrain is a challenge in regional climate modelling. Therefore, this study aims at identifying a set-up of the Weather Research and Forecasting Model (WRF) model that minimises systematic errors of surface winds in hindcast simulations. Major factors of the model configuration are tested to find a suitable set-up: the horizontal resolution, the planetary boundary layer (PBL) parameterisation scheme and the way the WRF is nested to the driving data set. Hence, a number of sensitivity simulations at a spatial resolution of 2 km are carried out and compared to observations. Given the importance of wind storms, the analysis is based on case studies of 24 historical wind storms that caused great economic damage in Switzerland. Each of these events is downscaled using eight different model set-ups, but sharing the same driving data set. The results show that the lack of representation of the unresolved topography leads to a general overestimation of wind speed in WRF. However, this bias can be substantially reduced by using a PBL scheme that explicitly considers the effects of non-resolved topography, which also improves the spatial structure of wind speed over Switzerland. The wind direction, although generally well reproduced, is not very sensitive to the PBL scheme. Further sensitivity tests include four types of nesting methods: nesting only at the boundaries of the outermost domain, analysis nudging, spectral nudging, and the so-called re-forecast method, where the simulation is frequently restarted. These simulations show that restricting the freedom of the model to develop large-scale disturbances slightly increases the temporal agreement with the observations, at the same time that it further reduces the overestimation of wind speed, especially for maximum wind peaks.The model performance is also evaluated in the outermost domains, where the resolution is coarser. The results demonstrate the important role of horizontal resolution, where the step from 6 to 2 km significantly improves model performance. In summary, the combination of a grid size of 2 km, the non-local PBL scheme modified to explicitly account for non-resolved orography, as well as analysis or spectral nudging, is a superior combination when dynamical downscaling is aimed at reproducing real wind fields.

show abstract

“…4b. Both observed and simulated thermal profiles are stable: this is a remarkable storm feature already noted during the storm-averaged profiles (Goyette 2008), as well as during the specific Lothar and Vivian storms (Goyette et al 2003, Goyette et al 2001. , the p msl in solid black with isobars drawn every 5 hPa, the 500 geopotential height in dotted grey with contour lines drawn every 5 dam, and the 1,000 hPa wind vectors in m s -1 with scales in inserts…”

Section: Differences In Various Statisticsmentioning

confidence: 62%

Synoptic conditions of extreme windstorms over Switzerland in a changing climate

Goyette

2010

Clim Dyn

Self Cite

View full text Add to dashboard Cite

This paper reports on a method using composites for studying synoptic conditions of a series of windstorm events selected on the basis of maximum wind speeds in Switzerland. The composite storm-averaged conditions indicate how flow fields, as well as related surface conditions, are organised so as to produce high wind speeds near the surface. On average, high winds in Switzerland, mainly generated by transient synoptic-scale eddies, are characterised by a minimum in the mean sea level pressure field over southern Norway, anticyclonic conditions south of 35°N and a steep pressure gradient over continental western Europe. The geopotential aloft has a predominant zonal structure, producing high winds between 45°N and 50°N over the eastern Atlantic and further inland; the jet stream has its maximum speed at 50°N over the Celtic Sea and Brittany at 250 hPa. Close to the surface, large temperature contrasts between the warm waters of the Atlantic Ocean and Mediterranean Sea and the cooler continent are diagnosed. The results thus obtained differ to those produced by other methods based on the analysis of deep cyclones or of strong vorticity in the northern North Atlantic Ocean basin. Differences of the composite mean synoptic conditions for current and future climate (2071-2100) as simulated by the Global Climate Model HadAM3H in the context of the EU PRUDENCE project indicate that windstorms in a warmer world are generated by a subtle modification of the atmospheric baroclinicity, especially over the ocean and where greater ocean-continent temperature contrasts are simulated during winters. However, there are no signs of reduced storm activity as the climate warms by the end of the twenty-first century.

show abstract

Development of a model-based high-resolution extreme surface wind climatology for Switzerland

Cited by 11 publications

References 26 publications

Spatial Predictions of Extreme Wind Speeds over Switzerland Using Generalized Additive Models

Spatial Predictions of Extreme Wind Speeds over Switzerland Using Generalized Additive Models

Sensitivity of the WRF model to PBL parametrisations and nesting techniques: evaluation of wind storms over complex terrain

Synoptic conditions of extreme windstorms over Switzerland in a changing climate

Contact Info

Product

Resources

About