Next Article in Journal
A High Resolution Coupled Fire–Atmosphere Forecasting System to Minimize the Impacts of Wildland Fires: Applications to the Chimney Tops II Wildland Event
Next Article in Special Issue
Current Challenges in Understanding and Predicting Transport and Exchange in the Atmosphere over Mountainous Terrain
Previous Article in Journal
A Comparative Study on the Statutory and Technical Regulations for Controlling Indoor Volatile Organic Compounds in Taiwan and Japan
Previous Article in Special Issue
Atmospheric Processes in the South Baikal Basin and Their Role in Relief Formation
Article Menu
Issue 5 (May) cover image

Export Article

Open AccessArticle
Atmosphere 2018, 9(5), 196; https://doi.org/10.3390/atmos9050196

Accuracy of Simulated Diurnal Valley Winds in the Swiss Alps: Influence of Grid Resolution, Topography Filtering, and Land Surface Datasets

1
Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, 60438 Frankfurt, Germany
2
Institute for Atmospheric and Climate Science, ETH Zurich, 8092 Zurich, Switzerland
3
Institute for Climate and Atmospheric Science, University of Leeds, Leeds LS2 9JT, UK
4
Federal Institute of Meteorology and Climatology, MeteoSwiss, 8058 Zurich-Flughafen, Switzerland
*
Author to whom correspondence should be addressed.
Received: 23 February 2018 / Revised: 6 May 2018 / Accepted: 15 May 2018 / Published: 18 May 2018
(This article belongs to the Special Issue Atmospheric Processes over Complex Terrain)
Full-Text   |   PDF [3584 KB, uploaded 18 May 2018]   |  

Abstract

We evaluate the near-surface representation of thermally driven winds in the Swiss Alps in a numerical weather prediction model at km-scale resolution. In addition, the influence of grid resolution (2.2 km and 1.1 km), topography filtering, and land surface datasets on the accuracy of the simulated valley winds is investigated. The simulations are evaluated against a comprehensive set of surface observations for an 18-day fair-weather summer period in July 2006. The episode is characterized by strong diurnal wind systems and the formation of shallow convection over the mountains, which transitions to precipitating convection in some areas. The near-surface winds (10 m above ground level) follow a typical diurnal pattern with strong daytime up-valley flow and weaker nighttime down-valley flow. At a 2.2 km resolution the valley winds are poorly simulated for most stations, while at a 1.1 km resolution the diurnal cycle of the valley winds is well represented in most large (e.g., Rhein valley at Chur and Rhone valley at Visp) and medium-sized valleys (e.g., Linth valley at Glarus). In the smaller valleys (e.g., Maggia valley at Cevio), the amplitude of the valley wind is still significantly underestimated, even at a 1.1 km resolution. Detailed sensitivity experiments show that the use of high-resolution land surface datasets, for both the soil characteristics as well as for the land cover, and reduced filtering of the topography are essential to achieve good performance at a 1.1 km resolution. View Full-Text
Keywords: valley winds; diurnal cycle; high-resolution simulation; land surface datasets; topography filtering valley winds; diurnal cycle; high-resolution simulation; land surface datasets; topography filtering
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Schmidli, J.; Böing, S.; Fuhrer, O. Accuracy of Simulated Diurnal Valley Winds in the Swiss Alps: Influence of Grid Resolution, Topography Filtering, and Land Surface Datasets. Atmosphere 2018, 9, 196.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Atmosphere EISSN 2073-4433 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top