Does resolution matter? Model simulated coastal low-level wind jets
2016 (English)In: Meteorology and atmospheric physics (Print), ISSN 0177-7971, E-ISSN 1436-5065, Vol. 128, no 2, 263-278 p.Article in journal (Refereed) Published
Atmospheric flows in coastal regions are impacted by land–sea temperature contrasts, complex terrain, shape of the coastline, among many things. Along the west coast of central North America, winds in the boundary layer are mainly from north or northwest, roughly parallel to the coastline. Frequently, the coastal low-level wind field is characterized by a sharp wind maximum along the coast in the lowest kilometre. This feature, commonly referred to as a coastal low-level jet (CLLJ), has significant impact on the climatology of the coastal region and affects many human activities in the littoral zone. Hence, a good understanding and forecasting of CLLJs are vital. This study evaluates the issue of proper mesoscale numerical model resolution to describe the physics of a CLLJ, and its impact on the upper ocean. The COAMPS® model is used for a summer event to determine the realism of the model results compared to observations, from an area of supercritical flow adjustment between Pt. Sur and Pt. Conception, California. Simulations at different model horizontal resolutions, from 54 to 2 km are performed. While the model produces realistic results with increasing details at higher resolution, the results do not fully converge even at a resolution of only few kilometres and an objective analysis of model errors do not show an increased skill with increasing resolution. Based on all available information, a compromise resolution appears to be at least 6 km. New methods may have to be developed to evaluate models at very high resolution.
Place, publisher, year, edition, pages
2016. Vol. 128, no 2, 263-278 p.
Meteorology and Atmospheric Sciences
IdentifiersURN: urn:nbn:se:su:diva-124363DOI: 10.1007/s00703-015-0413-1OAI: oai:DiVA.org:su-124363DiVA: diva2:885552