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Climatology of the Iberia coastal low-level wind jet: weather research forecasting model high-resolution results

Soares, Pedro M.M; Cardoso, Rita M.; Semedo, Álvaro; Chinita, Maria J. and Ranjha, Raza LU (2014) In Tellus. Series A: Dynamic Meteorology and Oceanography 66. p.18-22377
Abstract
Coastal low-level jets (CLLJ) are a low-tropospheric wind feature driven by the pressure gradient produced by a sharp contrast between high temperatures over land and lower temperatures over the sea. This contrast between the cold ocean and the warm land in the summer is intensified by the impact of the coastal parallel winds on the ocean generating upwelling currents, sharpening the temperature gradient close to the coast and giving rise to strong baroclinic structures at the coast. During summertime, the Iberian Peninsula is often under the effect of the Azores High and of a thermal low pressure system inland, leading to a seasonal wind, in the west coast, called the Nortada (northerly wind). This study presents a regional climatology of... (More)
Coastal low-level jets (CLLJ) are a low-tropospheric wind feature driven by the pressure gradient produced by a sharp contrast between high temperatures over land and lower temperatures over the sea. This contrast between the cold ocean and the warm land in the summer is intensified by the impact of the coastal parallel winds on the ocean generating upwelling currents, sharpening the temperature gradient close to the coast and giving rise to strong baroclinic structures at the coast. During summertime, the Iberian Peninsula is often under the effect of the Azores High and of a thermal low pressure system inland, leading to a seasonal wind, in the west coast, called the Nortada (northerly wind). This study presents a regional climatology of the CLLJ off the west coast of the Iberian Peninsula, based on a 9 km resolution downscaling dataset, produced using the Weather Research and Forecasting (WRF) mesoscale model, forced by 19 years of ERA-Interim reanalysis (1989–2007). The simulation results show that the jet hourly frequency of occurrence in the summer is above 30% and decreases to about 10% during spring and autumn. The monthly frequencies of occurrence can reach higher values, around 40% in summer months, and reveal large inter-annual variability in all three seasons. In the summer, at a daily base, the CLLJ is present in almost 70% of the days. The CLLJ wind direction is mostly from north-northeasterly and occurs more persistently in three areas where the interaction of the jet flow with local capes and headlands is more pronounced. The coastal jets in this area occur at heights between 300 and 400 m, and its speed has a mean around 15 m/s, reaching maximum speeds of 25 m/s. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
regional climate modelling, coastal wind jet, Iberian Peninsula, sea land contrast, WRF, wind energy
in
Tellus. Series A: Dynamic Meteorology and Oceanography
volume
66
pages
18 - 22377
publisher
Wiley-Blackwell
external identifiers
  • wos:000329869400001
  • other:22377
  • scopus:84894434809
ISSN
1600-0870
DOI
10.3402/tellusa.v66.22377
language
English
LU publication?
yes
id
20227656-d2f7-421a-96e0-c0ba1c5a608d (old id 4255121)
date added to LUP
2014-02-24 11:28:55
date last changed
2017-11-19 03:43:38
@article{20227656-d2f7-421a-96e0-c0ba1c5a608d,
  abstract     = {Coastal low-level jets (CLLJ) are a low-tropospheric wind feature driven by the pressure gradient produced by a sharp contrast between high temperatures over land and lower temperatures over the sea. This contrast between the cold ocean and the warm land in the summer is intensified by the impact of the coastal parallel winds on the ocean generating upwelling currents, sharpening the temperature gradient close to the coast and giving rise to strong baroclinic structures at the coast. During summertime, the Iberian Peninsula is often under the effect of the Azores High and of a thermal low pressure system inland, leading to a seasonal wind, in the west coast, called the Nortada (northerly wind). This study presents a regional climatology of the CLLJ off the west coast of the Iberian Peninsula, based on a 9 km resolution downscaling dataset, produced using the Weather Research and Forecasting (WRF) mesoscale model, forced by 19 years of ERA-Interim reanalysis (1989–2007). The simulation results show that the jet hourly frequency of occurrence in the summer is above 30% and decreases to about 10% during spring and autumn. The monthly frequencies of occurrence can reach higher values, around 40% in summer months, and reveal large inter-annual variability in all three seasons. In the summer, at a daily base, the CLLJ is present in almost 70% of the days. The CLLJ wind direction is mostly from north-northeasterly and occurs more persistently in three areas where the interaction of the jet flow with local capes and headlands is more pronounced. The coastal jets in this area occur at heights between 300 and 400 m, and its speed has a mean around 15 m/s, reaching maximum speeds of 25 m/s.},
  author       = {Soares, Pedro M.M and Cardoso, Rita M. and Semedo, Álvaro and Chinita, Maria J. and Ranjha, Raza},
  issn         = {1600-0870},
  keyword      = {regional climate modelling,coastal wind jet,Iberian Peninsula,sea land contrast,WRF,wind energy},
  language     = {eng},
  pages        = {18--22377},
  publisher    = {Wiley-Blackwell},
  series       = {Tellus. Series A: Dynamic Meteorology and Oceanography},
  title        = {Climatology of the Iberia coastal low-level wind jet: weather research forecasting model high-resolution results},
  url          = {http://dx.doi.org/10.3402/tellusa.v66.22377},
  volume       = {66},
  year         = {2014},
}