engleski

Phases of the sea breeze in the island of Mallorca

In order to better understand the diurnal cycle of the Sea-Breeze (SB) in the island of Mallorca, during September 2013 and June 2014 two experimental field campaigns have been conducted in the Campos basin (at the south side). A total of 6 IOPs (clear skies and weak pressure gradient conditions) are analysed using data from the AEMET network and the observations taken close to the coastline (about 900 m inland). They consist on a surface portable station (equipped with an IR camera and a sonic anemometer), a captive balloon (temperature and humidity) and a multicopter (temperature and humidity). Preliminary analysis of the observations show a good agreement between the different sources of data. During the previous phase (0430-0730 UTC) land-breeze conditions were present and after sunrise the sensible heat flux turned to positive meanwhile the turbulence started. In the preparatory phase (0730-0900 UTC) the wind close to the coast started to veer progressively towards the SB direction. As soon as the SB was initiated (0900-1200 UTC), the SB front progressed to the inland direction reaching a mature phase between 1200-1500 UTC. Afterwards, the SB decaying starts and at about 1900 UTC the wind speed was close to zero and the wind veered towards the land to sea direction. During the campaign all phases were measured, except the sounding systems for the mature phase due to the strong wind. Some selected IOPs are further analysed through the use of high-resolution mesoscale simulation. It is found that the model is able to reproduce the observed establishment of the SB although the observed temperature gradients are larger than those observed.

sea/land breeze; Western Mediterranean; mesoscale model

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