engleski

TKE budget analysis of a single long-lived winter bora flow

Over the eastern Adriatic coast often blows a downslope windstorm called bora, causing difficulties in traffic, industry and generally in everyday life. Hence, bora is a subject of intensive scientific research. While the statistical and synoptic characteristics of the bora flow have been investigated intensively, some aspects of bora dynamics still remain unexplored, especially its turbulence. This was due to the lack of suitable measurements needed to asses these aspects, which was especially true for the middle and southern NE Adriatic coast where, until only recently, no turbulence measurements were conducted. A three level tower (10, 20 and 40 m) was equipped with WindMaster Pro ultrasonic anemometers (Gill Instruments), measuring 3D wind speed and sonic temperature at 5 Hz sampling rate at the top of Pometeno brdo (≈ 600 m ASL) in Dugopolje (bora upwind site from the city of Split). Measurements lasted from April 2010 to June 2011, capturing multiple bora events in all annual seasons. This work concentrates on a single long lasting (more than 120 h) winter bora event on Pometeno brdo. Three levels of high frequency measurements have made possible the investigation and calculation of the turbulent kinetic energy (TKE) budget equation. We calculate all terms from the simplified TKE budget equation (1D model of the TKE budget ; horizontal homogeneity assumption is made), except for the pressure covariance term. We discuss then to what extent the 1D TKE budget model is applicable to this particular bora event.

Bora flow; Pometeno brdo; TKE budget

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