Original scientific paper

The relationship between shallow thermal circulation regimes and cumulonimbus clouds along the northeastern Adriatic coast

Karmen Babić ; University of Zagreb, Faculty of Science, Department of Geophysics, Andrija Mohorovičić Geophysical Institute, Zagreb, Croatia
Petra Mikuš ; University of Zagreb, Faculty of Science, Department of Geophysics, Andrija Mohorovičić Geophysical Institute, Zagreb, Croatia
Maja Telišman Prtenjak ; University of Zagreb, Faculty of Science, Department of Geophysics, Andrija Mohorovičić Geophysical Institute, Zagreb, Croatia

Abstract

The aim of this study is to determine the relationship between the occur¬rence of a sea breeze (SB) and cumulonimbus (Cb) clouds over the Istrian Pe¬ninsula. For this purpose, available standard surface measurements, i.e., the near-surface wind, the air and sea surface temperatures and cloudiness at two stations (Pula-Airport and Pazin), and satellite images were analyzed. The study was performed during the summer months (from June to September) for the years 1997–2006. The analysis showed that the Cb development was typically associated with certain meteorological conditions. These conditions were as follows: (i) SB speed at Pula-Airport in the range of 3–5 m s–1, (ii) maxi¬mum temperature difference between sea and land near Pula-Airport around 4 °C, and (iii) maximum air temperature in Pazin in the range of 25 to 31 °C. On average, during the days with simultaneous development of SB and Cb clouds, the land breeze was weaker and the air temperature was higher than on other analyzed days. Diurnal cloud evolution showed that Cb clouds usually develop (above Pazin) between 13 and 14 h of Central European Time (CET). Cumulus clouds, as indicators of the SB inland penetration, preceded the Cb development. Satellite images for 2000–2006 obtained by the geostationary satellites Meteosat 7 and 8 were investigated, and a spatial distribution and a temporal development of 30 chosen Cb events were detected. Two characteris¬tic regions of the Cb origin were noted: the northern and southeastern parts of the Istrian Peninsula. The Cb clouds usually formed between 11 and 13 CET, lasting in general from 3 to 5 hours and disintegrating between 15 and 17 CET.

Keywords

sea/land breeze; Istria; convergence zone; satellite images; sea breeze index

Hrčak ID:

84997

URI

https://hrcak.srce.hr/84997

Publication date:

30.6.2012.

Article data in other languages: croatian

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