Naslov
Impact of mesoscale meteorological processes on anomalous propagation conditions over the northern Adriatic area

Autori
Telišman Prtenjak, Maja ; Horvat, Igor ; Tomažić, Igor ; Kvakić, Marko ; Viher, Mladen ; Grisogono, Branko

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Skup
5th International Conference on Meteorology and Climatology of the Mediterranean

Mjesto i datum
Istanbul, Turska, 02.03.2015. - 04.03.2015

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
bora; sea/land breeze; cumulonimbus cloud; anomalous propagation; radio waves refraction; WRF model

Sažetak
The impacts of mesoscale processes on the occurrence of anomalous propagation conditions (named anaprop) for radio waves, including ducts, super refractions and subrefractions, were studied. The chosen formations are the famous bora winds, and the sporadical sea/land breeze (SB/LB) during three selected cases over a large portion of the northern Adriatic. For this purpose, we used available radiosoundings and numerical WRF-ARW model simulations (of real cases and their sensitivity tests) at a horizontal resolution of 1.5 km. The model simulated the occurrences of anaprop satisfactorily, although their intensities and frequency were underestimated at times. Certain difficulties existed in reproducing the vertical profile of the modified refractive index, which is mainly dependent on the accuracy of the modeled relative humidity. The spatial distributions of summer anaprop reveal that the surface layer above the sea (roughly between 30 and 100 m asl) is often covered by super refractions and ducts. The SB is highly associated with the anaprop formations: (i) in the first 100 m asl, where super refractions and ducts form because of the advection of colder and moister air, and (ii) insi de the transition layer between the SB body and the anti-SB current in the form of subrefractions. When a deep convection occurs, all three types of anaprop are caused by the downdraft beneath the cumulonimbus cloud base in its mature phase that creates smaller but significant pools of cold and dry air. The bora wind usually creates an anaprop pattern associated with the hydraulic jump and influences anaprop distribution over the sea surface.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Geologija

Napomena
HRZZ projekt CATURBO #09/151

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