CORRELATION OF ICE LOAD WITH LARGE-SCALE AND LOCAL METEOROLOGICAL CONDITIONS IN HUNGARY

Conditional probability of icing in correlation with local weather ele ments, as well as with different macrocirculation types are investigat ed on the basis of 23 years of daily observations for two stations sit uated in the Pannonian Plain (Debrecen) and in mountainous region (Kek esteto, 1000 m above sea-level). Empirical histograms are calculated a nd a theoretical model of the distribution is elaborated. Ice is gener ally twice as frequent at night as during the day. Icing is 5-6 times as frequent on the top of the hill as on the plain, especially conside ring larger water-contents. Macrosynoptic conditions favourable for ic ing are essentially different in the two circumstances. At the higher altitude icing is more frequent in cyclonic situations. Considerable l oad is often accompanied with southwesterly, southerly currents. On th e plain station however the anticyclonic situations are somewhat more frequently accompanied with ice formation. Wind speed is practically i ndifferent at the top of the hill, but on the plain ice formation pref ers low wind speeds. These differences are in coincidence with the a p riori information of the different nature of ice load. Namely, at the top of hill in-cloud icing is the predominant form, while on the plain fine rime and frozen precipitation represent the overwhelming majorit y of ice load events. No clear differences in probabilities of icing i n any of the above relations appear, however, between the two perpendi cular directions of measuring devices. From among the possible applica tions of the results, a local scenario on ice load changes assuming a 0.5 K global warming is presented.