engleski

Regional short-term heavy rainfalls and their causes

This paper deals with the investigation of magnitude (design parameter) and causes (forecasting input) of rainfall extremes over this region (coastal and inland sites). Extreme value analysis (GEV) according to Jenkinson (Jenkinson, 1969, Faragó and Katz, 1990, Gajic-Capka, 1991) has been applied to rainfall maxima for intervals t up to two hours that are relevant for surface drainage. Jenkinson distribution for almost all intervals has positive values of curvature parameter k, except for very short intervals (10-40 min) in inland, but close to zero. Estimated short-term rainfall maxima are a little bit higher in inland than at coastal site (10-15%).During the period 1985-2002 weather type characterized by front side of the cyclone caused heavy precipitation in 26% of the episodes at the coast and in 31% in inland. These were the weak cyclones with the pressure of 1000 hPa in its centre and their front side over the Istra peninsula and Northern Adriatic. It was followed by low air pressure weather types, front side of trough, with 12% of episodes in inland and back side of trough, with 14% of episodes at the coast. Unexpectedly 11% of rainfall episodes were caused by low gradient anticyclone surface field. In the most cases they were accompanied by upper level cyclones or low pressure troughs.

heavy reanfall; extreme value analysis; weather types; Croatia

nije evidentirano