Hidrológiai Közlöny 1988 (68. évfolyam)
5. szám - Winter János: Az ország rövid időtartamú csapadékainak értékelése
254 HIDROLÓGIAI KÖZLÖNY 198B. OL) . ÉVF., 5. SZÁM Analysis of short duration rainfalls in Hungary Winter, J. Abstract: The studies performed overt the past 20 years on rainfalls of a duration shorter than one day are reviewed for use in the National Water Management Master Plan. The rains of engeneering interest oeeur in the May-August period. The data series fo the heaviest 5 minutes1 day rainfalls fit well to a lognormal distribution function. The distributions of rains of any particular duration during the four months are very close to each other (Fig. 1). The variation of the distribution function parameters with increasing rainfall duration can be described in a very simple manner (Fig. 2). A mathematical verification will reveal that the distributions of rainfalls of any particular duration do not differ significantly from each other and can thus be treated as a single data series. The short-duration rainfalls observed at 15 stations in Hungary are also similar (Fig. 3). The absence of any significant difference can be demonstrated, so that the rainfall data of the 15 stations can be considered in combination. The confidence band of the distribution function of the 4X15 = 60 times longer data series is round 8 times narrower than the original one. The maximum rainfall function produced on the basis of these distribution functions is valid for the entire country and substantially more reliable than the previous ones. From the maximum rainfall function (Fig. 4) produced by taking the annual heaviest rainfalls into account it will be perceived that in Hungary, and especially in the Plains, the duration of the heaviest storm does not exceed three hours. The regularities in the areal coverage of short-duration rainfalls are less understood than of the heavy ones, or those applying to the temporal variations of precipitation. The results of studies performed in two experimental catchments in Hungary are compared in Fig. 5 with those obtained in the US. The similarity is a conspicuous one, regardless of the great geographical difference. From the study on the temporal variation of heavy, short-duration rainfalls it is concluded that (1) Within a particular rainfall event intensity tends to attenuate as the duration increases ( Fig. 6 ). (2) Rainfall events contrary to the general trend also occur frequently ( Fig. 7 ). (3) The empirical distributions of the rainfall depht up to particular times are shown in Fig. 8. Keywords: rainfall maximum function, short-duration rainfalls, storms, mathematical statistics, variance analysis WINTER JÁNOS 1963-ban szerzett oklevelet az ÉK ME Mérnöki Karán. 1963-tól az ÉKME Vízgazdálkodási Tanszékén gyakornok, majd tanársegéd. 1968—69-ben a Középdunavölgyi Vízügyi Igazgatóság Vízellátási Osztályán szerzett szakmai gyakorlatot. 1970-ben gazdasági mérnöki oklevelet, majd műszaki doktori címet szerzett. 1970-től a BME Vízgazdálkodási Tanszékén adjunktus. Hidrológiát és liidrometriát tanít. Rendszeresen tart szakmérnöki előadásokat. Kutatási területei: csapadék, talajvíz, hidrometria, vízrendezés, a matematikai statisztika és valószínűségszámítás hidrológiai alkalmazása. (Rövid időtartamú csapadékok sztochasztikus generálása a Zsuffa—üsze'iif-módszerrel.)
