Vízügyi Közlemények, 1974 (56. évfolyam)
1. füzet - Péczely György: Mértékadó csapadékmaximumok terület-idő függvényei Magyarországon
72 Dr. Péczely György Area-time functions oï design precipitation maxima in Hungary By Dr. Péczely, Gy. Notations and definitions : x = point precipitation. The quantity of precipitation during a given length of time at a particular observing station. X— Annual maximum of point precipitation. Peak value observed during one year of precipitation quantities x related to a given period at a particular observing station. X= Average annual peak Of point precipitation. Climatically representative longyear average of peak precipitations X at a particular observing station. A* = Areal mean value of average annual peak of point precipitation. Arithmetic mean of X values for stations within the boundaries of a particular region. x'= Areal precipitation. Arithmetic mean of x values for stations within Lhe boundaries of a particular region. X' = Annual peak of areal precipitation. Peak value observed during one year of x values related to a particular region. X'= Average annual peak of areal precipitation. Climatically representative longyear average of precipitation values X' for a particular region. In analysing precipitation conditions from the engineer's point of view, the value of areal precipitation maxima pertaining to a specific confidence level yields important information. Investigations in Hungary conducted thus far have presented information on no more that the probability values of point maxima related to individual stations. The objective of the present study is to develop computation aids, using which the annual peaks of areal precipitation pertaining to a confidence level P can be estimated for areas A = 1 to 5000 sq. km in magnitude and for periods T= 1 to 0 days in length. The computation aids derived can be applied to any region of Hungary, using the data obtained by conventional meteorological processing for the rapid and approximate solution of the above problem. 1. Principle of the computation procedure The starting basis of computations is the average annual peak of 1-day point precipitation Х(т=i) , which is available for an adequate number of observing stations with precipitation records extending to several decades. In the knowledge of X(r=i) the formula of Eq. (3) is used for finding the Х(Т) value, with the period T ranging from 2 to 6 days. The next step involves lhe determination of the ratio, which exists between the average annual peak Х(Т) of areal precipitation related to the period T in given regions and the areal mean value Х*т) of average annual peak of point precipitation within these regions and related to the same period T. This ratio is a function of Lhe area A of the regions. For this purpose Eq. (4) is used. Once the relations given by Eqs. (3) and (4) are known it is possible to determine the Х(т) values from the average annual peak values of 1-day point precipitation, which are available for the stations within a particular area. It is possible to demonstrate that for any period length T the ratio Q of the value X Pj) of annual peak of areal precipitation pertaining to the confidence level P and of the arithmetic mean Х(т) is a function of the confidence level P, the magnitude of the reference area A and of the period length T, as expressed in a general form by Eq. (7). The last step in the solution of the problem involves the specification of this functional relationship.
