Hidrológiai Közlöny 1988 (68. évfolyam)

6. szám - Nováky Béla: Az évi lefolyás változékonyságának függése az éghajlati elemektől

NOV

ÄKY B.: A lefolyás éghajlati függése 319 and the annual precipitalion depth depends also on the time adopted as the beginning of the year (Fig. 2). The 22 year long record of annual runoff through the Verpelét ganging section of the Tarna River is analyzed in detail. The component determined by the climate is described by Eq. (4), the time series remaining after the separation of the latter is approximated by the AR (2) model represented by Eq. (6). The time series yi remaining once the stochastic part is separated is substantially a random process. The inherent inertia of the changes in condition is implied by Eq. (6), while the inherent inertia reflects the storage processes in the catchment. The variations over time in the storage levels of the(imaginary) reservoir spaces in the catchment are illu strated in Fig. 1. This reservoir storage level is correlated with the climate, primarily with the precipitation, over the antecedent period, as expressed by Eq. (7). The annual runoff —- climatological elements correlation is summarized in Eq. (8), where y\ is the random process. The correlation coefficient between the runoff values estimated using the equation and those actually observed is 0,77. Of the variability in annual runoff 60 % can be attributed to the climatic fluctuations (Fig. 4). The expression suggested by Tshebotariev — Eq (12) — for correlating the variability coefficients of the annual runoff C

v( Y

) and the annual precipitation C

v(X

) can be accepted as a fair approximation also to the streams in Hungary (Fig. 6). The expression can be improved by taking into consideration that the geographical parameter m (which has a average value of 0,5 for the streams in the European part of the Soviet Union) is a function of the runoff coefficient. The G

v( Y

) values can be found from the C

v(X) values with a mean error of 10 % using Eq. (14). Separation of the annual runoff time series offers the possibility of identifying for a particular catchment the relationship between the variability coefficients of runoff and the climatological factors. The general form of this relationship is described by Eq. (19,) the forms for the Tarna catchment being given by Eqs (21) and (22). For the latter the analytical value C

v(Y) — 0,604 compares favourable with the 0,592 estimated from the observation data. The method described is suited to (1) exploring the deterministic relationships inherent in annual runoff time series and to evaluating the anthropogenic, human effects, (2), to generating on the basis of climatological elements the typical parameters involed in the annual runoff time series and the series themselves and (3) to exploring the climatic sensitivity of variations in the annual runoff. Keywords: annual runoff, changes in state, inertia, variability of climatic elements, variability coefficient NOVÁKY IÍÉI.A szakmai munkásságának összefoglalóját a Hidrol. Köd. 1988/4. számának oldalán közöltük.