Historical Change of Large Alluvial Rivers: Western Europe Ed. by G. E. Petts with H. Möller and A. L. Roux.–355 pp. 115 figs., 60 tabs. Chichester: John Wiley and Sons Ltd. 1989. ISBN 0‐471‐92163‐7. £ 45.00

The three main components of the water cycle are precipitation (P), evapotranspiration (E), and runoff (R) which results in the difference between the two first components (R=P-E). River discharges may be considered as the runoff component of the water cycle in a natural system, represented by the drainage basin. Considering large rivers in Europe, the water cycle can be studied most appropriately at regional scale. River discharge depends on several factors but it may be viewed as an integral of the different hydroclimatic factors which have affected the drainage basin. The river discharge fluctuations in 14 different regions may be compared following latitudinal and longitudinal transects. The long-term discharge fluctuations of large rivers may be viewed as a regional barometer that allows the identification of the major hydroclimatic periods which have affected, on average, the river basins. In a small continental area, such as Europe, the river discharges fluctuate more or less synchronously over long time periods. The progressive lags of the hydroclimatic periods, going from west to east and from south to north, have not yet been completely elucidated, but may be related to the general atmospheric circulation and more particularly to the zonal and meridional propagation of the two-dimensional pressure anomaly pattern. European runoff fluctuations, reconstituted using regression analysis between river discharges, appear to be in phase with European rainfall patterns. (See also (W90-03689) (Fish-PTT