Exchange processes at the land surface for a range of space and time scales : proceedings of an international symposium held at Yokohama, Japan, 13-16 July 1993 / jointly organized by the International Association of Hydrological Sciences and the International Association of Meteorology and Atmospheric Physics ; ed. by H.-J. Bolle, R.A. Feddes, J.D. Kalma / Wallingford (Oxfordshire - GB) : IAHS Press , 1993