Simulation and downscaling models for potential evaporation

As hydrologists begin to explore the potential of modern computers to simulate hydrological systems over long periods of time, there is an increasing need for high-quality tools that can generate appropriate inputs to these systems. This paper presents some statistical models for generating sequences of potential evaporation (PE), possibly conditioned on rainfall, applied to data from southern England. There have been significant trends in PE in this area over the period 1961-1993; moreover, the variance of the series shows strong seasonal structure. The methodology presented here provides an intuitively simple means of reproducing such features. Moreover, as well as allowing the generation of simulated sequences, it can be used to produce sequences at a fine timescale from coarse-resolution data.