A simple weather generator that converts statistical information from downscaled global climate models to sequences of daily precipitation and temperature

A simple weather generator is presented that is designed to provide a link between downscaled precipitation or temperature statistics on the one hand, and impact models on the other. It generates time series of daily data that may be used as input for e.g. a hydrological model. It has a simple design which is described in this paper together with results from an evaluation against three rain gauge observations from Norway, Ghana and Romania respectively. It has also been tested for daily precipitation and temperatures from a number of sites representing different local climates in Ghana and Norway, and the results from these evaluations indicate that it reproduces the salient character in terms of the daily data and the observed climatology in different climatological settings. The simple design for precipitation, however, underestimate the duration of dry and wet spells for some sites to some degree. An assessment of the performance of daily temperature simulations from complimentary temperature-based weather generator for test sites in Ghana and Norway suggests that its output follows a similar statistical distribution as the original observations, however, there was some deviations particularly for the lowest temperatures. These two weather generators for daily precipitation and temperature respectively are part of the open-access R-package “esd” (version 1.11.30 or higher).