Application of the multivariate spectral weather generator to the contiguous United States

The objective of this study was to describe improvements to the spectral weather generator and its application to diverse climates within the contiguous USA. The precipitation model, based on a second-order Markov chain coupled with the mixed-exponential distribution was found to closely reproduce the observed precipitation climatology, although interannual variability was underestimated at most locations. This underestimation was found to be due primarily to the precipitation occurrence process, but also to the precipitation intensity process. For the non-precipitation variables, which included maximum and minimum daily temperatures and daily solar radiation, the spectrally generated data were found to exhibit strong agreement with observations in terms of skewness, interannual variability and extreme values. With the use of an iterative method, the model was also able to reproduce the observed correlation and autocorrelation structure.