Multisite temporal rainfall disaggregation using methods of fragments conditioned on circulation patterns

Abstract

A multisite method of fragments-based rainfall temporal (daily to hourly) disaggregation procedure conditioned on circulation pattern (CP) classification is developed and applied to the German part of the Rhine river basin. The performance of the CP-based disaggregation in representing key rainfall characteristics is evaluated and the influence of different number of CP classes is investigated. Compared with the standard (monthly-based) method of fragments disaggregation, the CP-based procedure including a seasonal stratification improves the disaggregation quality in hourly rainfall extremes, although it shows no improvement in reproducing standard rainfall statistics, such as mean and standard deviation. CP classifications with more classes tend to perform better in representing hourly rainfall statistics in the Rhine basin. The developed procedure opens up the possibility to consider dynamic changes in the atmosphere, such as changes in the frequency, persistence and seasonality of circulation patterns, that may be associated with climate change.