Homogenization of Precipitation Series in Greece

Abstract

To study climate change and variability long term instrumental data are essential since they provide the most reliable records of climate in the past. However, the value of these datasets strongly depends on the homogeneity of the underlying time series. Unfortunately, most of the instrumental data series suffer from inhomogeneities caused by non-climatic changes (e.g. changes in measurement location, in observation practices, in calibration etc.). Thus, to reliably study the real development of the climate, non-climatic changes have to be removed. In this work three different homogenization methods namely MASH, ACMANT and HOMER were applied to monthly precipitation series of synoptic stations for the period 1974–2004, belonging to the operational weather network of the Hellenic National Meteorological Service (HNMS). The main objective of this study is to identify breakpoints caused by non-climatic changes, to correct them and to assess their impact on precipitation series.