Analysis of Turkish precipitation data: Homogeneity and the Southern Oscillation forcings on frequency distributions

The homogeneity of newly compiled 212 precipitation records in Turkey for the period 1973-2002 was checked by the Standard Normal Homogeneity Test (SNHT) and Pettitt Test. Stations were considered inhomogeneous if at least one of the tests rejects the homogeneity. As a result, 43 out of 212 stations were found to be inhomogeneous. In addition, the previously detected Southern Oscillation (SO)-related precipitation anomalies by the authors were quantified at each station using the gamma distribution. The observed SO-related shifts in the median precipitation amounts expressed as gamma percentiles may be considered as a typical SO response of that station. The results of this study confirm the wet responses of Turkish precipitations to El Nino events, whereas those for La Nina events seem to be masked by sampling variations within the study period.