Documenting the heterogeneity of rainfall regimes is a prerequisite for water resources management, mitigation of risks associated to extremes weather events and for impact studies. In this paper, we present a method for regionalization of rainfall over the Peruvian Pacific slope and coast, which is the main economic zone of the country and concentrates almost 50% of the population. Our approach is based on a two-step process based on k-means clustering followed by the regional vector method (RVM) applied to a network of 145 rainfall stations covering the period 1964–2011. The advantage of combining cluster analysis and RVM is demonstrated compared with just applying each of these methods. Nine homogeneous regions are identified that depict the salient features of the rainfall variability over the study area. A detailed characterization of the rainfall regime in each of the identified ...

The PGSC-Peruvian team was funded by grants from the Peruvian Fund for Innovation in Science and Technology (FINCYT), the Peruvian Ministry of Agriculture (MINAG) and the Peruvian Council of Science and Technology (Concytec). Additional support was received from Universidad Peruana Cayetano Heredia, Universidad Nacional San Cristobal de Huamanga and the Peruvian Ministry of foreign affairs. The PGSC-Chilean initiative has been supported by National Commission of Scientific and Technologic Research (CONICYT) and the Foundation for the Innovation in Agriculture (FIA).