Spatial variability of rainfall for the State of Espirito Santo, Brazil using multivariate methods

Abstract

One of the major concerns of the scientific community over the last decade regards to climate change and its consequences for humanity. The objective of this study was to estimate the spatial variability of rainfall in the State of Espirito Santo, Brazil, based on the values of geographical coordinates and altitude of the measuring stations. The rainfall values raised for 55 climatic stations located within the state area were used, considering the monthly and annual means of the time series used. The geographic coordinates and altitude data were submitted to the multivariate statistical analysis based on the principal components for its dimensional reduction. The rainfall data and the selected component were submitted to the multivariate geostatistical analysis, which yielded satisfactory results in estimating rainfall values at non-sampled areas, increasing the spatial continuity of the phenomenon. The monthly and annual rainfall in the State of Espírito Santo presented high spatial dependence for the series studied, with less variability in the northern region, where the rainfall rates are reduced. The rainfall survey is not solely dependent on the number of rain gauge stations, but mostly on their distribution throughout the area to be sampled, whereas the ideal mapping model is the one that considers both parameters together.