Summer daily precipitation and wet day climatological features in southeast São Paulo, Brazil

Abstract

The development of novel diagnostic tools for enhancing climate monitoring capabilities is being increasingly demanded by several important societal sectors, such as agriculture, energy production, and industry, among others. This study aims to contribute to such developments by characterizing the observed daily precipitation conditions within the climatic context for the austral summer months over the southeast region of the state of Sao Paulo, Brazil. The characterization was designed to quantify the climatological features of daily precipitation and of the number of rainy (or wet) days. The objective is to provide complementary information to the traditionally available monthly and annual precipitation monitoring. Such a diagnostic characterization can assist answering the following questions: How did daily precipitation behave in southeast Sao Paulo during the last two decades? What is the typical distribution of summer precipitation in southeast Sao Paulo? How many wet summer days are typically observed in southeast Sao Paulo? How many wet summer days were observed during the last two decades? What is the typical distribution of wet summer days in southeast Sao Paulo? How have the latest years been in terms of wet summer days? The daily precipitation and wet day characterization was performed using historical data for the 1998/1999 to 2017/2018 period. The representativeness of these characteristics was assessed using a four times longer time series from a meteorological station located within the investigated region. The analysis indicated that for the southeast region of the state of Sao Paulo, the 2013/2014 summer period presented values ​well below those previously recorded in association with exceptionally dry conditions established over this region, corroborating previous findings but now from the perspective of daily precipitation information.