Future scenarios (2011-2040) of temporal and spatial changes in precipitation in the Paraitinga and Paraibuna watersheds, São Paulo, Brazil

Rodrigo Cesar Da Silva,Gilberto Fisch,Thiago Adriano Dos Santos

doi:10.4136/ambi-agua.2302

Abstract

The alteration of global climate regimes due to anthropic action and excessive emission of greenhouse gases has been widely researched because it alters the patterns of climatological normals, generating changes in temperatures and precipitation worldwide. This study aimed to analyze the spatial and temporal variability of precipitation in the Paraitinga and Paraibuna watersheds that together form the Paraibuna Dam, the main one of the Paraiba do Sul river watershed. This dam supplies the São Paulo Metropolitan Region by transporting water to the Cantareira System, the Rio de Janeiro Metropolitan Region by transporting water to the Guandu watershed, and the Paraiba Valley Metropolitan Region, one of the most industrialized in Brazil. To investigate future precipitation trends, past and future climate simulations were used from the HadCM3/Eta model using the SRES (Special Report Emission Scenarios) A1B, and precipitation analysis using Quantis techniques to determine extreme rainfall and drought periods. The results point to an increase in precipitation averages in the region, followed by a greater intensity of extreme rainfall, which may lead to a higher occurrence of natural disasters such as landslides.

Highlights

Technological modernization and the development of industrial activities resulting from the Industrial Revolution has accelerated the emission of greenhouse gases, which aggravates this natural phenomenon, changing climate regimes on a planetary scale (IPCC, 2019)
Lyra et al, (2017) analyzed climate change projections for the metropolitan regions of São Paulo, Rio de Janeiro and Santos by the end of the 21st century using the HadGEM2-ES climate simulation model regionalized by the Eta model with a 5km resolution
It is important to highlight that the average precipitation value for the study area in the past period of 1346.2mm is compatible with the results obtained by Fisch (1995) and the climatological normal values in the municipality of Taubate/SP, which has an average precipitation of 1360.9mm (INMET, 2019)

Summary

Introduction

Technological modernization and the development of industrial activities resulting from the Industrial Revolution has accelerated the emission of greenhouse gases, which aggravates this natural phenomenon, changing climate regimes on a planetary scale (IPCC, 2019). Lyra et al, (2017) analyzed climate change projections for the metropolitan regions of São Paulo, Rio de Janeiro and Santos by the end of the 21st century using the HadGEM2-ES climate simulation model regionalized by the Eta model with a 5km resolution They noted that there will be a trend of an average increase in temperature above the normal climate of up to 8°C for the 2017-2100 period, coupled with a considerable decrease in rainfall during the summer period, ranging from 3 to 6 mm/day-1 by the end of the century, followed by an increase in extreme rainfall in the mountainous areas of the region, accompanied by a general decrease in precipitation rates. Such extreme event associations could impact the region's water reservoirs and affect water availability for human consumption and power generation

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