Spatial-temporal reconstruction of climate in the Metropolitan Region of São Paulo using tree-ring stable isotopes

• Grant number: 17/23521-7
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: February 07, 2018
• End date: July 06, 2018
• Field of knowledge: Biological Sciences - Botany
• Principal Investigator: Paulo Hilário Nascimento Saldiva
• Grantee: Giuliano Maselli Locosselli
• Supervisor: Roel Jacobus Wilhelmus Brienen
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: University of Leeds, England
• Associated to the scholarship: 15/25511-3 - Climate and pollution reconstruction based on urban tree-rings growth records, BP.PD

Abstract

More than half of world's population lives in cities and it will reach 66% by 2050. A share of this population lives in the mega-cities with 10 million or more inhabitants, often found in poor and / or developing countries. In these countries, the mega-cities experienced a rapid and unplanned growth that resulted in strong inequalities and environmental degradation. This condition makes these cities and their inhabitants strongly vulnerable to the consequences of climate change. Earth's rising temperature is already leading to changes in climate regimes. The metropolitan region of São Paulo is already under the influence of increasing number of extreme precipitation events that inevitably lead to flooding. On the other hand, this region is also vulnerable to drought events that lead to shortage in water supply. The year of 2014 was marked as the worst water supply crisis of São Paulo. It was a consequence of an unusual dry summer with unevenly distributed rainfall, with low precipitation in the northern water reservoirs and normal precipitation in the southern ones. The complex urban landscape makes the climate heterogeneous in the cities. Therefore, the aim of this study is to reconstruct the spatial-temporal variability in precipitation and temperature using stable isotopes in tree rings. This reconstruction will provide information for areas and periods with no available instrumental data. In addition, this study will evaluate the intra-annual variability of precipitation during the period of the worst water supply crisis of São Paulo. For this purpose, three populations do Tipuana tipu (FABACEAE) were sampled close the Cantareira, Gurarapiranga and Rio Grande reservoirs. Tree-rings will be measured and dated according to dendrochronological procedures. In addition, the stable isotopes of oxygen and carbon will be measured in the tree rings of four individuals of each population. An intra-annual analysis of oxygen stable isotopes for the years between 2012 and 2015 will provide further information about the precipitation during the water crisis in 2014. (AU)