Impact of climate change on Mesoscale Convective Systems over the Amazon basin

• Grant number: 21/07992-5
• Support Opportunities: Scholarships in Brazil - Post-Doctorate
• Effective date (Start): February 01, 2022
• Status: Discontinued
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Meteorology
• Principal Investigator: Tercio Ambrizzi
• Grantee: Amanda Rehbein
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated scholarship(s): 22/05622-9 - Atmosphere dynamics and thermodynamics associated to mesoscale convective systems over the Amazon basin using observational and cloud-resolving model simulations, BE.EP.PD

Abstract

Climate projections indicate a continuous increase in air temperature and a reduction inprecipitation over the Amazon basin until the end of this century. But what will actually causethe reduction (and how) in precipitation is not very well understood. What is known is that oneof the main meteorological systems causing precipitation in the Amazon basin, the mesoscaleconvective systems (MCSs), have shown negative occurrence trends between September andNovember (SON) over the Amazon basin and positive between June and August (JJA) in thesouthern part from 1950 to the near future (Rehbein, 2021). However, the conditions associatedwith its formation and maintenance are not well understood over the Amazon basin and severalgaps remain open. For instance, what has caused these trends? Would the increase in MCSs,mainly in the southern Amazon basin, in JJA be associated with the frequency and intensity ofextratropical cyclones that disturb the Amazon synoptic environment, increasing wind shear,favoring instability and the formation of clustered systems? Or is it due to changes in thepositioning of the intertropical convergence zone or the descending branch of the Hadley cell?Or, simply they are associated with the local temperature increases, temperature gradients andthermodynamic factors? On the other hand, what are the factors that lead to a decrease in MCSsduring SON? Within this context, the objective of this work is to identify the factors that haveimpacted and will impact the long-term trends in the occurrence of MCSs in the Amazon basinand, consequently, in its precipitation. Furthermore, this study will contribute to theunderstanding of the interactions between the climatic and higher frequency scales, generatingmethodology and dataset that can help future works on the topic.