Ocean controls on the variability of the Hadley cell over the last 2000 years

• Grant number: 21/04596-1
• Support Opportunities: Scholarships in Brazil - Doctorate
• Effective date (Start): January 01, 2022
• Status: Discontinued
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Physical Oceanography
• Principal Investigator: Ilana Elazari Klein Coaracy Wainer
• Grantee: Paulo Sérgio da Silva Júnior
• Host Institution: Instituto Oceanográfico (IO). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated scholarship(s): 22/11857-9 - Ocean controls on the variability of the Hadley Cell over the last 2000 years, BE.EP.DR

Abstract

Human activities are highly dependent on climatic conditions. Rainfall in particular is crucial for agriculture and availability of water resources. Nonetheless, extreme rainfall events, as well as prolonged periods with little or no rainfall, may have deep economic and societal impacts and lead to the loss of lives. In the Tropics, the Hadley circulation plays a key role in controlling precipitation patterns, since it is related to the position of the ITCZ, which is also a main component of the South America Monsoon System (SAMS). The position of the ITCZ over the ocean is locked to the sea surface temperature patterns and the net northward heat transport in the Atlantic ocean, by the meridional overturning circulation (AMOC), and atmospheric redistribution of this heat lead the average ITCZ position to be displaced North of the Equator. Therefore, changes in heat transport and surface temperature patterns in the tropical region may impact precipitation in the surrounding continents, via their influence on the Hadley Circulation. In addition to SST variability, other factors such as Greenhouse Gases (GHG) concentration, stratospheric ozone depletion and pollution have been identified as drivers of a poleward expansion of the Hadley Cell in the last decades. Considering the close link between the Hadley Cell circulation, the AMOC and their impacts on precipitation, as well as their sensitivity to both natural and anthropogenic external forcings, this project aims to study the variability of the Hadley Cell in connection with the AMOC and the tropical hydroclimate from the last 2K into the future. We will investigate the mechanisms driving this variability considering both the natural and anthropogenic forcing (greenhouse gases, stratospheric ozone and tropospheric aerossols). We will rely on CMIP6 and AMIP simulations, as well as on ensemble simulations of the IPSL-CM6A-VLR model and reanalyses. (AU)