Author(s)

Rose Ane Pereira De Freitas¹, Fernanda Casagrande², Douglas Da Silva Lindemann¹, Maria Angélica Gonçalves Cardoso³, Jeferson Prietsch Machado⁴

¹Forecasting and Meteorological Research Center, Federal University of Pelotas (UFPEL), Pelotas, Brazil.
²Earth System Science Centre (CCST-INPE), National Institute for Space Research (INPE), São José dos Campos, Brazil.
³Federal University of Santa Maria (UFSM), Santa Maria, Brazil.
⁴Oceanography Institute, Federal University of Rio Grande (FURG), Rio Grande, Brazil.

Here we investigate the ocean-atmosphere coupling and the contribution of the Sea Surface Temperature (SST) variations in: 1) Brazil-Malvinas Confluence (BMC) region, 2) Southwest Atlantic Ocean and 3) Southern Brazil. Numerical simulations of the ECHAM5/MPI-OM coupled ocean-atmosphere model were used to analyze the changes in the seasonal trajectory of the extratropical cyclones, in terms of intensification of physical mechanisms and implications for future scenarios. The numerical experiment for the future scenario considered an atmospheric CO₂ concentration of approximately 770 ppm, which represents an increment of more than 350 ppm over the current values recorded by the Mauna Loa reference station. For this scenario, the results indicated a Storm Tracks (ST) displacement of 5° latitude toward south and changes of the meridional transport of sensible heat, close to 50°S. The increase in SST induces ST intensification and consequently an increase in the occurrence of extratropical cyclones. Overall, in the BMC region, we found a change in the pattern of cyclogenetic activity occurrence, with less frequent, but more intense events. On the Southern Brazilian region, the results of this study indicate increases in rainfall during summer months, whereas, a decrease in frequency and an increase in intensity were found for wintertime. We suggest that these changes could impact the climate dynamic of the Brazilian South coast, with a magnitude yet unknown.

Storm Tracks, Confluence Brazil-Malvinas, Atlantic Ocean

Ane Pereira De Freitas, R. , Casagrande, F. , Da Silva Lindemann, D. , Angélica Gonçalves Cardoso, M. and Prietsch Machado, J. (2019) The Storm Tracks Response to Changes in Atmospheric Greenhouse Gas Concentration at the South of Brazil and Southwest Atlantic Ocean. Atmospheric and Climate Sciences, 9, 545-557. doi: 10.4236/acs.2019.94035.