The Interannual Variability of the Brazil Current and Regional Impacts
- Masters Students
- High School Interns
Marlos Goes (USA, NOAA/AOML, UM/CIMAS)
Yanyun Liu (USA, NOAA/AOML, UM/CIMAS)
Sudip Majumder (USA, NOAA/AOML, UM/CIMAS)
Vinicius Webber (UM/RSMAS)
Mateus Lima (UFBA/Brazil)
Steve Marrero (MAST)
Sang-Ki Lee (USA, NOAA/AOML)
Leo Siqueira (USA, UM/RSMAS)
Ben Kirtman (USA, UM/RSMAS)
Shenfu Dong (USA, NOAA/AOML)
Greg Foltz (USA, NOAA/AOML)
Gustavo Goni (USA, NOAA/AOML)
Molly Baringer (USA, NOAA/AOML)
Mauro Cirano (Brazil, UFRJ)
Mauricio Mata (Brazil, FURG)
The broad goal of this work is to improve understanding of the Brazil Current (BC) system variability on interannual timescales, and the impact of the local and remote surface forcings on the regional variability of the BC. To achieve this goal, we will use a set of oceanographic (in-situ and satellite) data, ocean reanalysis and eddy-resolving model experiments. One of the strengths of the proposed work is that we will use a collection of over a decade long direct measurements of the BC at mesoscale sampling in two locations (22°S and 34°S). In addition, we will examine the interannual variability of the South Atlantic Ocean temperature structure, its relation to sea level and heat content variability, the relationship with the subtropical gyre variability, and their causes. BC variability will provide better climate predictability for the region. In addition, this project will promote a strong collaboration between the University of Miami and the Brazilian scientists. As follows, our research plan will detail the objectives and work tasks to be completed in order to answer the questions above described.
Current observational estimates and climate models are moving toward higher spatial and temporal resolutions, allowing for better representations of mesoscale features and their associated air-sea interactions. Western boundary currents in the subtropics are associated with intense heat transport and strong upper temperature fronts. The ability of current climate models to simulate the impact of these currents on the extreme weather events is constrained by to their generally coarse resolution. This work examines the role of increased ocean resolution and a better represented Brazil Current on the air-sea interaction in the western South Atlantic. For this, current observations and two 150-year global climate model simulations with identical atmospheric resolution but contrasting ocean resolutions are used. The boundaries in the South Atlantic ocean present intense coupling between the wind and SST gradients. The impact of the DJF rainfall variability over Subtropical South America is captured by both models, but significant regional differences arise over the Brazil Current region. Ocean temperature sections near the coast also show large differences, with the eddy-resolving model in better agreement with observational estimates. This shows the importance of the resolution of the western boundary current to improving the representation and prediction of regional summer precipitation, and extreme events such as floods and droughts.
Goes, M., et al., 2017: The variability of the Brazil Current at 22°S from high-density XBT transect and satellite altimetry J. Geophys. Res., in prep.
Siqueira, L., M. Goes, G. Foltz, B. Kirtman, and D. Putrasahan, 2017: Impact of Ocean Resolution on Western South Atlantic Air-sea Interaction during Extreme SST Events J. Climate, submitted.
Lima, M., M. Cirano, M. Mata, M. Goes, G. Goni, and M. O. Baringer, 2016: An assessment of the Brazil Current baroclinic structure and variability near 22°S in distinct Ocean Forecasting and Analysis systems, Ocean Dynamics, 66:893, doi:10.1007/s10236-016-0959-6.
Goes, M., I. Wainer, N. Signorelli, 2014: Investigation of the causes of historical changes in the sub-surface salinity minimum of the South Atlantic. J. Geophys. Res. Oceans, 119, 5654-5675, doi: 10.1002/2014JC009812.