@InProceedings{GiarollaNobrMala:2013:KnBiPo,
               author = "Giarolla, Emanuel and Nobre, Paulo and Malagutti, Marta",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)}",
                title = "The Atlantic Equatorial Thermocline as simulated by the Brazilian 
                         Earth System Model: known biases and possible causes",
            booktitle = "Extended Abstracts...",
                 year = "2013",
                pages = "2",
         organization = "American Geophysical Union - Spring Meeting 2013.",
                 note = "{abstract #A52A-02}",
             keywords = "Atmospheric Processes, Global Climate Models, Atmospheric Process, 
                         Model Calibration, Atmospheric Processes, Ocean atmosphere 
                         interactions, Atmospheric Processes, Tropical Meteorology.",
             abstract = "As a result of a coordinated effort of several institutions in 
                         Brazil, the Brazilian Earth System Model has been developed to 
                         help the investigation of global climate changes, its effects and 
                         impacts on society. The first version of this model, here named 
                         Brazilian Earth System Model - Ocean-Atmosphere version 2.3 
                         (BESM-OA2.3), followed the criteria for participation in the 
                         Coupled Models Intercomparison Project 5 (CMIP5) protocol, 
                         simulating the behavior of the coupled ocean-atmosphere system on 
                         decadal time scales under varying green house gases concentrations 
                         in the atmosphere. Extended runs with over 2,000 years of ensemble 
                         members showed many coherent results, such as the response of the 
                         model to increasing atmospheric CO2 concentrations in a consistent 
                         manner. In spite of that, the model still has biases and 
                         discrepancies when compared to observations, some of them also 
                         detected in other global coupled ocean-atmosphere models. As an 
                         example of known bias, the thermocline along the Atlantic equator 
                         flattens after the second year of simulation. In other words, it 
                         anomalously deepens at the eastern region near the African coast 
                         after some months. This issue is observed in all CMIP5-based 
                         experiments made with the BESM-OA2.3. However, a newer version of 
                         the BESM-OA, with updated microphysics parameterizations and the 
                         Integrated Biosphere Simulator (IBIS) included, has shown 
                         promising results, i.e., the thermocline tends to maintain its 
                         inclination in the second year better than the first version of 
                         BESM-OA. In this work we discuss the possible causes of the 
                         thermocline flattening comparing simulations of both model 
                         versions. We don't have conclusive explanations since the study is 
                         still in progress, but some results indicate that the seasonal 
                         eastward shift of the zonal wind reversion (represented as the 
                         zero zonal wind line) at the Atlantic equator, in April-May, is 
                         better represented in the newest version of the model. With more 
                         realistic winds at the equator, the mean Equatorial Undercurrent 
                         core at 23o W, averaged after the first year, does not become 
                         shallower as in the previous version of the model, causing the 
                         thermocline to keep its slope after the first year of 
                         simulation.",
  conference-location = "San Francisco, CA",
      conference-year = "05/2013",
                label = "self-archiving-INPE-MCTI-GOV-BR",
             language = "en",
           targetfile = "giarolla_atlantic.pdf",
               volume = "1",
        urlaccessdate = "2021, Feb. 28"
}