author = "Barbosa, Henriue M. and Alves, Carlos Felipe and Pauliquevis, 
                         Theotonio and Gouveia, Diego Alves and Santos, Amanda Vieira dos 
                         and Calheiros, Alan James Peixoto and Adams, David K.",
          affiliation = "{Universidade de S{\~a}o Paulo (USP)} and {Universidade Federal 
                         de S{\~a}o Paulo (UNIFESP)} and {Universidade Federal de S{\~a}o 
                         Paulo (UNIFESP)} and {Universidade de S{\~a}o Paulo (USP)} and 
                         {Universidade de S{\~a}o Paulo (USP)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {National Autonomous University of 
                title = "On the trigger and time-scales of shallow-to-deep convection in 
                 year = "2018",
         organization = "AGU Fall Meeting",
             abstract = "Deep atmospheric convection over Tropical forests continues to be 
                         a challenge, partially because it is a complicated process that 
                         involves a large range of spatial and time scales, and partially 
                         because of the lack of continuous observations with high 
                         resolution. As a consequence, the shallow-to-deep convective 
                         transition is often not properly represented in numerical models, 
                         hampering our ability to trust, for instance, important studies 
                         about climate change impacts on the hydrological cycle. To further 
                         our understanding of the s-t-d transition we used 2-years of data 
                         from the GoAmazon 2014/5 experiment (Martin et al., 2017) to study 
                         the evolution of convective events over the T3 site, in the 
                         central Amazonia (3 12' 47.88{"} S, 60 35' 55.32{"} W). 
                         Cloud-top brightness temperature (CTT) from GOES13 was used to 
                         identify 151 afternoon transition events as in Adams et al. 
                         (2017). In an Eulerian approach, we built composites (centered at 
                         time of minimum CTT, t0) to investigate the transition timescales 
                         and evaluate the thermodynamic and environmental conditions. 
                         According to our analysis, the typical s-t-d transition with the 
                         sunrise. The boundary layer height and the lifting condensation 
                         level (LCL) rise from 200m (t0-8h) to 600m (t0-4h), at the same 
                         time as the level of free convection (LFC) drops from 1800m to 
                         600m, and CAPE increased from 200 J to 1000 J. During this period, 
                         warm-cloud fraction (CTT > 0oC) is about 25% and deep-cloud 
                         fraction is negligible (<3%, CTT < -38oC). After the atmospheric 
                         trigger (LFC = LCL), shallow clouds grow into congestus (t0-4h to 
                         t0-2h), with warm-cloud fraction decreasing to 15% and cold- 
                         fraction increasing to 15%. Since sunrise (t0-8h), column water 
                         vapor increased from 5.5 to 5.8 cm. The next phase is congestus 
                         organizing into deep convection, which happens from t0-2h to t0, 
                         at the expense of CAPE consumption. CTT drops from 280K to 220K. 
                         Evaporation of rain, which started at t0-2h, moistens the PBL, 
                         increasing RH and lowering the LCL, which decouples from the LFC 
                         that started to rise, as CAPE is reduced. Precipitation persists 
                         until t0+2h. Warm-cloud fraction reaches a minimum of 8% around 
                         t0+1h, when cold- fraction is maximum (60%).",
  conference-location = "Washington, D. C.",
      conference-year = "10-14 dec.",
             language = "en",
           targetfile = "barbosa_trigger.pdf",
        urlaccessdate = "04 dez. 2020"