FIGUEIRA, W. S.; FIGUEIRA, WALÉRIA SOUZA.; http://lattes.cnpq.br/2864963142672150; FIGUEIRA, Waléria Souza.
Resumen:
The aim of this work was to study the role played by congestus cumulus on the configuration
of the Amazonian deep convection. The shallow convection scheme of the BRAMS model
was adjusted by inserting the stage of transition from shallow to congestus cumulus, since its
parameterization is even more important when the study refers to tropical regions. Thus, three
experiments were performed: in the first control experiment (EXP-CTRL), the model was
initialized in its original form and the others (EXP-AJUST1 and EXP-AJUST4), the model
was run to the same conditions as the EXP-CTRL but with due adjustment made in BRAMS
code, the model has the capacity to produce some precipitation after the congestus cumulus
stage, before the formation of deep convection. The model was integrated for a period of 270
hours, with spatial resolution of 20 km, for a domain centered on the Amazon. Analysis of
the mean daily cycle of convective precipitation and thermodynamic vertical profile was
performed in two distinct areas, located in Manaus-Amazonas. Overall, the results show that
there were important differences in the thermodynamic profile of the lower troposphere due
to the implementation of new setting in the BRAMS code. It was observed that the effect of
precipitation produced by congestus intensified and displaced the maximum values of
moistening and heating rates by the shallow convection in the adjusted experiments, as a
consequence of part of its precipitation being used to wet and cool the surface, thus increasing
the heat fluxes and the moisture at the lower levels of the atmosphere. The timing of
maximum congestus activity substantially reduced convective precipitation between 08 and
12 LT, mainly in EXP-AJUST4 than EXP-AJUST1, as it stabilized the environment at that
time, postponing the process of deep convection formation, which had its maximums
between 16 and 19 LT. That is, a delay of the deep convection occurred as response to the
preconditioning of the atmosphere by the congestus cumulus. This result agrees with
observational studies.