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Mesoscale Fluxes

Osvaldo Luiz de Moraes, UFSM, moraes@mail1.ufsm.br (Presenting)
Otávio Costa Acevedo, UFSM, otavio@smail.ufsm.br
David Roy Fitzjarrald, SUNY, fitz@asrc.cestm.albany.edu
Ricardo Kendi Sakai, SUNY, sakai@asrc.cestm.albany.edu
Matt Czikowsky, SUNY, matt@asrc.cestm.albany.edu
Rodrigo da Silva, UFPA, rodriogo@lbaeco.com.br

Recent studies show that surface fluxes consist of two distinct types of interactions. In smaller temporal scales, the exchange is performed by turbulent eddies, which are organized and well related to properties such as vertical gradients, so that they are commonly expressed in terms of similarity relationships. On larger scales, the interaction is more erratic, not clearly controlled by the flow characteristics. These larger scale transport have been generically regarded as “mesoscale fluxes”. In most cases, the mesoscale transport is larger in magnitude than the turbulent one, but, in the long term, it averages out, as a consequence of its erratic character. On the other hand, if there are consistent mesoscale circulations, caused by any forcing, the fluxes in these larger timescales may also be consistent and, in this case, they may be responsible for an important portion of the exchange between the surface and the atmosphere. In the present work, we show the existence of consistence mesoscale fluxes at the LBA pasture/agricultural site, in Santarém. These fluxes are shown to be seasonal: in the wet season they have the same sign as the turbulent portion, while they are opposed to the turbulent exchange during the dry season.

Science Theme:  CD (Carbon Dynamics)

Presentation Type:  Poster

Abstract ID: 79

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