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Genesis of Cloud Streets and Convection over Pristine Amazon Forest

Renato Ramos-da-Silva, Universidade Federal do Pará, (Presenting)
Adilson Wagner Gandu, Universidade de São Paulo,
Leonardo Sá, Museu Emilio Goeldi,
Maria Silva Dias, Universidade de São Paulo,
Julia Cohen, Universidade Federal do Pará,

Cloud streets are daily phenomena over the pristine Amazon. A modeling approach that includes a mesoscale domain and nested grids up to Large Eddy Simulations (LES) is used to understand their formation and behavior over a particular pristine forest in the Amazon. The modeling approach is supported by meteorological data collected during the COBRA-PARÁ (Caxiuanã Observations in the Biosphere, River and Atmosphere of Pará) field campaign held on November 2006 at the Caxiuanã National Reserve. The modeling simulations show that the interaction between the atmosphere dynamics and the surface creates upward vertical motion aligned with the predominant wind flow. Those moisture rich pathways favor the genesis and movement of the cumulus clouds during the first hours of the day producing the cloud streets. During the late afternoon and early night time, storms move along with the easterly winds and become stronger after crossing water surfaces such as the Caxiuanã Water Bay. Further analysis show that those storms release downdrafts that are probably the cause of strong mixing observed in the instrumented towers located at the Caxiuanã Forest.

Science Theme:  HY (Hydrometeorology)

Session:  2A: Evapotranspiration and Precipitation

Presentation Type:  Oral (view presentation (8465 KB))

Abstract ID: 31

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