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Local circulations and climate data in the eastern Amazon region

David Roy Fitzjarrald, ASRC, UAlbany, SUNY, (Presenting)
Ricardo Kendi Sakai, ASRC, UAlbany, SUNY,
Osvaldo M. M. Moraes, Universidade Federal de Santa Maria,
Otavio C. Acevedo, Universidade Federal de Santa Maria,
Matthew J. Czikowsky, ASRC, UAlbany, SUNY,
Maria Assunção F. Silva Dias, CPTEC, Cachoeira Paulista, SP,
Rodrigo da Silva, LBA Office, Santarém,

We present recent efforts studying the effects of local circulations on climatic observations in the Amazon, with emphasis on the accumulating data from eight automatic weather stations and three flux towers in the LBA-ECO Santarém study area. To generalize certain findings for a wider region we compare in situ data with reanalysis and gridded data products. We assess the hypothesis that largest biases occur for stations for which the river is oriented parallel to the mean wind vector. Several themes are emphasized: Precipitation: We compare precipitation measurements from the Santarém mesoscale network with the CPTEC reanalysis, the Liebman gridded data, and the NOAA CMORPH inferred rainfall and identify the breeze bias. At Santarém, published results indicate that nocturnal rainfall associated with organized flows originated in the coastal sea breeze dominate. Measurements from only a few kilometers inland show the overlooked second afternoon convective peak. Radiative flux measurements: We compare direct observations among the sites with the CPTEC renanalysis product. Through reference to ceilometer and GOES images, we link in situ global radiative fluxes to cloud type and cover fraction. We test whether or not simple global short wave flux extremes can indicate the effects of smoke and haze during the dry season. We present the temporal statistics incident radiation, cloud fraction. By forming temporal ensembles of eddy covariance data, we study how clouds affect CO2 uptake at the Tapajós tower sites. Breeze circulation near Santarem: We quantify the observed mesoscale and larger scale pressure gradients associated with the breeze and compare both to the CIRSAN modeling studies and the CPTEC reanalysis. The aim is to determine the critical large-scale pressure gradient that leads to wind direction reversal in the afternoon. We identify the frequency of these conditions over longer time periods.

Science Theme:  HY (Hydrometeorology)

Session:  2A: Hydrological and Meteorological Processes

Presentation Type:  Oral

Abstract ID: 78

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