An observational analysis was conducted in five different cities in Eastern Amazonia, in order to detect the breeze circulations in the region. The frequency of wind direction, wind speed, and precipitation was analyzed along with estimated spatio-temporal rainfall through the Climate Prediction Center Morphing Technique (CMORPH). The results show different types of breezes that occur in these cities, with regular time from 0900-2100 UTC for SB (sea breeze), 0000-0900 UTC for LB (land breeze), and 1200-0000 UTC for RB (river breeze). The SB has been shown to be more frequent from September to November (SON), while the LB is more prominent from March to May (MAM). However, the RB highlights throughout the whole year in Belém. The hour of occurrence of the SB circulation and the precipitation along the coast has shown a relationship.

A high-resolution simulation of a real case is carried out in Eastern Amazon (Northeastern coast of State of Pará) with the Weather Research and Forecasting (WRF) model in order to analyze/detect local circulation features in the region. To this end, we simulated a case with low interference of synoptic weather systems and precipitation aiming to eliminate the effects of convective systems in local circulations. The performance of the model for the day studied was evaluated and the existence of circulations found in the simulation was confirmed through observational data. The model performance evaluation showed that the model was able to capture most of the patterns for the studied area. The simulation captured the presence of three main circulations: the Sea Breeze (SB), on the coast; the Land Breeze (LB), also on the coast; and the Bay Breeze (BB), which forms on both banks of Marajó Bay. In addition to these three major circulations, the high-resolution simulations also revealed the presence of a river breeze (RB) from Guamá River and a fan-shaped circulation on the entrance of Guajará Bay. The observational data confirmed the presence of Guamá River breeze from the Southeast, which is more active from July to September.

An unprecedented study was carried out in a mangrove ecosystem in the northeastern coast of the Brazilian Amazon to understand the behavior of climatic elements in a year with the occurrence of El Niño (2015), associated with the seasonal function source/sink of CO2 by the ecosystem. Global radiation (Rg), net radiation (Rn), temperature, relative humidity, precipitation, horizontal wind speed and direction, as well as turbulent flows of sensible heat (H), latent heat (LE), and carbon (f_CO2) were recorded using eddy covariance, a system for studying turbulent flows of heat and gases in the atmosphere. We observed a drastic reduction in rainfall volumes, which accounts for 63.7% of the expected total according to the region’s climatology. Regarding f_ CO2, the highest values of photosynthesis, autotrophic, and heterotrophic respiration of the ecosystem occurred in the wet season due to precipitation, ideal photosynthetically active radiation, lower soil salinity, and higher NDVI of the ecosystem. In the 2nd semester of the year, we observed that the decrease in cloudiness, causing a higher radiation supply in the forest canopy, accompanied by a reduction in precipitation and an increase in the value of H and soil salinity, favored the increase of foliar abscission by the dominant genus Rhizophora and Avicennia, thus influencing the reduction of magnitudes of carbon source/sink functions in the ecosystem during this season, even on high tide days.

As circulações de brisas marítimas e terrestres e o seu papel na precipitação no litoral paraense são amplamente investigados neste estudo. Para isso, foram coletados dados de vento (direção e velocidade) e precipitação, em uma frequência de dez minutos, a partir da torre micrometeorológica localizada no sítio experimental da Universidade Federal Rural da Amazônia (UFRA), em Cuiarana, município de Salinopólis, Pará. Além disso, foram utilizadas imagens de satélite feitas no canal visível do Geostationary Operational Environmental Satellite (GOES), bem como dados do CPC MORPHing technique (CMORPH), para a visualização espacial da precipitação. Os resultados demonstram que as circulações de brisas são mais intensas durante o período chuvoso (março) em relação ao período menos chuvoso (agosto). A precipitação local observada, que pode estar relacionada com a brisa marítima, apresentou maior frequência durante o final da tarde e o início da noite. Estes resultados permitem evidenciar a influência das brisas na precipitação local.