Navegando por Assunto "Micrometeorologia"

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Acesso aberto (Open Access)
Análise dos fluxos turbulentos de CO2 e energia, associada a percepção dos serviços ecossistêmicos em um manguezal amazônico
(Universidade Federal do Pará, 2018-04-30) FREIRE, Antonio Sérgio Cunha; VITORINO, Maria Isabel; http://lattes.cnpq.br/4813399912998401
This interdisciplinary work proposal for the PhD in environmental sciences, in the field of physical climate research, investigated the turbulent flows of CO2 and energy in the mangrove forest at the Cuiarana experimental site, in the city of Salinópolis, Pará, under the influence of local atmospheric variability during the year 2015. Also, within this interdisciplinary perspective, the relationship between the local community and the forest surrounding the study area was also studied. In order to collect the turbulent data, a micrometeorological tower was installed in the mangrove, with high frequency sensors that collected the data of the atmospheric variables above the forest canopy. The meteorological data was collected from the UFRA tower, located 400m from the mangrove tower. For the social investigations, a case study was carried out based on the perception of the decision-makers, who occupy leadership positions in several organizational structures in the city of Salinópolis and in the town of Cuiarana, on the perception of the ecosystem services generated by the ecosystem of mangrove. It was verified that in the Cuiarana mangrove, in the year 2015, under ENOS, there was a reduction of precipitation in the region where it rained only 63.7% of the expected climatological variable. As for the sensible (H) and latent (LE) heat flux in the mangrove, it was observed that the maximum values for both variables were recorded at 14h, with LE peak in the rainy season and H in the less rainy season. In the analysis of the seasonal CO2 flow, it was verified that the highest magnitudes of absorption occurred in the rainy season, with a peak of absorption at 13h with -13.56 μmol.m2, whereas in the less rainy period, absorption peak was recorded of CO2 at 13h with -8.95 μmol.m2. Regarding the perception of the local leadership within the ecosystem services generated by the mangrove, it was noted that the valuation of these goods and services was considered by the interviewees, where direct use services such as habitation, fishing, generation of work, and income are mentioned as fundamental factors for the well-being of the riverside population. It was noticed from accounts of the fishermen that the transmission of knowledge occurs generation to generation with the purpose of maintaining the traditional labor practices and conservation of the mangrove.
Acesso aberto (Open Access)
Aspectos observacionais e numéricos da interação floresta-atmosfera na Amazônia oriental: fenômenos turbulentos noturnos
(Universidade Federal do Pará, 2008) NOGUEIRA, Daniele Santos; GANDU, Adilson Wagner; http://lattes.cnpq.br/8491359374260645; SÁ, Leonardo Deane de Abreu; http://lattes.cnpq.br/0107976161469463
This study identified two nocturnal turbulent phenomena above Caxiuanã region, in the eastern Amazonia, during its dry season: low level jets (LLJ) and wind gusts, using data from the field campaigns CiMeLA (dry season of 2003) and COBRA-PARÁ (dry season of 2006). Both of them were analyzed observationally, considering aspects such as time of occurrence, intensity, height and duration, as well as their nocturnal evolution. It was verified that most of the LLJ events were accompanied by a drop in equivalent potential temperature. It was also found that the wind gusts had an important influence over the forest-atmosphere exchanges. The genesis of these phenomena was also investigated. It was noted, using the mesoscale model BRAMS, that the origin of the jets is possibly associated to the sea breeze and the intensification of the northeasterly winds. These results were based on sensibility tests, which included the removal of the rivers, the ocean-continent interface, the effects of downdrafts and the deforestation of the region. It was observed that the origin of the wind gusts is associated to the existence of Caxiuanã bay, which resembles a lake, and to the local convective activity. Furthermore, it was found that both phenomena did not exist simultaneously, except for one single night. This can be explained by a shear-sheltering effect that impedes that propagation of the turbulence downward, to the surface. This effect is generated by the presence of strong LLJs. This research reflects the importance and complexity of the atmospheric phenomena near the coast of Pará.
Acesso aberto (Open Access)
Equações alométricas para estimar a biomassa acima do solo em floresta plantada com tachi-branco (Tachigali vulgaris), Dom Eliseu/ Pará.
(Universidade Federal do Pará, 2019-07-24) CERVEIRA, Suzane Serrano; CATTANIO, José Henrique; http://lattes.cnpq.br/1518769773387350
The biomass study in tropical FORESTS has played a major role in relation to the contribution of ecosystems to the global carbon cycle. Many articles suggest planting Tachigali vulgaris (Taxi-White) for carbon capture projects in the Amazon and the generation of carbon credits. However little is known how to estimate the biomass increment and how different spacing interferes with the local microclimate. The present study was conducted at Genesis farm in Dom Eliseu city, Pará State, aimed to determine allometric curves for accumulation of aboveground biomass using destructive methods, and the carbon in the biomass and consequent micrometeorological variations in Taxi-White in spacing 4mx2m, 4mx3m and 4mx4m, with population density ranging from 208 to 403 plants per plot. For the equations used a database of 54 trees of a single species, in which were measured variables total height, diameter at breast height (DBH), each sample tree was felled and split the trunk components, branches, and leaves. The fresh weight of each component was obtained in place, and green samples were collected, weighed and brought to the laboratory in Bethlehem to oven drying to constant weight. 17 models of regression equations were used commonly used in the literature, being chosen equations with a higher coefficient of determination (R²). The stock biomass and shoot carbon were observed in the denser spacing, ie, 4mx4m, focusing mainly on the tree trunk. The distribution of the moisture content of classes was: leaves > branches > trunk. The trunk segment is divided according to their height into steps (BASE, DAP, 25%, 50%, 75% and 100% of the total stem height, DAP had a higher moisture content than the other compartments. The temperature was greater spacing with lower density (4mx4m) and the relative humidity had its highest values for spacing with higher densities (4mx2m). The months of September and October showed higher temperature and lower relative humidity, however, the months of November and December, showed lower temperature and higher relative moisture.
Acesso aberto (Open Access)
Estudo comparativo da estrutura da turbulência atmosférica na camada limite superficial acima da floresta primária e região desmatada da Amazônia: análise de ondeletas aplicadas à detecção de estruturas correntes
(Universidade Federal do Pará, 2008) DIAS JÚNIOR, Cléo Quaresma; MARQUES FILHO, Edson Pereira; http://lattes.cnpq.br/3112476528507003; SÁ, Leonardo Deane de Abreu; http://lattes.cnpq.br/0107976161469463
Fast response turbulent data measured in micrometeorological towers located at the Caxiuanã Reserve, PA, (54m height), the Rebio-Jaru, RO, (60m height) and the Fazenda Nossa Senhora, RO, (4,04m height) have been analysed. A comparative study of coherent structures detection above experimental sites with distinct roughness surface conditions, forest and pasture, has been performed. The wavelet of Morlet has been used to identify the occurrence scale of coherent structures in temperature series data. Mean time and space scales of the coherent structures above two surfaces with different surface roughnesses have bean compared: for Caxiuanã and Fazenda Nossa Senhora experimental sites. Atmospheric stability parameters have been calculated to provide information to study the variability of coherent structures and its relationship with atmospheric stability conditions. For the Rebio-Jaru experimental site, the inflexional point height concerning the mean wind velocity vertical profile above and inside the forest canopy has been to determined, too. Finally, to better understand the earlier findings regarding turbulent mixing coherent structures characteristics, correlation coefficients between the vertical velocity and temperature time series have been calculated: a) for the measured data; b) for the wavelet coefficients on the time-scale of coherent structures occurrence. The results have shown clear differences between coherent structures occurrence scales above rough surfaces, as forestas, and smoother surfaces, as pastures. Above forest, under near neutral conditions, oscillation patterns with 80s time-scale are dominant, probably associated with “like rolls” structures. However, lesser was the inflexional point height of the wind profile, lesser was the coherent structures time-scale, probably as a consequence of the greater dissipation effect resulting of the impact action of the canopy physical structure upon the flow turbulent eddies. Further, correlation coefficients between the vertical velocity and the temperature calculated from the wavelet coefficients on the timescale of coherent structures occurrence are clearly greater than the ones resulting of the measured data (all available time-scales). Overall, the results suggest that there are crucial changes in the turbulence structure of the flows above deforested regions comparatively with the ones above pristine forest in Amazonia.
Acesso aberto (Open Access)
A influência da variabilidade espacial e sazonal sobre o efluxo de dióxido de carbono do solo em ambientes modificados na FLONA Caxiuanã-PA
(Universidade Federal do Pará, 2014) TEIXEIRA, Ana Paula Assunção; CATTANIO, José Henrique; http://lattes.cnpq.br/1518769773387350
This study aimed to investigate the influence of spatial and seasonal variability on the efflux of CO2 from the soil to the atmosphere by comparing with heat sensitive streams and latent heat as with the environmental variables (air and soil temperature, relative humidity and volumetric soil moisture) and total organic carbon in soil. This study was conducted in environments modified naturally (AMN) and antropicamente (AMA) on the FLONA of Caxiuanã, PA, during the transitional period of rainy-dry season and dry period in the year 2013. We have seen that the opening of anthropogenic and natural gaps promote variations of environmental factors arriving at the interior of the modified environments, causing greater intensity in the heat flux, favoring thus the spatial variability of CO2 efflux. The AMN showed an increase of CO2 efflux from the period of transition from the rainy–dry season to the dry period, where the highest rates of efflux occurred in the afternoon with the removal of the gap to the interior of the forest under closed canopy in east and west the gap. Contrasting with the AMA where it was verified reduction of rates of efflux of the transitional period of rainy– dry season to the dry period. Correlations between soil temperature and soil moisture with the CO2 efflux presented significant correlation mainly in the center of the gaps, influenced by heat transport more intense at this location. In this way, the CO2 efflux receives influence of environmental micrometeorological variables, soil physical and chemical characteristics and contribution of total organic carbon, showing variations of behavior with the opening of natural gap and anthropized in the Amazon rainforest.
Acesso aberto (Open Access)
Insights of meso and micro-scale processes for the Caxiuanã forest region from high resolution simulation
(2012-07) MESQUITA, Renata Leitão da Conceição; SILVA, Renato Ramos da
Meteorological data and high resolution numerical simulations were used to estimate spatial fields in eastern Amazonia where is located the Forest and the Bay of Caxiuanã. The study were performed for the period of November 2006, when occurred the field experiment COBRA-PARA. Analysis of the MODIS sensor from the Terra Satellite images show the occurrence of various phenomena such as local cloud streets, precipitating convective systems and an important influence of the interfaces between the forest and water surfaces. Numerical simulations for November 7, 2006 showed that the model represented well the major meteorological processes. The results show that the Caxiuanã Bay causes significant impact on adjacent meteorological fields mainly through advection by the northeast winds that induce to colder canopy temperature to the west of the bay and convective rainfall. Simulations with high resolution (LES) produced spatial patterns of temperature and humidity aligned with the winds during the daytime, and at nighttime the patterns are influenced mainly by the presence of the bay. Correlations between the mid-level winds and the latent heat fluxes showed that there is a change from negative correlations for the early hours to positive correlations for the afternoon and early evening.