Armazenamento Térmico Acima do Solo e Balanço de Energia em Floresta de Terra Firme na Amazônia Central

Armazenamento térmico acima do solo e balanço de energiaem floresta de terra firme na Amazônia centra

Impacto da Altura das Falésias na Geração de Turbulência

Impacto da altura das falésias na geração de turbulênci

LANDSCAPE FRAGMENTATION AND FIRE VULNERABILITY IN PRIMARY FOREST ADJACENT TO RECENT LAND CLEARINGS IN THE AMAZON ARC OF DEFORESTATION

Deforestación extensiva en el Amazonas ha creado una selva bastante fragmentada en regiones con tasas altas de deforestación y de uso del fuego para limpia y mantenimiento de terrenos. El bosque en la interfase con estas deforestaciones sufre cambios drásticos en microclima, vegetación y procesos ecológicos, los cuales son favorables para la combustión bajo las copas después de una sequía prolongada. Un incremento en el uso del fuego, aunado a una mayor área de bosque vulnerable a incendios es una amenaza para la integridad y sustentabilidad de selvas tropicales. Se presentan resultados de estudios conducidos en Mato Groso de 1997 al 2003 como parte de experimentos para estudiar combustión de biomasa, tasas de liberación de carbono y flamabilidad de selvas. Se monitorearon cambios en susceptibilidad a incendios en la interfase entre el bosque y áreas recientemente deforestadas durante la temporada de sequía, al final de la cual se desarrollaron quemas experimentales. Abstract Extensive deforestation in the Amazon has created a highly fragmented forest in regions with an extensive rate of land use conversion and use of fire for land clearing, agriculture and grassland maintenance. The forest on the interface with land clearings suffers drastic changes in micro weather, vegetation, and ecological processes. Those altered conditions are favorable to sustaining understory fires after a prolonged drought. An increasing amount of fire usage, coupled with large areas of forest vulnerable to fire creates a new threat to the integrity and sustainability of the tropical forests in Amazonia and elsewhere in the tropical world. This paper presents the results of experimental burnings conducted from 1997 to 2003 in Mato Grosso. The study monitored the change in vulnerability of the interface between primary forest and recent deforested patches, monitored fire behavior and depth of fire penetration in the undisturbed forest on the edge of land clearing

Calibration of the simplified simple biosphere model (SSiB) for Amazonian pasture and forest sites using LBA data

The parameters of the Simplified Simple Biosphere Model - SSiB were validated and subsequently calibrated for the Fazenda Nossa Senhora Aparecida (62º22'W; 10º45'S) pasture site and the Reserva Biológica do Jaru (62º22'W; 10º45'S) forest site, both located in the state of Rondônia. Micrometeorological and hydrological data collected during the dry period of 2001, as part of the Large-Scale Biosphere-Atmosphere Experiment in Amazonia - LBA, were used. The results showed that the model simulated well the net radiation, both at the pasture and at the forest. The latent heat flux was super-estimated in both sites. The model sub-estimated the sensible heat flux at the pasture and at the forest, mainly during the night period; notwithstanding, the values for the forest were nearer to the observed ones. With the calibrated parameters, the model generated better estimations of the latent and the sensible heat fluxes, thus better representing the energy partition both at the forest and at the pasture.", 'enOs parâmetros do "Simplified Simple Biosphere Model"-SSiB foram validados e posteriormente calibrados para os sítios de pastagem da Fazenda Nossa Senhora Aparecida (62º22\'W; 10º45\'S) e de floresta da Reserva Biológica do Jaru (62º22\'W; 10º45\'S), ambos situados no estado de Rondônia. Foram utilizadas medidas micrometeorológicas e hidrológicas obtidas durante o período seco de 2001, como parte do Experimento de Grande Escala da Biosfera-Atmosfera na Amazônia - LBA. Os resultados indicam que o modelo simulou bem o saldo de radiação, tanto na pastagem quanto na floresta. O fluxo de calor latente foi superestimado nos dois sítios nos períodos de simulação, o que deve estar relacionado aos parâmetros utilizados no cálculo dessa variável. O modelo subestimou o fluxo de calor sensível na pastagem e na floresta, principalmente no período noturno; porém, para a floresta, os valores foram mais próximos daqueles observados. Com os parâmetros ajustados, melhores estimativas dos fluxos de calor latente e de calor sensível foram geradas e, conseqüentemente, representou melhor as partições de energia na floresta e na pastagem

Estudo da particao de energia sobre terrenos complexos cobertos com lamina d'agua em setor do Pantanal Sul Matogrossense

The partition of energy in Passo do Lontra, MS, 19o3348,2S; 57o0053,8W, in the flooded Pantanal Sulmatogrossense, is modeled considering the advective transport of sensible and latent heats, resulting in a better agreement with the values measured for all fluxes, than that one obtained without advection

Rates of energy storage and stem heat fluxes in a terra firme forest in Central Amazonia

To obtain the rate of energy storage (RES) in a "Terra Firme" forest during the dry season, an experiment was effected in Central Amazonia. Thus, the temperatures in three heigths and several radial depths of 4 stems of dominant species among the 670 trees of an 1 hectare site selected at the Estação ZF-2 (02°3645" S, 60°1240" W), plus the air temperatures and moistures, were measured. To compute the RES, all components which store energy during the day were considered: litter, minor components (palm trees and lianas), stem, branches, twigs, leaves and air. To obtain the RES of the stems, three methods were used. The first one uses all stem temperature measurements. The other ones, which are based on an analytical solution of the heat conduction equation, depend only on the temperature measurements in one radial depth of a tree with the average characteristics of the complete set. The RES of the other components was determined with the air and the average tree stem surface temperature measurements, plus the air moisture. One third of the RES of the forest is due to the stems, while other third is due to the air; finally, the last one is divided among the other parts. During the night and the transition periods, the RES of the forest (S) may constitute a sizable fraction of the net radiation (Rn), or even exceed it. On a daily basis, the values of S were observed between 1 and 10% of Rn, depending on the weather conditions

Taxas de armazenamento de energia e fluxos de calor nos troncos em floresta de terra firme na Amazônia central

Para obter a taxa de armazenamento de energia (TAE) em floresta de terra firme, realizou-se um experimento, durante a estação seca, na Amazônia Central. Para tal, mediram-se temperaturas, em três alturas e diversas profundidades radiais, de 4 troncos de árvores de espécies dominantes num hectare com 670 árvores, selecionado na floresta da Estação ZF-2 (02°36’45” S e 60°12’40” O), além da temperatura e da umidade relativa do ar. Para a determinação da TAE consideraram-se todos os componentes que armazenam e liberam energia ao longo do dia na floresta: liteira, componentes de pequeno porte (palmáceas, cipós, etc.), troncos, galhos, ramos, folhas e ar. Um terço da TAE na floresta é devido aos troncos, enquanto outro terço é devido ao ar; finalmente o último terço é dividido entre as outras partes. Durante a noite e em períodos de transição a TAE na floresta (S) pode ser uma fração bastante significativa ou mesmo exceder o saldo de radiação (Rn). Em totais diários, observaram-se valores de S entre 1 e 10% de Rn, sendo estes dependentes das condições do tempo ao longo do dia. ABSTRACT: To obtain the rate of energy storage (RES) in a “Terra Firme” forest during the dry season, an experiment was effected in Central Amazonia. Thus, the temperatures in three heigths and several radial depths of 4 stems of dominant species among the 670 trees of an 1 hectare site selected at the Estação ZF-2 (02°36’45” S, 60°12’40” W), plus the air temperatures and moistures, were measured. To compute the RES, all components which store energy during the day were considered: litter, minor components (palm trees and lianas), stem, branches, twigs, leaves and air. One third of the RES of the forest is due to the stems, while other third is due to the air; finally, the last one is divided among the other parts. During the night and the transition periods, the RES of the forest (S) may constitute a sizable fraction of the net radiation (Rn), or even exceed it. On a daily basis, the values of S were observed between 1 and 10% of Rn, depending on the weather conditions