Balanço de radiação em áreas de floresta e de pastagem em Rondônia

• Autor(a) principal: Aguiar, Leonardo José Gonçalves
• Data de Publicação: 2007
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5220
• topic: Balanço de radiação; Albedo; Amazônia; Radiation balance; Albedo; Amazon region; CNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::METEOROLOGIA::MICROMETEOROLOGIA

The present work objective to analyze the daily and sazonal variations of radiation balance components including photosynthetic active radiation at forest and pasture sites in Rondonia. Several models estimated atmospheric long wave radiation tested at both experimental sites. For accomplishment of this work, were used data from solar global radiation (Sin) and reflected solar radiation (Sout), incident photosynthetic active radiation (PARin) and reflected (PARout), atmospheric long wave radiation (Lin) and emitted by surface (Lout), radiation balance (Rnet), precipitation (P), air temperature (T) and air relative humidity (UR), measured continually since June, 2005 to May, 2006 in two experimental sites at The Large Scale Atmosphere-Biosphere Experiment in Amazônia LBA, Rondônia State. The pasture area is located at Fazenda Nossa Senhora (FNS) (10º45' S; 62º21' W), with 293 meters altitude, and the forest area at Reserva Biológica do Jaru (JAR) (10o4' S; 61o55' W). The altitude of forest area varies between 120 and 150 meters. The Lin estimates , in hourly base, were done through of Brunt (1932), Swinbank (1963), Idso and Jackson (1969), Brutsaert (1975), Satterlund (1979), Idso (1981) and Prata (1996) equations. The seasonal variation of radiation balance components, especially, solar global radiation, reflected solar radiation and net radiation was well characterized at both experimental sites. The albedo increase between forest and pasture was of 79,5%, that contributes to largest reduction of radiation balance among those two types of vegetable covering. The reduction of net radiation in pasture in relation to forest was 19%. The fraction among photosynthetic active radiation and solar global radiation presented small seasonal variation, 0,46 at pasture and 0,44 at forest (medium values). Atmospheric long wave radiation estimations were satisfactory in both experimental sites only during the dry season. The equations considering the water vapor pressure and the air temperature had better performance than the ones that use the air temperature, as Swinbank (1963) and Idso and Jackson (1969) equations. The Idso (1981), Brunt (1932) and Brutsaert (1975) models were the ones that presented better performance.