| Abstrakt: |
The results from two micrometeorological data sets obtained during both the dry season of 1999 (September), and the transition from the dry to the rainy season of 2000 (September to November) in the Southern Mato Grosso Pantanal are described. The components of the radiation balance were evaluated, as well as the estimation of the net radiation, through the global incident radiation and the short wave radiation balances. The estimation of the ratio between the photosynthetically active radiation and the global incident radiation was obtained for both data sets. The analysis of the net radiation in the near infrared region, plus the evaluation of the variability of the albedo in the short wave, PAR and near infrared regions, and the estimation of the albedo as a function of the solar zenith angle were carried out. The results show that, from one year to the other, there were significant variations in certain components of the radiation balance. They were due specially to the differences in the surface conditions, that is, drier vegetation in 1999, opposed to a greener subsequent year. The average value of the ratio between incident photosynthetically active and global incident radiations for the 1999 period was 0.48±0.02, while for the 2000 period it was 0.46±0.01. The average albedo of the solar (αK), of the PAR (αPAR) and of the NIR (αIR) radiations, for the days considered in 1999 were, respectively, 0.17±0.02, 0.08±0.01 and 0.26±0.03; for 2002, they were, respectively, 0.17±0.02, 0.06±0.01 and 0.26±0.06. Finally, it should be noted that the variation of the microclimatic and the radiation parameters between 1999 and 2000 are related with the different conditions observed in both periods, that is, the presence of aerosols in the atmosphere due to the occurrence of fires in the region in 1999, and the occurrence of rainfall and the changes in the cloudiness in 2000. [ABSTRACT FROM AUTHOR] |
