Reanálise CFSR-NCEP aplicada ao modelo SiB2 na simulação de fluxos de CO2 sobre o cultivo de soja em Cruz Alta.

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

2012

RESUMO

The present work aimed to evaluate the behavior of CO2 fluxes, run by the Simple Biosphere Model (SiB2), by adopting CFSR-NCEP data reanalyzed as an atmospheric boundary condition. A statistical analysis was used in order to validate the results obtained using a coefficient for the adjusted model based on the simulation parameters when compared to the data observed in field, which was obtained by the micrometeorological tower located on the cultivation areas. The study was applied in a soybean experimental site located in Cruz Alta (-28,6036; -53,6736), in the state of Rio Grande do Sul, Southern Brazil between 2008 and 2009. Some of the parameters presented in the subroutines of the model had to be adjusted first. For such, a methodology in which the parameters were calibrated in sequential modules was applied according to the following order: aerodynamics, radiative transfer, hydraulic diffusion of the soil and photosynthesis and stomatal conductance. In the aerodynamics module, the calibration was made using the parameters for the canopy height, vegetation coverage and leaf-angle distribution. For the radiative transfer, the calibration used the parameters for the live leaf transmittance visible reflectance. The calibration for the hydraulic diffusion of the soil was accomplished in the soil porosity, depth of individual layers and humidity exponent. For the photosynthesis and stomatal conductance, the parameters tested were the leaf area index, minimum stomatal conductance and leaf respiration critical temperature. It could thus be possible to obtain a considerable improvement for the simulation of the CO2 fluxes in this model for a high-quality simulation. That stage was significantly important since it enabled the reanalysis data to be set in the best model for the studied area. Regarding the final stage of this study, data from the CFSR were used as the atmospheric boundary condition instead of originally applied meteorological variables from the INMET station. Variables concerning air temperature, air pressure at sea level, precipitation, incident short-wave radiation and wind speed were used in order to describe the physical condition of the atmosphere in new simulations with CO2 fluxes, and then compared to the data observed in the micrometeorological tower. From the results, using the CFSR-NCEP reanalysis data can be considered acceptable for studies on CO2 fluxes from the SiB2 model. Yet, calibrating this model for the studied area is a key factor for its suitability and for obtaining adequate results.

ASSUNTO(S)

sib2 sensoriamento remoto co2 fluxes cfsr

ACESSO AO ARTIGO

Documentos Relacionados