REGIONAL CLIMATE MODELING OF RADIATION BALANCE COMPONENTS OVER THE CAATINGA BIOME
RegCM4, Caatinga, Radiation balance, RRTM, CCM3.
In recent years, regional modeling has proven to be one of the most powerful tools for climate science, from the operational field to future climate projections, models play a key role. This work aims to evaluate which of the radiation schemes present in the Regional Climate Model 4 (RegCM4.7) presents a better capacity to represent the balance of radiation (Rn), latent heat (E) and sensible heat (H) in the Caatinga. The study covers the years 2014 and 2015, with two numerical simulations, one using the Rapid Radiation Transfer Model (RRTM) as a radiative transfer model and the second using the Community Climate Model 3 (CCM3) as parameterization. To validate the experiments, three sets of data obtained from a micrometeorological tower equipped with an eddy covariance (EC) system located at the Seridó Ecological Station (ESEC-Seridó), in Serra Negra do Norte/RN, Caatinga region were used. preserved. The evaluation of the results occurred through the evaluation of the errors, using the BIAS, the root mean square error (RMSE), the coefficient of agreement of Willmott (d) and the correlation (r). It was possible to verify that the model is capable of representing well the daily cycle of Rn, in addition to the average values, underestimating the minimum values and overestimating the maximum values. The results show that RegCM4 is able to represent the daily cycle of Rn well when analyzing the entire data series, however there are deficiencies for seasonal analyses, especially in the wet-dry and dry-wet transition seasons.
When evaluating the RMSE it was possible to find the values of 160.11 W/m² for the EXP_RRTM and 158.16 W/m² for the EXP_CCM3, the BIAS values also presented similar results, the d was 0.89 for both simulations, indicating a strong similarity between simulated and observed data. In short, the simulations do not bring significant differences between them, indicating that both parameterizations are satisfactory for the region.