Balanço de radiação e energia na maior região urbana da Amazônia: análises observacionais e simulações numéricas

Abstract

This study addressed the complexity of energy and radiation balance in the urban area of Manaus, seeking a comprehensive understanding through observational analyses and modeling. The observational analysis, conducted at two experimental sites in the central Amazon, revealed discrepancies in radiation balance components between forested and urban areas. Factors such as radiative parameters (albedo and emissivity) and thermal parameters (absorptivity) of the surface, coupled with urban pollution, demonstrated a significant influence on the sensible heat flux in the city, resulting in an equitable partition of energy between sensible and latent heat fluxes. The seasonality of energy and radiation balance in Manaus highlighted the duality of the city, exhibiting characteristics of both densely populated urban areas and forested regions. The analysis revealed values of reflected longwave radiation comparable to cities like São Paulo, while the latent heat flux remained relatively constant, with no significant decline during the transition from the rainy to the dry season, akin to the observed behavior over the Amazon rainforest. Modeling studies, conducted both offline (SLUCM) and coupled (WRF/SLUCM/Noah-MP), explored the model sensitivity in representing radiation and energy balances. Key parameters, such as roof albedo, roof heat capacity, and thermal conductivity of the roof and wall, emerged as significant modulators of the model's sensible heat. Implementing these adjusted parameters in coupled simulations, calibrated with observational data, resulted in a reduction of biases associated with sensible heat flux, radiation balance, and 2-meter air temperature. However, the overall assessment indicated the need for enhancements, particularly in soil interaction and integration with the Noah-MP model. This study underscores the importance of a precise physical representation of the urban surface, highlighting that its properties play a crucial role in the robustness of climate simulations for urban surfaces and associated circulations under local meteorological conditions.