The Amazon Energy Budget Using the ABLE-2B and FluAmazon Data

Abstract

Radiosonde and satellite data collected from the Atmosphere Boundary Layer Experiment?Wet Season and Amazon Water Vapor Flux Experiment are used to investigate the energy budget. The relationship between the cloud cover variability and the different terms of the energy budget equations was examined. The radiosonde data were used to compute the energy divergence flux for each triangle composed by three radiosonde stations. Earth Radiation Budget Experiment data were used to compute the radiative flux in the top of the atmosphere. The cloud cover variability were computed from the International Satellite Cloud Climatology Project data. When the atmosphere undergoes a change from the mean state to the convective state, it stores energy mainly in the middle layers, while the maximum energy storage was found around 650 hPa mainly due to the perturbation of the latent energy. Conversely, when the atmosphere undergoes a change from a mean state to a nearly clear sky situation, the atmosphere column loses energy, principally due to the changes in the latent energy profile, and the atmosphere became drier, in the 700?200-hPa layer. The advective term of the energy divergence flux is of a lower order and the energy divergence flux is determined mainly from the divergent term. The profiles of the components of the energy divergence flux are essentially a result of the wind divergence weighted by the specific humidity (latent term), temperature (enthalpy term), and height (potential term). The latent energy divergence flux, for convective situations, presents a maximum in 950 hPa and is always negative (convergent) up to 400 hPa. For the nearly clear-sky situation a convergence of humidity in the lower levels and an important humidity divergence above 800 hPa were observed. The enthalpy and the latent energy divergence flux mainly describe the middle/low levels and the potential energy divergence flux represents mainly the upper troposphere. During the experiments, the solar energy absorbed by the surface was always smaller than the total surface flux supplied to the atmosphere during convective events and always larger than the total surface flux supplied to the atmosphere during nonconvective events. This means that the surface loses more energy than it receives in convective events and vice versa. The quantity of energy stored at the surface seems to be limited, defining a timescale, during which the surface needs to export or receive energy to control its deficit or gain of energy.