Estimativa do fluxo de calor em dois lagos tropicais: lago Dom Helvécio e lago Carioca, MG

Abstract

The heat flux of lakes is estimated by the amount of heat added to the systems minus the amount stored and lost. This study presents an analysis about the temporal variation of the heat flux in the Dom Helvécio and Carioca lakes in 2012. Those lakes are located within the Rio Doce State Park (PERD-MG). Using the bulk aerodynamic model, the net radiation flux (QRL), sensible heat (QSENS) and latent heat (QLAT) were estimated. The heat content was calculated to estimate the storage heat throughout the year. Hydrometeorology data were obtained insitu (wind speed, water temperature, atmospheric pressure and solar shortwave radiation) and at weather station located in PERD (air temperature, relative humidity and rainfall). The relative importance of each component of the heat flux was evaluated by decomposing the explained variance. Dom Helvécio Lake presented monthly average of QRL=92 Wm-2, loss of QLAT= 33.6 Wm-2 and QSENS= 8.1 Wm-2. This lake lost heat between April and Julyand presented a monthly average loss of 0.5 Wm-2. In the Carioca lake monthly average values were: QRL= 94 Wm-2, QLAT= 29.5 Wm-2 and QSENS= 6.2 Wm-2.Carioca Lake lost heat between March and July (monthly average of 0.9 Wm-2). Solar shortwave radiation was the major parameter to determine the QRL, while wind speed had a greater influence on the estimation of QLATand QSENS.