The Atmospheric Boundary Layer height (zi) is an important quantity used in many parameterizations in surface flux calculations. However, to obtain this height, it is necessary to use atmospheric radiosonde, which can be expensive or even logistically unfeasible in some places in the Amazon. The objective of this work is to estimate zi through the spectrum of the zonal wind component above multiple surfaces of the Amazon region, comparing with the results available in the literature. The zi daily cycle information was generally consistent with minimum values at night and maximum values during the day on all surfaces studied. On the other hand, results seem to run away from expectations, such as zi being larger for the lake than for the savana. It follows that the method has potential to be used in the zi calculation, but still needs further study to improve it.