A brief observation of the formation of coherent structures and turbulence over a rain forest area in central Amazonia: The ATTO-CLAIRE/IOP – 1/2012 experiment

Abstract

This work used micrometeorological measurements of temperature and wind in order to characterize the turbulence due to wind in a terra firme forest in central Amazonia as part of the ATTO-CLAIRE / IOP-1 (2012) (Amazon Tall Tower Observatory – Cooperative LBA Airborne Regional Experiment / Intensive Observation Period – 2012 / LBA – Large Scale Biosphere-Atmosphere Experiment in the Amazon). This research was conducted at the Uatumã ATTO Sustainable Development Reserve in the State of Amazonas, Brazil, from February to September, 2012, and used data from February 26 to September 07, 2012, dates that partially encompass the wet and dry seasons, respectively. The ATTO site has 5 towers: one that is 320m, and four that are 80 m in height, and this research was conducted on an 80 m triangular tower. A total of ten 3D and 2D ultrasonic anemometers were installed on the tower, and the importance of these instruments used for flux measurements is also evident when taking into account the fact that the dissemination and diffusion of seeds and chemical composts in the forest happens through the action of turbulent fluxes. In order to understand the wind profile, the inflection point of the wind velocity, and coherent structures (ECs) and local turbulence, box-plot diagrams, quadrant analyses, wavelet potential spectrum, and energy potential analyses were conducted. The turbulence characterized at the ATTO had a roll or ramp structure during the study period, which represents favorable conditions for the maintenance of the forest during the wet and dry seasons in the Central Amazon.