A021-05
UAV studies of atmospheric chemistry and meteorology over the tropical forest in the central Amazon

Monday, 7 December 2020: 16:32
Virtual
Scot T Martin1, Jianhuai Ye1, Carla E Batista2, Patrícia C Guimarães2, Tianning Zhao1, Yongjing Ma1, Igor Ribeiro2, Adan S.S. Medeiros2, Rafael G Barbosa2, Rafael L Oliveira2, Sergio Duvoisin Jr.2, Kolby Jardine3, Alex B Guenther4 and Rodrigo Augusto Ferreira de Souza2, (1)Harvard University, Cambridge, MA, United States, (2)Amazonas State University, Manaus, Brazil, (3)Lawrence Berkeley National Laboratory, Climate and Ecosystem Sciences Division, Berkeley, CA, United States, (4)University of California, Irvine, Department of Earth System Science, Irvine, CA, United States
Recorded Presentation
Abstract:
Unmanned Aerial Vehicle (UAV) represents an emerging advance in atmospheric chemistry and meteorology for its excellent maneuverability on measurements at intermediate scales of 100s of meters. This presentation showcases how observations collected by UAV-enabled technologies fill a missing niche among leaf-level, tower, aircraft, and satellite scales.

The emissions and chemistry of volatile organic compounds (VOCs) over the tropical forest are thought to be influenced by underlying landscape heterogeneity at intermediate scales. Quantitative observations at these scales, however, remain lacking. Herein, horizontal heterogeneity in the concentrations of VOCs and their semivolatile oxidation products (SVOCs) over the near-canopy atmosphere was examined by sampling from a copter UAV in the central Amazon during the wet season of 2018. Distinct VOC and SVOC concentrations were observed over two forest types separated from one another by a few hundred meters. A gradient transport model together with a large-eddy simulation (LES) model, was utilized to investigate the relationship between variable VOC emissions from underlying forests and the observed VOC and SVOC concentrations. Results from this study highlight the importance of quantifying VOC emissions and chemistry at intermediate scales to better represent them in the climate and air quality models.

In addition, the UAV sensing technique was employed to examine the impacts of river breeze on pollutant dispersion over the topical forest. Wide rivers in Amazonia can induce important atmospheric processes such as river breeze, affecting the dispersion of air pollutants. Herein, the roles of river breeze were evaluated by sensors onboard UAV over the Negro River in the central Amazon during the dry season of 2019. The presence of river breeze was observed, and the major features of the river breeze in the central Amazon were summarized. Relationship between the strength of the river breeze and the thermal properties of the land and the river surfaces was investigated by the LES model. The effects of horizontal trade wind on the extent of the influence on VOC dispersion by river breeze were further discussed. Results from this study provide a comprehensive understanding on how the rivers affect pollutant transport and dispersion in the Amazonian ecosystem.

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