Vertical Profiles of Atmospheric Species Concentrations and Nighttime Boundary Layer Structure in the Dry Season over an Urban Environment in Central Amazon Collected by an Unmanned Aerial Vehicle

Patrícia Guimarães,Patrícia Guimarães,Rodrigo Souza,Adan Medeiros,Hui-Ming Hung,Wei-Chun Hwang,Igor Ribeiro,Igor Ribeiro,Rafael Barbosa,Scot T Martin,Scot T Martin,Tianning Zhao,Carla Batista,Carla Batista,Jianhuai Ye

doi:10.3390/atmos11121371

Abstract

Nighttime vertical profiles of ozone, PM2.5 and PM10 particulate matter, carbon monoxide, temperature, and humidity were collected by a copter-type unmanned aerial vehicle (UAV) over the city of Manaus, Brazil, in central Amazon during the dry season of 2018. The vertical profiles were analyzed to understand the structure of the urban nighttime boundary layer (NBL) and pollution within it. The ozone concentration, temperature, and humidity had an inflection between 225 and 350 m on most nights, representing the top of the urban NBL. The profile of carbon monoxide concentration correlated well with the local evening vehicular congestion of a modern transportation fleet, providing insight into the surface-atmosphere dynamics. In contrast, events of elevated PM2.5 and PM10 concentrations were not explained well by local urban emissions, but rather by back trajectories that intersected regional biomass burning. These results highlight the potential of the emerging technologies of sensor payloads on UAVs to provide new constraints and insights for understanding the pollution dynamics in nighttime boundary layers in urban regions.

Highlights

IntroductionIn 1985 and 1987, the Amazon Boundary Layer Experiment (ABLE) provided important characterization of the structure of the atmospheric boundary layer in the Amazon region [1,2,3,4]
In 1985 and 1987, the Amazon Boundary Layer Experiment (ABLE) provided important characterization of the structure of the atmospheric boundary layer in the Amazon region [1,2,3,4].The ABLE focus was for the daytime, and less attention was given to the nighttime boundary layer (NBL)
Observations of nighttime ozone concentration recorded by the unmanned aerial vehicle (UAV) flights at different altitudes at the urban UEA campus in central Amazon are presented in Figure 2 for the wet and dry seasons

Summary

Introduction

In 1985 and 1987, the Amazon Boundary Layer Experiment (ABLE) provided important characterization of the structure of the atmospheric boundary layer in the Amazon region [1,2,3,4]. Radiative effects at night lead to the development of a temperature inversion in the atmospheric profile Stull [11] Under ideal circumstances, this inversion is associated with calm conditions and little turbulence, and an isolated near-surface air mass called the nighttime boundary layer forms. The study of the NBL in both seasons is important for understanding the NBL over urban landscapes, where factors such as anthropogenic emissions and radiative effects which reinforce the effects of heat islands, are not experienced over forest and pasture landscapes. Earth’s surface can drop below the detection level of commonly employed instruments This nighttime ozone behavior means that vertical profiles of ozone concentration can be used to investigate the NBL structure [10]. Process-wise, the two sets of species strongly complement one another

Experiment

Representative image of the study area in in thethe city ofof

13 October

Results and Discussion

Conclusions