A Case Study of Ozone Diurnal Variation in the Convective Boundary Layer in the Southeastern United States Using Multiple Observations and Large-Eddy Simulation

Guanyu Huang,Shi Kuang,M Newchurch ,H G Ouwersloot

doi:10.3390/cli7040053

Abstract

We investigated the diurnal ozone variation on 6 September 2013 in a midsize urban environment using multiple in situ and remote-sensing measurements along with the Dutch atmospheric large-eddy simulation (DALES) model coupled with a chemical module and a dry deposition module that we added for this study. Our study area was Huntsville, Alabama, USA, a typical midsize city in the Southeastern United States. The ozone variation in the convective boundary layer (CBL) resulted mainly from local emissions and photochemical production stemming from weather conditions controlled by an anticyclonic system on that day. Local chemical production contributes approximately two thirds of the ozone enhancement in the CBL and, in this case, dynamical processes including ozone transport from the free troposphere (FT) to the CBL through the entrainment processes contributed the remainder. The numerical experiments performed by the large-eddy simulation (LES) model showed acceptable agreement with the TOLNet (The tropospheric ozone lidar network)/RO3QET (Rocket-city ozone quality evaluation in the troposphere) ozone DIAL (differential absorption lidar) observations. This study indicated the need for fine-scale, three-dimensional ozone observations with high temporal and spatial resolution for air quality studies at the urban scale and smaller.

Highlights

Ozone is one of the most important air pollutants due to its harmful effects on human health, agriculture, and forests, and the material damage it causes [1,2]
We investigated the diurnal ozone evolution on 6 September 2013 in Huntsville, Alabama, using multiple measurements the Dutch atmospheric large-eddy simulation (DALES)
We investigated theand diurnal ozone evolution on 6 September

Summary

Introduction

Ozone is one of the most important air pollutants due to its harmful effects on human health, agriculture, and forests, and the material damage it causes [1,2]. In the Southeastern United States, ozone concentrations are more sensitive to nitrogen oxides in rural areas due to the high VOC emissions of dense forests [9,10]. In urban areas (e.g., Atlanta, Georgia, USA), ozone concentrations are sensitive to both nitrogen oxidants and VOCs from both anthropogenic and natural sources [9,11]. Air stagnation regimes have more influence on the episode days than synoptic-scale transport in the Southeastern United States [12].

Methods

Results

Conclusion