High-resolution measurements from the airborne Atmospheric Nitrogen Dioxide Imager (ANDI)

Abstract

Abstract. Nitrogen Dioxide is both a primary pollutant with direct health effects and a key precursor of the secondary pollutant ozone. This paper reports on the development, characterisation and test flight of the Atmospheric Nitrogen Dioxide Imager (ANDI) remote sensing system. The ANDI system includes an imaging (UV)-vis grating spectrometer able to capture scattered sunlight spectra for the determination of tropospheric nitrogen dioxide (NO2) concentrations by way of DOAS slant column density and vertical column density measurements. Results are shown for an ANDI test flight over Leicester City in the UK. Retrieved NO2 columns at a surface resolution of 80 m x 20 m revealed hot spots in a series of locations around Leicester City, including road junctions, the train station, major car parks, areas of heavy industry, a nearby airport (East Midlands) and a power station (Ratcliffe-on-Soar). In the city centre the dominant source of NO2 emissions was identified as road traffic, contributing to a background concentration as well as producing localised hot spots. Quantitative analysis revealed a significant urban increment over the city centre which increased throughout the flight.

Intercomparison of four airborne imaging DOAS systems for tropospheric NO<sub>2</sub> mapping – the AROMAPEX campaign

“…The corresponding surface reflectances and viewing and sun geometries recorded by the AirMAP instrument are also provided in the plot, as well as the other RTM parameter settings. A strong dependence of the AMF on the surface reflectance can be observed, consistent with previous studies reported in Lawrence et al (2015), Meier et al (2017), and Tack et al (2017). In the upper panel of Fig.…”

“…The majority of these studies have focused on the retrieval of the NO 2 field over urban areas and/or industrial sites, i.e. Heue et al (2008), Kowalewski and Janz (2009), Popp et al (2012), General et al (2014), Lawrence et al (2015), Schönhardt et al (2015), Nowlan et al (2016), Lamsal et al (2017), Meier et al (2017), Tack et al (2017), Vlemmix et al (2017), Broccardo et al (2018), Merlaud et al (2018), and Nowlan et al (2018).…”

Investigating large methane enhancements in the U.S. San Juan Basin

“…Atmospheric in situ measurements or remote sensing scans can be powerful tools to map pollution hot spots (Worden et al, 2013;Kort et al, 2014;Lawrence et al, 2015;Jacob et al, 2016) or identify and quantify larger than expected pollution sources (de Gouw et al, 2009;Karion et al, 2013). Kort et al's (2014) U.S. CH 4 anomaly map relied on retrievals of total column average CH 4 dry air mixing ratio (XCH 4 , hereafter) from near infrared radiance measurements aboard the SCIAMACHY satellite (Frankenberg et al, 2006(Frankenberg et al, , 2011.…”

Mapping the spatial distribution of NO<sub>2</sub> with in situ and remote sensing instruments during the Munich NO<sub>2</sub> imaging campaign

“…However, satellite instruments have been shown to be capable of observing the downwind plume of large cities (e.g., Beirle et al, 2011Beirle et al, , 2019Lorente et al, 2019). In contrast, airborne imaging spectrometers have inherently much higher spatial resolutions of a few tens of meters and thus can retrieve detailed NO 2 maps for whole cities (Heue et al, 2008;Lawrence et al, 2015;Popp et al, 2012;Schönhardt et al, 2015;Tack et al, 2017;Nowlan et al, 2016;Tack et al, 2019). However, satellite and airborne instruments measure (tropospheric) vertical column densities (VCDs), while near-surface concentrations (NSCs) are the quantity of interest for the assessment of air pollution exposure.…”