UZH-Logo

Maintenance Infos

High-resolution NO₂ remote sensing from the Airborne Prism EXperiment (APEX) imaging spectrometer


Popp, C; Brunner, Dominik; Damm, Alexander; Van Roozendael, M; Fayt, C; Buchmann, B (2012). High-resolution NO₂ remote sensing from the Airborne Prism EXperiment (APEX) imaging spectrometer. Atmospheric Measurement Techniques, 5(9):2211-2225.

Abstract

We present and evaluate the retrieval of high spatial resolution maps of NO₂ vertical column densities (VCD) from the Airborne Prism EXperiment (APEX) imaging spectrometer. APEX is a novel instrument providing airborne measurements of unique spectral and spatial resolution and coverage as well as high signal stability. In this study, we use spectrometer data acquired over Zurich, Switzerland, in the morning and late afternoon during a flight campaign on a cloud-free summer day in June 2010. NO₂ VCD are derived with a two-step approach usually applied to satellite NO₂ retrievals, i.e. a DOAS analysis followed by air mass factor calculations based on radiative transfer computations. Our analysis demonstrates that APEX is clearly sensitive to NO₂ VCD above typical European tropospheric background abundances (> 1 × 10¹⁵ molec cm⁻²). The two-dimensional maps of NO₂ VCD reveal a very convincing spatial distribution with strong gradients around major NOx sources (e.g. Zurich airport, waste incinerator, motorways) and low NO₂ in remote areas. The morning overflights resulted in generally higher NO₂ VCD and a more distinct pattern than the afternoon overflights which can be attributed to the meteorological conditions prevailing during that day with stronger winds and hence larger dilution in the afternoon. The remotely sensed NO₂ VCD are also in reasonably good agreement with ground-based in-situ measurements from air quality networks considering the limitations of comparing column integrals with point measurements. Airborne NO₂ remote sensing using APEX will be valuable to detect NO₂ emission sources, to provide input for NO₂ emission modelling, and to establish links between in-situ measurements, air quality models, and satellite NO₂ products.

Abstract

We present and evaluate the retrieval of high spatial resolution maps of NO₂ vertical column densities (VCD) from the Airborne Prism EXperiment (APEX) imaging spectrometer. APEX is a novel instrument providing airborne measurements of unique spectral and spatial resolution and coverage as well as high signal stability. In this study, we use spectrometer data acquired over Zurich, Switzerland, in the morning and late afternoon during a flight campaign on a cloud-free summer day in June 2010. NO₂ VCD are derived with a two-step approach usually applied to satellite NO₂ retrievals, i.e. a DOAS analysis followed by air mass factor calculations based on radiative transfer computations. Our analysis demonstrates that APEX is clearly sensitive to NO₂ VCD above typical European tropospheric background abundances (> 1 × 10¹⁵ molec cm⁻²). The two-dimensional maps of NO₂ VCD reveal a very convincing spatial distribution with strong gradients around major NOx sources (e.g. Zurich airport, waste incinerator, motorways) and low NO₂ in remote areas. The morning overflights resulted in generally higher NO₂ VCD and a more distinct pattern than the afternoon overflights which can be attributed to the meteorological conditions prevailing during that day with stronger winds and hence larger dilution in the afternoon. The remotely sensed NO₂ VCD are also in reasonably good agreement with ground-based in-situ measurements from air quality networks considering the limitations of comparing column integrals with point measurements. Airborne NO₂ remote sensing using APEX will be valuable to detect NO₂ emission sources, to provide input for NO₂ emission modelling, and to establish links between in-situ measurements, air quality models, and satellite NO₂ products.

Citations

14 citations in Web of Science®
14 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

14 downloads since deposited on 26 Feb 2013
4 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute of Geography
Dewey Decimal Classification:910 Geography & travel
Language:English
Date:2012
Deposited On:26 Feb 2013 14:11
Last Modified:21 Nov 2016 08:35
Publisher:Copernicus Publications
ISSN:1867-1381
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.5194/amt-5-2211-2012

Download

[img]
Preview
Content: Published Version
Language: English
Filetype: PDF
Size: 23MB
View at publisher

TrendTerms

TrendTerms displays relevant terms of the abstract of this publication and related documents on a map. The terms and their relations were extracted from ZORA using word statistics. Their timelines are taken from ZORA as well. The bubble size of a term is proportional to the number of documents where the term occurs. Red, orange, yellow and green colors are used for terms that occur in the current document; red indicates high interlinkedness of a term with other terms, orange, yellow and green decreasing interlinkedness. Blue is used for terms that have a relation with the terms in this document, but occur in other documents.
You can navigate and zoom the map. Mouse-hovering a term displays its timeline, clicking it yields the associated documents.

Author Collaborations