A wide field-of-view imaging DOAS instrument for two-dimensional trace gas mapping from aircraft
The Airborne imaging differential optical absorption spectroscopy (DOAS) instrument for Measurements of Atmospheric Pollution (AirMAP) has been developed for the purpose of trace gas measurements and pollution mapping. The instrument has been characterized and successfully operated from aircraft. Ni...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-12-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | http://www.atmos-meas-tech.net/8/5113/2015/amt-8-5113-2015.pdf |
| _version_ | 1811215794368937984 |
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| author | A. Schönhardt P. Altube K. Gerilowski S. Krautwurst J. Hartmann A. C. Meier A. Richter J. P. Burrows |
| author_facet | A. Schönhardt P. Altube K. Gerilowski S. Krautwurst J. Hartmann A. C. Meier A. Richter J. P. Burrows |
| author_sort | A. Schönhardt |
| collection | DOAJ |
| description | The Airborne imaging differential optical
absorption spectroscopy (DOAS) instrument for Measurements of Atmospheric
Pollution (AirMAP) has been developed for the purpose of trace gas
measurements and pollution mapping. The instrument has been characterized and
successfully operated from aircraft. Nitrogen dioxide (NO<sub>2</sub>) columns
were retrieved from the AirMAP observations. A major benefit of the push-broom imaging instrument is the spatially continuous, gap-free measurement
sequence independent of flight altitude, a valuable characteristic for
mapping purposes. This is made possible by the use of a charge coupled
device (CCD) frame-transfer detector. A broad field of view across track of around 48° is
achieved with wide-angle entrance optics. This leads to a swath width of
about the same size as the flight altitude. The use of fibre coupled light
intake optics with sorted light fibres allows flexible instrument positioning
within the aircraft and retains the very good imaging capabilities. The
measurements yield ground spatial resolutions below 100 m depending on
flight altitude. The number of viewing directions is chosen from a maximum of
35 individual viewing directions (lines of sight, LOS) represented by 35
individual fibres. The selection is adapted to each situation by averaging
according to signal-to-noise or spatial resolution requirements. Observations
at 30 m spatial resolution are obtained when flying at 1000 m altitude and
making use of all 35 viewing directions. This makes the instrument a suitable
tool for mapping trace gas point sources and small-scale variability. The
position and aircraft attitude are taken into account for accurate spatial
mapping using the Attitude and Heading Reference System of the aircraft. A
first demonstration mission using AirMAP was undertaken in June 2011. AirMAP
was operated on the AWI Polar-5 aircraft in the framework of the AIRMETH-2011
campaign. During a flight above a medium-sized coal-fired power plant in
north-west Germany, AirMAP clearly detected the emission plume downwind from
the exhaust stack, with NO<sub>2</sub> vertical columns around
2 × 10<sup>16</sup> molecules cm<sup>−2</sup> in the plume centre. NO<sub><i>x</i></sub>
emissions estimated from the AirMAP observations are consistent with reports
in the European Pollutant Release and Transfer Register. Strong spatial
gradients and variability in NO<sub>2</sub> amounts across and along flight
direction are observed, and small-scale enhancements of NO<sub>2</sub> above a
motorway are detected. |
| first_indexed | 2024-04-12T06:28:29Z |
| format | Article |
| id | doaj.art-b53b2501637146389c3a8f9a81b0a492 |
| institution | Directory Open Access Journal |
| issn | 1867-1381 1867-8548 |
| language | English |
| last_indexed | 2024-04-12T06:28:29Z |
| publishDate | 2015-12-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Measurement Techniques |
| spelling | doaj.art-b53b2501637146389c3a8f9a81b0a4922022-12-22T03:44:05ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482015-12-018125113513110.5194/amt-8-5113-2015A wide field-of-view imaging DOAS instrument for two-dimensional trace gas mapping from aircraftA. Schönhardt0P. Altube1K. Gerilowski2S. Krautwurst3J. Hartmann4A. C. Meier5A. Richter6J. P. Burrows7Institute of Environmental Physics, University of Bremen, GermanyInstitute of Environmental Physics, University of Bremen, GermanyInstitute of Environmental Physics, University of Bremen, GermanyInstitute of Environmental Physics, University of Bremen, GermanyAlfred-Wegener-Institute (AWI) Bremerhaven, GermanyInstitute of Environmental Physics, University of Bremen, GermanyInstitute of Environmental Physics, University of Bremen, GermanyInstitute of Environmental Physics, University of Bremen, GermanyThe Airborne imaging differential optical absorption spectroscopy (DOAS) instrument for Measurements of Atmospheric Pollution (AirMAP) has been developed for the purpose of trace gas measurements and pollution mapping. The instrument has been characterized and successfully operated from aircraft. Nitrogen dioxide (NO<sub>2</sub>) columns were retrieved from the AirMAP observations. A major benefit of the push-broom imaging instrument is the spatially continuous, gap-free measurement sequence independent of flight altitude, a valuable characteristic for mapping purposes. This is made possible by the use of a charge coupled device (CCD) frame-transfer detector. A broad field of view across track of around 48° is achieved with wide-angle entrance optics. This leads to a swath width of about the same size as the flight altitude. The use of fibre coupled light intake optics with sorted light fibres allows flexible instrument positioning within the aircraft and retains the very good imaging capabilities. The measurements yield ground spatial resolutions below 100 m depending on flight altitude. The number of viewing directions is chosen from a maximum of 35 individual viewing directions (lines of sight, LOS) represented by 35 individual fibres. The selection is adapted to each situation by averaging according to signal-to-noise or spatial resolution requirements. Observations at 30 m spatial resolution are obtained when flying at 1000 m altitude and making use of all 35 viewing directions. This makes the instrument a suitable tool for mapping trace gas point sources and small-scale variability. The position and aircraft attitude are taken into account for accurate spatial mapping using the Attitude and Heading Reference System of the aircraft. A first demonstration mission using AirMAP was undertaken in June 2011. AirMAP was operated on the AWI Polar-5 aircraft in the framework of the AIRMETH-2011 campaign. During a flight above a medium-sized coal-fired power plant in north-west Germany, AirMAP clearly detected the emission plume downwind from the exhaust stack, with NO<sub>2</sub> vertical columns around 2 × 10<sup>16</sup> molecules cm<sup>−2</sup> in the plume centre. NO<sub><i>x</i></sub> emissions estimated from the AirMAP observations are consistent with reports in the European Pollutant Release and Transfer Register. Strong spatial gradients and variability in NO<sub>2</sub> amounts across and along flight direction are observed, and small-scale enhancements of NO<sub>2</sub> above a motorway are detected.http://www.atmos-meas-tech.net/8/5113/2015/amt-8-5113-2015.pdf |
| spellingShingle | A. Schönhardt P. Altube K. Gerilowski S. Krautwurst J. Hartmann A. C. Meier A. Richter J. P. Burrows A wide field-of-view imaging DOAS instrument for two-dimensional trace gas mapping from aircraft Atmospheric Measurement Techniques |
| title | A wide field-of-view imaging DOAS instrument for two-dimensional trace gas mapping from aircraft |
| title_full | A wide field-of-view imaging DOAS instrument for two-dimensional trace gas mapping from aircraft |
| title_fullStr | A wide field-of-view imaging DOAS instrument for two-dimensional trace gas mapping from aircraft |
| title_full_unstemmed | A wide field-of-view imaging DOAS instrument for two-dimensional trace gas mapping from aircraft |
| title_short | A wide field-of-view imaging DOAS instrument for two-dimensional trace gas mapping from aircraft |
| title_sort | wide field of view imaging doas instrument for two dimensional trace gas mapping from aircraft |
| url | http://www.atmos-meas-tech.net/8/5113/2015/amt-8-5113-2015.pdf |
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