Spatiotemporal Patterns in Data Availability of the Sentinel-5P NO<sub>2</sub> Product over Urban Areas in Norway
Due to its comparatively high spatial resolution and its daily repeat frequency, the tropospheric nitrogen dioxide product provided by the TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor platform has attracted significant attention for its potential for urban-scale moni...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-05-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/13/11/2095 |
| _version_ | 1797532485651791872 |
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| author | Philipp Schneider Paul D. Hamer Arve Kylling Shobitha Shetty Kerstin Stebel |
| author_facet | Philipp Schneider Paul D. Hamer Arve Kylling Shobitha Shetty Kerstin Stebel |
| author_sort | Philipp Schneider |
| collection | DOAJ |
| description | Due to its comparatively high spatial resolution and its daily repeat frequency, the tropospheric nitrogen dioxide product provided by the TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor platform has attracted significant attention for its potential for urban-scale monitoring of air quality. However, the exploitation of such data in, for example, operational assimilation of local-scale dispersion models is often complicated by substantial data gaps due to cloud cover or other retrieval limitations. These challenges are particularly prominent in high-latitude regions where significant cloud cover and high solar zenith angles are often prevalent. Using the example of Norway as a representative case for a high-latitude region, we here evaluate the spatiotemporal patterns in the availability of valid data from the operational TROPOMI tropospheric nitrogen dioxide (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>NO</mi><mn>2</mn></msub></semantics></math></inline-formula>) product over five urban areas (Oslo, Bergen, Trondheim, Stavanger, and Kristiansand) and a 2.5 year period from July 2018 through November 2020. Our results indicate that even for relatively clean environments such as small Norwegian cities, distinct spatial patterns of tropospheric <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>NO</mi><mn>2</mn></msub></semantics></math></inline-formula> are visible in long-term average datasets from TROPOMI. However, the availability of valid data on a daily level is limited by both cloud cover and solar zenith angle (during the winter months), causing the fraction of valid retrievals in each study site to vary from 20% to 50% on average. A temporal analysis shows that for our study sites and the selected period, the fraction of valid pixels in each domain shows a clear seasonal cycle reaching a maximum of 50% to 75% in the summer months and 0% to 20% in winter. The seasonal cycle in data availability shows the inverse behavior of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>NO</mi><mn>2</mn></msub></semantics></math></inline-formula> pollution in Norway, which typically has its peak in the winter months. However, outside of the mid-winter period we find the TROPOMI <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>NO</mi><mn>2</mn></msub></semantics></math></inline-formula> product to provide sufficient data availability for detailed mapping and monitoring of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>NO</mi><mn>2</mn></msub></semantics></math></inline-formula> pollution in the major urban areas in Norway and see potential for the use of the data in local-scale data assimilation and emission inversions applications. |
| first_indexed | 2024-03-10T11:00:55Z |
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| institution | Directory Open Access Journal |
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| language | English |
| last_indexed | 2024-03-10T11:00:55Z |
| publishDate | 2021-05-01 |
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| series | Remote Sensing |
| spelling | doaj.art-d2895f209f314c48bad1ac1ec966961f2023-11-21T21:34:49ZengMDPI AGRemote Sensing2072-42922021-05-011311209510.3390/rs13112095Spatiotemporal Patterns in Data Availability of the Sentinel-5P NO<sub>2</sub> Product over Urban Areas in NorwayPhilipp Schneider0Paul D. Hamer1Arve Kylling2Shobitha Shetty3Kerstin Stebel4NILU—Norwegian Institute for Air Research, P.O. Box 100, 2027 Kjeller, NorwayNILU—Norwegian Institute for Air Research, P.O. Box 100, 2027 Kjeller, NorwayNILU—Norwegian Institute for Air Research, P.O. Box 100, 2027 Kjeller, NorwayNILU—Norwegian Institute for Air Research, P.O. Box 100, 2027 Kjeller, NorwayNILU—Norwegian Institute for Air Research, P.O. Box 100, 2027 Kjeller, NorwayDue to its comparatively high spatial resolution and its daily repeat frequency, the tropospheric nitrogen dioxide product provided by the TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor platform has attracted significant attention for its potential for urban-scale monitoring of air quality. However, the exploitation of such data in, for example, operational assimilation of local-scale dispersion models is often complicated by substantial data gaps due to cloud cover or other retrieval limitations. These challenges are particularly prominent in high-latitude regions where significant cloud cover and high solar zenith angles are often prevalent. Using the example of Norway as a representative case for a high-latitude region, we here evaluate the spatiotemporal patterns in the availability of valid data from the operational TROPOMI tropospheric nitrogen dioxide (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>NO</mi><mn>2</mn></msub></semantics></math></inline-formula>) product over five urban areas (Oslo, Bergen, Trondheim, Stavanger, and Kristiansand) and a 2.5 year period from July 2018 through November 2020. Our results indicate that even for relatively clean environments such as small Norwegian cities, distinct spatial patterns of tropospheric <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>NO</mi><mn>2</mn></msub></semantics></math></inline-formula> are visible in long-term average datasets from TROPOMI. However, the availability of valid data on a daily level is limited by both cloud cover and solar zenith angle (during the winter months), causing the fraction of valid retrievals in each study site to vary from 20% to 50% on average. A temporal analysis shows that for our study sites and the selected period, the fraction of valid pixels in each domain shows a clear seasonal cycle reaching a maximum of 50% to 75% in the summer months and 0% to 20% in winter. The seasonal cycle in data availability shows the inverse behavior of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>NO</mi><mn>2</mn></msub></semantics></math></inline-formula> pollution in Norway, which typically has its peak in the winter months. However, outside of the mid-winter period we find the TROPOMI <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>NO</mi><mn>2</mn></msub></semantics></math></inline-formula> product to provide sufficient data availability for detailed mapping and monitoring of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>NO</mi><mn>2</mn></msub></semantics></math></inline-formula> pollution in the major urban areas in Norway and see potential for the use of the data in local-scale data assimilation and emission inversions applications.https://www.mdpi.com/2072-4292/13/11/2095air qualityremote sensingSentinel-5PTROPOMInitrogen dioxideNorway |
| spellingShingle | Philipp Schneider Paul D. Hamer Arve Kylling Shobitha Shetty Kerstin Stebel Spatiotemporal Patterns in Data Availability of the Sentinel-5P NO<sub>2</sub> Product over Urban Areas in Norway Remote Sensing air quality remote sensing Sentinel-5P TROPOMI nitrogen dioxide Norway |
| title | Spatiotemporal Patterns in Data Availability of the Sentinel-5P NO<sub>2</sub> Product over Urban Areas in Norway |
| title_full | Spatiotemporal Patterns in Data Availability of the Sentinel-5P NO<sub>2</sub> Product over Urban Areas in Norway |
| title_fullStr | Spatiotemporal Patterns in Data Availability of the Sentinel-5P NO<sub>2</sub> Product over Urban Areas in Norway |
| title_full_unstemmed | Spatiotemporal Patterns in Data Availability of the Sentinel-5P NO<sub>2</sub> Product over Urban Areas in Norway |
| title_short | Spatiotemporal Patterns in Data Availability of the Sentinel-5P NO<sub>2</sub> Product over Urban Areas in Norway |
| title_sort | spatiotemporal patterns in data availability of the sentinel 5p no sub 2 sub product over urban areas in norway |
| topic | air quality remote sensing Sentinel-5P TROPOMI nitrogen dioxide Norway |
| url | https://www.mdpi.com/2072-4292/13/11/2095 |
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