Spatiotemporal Patterns in Data Availability of the Sentinel-5P NO2 Product over Urban Areas in Norway

Abstract

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 (NO2) 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 NO2 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 NO2 pollution in Norway, which typically has its peak in the winter months. However, outside of the mid-winter period we find the TROPOMI NO2 product to provide sufficient data availability for detailed mapping and monitoring of NO2 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.

Spatial and temporal changes analysis of air quality before and after the COVID-19 in Shandong Province, China

“…This study has certain implications for remote sensing image data to conduct atmospheric monitoring studies. It demonstrates to some extent the usefulness of using the GEE platform to obtain Sentinel-5P data for spatial and temporal analysis in air pollution at different regional scales (Schneider et al 2021). First, Sentinel-5P data is a free, high spatial resolution product that provides offline and near realtime air pollution data.…”

“…Sentinel-5P is a global atmospheric pollution monitoring satellite launched by European Space Agency on October 13, 2017. The satellite carries tropospheric monitoring instruments and is capable of effectively observing trace gas constituents in the global atmosphere, including important indicators closely related to anthropogenic activities, e.g., NO 2 , O 3 , SO 2 , CH 4 and CO (Vîrghileanu et al 2020;Schneider et al 2021). Aerosol optical depth (AOD) from moderate resolution imaging spectrometer (MODIS) data and Sentinel-5P air pollution data were acquired from the GEE platform (see Table 1).…”

Satellite observations showed a negligible reduction in NO2 pollution due to COVID-19 lockdown over Poland

“…Low NO 2 concentrations were clearly observed throughout the summer months, while high NO 2 values were observed mainly during the winter months when energy is in high demand. This can also be attributed to reduced solar radiation due to substantial cloud cover and high solar zenith angles (Schneider et al, 2021) throughout the winter, resulting in the delayed removal of NO 2 pollution from the atmosphere. Additionally, the low-level cloud cover (<2 km) over Poland during wintertime is significant (Wang et al, 2020).…”

“…Satellite remote sensing, e.g., using instrumentation on-board the Copernicus Sentinel missions launched by the European Space Agency (ESA), is an important technique for measuring air pollution. It has the advantage of delivering full and synoptic views of broad areas in a single image on a systematic basis, which is essential for assessing and mapping air pollution (Stebel et al, 2021). Satellite observations can also be useful to demonstrate, among others, events with human health implications, such as pandemic lockdowns.…”

Nghiên cứu giải pháp đánh giá ô nhiễm không khí khu vực khai thác mỏ đất đắp bằng dữ liệu Sentinel-5P Tropomi

“…Trong trường hợp này, sử dụng ảnh viễn thám để giám sát ô nhiễm không khí sẽ là giải pháp rất phù hợp. Dựa trên các sản phẩm từ nguồn dữ liệu giám sát khí quyển (TROPOMI) của vệ tinh Sentinel-5P đã có rất nhiều nghiên cứu ứng dụng để giám sát ô nhiễm không khí ở nhiều nơi trên khắp thế giới [6,[9][10][11][12][13][14][15]. Khác với các thiết bị vệ tinh quan sát chất lượng không khí trước đây, Sentinel-5P TROPOMI với sứ mệnh cung cấp các phép đo toàn cầu hàng ngày về các chất gây ô nhiễm không khí ở độ phân giải không gian tương đối cao (từ dưới 8 km đến dưới 50 km, tùy thuộc vào bước sóng) [16].…”