The OMPS-N20 NM PCA SO2 Step1 Total Column 1-Orbit L2 Swath 17x13km collection 1 product contains the retrieved sulfur dioxide (SO2) measured by the Ozone Mapping and Profiling Suite (OMPS) Nadir-Mapper (NM) sensor on the NOAA-20 (JPSS-1) satellite. The product is based on the NASA Goddard Space Flight Center principal component analysis (PCA) spectral fitting algorithm (Li et al., 2013, 2017) used to retrieve the SO2 total column amounts assuming different SO2 plume heights, including the boundary layer (lowest 1 km of the atmosphere), the lower (centered at 3 km), middle (centered at 8 km) and upper (centered at 13 km) troposphere, as well as the lower stratosphere (centered at 18 km). Each granule contains data from the daylight portion for a single orbit or about 50 minutes. Spatial coverage is global (-90 to 90 degrees latitude), and there are about 14 orbits per day each with a swath width of 2600 km. There are 104 pixels in the cross-track direction before February 13, 2019 with a pixel resolution of about 17 km x 17 km at nadir. Since then, the pixel resolution has been enhanced to 17 km x 13 km at nadir, with 140 pixels in the cross-track direction. The files are written using netCDF version 4.

The OMPS-N20_NM_PCA_SO2 Step1 Total Column 1-Orbit L2 Swath 17x13km collection 1 product contains the retrieved sulfur dioxide (SO2) measured by the Ozone Mapping and Profiling Suite (OMPS) Nadir-Mapper (NM) sensor on the NOAA-20 (JPSS-1) satellite. The product is based on the NASA Goddard Space Flight Center principal component analysis (PCA) spectral fitting algorithm (Li et al., 2013, 2017) used to retrieve the SO2 total column amounts assuming different SO2 plume heights, including the boundary layer (lowest 1 km of the atmosphere), the lower (centered at 3 km), middle (centered at 8 km) and upper (centered at 13 km) troposphere, as well as the lower stratosphere (centered at 18 km). Each granule contains data from the daylight portion for a single orbit or about 50 minutes. Spatial coverage is global (-90 to 90 degrees latitude), and there are about 14 orbits per day each with a swath width of 2600 km. There are 104 pixels in the cross-track direction before February 13, 2019 with a pixel resolution of about 17 km x 17 km at nadir. Since then, the pixel resolution has been enhanced to 17 km x 13 km at nadir, with 140 pixels in the cross-track direction. The files are written using netCDF version 4.

The OMPS-N20 NM PCA SO2 Step1 Total Column 1-Orbit L2 Swath 17x13km collection 1 product contains the retrieved sulfur dioxide (SO2) measured by the Ozone Mapping and Profiling Suite (OMPS) Nadir-Mapper (NM) sensor on the NOAA-20 (JPSS-1) satellite. The product is based on the NASA Goddard Space Flight Center principal component analysis (PCA) spectral fitting algorithm (Li et al., 2013, 2017) used to retrieve the SO2 total column amounts assuming different SO2 plume heights, including the boundary layer (lowest 1 km of the atmosphere), the lower (centered at 3 km), middle (centered at 8 km) and upper (centered at 13 km) troposphere, as well as the lower stratosphere (centered at 18 km). Each granule contains data from the daylight portion for a single orbit or about 50 minutes. Spatial coverage is global (-90 to 90 degrees latitude), and there are about 14 orbits per day each with a swath width of 2600 km. There are 104 pixels in the cross-track direction before February 13, 2019 with a pixel resolution of about 17 km x 17 km at nadir. Since then, the pixel resolution has been enhanced to 17 km x 13 km at nadir, with 140 pixels in the cross-track direction. The files are written using netCDF version 4.

The OMPS_NPP_NMSO2_PCA_L2 product is part of the MEaSUREs (Making Earth Science Data Records for Use in Research Environments) suite of products. It is retrieved from the NASA/NOAA Suomi National Polar-orbiting Partnership (SNPP) Ozone Mapping and Profiler Suite (OMPS) Nadir Mapper (NM) spectrometer and provides contiguous daily global monitoring of anthropogenic and volcanic sulfur dioxide (SO2), an important pollutant and aerosol precursor that affects both air quality and the climate. The product is based on the NASA Goddard Space Flight Center principal component analysis (PCA) spectral fitting algorithm (Li et al., 2013, 2017), and continues (Zhang et al., 2017) NASA's Earth Observing System (EOS) standard Aura/Ozone Monitoring Instrument SO2 product (OMSO2). The latest OMPS_NPP_NMSO2_PCA_L2 V2 product uses new Jacobian lookup tables and more realistic model based a priori profiles in anthropogenic SO2 retrievals. This helps to more accurately account for the pixel-to-pixel variation in SO2 sensitivity due to different factors such as the vertical distribution of SO2, solar and viewing angles, surface reflectivity, and cloudiness. As compared with the previous OMPS_NPP_NMSO2_PCA_L2 V1.2 product that assumes the same SO2 sensitivity for all OMPS pixels, the new V2 anthropogenic SO2 retrievals have reduced retrieval biases especially over background regions (see Figure 1 for an example). The same updated PCA SO2 retrieval algorithm (Li et al., 2020) is also used to produce the recently released OMSO2 V2 product (doi:10.5067/Aura/OMI/DATA2022). The new OMPS_NPP_NMSO2_PCA_L2 V2 product thus offers enhanced consistency between the NASA EOS standard (OMI) and continuity (OMPS) SO2 data records Sulfur Dioxide (SO2) is a short-lived gas primarily produced by volcanoes, power plants, refineries, metal smelting and burning of fossil fuels. Where SO2 remains near the Earth's surface, it is toxic, causes acid rain, and degrades air quality. Where SO2 is lofted into the free troposphere, it forms aerosols that can alter cloud reflectivity and precipitation. In the stratosphere, volcanic SO2 forms sulfate aerosols that can result in climate change.

The Aura Ozone Monitoring Instrument (OMI) level 2 sulphur dioxide (SO2) total column product (OMSO2) has been updated with a principal component analysis (PCA)-based algorithm (v2) with new SO2 Jacobian lookup tables and a priori profiles that significantly improve retrievals for anthropogenic SO2. The data files (or granules) contain different estimates of the vertical column density (VCD) of SO2 depending on the users investigating anthropogenic or volcanic sources. Files also contain quality flags, geolocation and other ancillary information. The lead scientist for the OMSO2 product is Can Li.The OMSO2 files are stored in the version 5 EOS Hierarchical Data Format (HDF-EOS5). Each file contains data from the daylit half of an orbit (~53 minutes). There are approximately 14 orbits per day. The resolution of the data is 13x24 km2 at nadir, with a swath width of 2600 km and 60 pixels per scan line every 2 seconds.

The OMPS-NPP L2 NM Sulfur Dioxide (SO2) Total and Tropospheric Column swath orbital collection 2 version 2.0 product contains the retrieved sulfur dioxide (SO2) measured by the Ozone Mapping and Profiling Suite (OMPS) Nadir-Mapper (NM) sensor on the Suomi-NPP satellite. A direct vertical column fitting (DVCF) algorithm is used to retrieve the SO2 total column amount and column amounts in the lower (centered at 2.5 km), middle (centered at 7.5 km) and upper (centered at 11 km) troposphere, as well as the lower stratosphere (centered at 16 km).Each granule contains data from the daylight portion for a single orbit or about 50 minutes. Spatial coverage is global (-90 to 90 degrees latitude), and there are about 14 orbits per day each with a swath width of 2600 km. There are 35 pixels in the cross-track direction, with a pixel resolution of about 50 km x 50 km at nadir. The files are written using the Hierarchical Data Format Version 5 or HDF5.

The OMI/Aura Sulphur Dioxide (SO2) Total Column 1-orbit L2 Swath 13x24 km (OMSO2) data product has been updated with a principal component analysis (PCA)-based algorithm (v2) with new SO2 Jacobian lookup tables and a priori profiles that significantly improve retrievals for anthropogenic SO2. The data files (or granules) contain different estimates of the vertical column density (VCD) of SO2 depending on the users investigating anthropogenic or volcanic sources. Files also contain quality flags, geolocation and other ancillary information. The lead scientist for the OMSO2 product is Can Li.The OMSO2 files are stored in the version 5 EOS Hierarchical Data Format (HDF-EOS5). Each file contains data from the daylit half of an orbit (~53 minutes). There are approximately 14 orbits per day. The resolution of the data is 13x24 km2 at nadir, with a swath width of 2600 km and 60 pixels per scan line every 2 seconds.

The Aura Ozone Monitoring Instrument (OMI) level 2 sulphur dioxide (SO2) total column product (OMSO2) has been updated with a principal component analysis (PCA)-based algorithm (v2) with new SO2 Jacobian lookup tables and a priori profiles that significantly improve retrievals for anthropogenic SO2. The data files (or granules) contain different estimates of the vertical column density (VCD) of SO2 depending on the users investigating anthropogenic or volcanic sources. Files also contain quality flags, geolocation and other ancillary information. The lead scientist for the OMSO2 product is Can Li. The OMSO2 files are stored in the version 5 EOS Hierarchical Data Format (HDF-EOS5). Each file contains data from the daylit half of an orbit (~53 minutes). There are approximately 14 orbits per day. The resolution of the data is 13x24 km2 at nadir, with a swath width of 2600 km and 60 pixels per scan line every 2 seconds.

Version 3 is the current version of the data set. Older versions will no longer be available and have been superseded by Version 3.The goal of this data set is to create and archive a Level 2 SO2 Earth Science Data Record (ESDR) from backscatter Ultraviolet (BUV) measurements from Total Ozone Mapping Spectrometer (TOMS) flown on NASA's Nimbus - 7 satellite in 1978-1993. We apply TOMS ozone team calibration techniques and consistent MEaSUREs SO2 (MS_SO2) algorithm, to obtain the best measurement-based ESDR of volcanic and anthropogenic SO2 masses and emissions. As part of the NASA's Making Earth System Data Records for Use in Research Environments (MEaSUREs) program, the Goddard Earth Science (GES) Data and Information Data Center (DISC) has released a new SO2 Earth System Data Record (ESDR), TOMSN7SO2, re-processed using new 4 UV wavelength bands MS_SO2 algorithm that spans the full Nimbus 7 data period. TOMSN7SO2 is a Level 2 orbital swath product, which will be used to study the fifteen-year SO2 record from the Nimbus-7 TOMS and to expand the historical database of known volcanic eruptions. Sulfur Dioxide (SO2) is a short-lived gas primarily produced by volcanoes, power plants, refineries, metal smelting and burning of fossil fuels. Where SO2 remains near the Earth s surface, it is toxic, causes acid rain, and degrades air quality. Where SO2 is lofted into the free troposphere, it forms aerosols that can alter cloud reflectivity and precipitation. In the stratosphere, volcanic SO2 forms sulfate aerosols that can result in climate change.

Starting from August 6th in 2019, Sentinel-5P TROPOMI along-track high spatial resolution (~5.5km at nadir) has been implemented.Starting from July 13th in 2020, five Sentinel-5P TROPOMI level-2 products including total and tropospheric column ozone, sulfur dioxide, CLOUD, and formaldehyde have been generated in processor version 2.For data before August 6th of 2019, please check S5P_L2__SO2____1 data collection.For data between August 6th of 2019 and July 13th of 2020, please check S5P_L2__SO2____HiR_1 data collection.For data after July 13th of 2020, please check S5P_L2__SO2____HiR_2 data collection.The Copernicus Sentinel-5 Precursor (Sentinel-5P or S5P) satellite mission is one of the European Space Agency's (ESA) new mission family - Sentinels, and it is a joint initiative between the Kingdom of the Netherlands and the ESA. The sole payload on Sentinel-5P is the TROPOspheric Monitoring Instrument (TROPOMI), which is a nadir-viewing 108 degree Field-of-View push-broom grating hyperspectral spectrometer, covering the wavelength of ultraviolet-visible (UV-VIS, 270nm to 495nm), near infrared (NIR, 675nm to 775nm), and shortwave infrared (SWIR, 2305nm-2385nm). Sentinel-5P is the first of the Atmospheric Composition Sentinels and is expected to provide measurements of ozone, NO2, SO2, CH4, CO, formaldehyde, aerosols and cloud at high spatial, temporal and spectral resolutions.The retrieval algorithm for Sentinel-5P TROPOMI SO2 from ultraviolet spectral measurements is the Differential Optical Absorption Spectroscopy (DOAS) method. The relevant information of absorption cross section, instrument characteristics, cloud cover, and geolocation are utilized to derive SO2 slant column density (SCD). A sensitive spectral window of 312 to 326 nm is set as the baseline for the slant column fit with another two spectral windows (325 to 335 nm, 360 to 390 nm) to account for the non-linear effects in those high column amount cases. The SCD is then corrected with the empirical offsets to the systematic biases. The air mass factor (AMF) Look-up table has been created with the LIDORT radiative transfer model. The outputs of the DOAS algorithm are SO2 vertical column density (VCD), SCD, AMF, the DOAS-type averaging kernels (AK), and error estimates.