Sentinel-5P OFFL NO2: Offline Nitrogen Dioxide Data (COPERNICUS/S5P/OFFL/L3_NO2)

###Sentinel-5 Precursor

Sentinel-5 Precursor is a satellite launched on 13 October 2017
by the European Space Agency to monitor air pollution. The onboard sensor
is frequently referred to as Tropomi (TROPOspheric Monitoring Instrument).

All of the S5P datasets have two versions: Near Real-Time (NRTI) and Offline
(OFFL). The NRTI assets cover a smaller area than the OFFL assets, but
appear more quickly after acquisition. The OFFL assets contain data
from a single orbit (which, due to half the earth being dark, contains
data only for a single hemisphere).

The original Sentinel 5P Level 2 (L2) data is binned
by time, not by latitude/longitude. To make it possible to ingest the data
into Earth Engine, each Sentinel 5P L2 product is converted to L3, keeping
a single grid per orbit (that is, no aggregation across products
is performed).

Source products spanning the antimeridian are ingested as two Earth Engine
assets, with suffixes _1 and _2.

The conversion to L3 is done by the harpconvert
tool using the bin_spatial operation. The source data is filtered to
remove any values with QA values of less than 50.


This dataset provides OFFL high-resolution imagery of NO2 concentrations.

To make our OFFL L3 products, we find areas within the product’s bounding
box with data using a command like this:

harpconvert --format hdf5 --hdf5-compression 9
-a 'tropospheric_NO2_column_number_density_validity>50;derive(datetime_stop {time})'

We then merge all the data into one large mosaic (taking only one value for
pixels that may have different values for different times). From the
mosaic, we create a set of tiles containing orthorectified raster data.

Example harpconvert invocation for one tile:

harpconvert --format hdf5 --hdf5-compression 9
-a 'tropospheric_NO2_column_number_density_validity>50;derive(datetime_stop {time});
bin_spatial(2001, 50.000000, 0.01, 2001, -120.000000, 0.01);
NO2_column_number_densityTotal vertical column of NO2 (ratio of the slant column density of NO2 and the total air mass factor). mol/m^2
tropospheric_NO2_column_number_densitytropospheric vertical column of NO2mol/m^2
stratospheric_NO2_column_number_densitystratospheric vertical column of NO2mol/m^2
NO2_slant_column_number_densityNO2 slant column densitymol/m^2
tropopause_pressuretopopause pressurePa
absorbing_aerosol_indexAerosol index (at wavelengths 354/388, i.e. the OMI pair) from the AER_AI level 2 product. See [Level 2 Algorithms - Aerosol Index]( Dimensionless
cloud_fractionEffective cloud fraction. See the [Sentinel 5P L2 Input/Output Data Definition Spec](, p.220.fraction
sensor_altitudeAltitude of the satellite with respect to the geodetic sub-satellite point (WGS84). m
sensor_azimuth_angleAzimuth angle of the satellite at the ground pixel location (WGS84); angle measured East-of-North. degrees
sensor_zenith_angleZenith angle of the satellite at the ground pixel location (WGS84); angle measured away from the vertical. degrees
solar_azimuth_angleAzimuth angle of the Sun at the ground pixel location (WGS84); angle measured East-of-North. degrees
solar_zenith_angleZenith angle of the satellite at the ground pixel location (WGS84); angle measured away from the vertical. degrees


European Union/ESA/Copernicus (producer, licensor)
Google Earth Engine (host)
STAC Version 0.6.2
Keywords TROPOMI, air_quality, copernicus, esa, eu, knmi, nitrogen_dioxide, no2, pollution, s5p, sentinel
License proprietary
Temporal Extent 6/28/2018, 3:24:07 AM - now
Type image_collection
GSD arc degreesm
Platform Sentinel-5P
Instrument TROPOMI
cube:dimensions {"x":{"type":"spatial","axis":"x","extent":[-180,180]},"y":{"type":"spatial","axis":"y","extent":[-90,90]},"temporal":{"type":"temporal","extent":["2018-06-28T10:24:07Z",null]},"bands":{"type":"bands","values":["NO2_column_number_density","tropospheric_NO2_column_number_density","stratospheric_NO2_column_number_density","NO2_slant_column_number_density","tropopause_pressure","absorbing_aerosol_index","cloud_fraction","sensor_altitude","sensor_azimuth_angle","sensor_zenith_angle","solar_azimuth_angle","solar_zenith_angle"]}}