Sentinel-5P OFFL O3: Offline Ozone Data (COPERNICUS/S5P/OFFL/L3_O3)

###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 ozone 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 'O3_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 'O3_column_number_density_validity>50;derive(datetime_stop {time});
bin_spatial(2001, 50.000000, 0.01, 2001, -120.000000, 0.01);
sensor_altitude,sensor_azimuth_angle, sensor_zenith_angle,
NameDescriptionGee Unit
O3_column_number_densityTotal atmospheric column of O3 between the surface and the top of atmosphere, calculated with the [GODfit algorithm]( mol/m^2
O3_effective_temperatureOzone cross section effective temperatureK
cloud_fractionEffective cloud fraction. See the [Sentinel 5P L2 Input/Output Data Definition Spec](, p.220. fraction
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 0.6.0
Keywords TROPOMI, air_quality, copernicus, esa, eu, o3, ozone, pollution, s5p, sentinel
License proprietary
Temporal Extent 9/8/2018, 2:19:29 PM - now
Type image_collection
GSD arc degreesm
Platform Sentinel-5P
Instrument TROPOMI
gee:revisit_interval days
Asset schema {"name":"ALGORITHM_VERSION","description":"The algorithm version used in L2 processing. It's separate from the\nprocessor (framework) version, to accommodate different release\nschedules for different products.\n","type":"STRING"},{"name":"BUILD_DATE","description":"The date, expressed as milliseconds since 1 Jan 1970, when the software used to perform L2 processing was built.","type":"STRING"},{"name":"HARP_VESRION","description":"The version of the HARP tool used to grid the L2 data into an L3\nproduct.\n","type":"INT"},{"name":"INSTITUTION","description":"The institution where data processing from L1 to L2 was performed.","type":"STRING"},{"name":"L3_PROCESSING_TIME","description":"The date, expressed as milliseconds since 1 Jan 1970, when Google processed the L2 data into L3 using harpconvert.","type":"INT"},{"name":"LAT_MAX","description":"The maximum latitude of the asset (degrees).","type":"DOUBLE"},{"name":"LAT_MIN","description":"The minimum latitude of the asset (degrees).","type":"DOUBLE"},{"name":"LON_MAX","description":"The maximum longitude of the asset (degrees).","type":"DOUBLE"},{"name":"LON_MIN","description":"The minimum longitude of the asset (degrees).","type":"DOUBLE"},{"name":"ORBIT","description":"The orbit number of the satellite when the data was acquired.\n","type":"INT"},{"name":"PLATFORM","description":"Name of the platform which acquired the data.\n","type":"STRING"},{"name":"PROCESSING_STATUS","description":"The processing status of the product on a global level, mainly based\non the availability of auxiliary input data. Possible values are\n\"Nominal\" and \"Degraded\".\n","type":"STRING"},{"name":"PROCESSOR_VERSION","description":"The version of the software used for L2 processing, as a string of\nthe form \"major.minor.patch\".\n","type":"STRING"},{"name":"PRODUCT_ID","description":"Id of the L2 product used to generate this asset.\n","type":"STRING"},{"name":"PRODUCT_QUALITY","description":"Indicator that specifies whether the product quality is degraded or\nnot. Allowed values are \"Degraded\" and \"Nominal\".\n","type":"STRING"},{"name":"REVISION_CONTROL_IDENTIFIER","description":"Revision control system identifier for the source code of the\nsoftware used for L2 processing of this data.\n","type":"STRING"},{"name":"SENSOR","description":"Name of the sensor which acquired the data.","type":"STRING"},{"name":"SPATIAL_RESOLUTION","description":"Spatial resolution at nadir. For most products this is `3.5x7km2`,\nexcept for `L2__O3__PR`, which uses `28x21km2`, and\n`L2__CO____` and `L2__CH4___`, which both use `7x7km2`.\nThis attribute originates from the CCI standard.\n","type":"STRING"},{"name":"TIME_REFERENCE_DAYS_SINCE_1950","description":"Days from 1 Jan 1950 to when the data was acquired.","type":"INT"},{"name":"TIME_REFERENCE_JULIAN_DAY","description":"The Julian day number when the data was acquired.","type":"DOUBLE"},{"name":"TRACKING_ID","description":"UUID for the L2 product file.","type":"STRING"},{"name":"STATUS_MET_2D","description":"This dataset uses dynamic auxiliary weather data during L2 processing.\nThis field has a value of \"Nominal\" if ECMWF dynamic auxiliary data was\navailable or \"Fallback\" if not.\n","type":"STRING"}