Copernicus Sentinel-2 pre-Collection-1 MSI Level-1C (L1C)

Copernicus Sentinel-2 pre-Collection-1 MSI Level-1C (L1C)

The Sentinel-2 Level-1C pre-Collection-1 represents the product dataset generated up to processing baseline 03.01 included.

The evolutions of the processing baseline (PB) are tracked and justified in the 'Processing Baseline Status' section of the Data Quality Report that is published on a monthly basis by the Mission Performance Center (MPC) and available from the Sentinel-2 Document Library.

Table 1: Level-1C Processing Baseline summary up to 03.99
Processing Version Date Introduced Reason
02.00 23 November 2015 Initial product Baseline
02.01 15 December 2015 updated to accommodate changes in the Tiling Grid configuration file
02.02 3 May 2016 to correct an issue identified in which anomalous pixels with incorrect value are present in the overlap of datastrips. This occurred in only a few products.
02.03 9 June 2016 Affected by a strong spectral mis-registration anomaly, and withdrawn.
02.04 15 June 2016 To replace 02.03
02.05 27 April 2017 A fix introduced to the satellite ancillary metadata, to correct instances where the value of Instrument Measurement Time (IMT) is not represented correctly.
02.06 23 October 2017 An update of the ‘Product Discriminator’ component of the product name and filename, and the product-level Metadata file in the structure holding the quality control report summary references.
02.07 6 November 2018 The crenellation effect at the edge of images was significantly reduced by estimating the inverse locations for grid points lying just after the edge of the acquisition.

The accuracy of the tile sensing time reported in the tile metadata was improved by computing for each tile the average acquisition time of all relevant pixels.

The new tile sensing time will be reported in the field General_Info/ SENSING_TIME of the Tile Metadata without format change The detector footprint vector files provide the precise location of the boundary between detectors, without overlap. This improvement will enable Users to have an accurate estimation of the viewing direction for each pixel.

The correlated across-track noise on very dark images was significantly reduced thanks to an improved radiometric correction algorithm.
02.08 8 July 2019 Correction of the formatting to the instrument telemetry of the Datastrip metadata (FEE Temperature Value and GPS_Time date).
02.09 4 February 2020 Improvement of the NO DATA mask accuracy Improvement ECMWF GRIB reference time accuracy Correction of a sporadic anomaly on product footprint Removal of the spurious viewing angle information for detectors not present in the image.
03.00 30 March 2021 Activation of the Geometric Refinement. Use of the new Copernicus Digital Elevation Model (COP-DEM) at 90 m, with corresponding improvement of the geolocation performance over mountainous areas in particular Improvement of the Level-1C cloud detection algorithm over high-altitude terrains Improvement of the Level-1C Technical Quality (TECQUA) mask accuracy.

Additional On-Line Quality Control checks applicable to the geometrically refined products.
03.01 30 June 2021 Increment to introduce:
  1. A minor modification of the Datastrip metadata, to harmonise them with Refined products, by adding processing_specific_parameters fields for unrefined products
  2. Update to the algorithm used to derive the checksum - from MD5 to the more resilient SHA3 (Secure Hash Algorithm 3) with SHA3-256 instance hash codes


Level-1C Dataset Specification

The Sentinel-2 Level-1C pre-Collection-1 product provides orthorectified Top-Of-Atmosphere (TOA) reflectance, with sub-pixel multispectral and multitemporal registration accuracy. Technical quality masks are included in the product. The main characteristics of the L1C products are listed in Table 2.

Table 2: Sentinel-2 L1C Product Characteristics
Name Level-1C
High-level Description Top-of-atmosphere reflectances in cartographic geometry for 13 spectral bands (10 m, 20 m, 6 m depending on the wavelength).
Data Characteristics UTM/WGS84 projection
  • JPEG2000 image format
  • 12-bit pixel values
  • < 12 m at 95.5% confidence of Absolute Geolocation
  • < 5 m at 95.5% confidence of Multitemporal Registration
  • < 0.3 px at 99.7% confidence of Multispectral Registration
DEM used
  • PlanetDEM at 90 m horizontal resolution (until PB 02.09 included – 30 March 2021)
  • Copernicus DEM at 90 m horizontal resolution (starting from PB 03.00 included)
Auxiliary Data ECMWF
Production & Distribution Systematic generation and on-line distribution
Data Volume Data Volume 700 MB (each 100x100 km2)
Data Delivery Available within 6 hours from sensing

 

L1C Products are radiometric and geometric Top of atmosphere (TOA) products, delivered in tiles of 100x100 km2. The corrections include orthorectification and spatial registration on a UTM/WGS84 projection. The UTM (Universal Transverse Mercator) system divides the Earth’s surface into 60 zones.

Each UTM zone has a vertical width of 6° of longitude and horizontal width of 8° of latitude. (see image below).

Tiles are approximately 700 MB in size. Tiles can be fully or partially covered by image data. Partially covered tiles correspond to those at the edge or top/bottom of the Datastrip, which is a portion of image downlinked during a pass to a given station.

Level-1C product tiling
Level-1C product tiling

Resolution

The resolutions of the Copernicus Sentinel-2 mission and its payload, the MSI instrument, are threefold:

  1. The temporal resolution of a satellite in orbit is the revisit frequency of the satellite to a particular location. The revisit frequency of each single Sentinel-2 satellite is 10 days and the combined constellation revisit is 5 days

  2. The spatial resolution of an instrument is the at-ground representation of an individual detector in a satellite sensor array. Details on the spatial resolution of the MSI instrument resolution are provided in the Spatial Resolution section

  3. The radiometric resolution of an instrument is a determination of the incremental level of intensity or reflectance that can be represented or distinguished by the system. The higher the radiometric resolution, the more capable the device will be of detecting differences in intensity or reflectance. Details on the radiometric resolution of the MSI instrument are provided in the Radiometric Resolutions section.


Coverage Acquisition Maps

The Sentinel-2 mission provides systematic global coverage over land masses and coastal areas. Read more about Sentinel-2's Revisit and Coverage.


Quality Reports

The Coordinating Centre of the Mission Performance Centre (MPC) provides a monthly status of the Sentinel-2 product quality via the dissemination of a Data Quality Report (DQR). The report provides information on the monitoring and measurement of product performances against the proposed specification. It also documents observed anomalies and known issues, the list of defective pixels, and any processing chain improvements that lead to an increment of the Processing Baseline.

View available Sentinel-2 Data Product Quality Reports.


How to access this data

Products are freely available via the Copernicus Data Space Ecosystem. In addition to the download services, the Sentinel Data Products are available in the Copernicus Data and Information Access Service (DIAS) cloud environments. Each DIAS provides processing resources, tools and complimentary data sources at commercial conditions to further facilitate the access to Sentinel data. Learn more about how to access Sentinel data.


Resources


Tools

The Sentinel-2 Toolbox consists of a rich set of visualisation, analysis and processing tools for the exploitation of MSI data from the Sentinel-2 mission.


Data Citation Guidelines pre-Collection-1

Users, who, in their research, use ESA Earth Observation data that have been assigned a DOI, are asked to use it when citing the data source in their publications:

Copernicus Sentinel-2 (processed by ESA), 2021, MSI Level-1C TOA Reflectance Product. Collection 0. European Space Agency, https://doi.org/10.5270/S2_-d8we2fl

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