Copernicus Sentinel Earth Observation Missions

By default the EOxCloudless data offer is based on Sentinel-2 source data with convenient and efficient data refining and delivery. We have in-house tools to address Sentinel-1 data processing and delivery, however these are not off-the-shelf. EOxCloudless also offers integration of very high resolution imagery (VHR) into the default 10 meter resolution datasets. For other data types and sources, depending on the requirements a custom data source, processing and delivery we offer custom solutions.

Sentinel-1 Mission

Sentinel-1 carries C-band Synthetic Aperture Radar (SAR) instruments. These instruments operate at a frequency of 5.405 GHz with a wavelength of approximately 5.6 cm.

Sensor Characteristics

• SAR Mode: Interferometric Wide Swath (IW) mode is the primary operational mode, covering a swath of 250 km with a spatial resolution of 5 m × 20 m (range × azimuth).
• Polarization: Sentinel-1 operates in dual polarization modes: VV+VH or HH+HV, depending on acquisition scenario.
• Imaging Geometry: Side-looking SAR with incidence angles ranging approximately 29° to 46°, enabling surface roughness and structure analysis.
• Orbit: Sun-synchronous, near-polar orbit at 693 km altitude, 12-day repeat cycle for each satellite; constellation repeat cycle is 6 days, enabling high temporal revisit.

Data Products and Applications

• Level-1 Single Look Complex (SLC) for interferometry and coherent change detection.
• Level-1 Ground Range Detected (GRD) for general imaging applications.
• Applications include surface deformation mapping, flood monitoring, sea ice mapping, and maritime surveillance.

Sentinel-2 Mission

Sentinel-2 is equipped with the MultiSpectral Instrument (MSI).

• Swath Width: 290 km per satellite.
• Spatial Resolution: 10 m (visible, NIR), 20 m (red edge, SWIR), 60 m (atmospheric bands).
• Radiometric Resolution: 12-bit
• Revisit Time: With both satellites, revisit is 5 days at the equator; shorter at higher latitudes due to orbit overlap.
• Orbit: Sun-synchronous, near-polar orbit at ~786 km altitude, local solar time ~10:30 am (descending node).

Data Acquisition and Products

Level-1C:

• Orthorectified top-of-atmosphere reflectance in UTM/WGS84 projection.
• Type: Top-of-Atmosphere (TOA) reflectance
• Bands: All 13 MSI bands, including Band 10 (Cirrus)
• Purpose of Band 10: Detects high-altitude clouds — only meaningful before atmospheric correction
• Corrections:
  • Geometrically corrected (orthorectified)
  • No atmospheric correction
• Use Cases: Suitable for users who apply their own atmospheric correction or require raw reflectance values for specific models
• Includes:
  • Full spectral range (13 bands)
  • TOA reflectance
  • Granule tiling and metadata

Level-2A:

• Surface reflectance products after atmospheric correction (Sen2Cor).
• Type: Bottom-of-Atmosphere (BOA) reflectance
• Bands: 12 bands — excludes Band 10
• Reason for Exclusion: Band 10 is designed to detect cirrus clouds in TOA data and becomes irrelevant after atmospheric correction
• Corrections:
  • Includes atmospheric correction via the Sen2Cor processor
  • Generates Scene Classification Layer (SCL) with land, water, cloud, and shadow labels
• Use Cases: Recommended for most analysis-ready workflows (e.g., vegetation indices, time series)
• Includes:
  • 12 spectral bands (excluding Band 10)
  • BOA reflectance
  • Scene Classification Layer
  • Quality masks (e.g., cloud, shadow, saturation)
  • Granule tiling and metadata

Auxiliary Data:

• Scene classification maps, cloud and shadow masks, and quality indicators.

The Sentinel-2 acquisition coverage is over land masses, without some minor islands in the oceans. The coverage also does not cover poles due to the sun-synchronous orbit path.

Sentinel‑2 Channel Bandwidths for 2A and 2B

Band	Wavelength (nm)	Bandwidth 2A (nm)	Bandwidth 2B (nm)	Resolution (m)	Typical Use
B1	443	20	21	60	Coastal/Aerosol
B2	490	65	66	10	Blue
B3	560	35	36	10	Green
B4	665	30	31	10	Red
B5	705	15	16	20	Vegetation red edge 1
B6	740	15	15	20	Vegetation red edge 2
B7	783	20	20	20	Vegetation red edge 3
B8	842	115	106	10	Near Infrared (NIR)
B8a	865	20	21	20	Narrow NIR
B9	945	20	21	60	Water vapour
B10	1375	30	31	60	Cirrus detection
B11	1610	90	94	20	SWIR 1
B12	2190	180	185	20	SWIR 2