Sentinel-3 Reference Guide

This reference guide provides detailed information about Sentinel-3 data parameters and options available through the Copernicus Data Space Ecosystem.

Overview

Sentinel-3 is a constellation of two polar-orbiting satellites (Sentinel-3A and Sentinel-3B) carrying multiple instruments for ocean and land monitoring. The mission provides systematic measurements of Earth’s oceans, land, ice, and atmosphere.

Key Features: - Ocean and Land Colour Instrument (OLCI) - 21 spectral bands - Sea and Land Surface Temperature Radiometer (SLSTR) - thermal and optical channels - SAR Radar Altimeter (SRAL) - precise height measurements - Synergy products combining OLCI and SLSTR data - 27-day repeat cycle with daily global coverage - Systematic global coverage for ocean and land applications

Search Parameters

Parameter Types

When searching for Sentinel-3 data, parameters are passed in two ways:

Direct Parameters: Passed directly to the search() method - collection_name - Mission/collection identifier - product_type - Product type (OL_1_EFR___, OL_2_LFR___, etc.) - orbit_direction - Orbit direction (ASCENDING/DESCENDING) - aoi_wkt - Area of interest in WKT format - start_date / end_date - Temporal range - top - Maximum number of results

Attributes Dictionary

Attributes are passed in the attributes parameter dictionary. All values listed below have been comprehensively tested and verified against the Copernicus Data Space OData API.

Sentinel-3 Attribute Reference
Attribute	Verified Values	Description
`platformSerialIdentifier`	`'A'`, `'B'`	Satellite platform identifier
`instrumentShortName`	`'OLCI'`, `'SLSTR'`, `'SRAL'`	Instrument type
`processingLevel`	`'1'`, `'2'`	Processing level (numeric string)
`timeliness`	`'NR'`, `'NT'`, `'ST'`	Data delivery timeliness
`orbitDirection`	`'ASCENDING'`, `'DESCENDING'`	Satellite orbit direction
`orbitNumber`	Integer as string	Absolute orbit number
`relativeOrbitNumber`	`'1'`–`'385'` (string)	Relative orbit (27-day cycle)
`cycleNumber`	Integer as string	Mission cycle number
`processingBaseline`	Version string (e.g., `'03.46'`)	Processing baseline version
`operationalMode`	`'EO'` (Earth Observation)	Operational mode

Important

Processing Level Format

Sentinel-3 processingLevel must be specified as:

✓ '1' or '2' (numeric strings)
✗ NOT 'L1', 'L2', 'LEVEL1', or 'LEVEL2'

Note

Timeliness Categories

'NR' - Near Real-Time (3 hours)
'NT' - Non-Time-Critical (1 month)
'ST' - Short Time-Critical (48 hours)

Data availability varies by timeliness category and date range.

Basic Parameters

Collection Name

Use 'SENTINEL-3' as the collection name.

results = searcher.search(collection_name='SENTINEL-3')

Geographic Parameters

Geometry

Region of Interest defined in Well Known Text (WKT) format with coordinates in decimal degrees (EPSG:4326).

# Polygon example
aoi_wkt = 'POLYGON((0 35, 10 35, 10 45, 0 45, 0 35))'
results = searcher.search(
    collection_name='SENTINEL-3',
    aoi_wkt=aoi_wkt
)

Product Parameters

Product Types

Sentinel-3 offers various product types organized by instrument. Product types use specific identifiers:

Important Note: While the configuration file lists generic categories (S3OLCI, S3SLSTR, S3SRAL, S3SRSP), searches must use the specific product identifiers below for actual results.

OLCI (Ocean and Land Colour Instrument):

OL_1_EFR___ - Level 1 Earth Observation Full Resolution
OL_1_ERR___ - Level 1 Earth Observation Reduced Resolution
OL_2_LFR___ - Level 2 Land Full Resolution
OL_2_LRR___ - Level 2 Land Reduced Resolution
OL_2_WFR___ - Level 2 Water Full Resolution
OL_2_WRR___ - Level 2 Water Reduced Resolution

SLSTR (Sea and Land Surface Temperature Radiometer):

SL_1_RBT___ - Level 1 Radiance and Brightness Temperature
SL_2_LST___ - Level 2 Land Surface Temperature
SL_2_WST___ - Level 2 Water Surface Temperature
SL_2_FRP___ - Level 2 Fire Radiative Power

SRAL (SAR Radar Altimeter):

SR_1_SRA___ - Level 1 Standard Radar Altimetry
SR_1_SRA_A_ - Level 1 Standard Radar Altimetry A
SR_1_SRA_BS - Level 1 Standard Radar Altimetry BS
SR_2_LAN___ - Level 2 Land Altimetry
SR_2_LAN_HY - Level 2 Land Altimetry (Hydrology)
SR_2_LAN_LI - Level 2 Land Altimetry (Land Ice)
SR_2_LAN_SI - Level 2 Land Altimetry (Sea Ice)
SR_2_WAT___ - Level 2 Water Altimetry

SYNERGY Products:

SY_2_SYN___ - Level 2 Synergy
SY_2_V10___ - Level 2 VGT 1km
SY_2_VG1___ - Level 2 VGT 1/3km
SY_2_VGP___ - Level 2 VGT Parameters
SY_2_AOD___ - Level 2 Aerosol Optical Depth

# Search for OLCI Level 2 water products
results = searcher.search(
    collection_name='SENTINEL-3',
    product_type='OL_2_WFR___',
    attributes={'processingLevel': '2'}
)

Processing Level

Available processing levels:

1 - Level 1 (TOA radiances, brightness temperatures)
2 - Level 2 (Geophysical products)

# Search for Level 2 products
results = searcher.search(
    collection_name='SENTINEL-3',
    attributes={'processingLevel': '2'}
)

Platform Serial Identifier

Sentinel-3 constellation satellites:

A - Sentinel-3A (launched 2016)
B - Sentinel-3B (launched 2018)

# Search for Sentinel-3A data only
results = searcher.search(
    collection_name='SENTINEL-3',
    attributes={'platformSerialIdentifier': 'A'}
)

Instrument Short Name

Sentinel-3 instruments:

OLCI - Ocean and Land Colour Instrument
SLSTR - Sea and Land Surface Temperature Radiometer
SRAL - SAR Radar Altimeter

# Search for OLCI instrument data
results = searcher.search(
    collection_name='SENTINEL-3',
    attributes={'instrumentShortName': 'OLCI'}
)

Cloud Cover

Cloud Cover Percentage

Filter products by cloud cover percentage (0-100%). Applicable mainly to OLCI and SLSTR products.

# Search for products with less than 30% cloud cover
results = searcher.search(
    collection_name='SENTINEL-3',
    attributes={'cloudCover': '[0,30]'}
)

Orbit Parameters

Orbit Direction

ASCENDING - Satellite moving from south to north
DESCENDING - Satellite moving from north to south

results = searcher.search(
    collection_name='SENTINEL-3',
    orbit_direction='DESCENDING'
)

Orbit Number

Absolute orbit number (integer value or range).

# Single orbit
results = searcher.search(
    collection_name='SENTINEL-3',
    attributes={'orbitNumber': '12345'}
)

# Orbit range
results = searcher.search(
    collection_name='SENTINEL-3',
    attributes={'orbitNumber': '[12345,12350]'}
)

Relative Orbit Number

Relative orbit number (1-385 for Sentinel-3), representing the orbit within a repeat cycle.

# Search for relative orbit 100
results = searcher.search(
    collection_name='SENTINEL-3',
    attributes={'relativeOrbitNumber': '100'}
)

Quality and Timeliness

Timeliness

Data delivery timeliness categories:

NR - Near Real-Time
NT - Non Time-Critical
ST - Slow Time-Critical

# Search for non time-critical data
results = searcher.search(
    collection_name='SENTINEL-3',
    attributes={'timeliness': 'NT'}
)

Processing Baseline

Processing baseline version (affects product quality and algorithms used).

# Search for specific processing baseline
results = searcher.search(
    collection_name='SENTINEL-3',
    attributes={'processingBaseline': '03.00'}
)

Additional Coverage Attributes

Sentinel-3 supports various coverage-related attributes for filtering products based on surface type percentages:

Coverage Types

landCover - Percentage of land coverage
cloudCover - Percentage of cloud coverage
brightCover - Percentage of bright surface coverage
coastalCover - Percentage of coastal area coverage
closedSeaCover - Percentage of closed sea coverage
openOceanCover - Percentage of open ocean coverage
snowOrIceCover - Percentage of snow or ice coverage
salineWaterCover - Percentage of saline water coverage
tidalRegionCover - Percentage of tidal region coverage
continentalIceCover - Percentage of continental ice coverage
freshInlandWaterCover - Percentage of fresh inland water coverage

# Search for products with significant ocean coverage
results = searcher.search(
    collection_name='SENTINEL-3',
    product_type='S3OLCI',
    attributes={
        'openOceanCover': '[60,100]',
        'cloudCover': '[0,20]'
    }
)

Orbit Cycle Parameters

cycleNumber - Orbit cycle number
lastOrbitNumber - Last orbit number in product
lastOrbitDirection - Last orbit direction (ASCENDING/DESCENDING)
lastRelativeOrbitNumber - Last relative orbit number

# Search using cycle number
results = searcher.search(
    collection_name='SENTINEL-3',
    attributes={'cycleNumber': '100'}
)

Other Attributes

baselineCollection - Baseline collection identifier
processorName - Name of the processor used
processingCenter - Processing center identifier
processorVersion - Version of the processor
processingDate - Date of product processing

Practical Examples

Example 1: Ocean Color Monitoring

from phidown import CopernicusDataSearcher

searcher = CopernicusDataSearcher()

# Search for OLCI ocean color products
results = searcher.search(
    collection_name='SENTINEL-3',
    product_type='S3OLCI',
    aoi_wkt='POLYGON((0 35, 10 35, 10 45, 0 45, 0 35))',  # Mediterranean
    start_date='2023-06-01',
    end_date='2023-06-30',
    attributes={
        'instrumentShortName': 'OLCI',
        'processingLevel': 'L2',
        'cloudCover': '[0,20]',
        'openOceanCover': '[50,100]'
    }
)

print(f"Found {len(results)} ocean color products")

Example 2: Land Surface Temperature

from phidown import CopernicusDataSearcher

searcher = CopernicusDataSearcher()

# Search for SLSTR land surface temperature products
results = searcher.search(
    collection_name='SENTINEL-3',
    product_type='SL_2_LST___',
    aoi_wkt='POLYGON((10 40, 20 40, 20 50, 10 50, 10 40))',  # Central Europe
    start_date='2023-07-01',
    end_date='2023-07-31',
    attributes={
        'instrumentShortName': 'SLSTR',
        'processingLevel': '2',
        'timeliness': 'NT',
        'landCover': '[70,100]'
    }
)

print(f"Found {len(results)} land surface temperature products")

Example 3: Altimetry for Ocean Monitoring

from phidown import CopernicusDataSearcher

searcher = CopernicusDataSearcher()

# Search for SRAL ocean altimetry products
results = searcher.search(
    collection_name='SENTINEL-3',
    product_type='SR_2_WAT___',
    aoi_wkt='POLYGON((-10 30, 10 30, 10 50, -10 50, -10 30))',  # Atlantic
    start_date='2023-08-01',
    end_date='2023-08-31',
    attributes={
        'instrumentShortName': 'SRAL',
        'processingLevel': '2'
    }
)

print(f"Found {len(results)} ocean altimetry products")

Example 4: Synergy Products for Vegetation

from phidown import CopernicusDataSearcher

searcher = CopernicusDataSearcher()

# Search for SYNERGY vegetation products
results = searcher.search(
    collection_name='SENTINEL-3',
    product_type='SY_2_VG1___',
    aoi_wkt='POLYGON((0 40, 20 40, 20 60, 0 60, 0 40))',  # Europe
    start_date='2023-05-01',
    end_date='2023-05-31',
    attributes={
        'processingLevel': '2',
        'cloudCover': '[0,30]'
    }
)

print(f"Found {len(results)} vegetation products")

Example 5: Fire Detection

from phidown import CopernicusDataSearcher

searcher = CopernicusDataSearcher()

# Search for SLSTR fire products
results = searcher.search(
    collection_name='SENTINEL-3',
    product_type='SL_2_FRP___',
    aoi_wkt='POLYGON((-10 35, 5 35, 5 45, -10 45, -10 35))',  # Spain/Portugal
    start_date='2023-08-01',
    end_date='2023-08-31',
    attributes={
        'instrumentShortName': 'SLSTR',
        'processingLevel': '2',
        'timeliness': 'NR'
    }
)

print(f"Found {len(results)} fire detection products")

Example 6: Multi-Platform Time Series

from phidown import CopernicusDataSearcher
import pandas as pd

searcher = CopernicusDataSearcher()

# Search for data from both platforms
s3a_results = searcher.search(
    collection_name='SENTINEL-3',
    product_type='OL_2_LFR___',
    aoi_wkt='POLYGON((10 45, 15 45, 15 50, 10 50, 10 45))',
    start_date='2023-01-01',
    end_date='2023-12-31',
    attributes={
        'platformSerialIdentifier': 'A',
        'processingLevel': '2',
        'cloudCover': '[0,30]'
    }
)

s3b_results = searcher.search(
    collection_name='SENTINEL-3',
    product_type='OL_2_LFR___',
    aoi_wkt='POLYGON((10 45, 15 45, 15 50, 10 50, 10 45))',
    start_date='2023-01-01',
    end_date='2023-12-31',
    attributes={
        'platformSerialIdentifier': 'B',
        'processingLevel': '2',
        'cloudCover': '[0,30]'
    }
)

# Combine results
all_results = pd.concat([s3a_results, s3b_results], ignore_index=True)

print(f"Sentinel-3A: {len(s3a_results)} products")
print(f"Sentinel-3B: {len(s3b_results)} products")
print(f"Total: {len(all_results)} products")

Search Optimization Tips

Choose Appropriate Instrument: Select the right instrument for your application (OLCI for ocean color, SLSTR for temperature, SRAL for altimetry).
Use Processing Level Wisely: Level 1 for raw data processing, Level 2 for ready-to-use geophysical products.
Filter by Cloud Cover: For optical instruments (OLCI, SLSTR), use cloud cover filtering to get clear observations.
Consider Timeliness: Use Near Real-Time (NR) for urgent applications, Non Time-Critical (NT) for better quality.
Optimize Temporal Range: Use appropriate date ranges based on the 27-day repeat cycle.
Use Relative Orbit Numbers: For consistent geometry in time series analysis.
Select Proper Product Type: Choose full resolution (FR) for detailed analysis, reduced resolution (RR) for overview applications.

Common Use Cases

Ocean Applications: - Ocean color monitoring: OL_2_WFR___, clear conditions - Sea surface temperature: SL_2_WST___, thermal channels - Ocean altimetry: SR_2_WAT___, precise measurements - Marine ecosystem monitoring: OL_2_WFR___, regular coverage

Land Applications: - Land surface temperature: SL_2_LST___, thermal infrared - Vegetation monitoring: SY_2_VG1___, SYNERGY products - Land altimetry: SR_2_LAN___, elevation measurements - Fire detection: SL_2_FRP___, active fire monitoring

Atmospheric Applications: - Aerosol monitoring: SY_2_AOD___, atmospheric products - Cloud detection: All optical products with cloud masks - Atmospheric correction: Level 2 products

Ice Applications: - Sea ice monitoring: SR_2_LAN_SI, specialized altimetry - Ice surface temperature: SL_2_LST___, polar regions - Ice extent mapping: OLCI and SLSTR products

Technical Specifications

OLCI (Ocean and Land Colour Instrument): - Spectral range: 400-1020 nm - Spatial resolution: 300 m (FR), 1.2 km (RR) - Swath width: 1270 km - Spectral bands: 21 bands - Applications: Ocean color, vegetation, atmosphere

SLSTR (Sea and Land Surface Temperature Radiometer): - Spectral range: 0.55-12 μm - Spatial resolution: 500 m (optical), 1 km (thermal) - Swath width: 1400 km - Spectral bands: 9 bands (6 optical, 3 thermal) - Applications: Sea/land surface temperature, fire detection

SRAL (SAR Radar Altimeter): - Frequency: 13.575 GHz (Ku-band), 5.41 GHz (C-band) - Footprint: ~300 m (ocean), ~1.65 km (land/ice) - Precision: ~3 cm (ocean), ~10 cm (land/ice) - Applications: Ocean/land topography, ice thickness

Orbital Characteristics: - Altitude: 814.5 km - Inclination: 98.65° - Repeat cycle: 27 days - Revisit time: <1 day (depending on latitude) - Local time: 10:00 AM (descending node)

Coverage: - Global coverage: Daily - Polar coverage: Multiple times per day - Equatorial coverage: Every 2-3 days - Ice-free ocean: Complete coverage every 27 days

For more detailed information about Sentinel-3 specifications and applications, refer to the official ESA Sentinel-3 documentation.