Sentinel-3 SLSTR L1B

About Sentinel-3 SLSTR L1B Data

Mission information

SENTINEL-3 is a European wide-swath, medium-resolution, multi-spectral imaging mission designed to monitor ocean surface topography as well as land and sea surface temperature. The satellite hosts four instruments: the Sea and Land Surface Temperature Radiometer (SLSTR), the Ocean and Land Colour Instrument (OLCI), a Sar Radar Altimeter (SRAL) and a Microwave Radiometer (MWR). Sentinel-3A was launched on 16 February 2016 and its twin Sentinel-3B on 25 April 2018.

The SLSTR instrument was designed to provide data continuity with the Advanced Along Track Scanning Radiometer (AATSR) instrument flown on Envisat. The main objective of the instrument is to provide global sea surface temperature measurements with zero bias and uncertainties of ± 0.3 K, as well as land surface temperature readings and fire monitoring.

SLSTR has an along-track dual view scanning technique, enabling acquisitions at nadir and along-track in the backward direction, which include measurements of two blackbody calibration targets and a Visible Calibration Unit for high accuracy. The radiometer has 9 channels ranging from the visible and near-infrared (VNIR) to the thermal infrared (TIR). Two additional bands (active fire bands) in the TIR are optimised for fire monitoring with an increased dynamic range to prevent saturation. In single-view mode, SLSTR has a spatial resolution of 1 km, with less than half a day revisit time (with Sentinel-3 A and B) and a swath of 1400 km. In dual-view mode, a 500m resolution is reached, but only covering a swath of 744 Kilometers and with a daily revisit time.

Level 1B provides calibrated and ortho-geolocated Top Of Atmosphere (TOA) radiances for the 6 VNIR/SWIR bands (S1 to S6) and TOA brightness temperatures for the thermal IR and fire channels (S7 to S9 and F1, F2).

More information:

Basic facts

Spatial resolution500 m or 1 km per pixel
SensorSea and Land Surface Temperature Radiometer (SLSTR), 11 bands: 3 VNIR bands, 3 SWIR bands, 5 thermal IR bands.
UnitsRadiance: (Note that Sentinel Hub returns reflectance) / Brightness temperature: K.
Revisit time< 0.9 days at the equator with 2 satellites
Spatial coverageLand and coastal areas where the solar zenith angle < 80º
Data availabilitySince May 2016
MeasurementTop of the atmosphere (TOA) radiance and brightness temperature
Common usage/purposeClimate change monitoring, vegetation monitoring, active fire detection, land and sea surface temperature monitoring.

For processing Sentinel-3 SLSTR we use tie point grids from the SLSTR L1B products for geolocation. These are lower resolution than the full pixel grid so pixel positioning is less precise than exact. Unfortunately the exact grid is broken and cannot be used. Note, however, that with the lower resolution of SLSTR this method still offers reasonably precise geolocation accuracy.

Attribution and use

EU law grants free access to Copernicus Sentinel Data and Service Information for the purpose of the following use in so far as it is lawful: a) reproduction; b) distribution; c) communication to the public; d) adaptation, modification and combination with other data and information; e) any combination of points a to d.

See more details on the use of Copernicus Sentinel data and service information

Tracing based on Sentinel imagery is allowed for commercial purposes as well.

Acknowledgment or credit: Contains modified Copernicus Sentinel data [Year] processed by Sentinel Hub.

Accessing Sentinel-3 SLSTR Data

To access data you need to send a POST request to our process API. The requested data will be returned as the response to your request. Each POST request can be tailored to get you exactly the data you require. To do this requires setting various parameters which depend on the datasource you are querying. This chapter will help you understand the parameters for S3SLSTR data. To see examples of such requests go here, and for an overview of all API parameters see the API Reference.

Endpoint Locations

ServiceNotes since May 2016 since May 2016

Data type identifier: sentinel-3-slstr

Use sentinel-3-slstr (previously S3SLSTR) as the value of the parameter in your API requests. This is mandatory and will ensure you get Sentinel-3 SLSTR L1B data.

Filtering Options

This chapter will explain the object of the S3SLSTR process API.


Sets the order of overlapping tiles from which the output result is mosaicked. The tiling is based on ESA's Product Dissemination Units for easier distribution.

mostRecentthe pixel will be selected from the most recently acquired tileIf there are multiple products with the same timestamp then NTC will be used over NRT. Default value.
leastRecentthe pixel will be selected from the oldest acquired tileIf there are multiple products with the same timestamp then NTC will be used over NRT.
leastCCpixel is selected from tile with the least cloud coverage metadataNote that "per tile" information is used here.


Filters the acquisition orbit direction. For ascending orbits optical bands will typically return a black image as there is no sunlight to illuminate the earth, though you may get some usable data in regions of midnight sun. Thermal bands will return data normally as they do not depend on sunlight.

ASCENDINGData acquired when the satellite was traveling approximately towards the Earth's North poleNight (not for optical bands)
DESCENDINGData acquired when the satellite was traveling approximately towards the Earth's South poleDay (for optical bands)


Filters the acquisition by view.

NADIRthe image acquired by the nadir viewing scanner will be selectedDefault value
OBLIQUEthe image acquired by the oblique (rear) viewing scanner will be selected

Processing Options

This chapter will explain the object of the S3SLSTR process API.

upsamplingDefines the interpolation used for processing, regardless of the resolutionNEAREST - nearest neighbour interpolation
BILINEAR - bilinear interpolation
BICUBIC - bicubic interpolation
downsamplingNot used, use upsampling insteadN/AIgnored

Available Bands and Data

This chapter will explain the bands and data which can be set in the evalscript input object: Any string listed in the column Name can be an element of the input.bands array in your evalscript.

NameDescriptionWavelength centre (nm)Resolution (m/px)
S1Cloud screening, vegetation monitoring, aerosol554.27500
S2NDVI, vegetation monitoring, aerosol659.47500
S3NDVI, cloud flagging, pixel co-registration868500
S4Cirrus detection over land1374.80500
S5Cloud clearing, ice, snow, vegetation monitoring1613.40500
S6Vegetation state and cloud clearing2255.70500
S7SST, LST, Active fire37421000
S8SST, LST, Active fire108541000
S9SST, LST12022.501000
F1Active fire37421000
F2Active fire108541000
dataMaskThe mask of data/no data pixels (more).N/A*N/A**

*dataMask has no wavelength information, as it carries only boolean information on whether a pixel has data or not. See the chapter on Units for more.
**dataMask has no source resolution as it is calculated for each output pixel.

For more about Sentinel-3 SLSTR bands, visit this ESA website.


The data values for each band in your custom script are presented in the units as specified here. In case more than one unit is available for a given band, you may optionally set the value of input.units in your evalscript setup function to one of the values in the Sentinel Hub Units column. Doing so will present data in that unit. The Sentinel Hub units parameter combines the physical quantity and corresponding units of measurement values. As such, some names more closely resemble physical quantities, others resemble units of measurement.

The Source Format specifies how and with what precision the digital numbers (DN) from which the unit is derived are encoded. Bands requested in DN units contain exactly the pixel values of the source data. Note that resampling may produce interpolated values. DN is also used whenever a band is derived computationally (like dataMask); such bands can be identified by having DN units and N/A source format. DN values are typically not offered if they do not simply represent any physical quantity, in particular, when DN values require source-specific (i.e. non-global) conversion to physical quantities.

Values in non-DN units are computed from the source (DN) values with at least float32 precision. Note that the conversion might be nonlinear, therefore the full value range and quantization step size of such a band can be hard to predict. Band values in evalscripts always behave as floating point numbers, regardless of the actual precision.

The Typical Range indicates what values are common for a given band and unit, however outliers can be expected.

BandPhysical Quantity (units)Sentinel Hub UnitsSource FormatTypical RangeNotes
Optical bands
S1 - S6
Reflectance (unitless)REFLECTANCEUINT160 - 0.4Higher values in infrared bands. Reflectance values can easily be above 1.
Thermal infrared bands
S7 - F2
Brightness temperature (kelvin)BRIGHTNESS_TEMPERATUREUINT16250 - 320Roughly -20 to +50 C. Can reach outside this range in extreme environments.
dataMaskN/ADNN/A0 - no data
1 - data


All mosaicking types are supported.

Scenes Object

scenes object stores metadata. An example of metadata available in scenes object for Sentinel-3 SLSTR when mosaicking is ORBIT:

Property nameValue

Properties of a scenes object can differ depending on the selected mosaicking and in which evalscript function the object is accessed. Working with metadata in evalscript user guide explains all details and provides examples.

Catalog API Capabilities

To access Sentinel 3 SLSTR product metadata you need to send search request to our Catalog API. The requested metadata will be returned as JSON formatted response to your request.

Collection identifier: sentinel-3-slstr

Filter extension

Distinct extension

  • date
  • sat:orbit_state


S3SLSTR examples