Sentinel-3 OLCI L1B

About Sentinel-3 OLCI 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 4 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 OLCI instrument was designed to provide data continuity with the Medium Resolution Imaging Spectrometer (MERIS) instrument flown on Envisat. With its 21 spectral bands ranging from the visible to the near-infrared, the primary objective of the instrument is to measure information related to biology, including the monitoring of ocean colour, algae blooms, and land cover. The additional 6 bands compared to MERIS allow improved Atmospheric Composition measurements. The OLCI swath is not centred at nadir in order to mitigate the effects of sun glint.

Level-1B provides calibrated, ortho-geolocated and spatially re-sampled Top Of Atmosphere (TOA) radiances for the 21 OLCI spectral bands.

More information:

• https://sentinel.esa.int/web/sentinel/missions/sentinel-3
• Collection user guide

Basic facts

For processing Sentinel-3 OLCI we use the full resolution lat/lon grid from the OLCI L1B products so pixel positioning is exact.

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 OLCI L1B 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 S3OLCI data. To see examples of such requests go here, and for an overview of all API parameters see the API Reference.

Endpoint Locations

Data type identifier: sentinel-3-olci

Use sentinel-3-olci (previously S3OLCI) as the value of the input.data.type parameter in your API requests. This is mandatory and will ensure you get Sentinel-3 OLCI L1B data.

Filtering Options

This chapter will explain the input.data.dataFilter object of the S3OLCI process API.

mosaickingOrder

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.

Processing Options

This chapter will explain the input.data.processing object of the S3OLCI process API.

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.

*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 OLCI bands, visit this Copernicus website.

Units

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.

Mosaicking

All mosaicking types are supported.

Scenes Object

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

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 OLCI 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.

Endpoint Locations

Collection identifier: sentinel-3-olci

Distinct extension

• date

Examples

S3OLCI examples