SMOS Data Products
This page provides a structured access to all available information related to the SMOS mission data products.
The links in the following tables provides a quick access to the main resources.
| Access to SMOS data | SMOS data availability | SMOS data reader software |
| To access SMOS data see here | For SMOS data availability see here | For SMOS data reader software see here |
| The SMOS Data Products information brochure in PDF is available here | ||
| The access to the SMOS data portal is available here | ||
| SMOS data products quality information is available here | ||
The following SMOS data products description provides detailed information and links to exhaustive documentation: read-me-first notes, Algorithm Theoretical Baseline Documents, Product Specification Documents and Data Quality Reports. The definition of the data products is based on the the CEOS (Committee on Earth Observation Satellites) conventions.
Raw data
These are SMOS Payload data in their original format (CCSDS packets) comprised of instrument observation data and housekeeping telemetry, as received from the satellite.
Level 0 data products
These are SMOS payload data in so-called Source Packets with added Earth Explorer product headers. They are chronologically sorted by Source Packet type: Observation Data and Housekeeping Telemetry. Detailed description of the SMOS L0 data format is available in the Level 0 data product specifications document (PDF).
Level 1 data products
The level 1 data products are for scientific users and are generated by the L1OP Processor integrated in the Data Processing Ground Segment. They are available in Earth Explorer format from the SMOS data portal.
| Level 1A data products | Level 1B data products | Level 1C data products |
| Reformatted and calibrated observation and housekeeping data in engineering units. Scientific SMOS Level 1A products are the so-called calibrated visibilities between the individual antenna receivers prior to applying image reconstruction, and in full polarisation. | Output of the image reconstruction of the SMOS observation measurements and consist of Fourier components of brightness temperatures in the antenna polarisation reference frame. | Multi-incidence angle brightness temperatures at the top of the atmosphere, geolocated in an equal-area grid system (15Km, ISEA 4H9 grid). Separate dataset are available for sea and land pixels. Information is available per pixel and per snapshot. For each Level 1C product there is also a browse product containing the brightness temperatures averaged for an incidence angle of 42.5°. |
| For further information about the level 1 processing algorithms see the Data Processing Model documents: | ||
| SMOS L1A Data Processing Model Document (PDF) | SMOS L1B Data Processing Model Document (PDF) | SMOS L1C Data Processing Model Document (PDF) |
| Detailed descriptions of the SMOS L1 data format is available in the Level 1 and Auxilliary Data Product Specification Document (PDF) | ||
| For Level 1 product quality status see the SMOS data products quality page | ||
Previous level 1 data products V505 read-me-first note is available here
Level 1 Near Real Time data products
The level 1 Near Real Time (NRT) data products are similar to the L1C product but adjusted to requirements of operational meteorological agencies. The NRT products are generated by the NRT Processor integrated in the Data Processing Ground Segment in BUFR format. NRT data is available from ESA, NRT light is available from SMOS data portal, EUMETCast Europe and WMO GTS within three hours from sensing time.
For an optimal exploitation of the current SMOS L1 data set V620 consult the read-me-first note available here.
| NRT product | NRT light product |
| Multi-incidence angle brightness temperatures at the top of the atmosphere, geolocated in an equal-area grid system (15Km, ISEA 4H9 grid) with reduced spatial resolution over the Ocean (30Km ISEA 4H8 grid). | Multi-incidence angle brightness temperatures at the top of the atmosphere, geolocated on a N256 gaussian grid with a spatial resolution in the range of 30 - 50 Km. The product consist of Land pixel only. |
| Detailed description of the SMOS L1 NRT data format is available in the product specifcations documents: NRT Product Format Specifications Document (PDF) and NRT BUFR Speciifcation (PDF) | |
Level 2 data products
The level 2 data products are for scientific users and are generated by the L2OP Processors integrated in the Data Processing Ground Segment. They are available in Earth Explorer format and netCDF format from the SMOS data portal.
For an optimal exploitation of the current SMOS L2 data set V6 consult the read-me-first notes available for V650 soil moisture data and V662 sea surface salinity data.
| Level 2 soil moisture data product | Level 2 sea surface salinity data product |
| The product contains the retrieved swath-based soil moisture, vegetation optical depth and other ancillary data derived during the processing (surface temperature, roughness parameter, dielectric constant, brightness temperature at the top of the atmosphere and at the surface) with their corresponding uncertainties. | The product contains one single swath based Sea Surface Salinity (SSS) retrieved with and without Land-Sea contamination correction, SSS anomaly based on WOA-2009 referred to Land-Sea corrected SSS, brightness temperature at the top of the atmosphere and at the sea surface with their corresponding uncertainties. |
| For further information about the level 2 processing algorithms see the Algorithm Theoretical Basis documents: | |
| SMOS L2 SM Algorithm Theoretical Basis Document (ATBD) | SMOS L2 OS Algorithm Theoretical Basis Document (ATBD) |
| SMOS L2 Sea Surface Salinity Processor maintainer's website | |
| Detailed descriptions of the SMOS L2 data format is available in the Level 2 and Auxilliary Data Product Specification Document (PDF) | |
| For Level 2 product quality status see the SMOS data products quality page | |
Previous level 2 SM data products V620 read-me-first note is available here
Previous level 2 SM data products V551 read-me-first note is available here
Previous level 2 OS data products V622 read-me-first note is available here
Previous level 2 OS data products V550 read-me-first note is available here
Level 2 Soil Moisture Near Real Time Neural Network data
The Soil Moisture Near Real Time Neural Network product (SM-NRT-NN) provides fast access (within four hours from sensing time) of soil moisture measurements. The soil moisture is retrieved from the multi-angular brightness temperature as available inside the SMOS level 1 Near Real Time BUFR product. The retrieval is based on a neural network schema trained using the level 2 soil moisture data set generated by the operational L2 soil moisture processor V620. The SM-NRT-NN product is avaialble from EUMETCast Europe, WMO GTS and SMOS data portal in netCDF format.
For an optimal exploitation of the current SM-NRT-NN product v200 consult the read-me-first note available here.
| Soil Moisture NRT Neural Network product | ||
| The product contains the retrieved swath-based soil moisture and its uncertainty on the SMOS ISEA 4H9 grid for a slightly reduced swath width of about 915 Km. | ||
| Detailed description of the SMOS L2 SM-NRT-NN data format is available in the read-me-first note available here. | ||
Previous level 2 SM-NRT-NN data products v100 read-me-first note is available here.
Level 3 Sea-ice product
The level 3 sea-ice product is derived from ESA L1C product. The sea-ice thickness is retrieved up to a depth of ~ 0.5-1 m, depending on the ice temperature and ice salinity. The product is complementary with sea-ice thickness measurements from ESA's CryoSat-2 and Sentinel-3 missions. Daily maps are disseminated with a latency of about 24 hours. The product is available in netCDF format from the SMOS data portal.
| Sea-ice thickness product | ||
| The product contains daily map of sea-ice thickness for the thinner and younger ice at the edge of the Arctic Ocean, during the period October-April with a grid resolution of 12.5 km onto a polar-stereographic projection | ||
| Detailed description for the SMOS level 3 sea-ice thickness retrieval algorithm and product format is available here. | ||
Level 3 and 4 data products
For Sea Surface Salinity and Soil Moisture level 3 and 4 data products see the national French and Spanish processing entities: Centre Aval de Traitement des Données SMOS (CATDS) and SMOS CP34.
Auxiliary data
Level 1 auxiliary data
This type of data comprises the Discrete Global Grid (DGG), the land-sea mask, flat target transformation measurements, known RFI (Radio Frequency Interference) sources, etc.
Level 2 soil moisture auxiliary data
These static or dynamically updated auxiliary files contain information needed for generating soil moisture products, such as ECOCLIMAP surface cover information, ECMWF forecast geophysical fields, vegetation optical thickness, etc.
Level 2 ocean salinity auxiliary data
These datasets are used for generating ocean salinity products. Examples include ocean target transformation lookup tables, roughness information, long-term salinity climatologies, etc. More information/downloads: https://smos.argans.co.uk/
Related Links
Related (Key) Documentation
Related Software Tools