Soil moisture from ESA-CCI
Topics
- Access
- Description
- Parameters
- Coverage, spatial and temporal resolution
- Data quality
- Contact person
- References
- Data citation
Access
RESTRICTED: This link to the data set is only available for a restricted user group. The data set is only accessible in CEN/MPI net or accessible from external nets with a customer account. Please contact ICDC if you would like to access this data from outside the network.
- View soil moisture data at LAS
- Access soil moisture data via OPeNDAP
- Data access via file system: /data/icdc/land/esa_cci_soilmoisture
Description
A unique > 40-year long soil moisture data set, version 9.1, has been generated in the framework of the ESA-CCI Soil Moisture ECV projects. For this purpose C-band scatterometer data (among others: ERS-1/2 AMI scatterometer, MetOp Advanced Scatterometer) and multi-frequency radiometer data (among others: SMAP, SMOS, SMMR, SSM/I, TMI, AMSR-E, Windsat, AMSR2) are used to compute the soil moisture.
For the completely re-processed data set offered here, different (Level 2) soil moisture (SM) data sets are merged together. One strand of data comprises soil moisture retrieved using satellite active microwave data (C-Band scatterometers, see above); the second strand comprises soil moisture retrieved using satellite microwave radiometry. Data products from each strand are merged directly, together with a sophisticated uncertainty characterization (see ATBD in references). The approach makes best use of already established Level 2 services of ESA, EUMETSAT, NASA, JAXA, etc. for the different satellites and sensors. From the two separate strands of data two additional data products are generated. This new version v7.1 differs from the predecessors by a new processing scheme and continued updated usage of more recent relevant satellite observations.
For more information regarding retrieval schemes we refer to the ICDC web pages of ASCAT soil moisture, AMSR-E soil moisture, SMOS soil moisture as well as to the extensive number of documents created during the ESA-CCI Soil Moisture ECV project (see ESA CCI Soil Moisture website in references ).
We strongly recommend all interested users to register at the respective ESA web site (see references) to not miss information about updates of the data set. We recommend to regularly check the ESA CCI Soil Moisture website (see references) for updated information from the ESA-CCI Soil Moisture ECV project.
We are offering the daily "COMBINED" data set version v09.1.
Last update of data set at ICDC: August 14, 2025.
Parameters
| Name | Unit | Comment |
|---|---|---|
| Volumetric soil moisture | m³ / m³ | 0 ... 1 |
| Error of Volumetric soil moisture | m³ / m³ | 0 ... 1 |
| Day/Night flag | - |
|
| Quality flag data gaps | - | 0 ... 31 (0 = best quality) |
| Frequency band flag | - | 0 ... 130 (L to Ka-Band, single bands and combinations) |
| Satellite orbit flag | - |
|
| Sensor flag | - | 0 ... 1888 (single sensors and combinations) |
| Time | Days since 1970-01-01 00 UTC |
Coverage, spatial and temporal resolution
Period and temporal resolution:
- 1978-11-01 to 2023-12-31
- Daily
Coverage and spatial resolution:
- Global
- Spatial resolution: 0.25° x 0.25°, cartesian grid
- Geographic latitude: 89.875°S to 89.875°N
- Geographic longitude: 179.875°W to 179.875°E
- Dimension: 720 rows x 1440 columns
- Altitude: following terrain
Format:
- NetCDF
Data quality
Each file of the data set contains an uncertainty estimate (when observations from at least two sensors are merged) and a set of quality flags which basically document the reason why data have been discarded from the data set (see parameters); in addition each file gives information about the sensors used. Beginning with version v08.1 the uncertainty estimates obtained through Triple Collocation Analysis and the resulting merging weights are generated on a seasonal basis. The product uncertainty is therefore more representative of seasonal errors in the soil moisture retrieval.
The barren ground flagging strategy has been changed to a majority decision, where at least 50% + 1 of the observing sensors need to raise the flag. The flag is kept optional, i.e., the soil moisture data is not masked.
We note, that soil moisture retrieval is less reliable and/or impossible in regions of pronounced topography, in case of standing water, and in areas of dense vegetation. For snow covered areas and frozen soil a soil moisture retrieval is also not possible.
Substantial gaps occur in the data set - particularly during the initial years of the time series. These stem from the fact that the used satellite sensors only view a limited portion of the Earth's surface during their overpasses during one day.
We recommend to take a look at the documents in the references for more details about data quality, validation, and inter-comparison studies and to regularly check the ESA CCI Soil Moisture website (see references) for updated information from the ESA-CCI Soil Moisture ECV project.
Contact
Vienna University of Technology, Austria
Transmissitivity B.V. / VanderSat B.V. Noordwijk, The Netherlands
email: ecv_sm_contact (at) eodc.euRichard Kidd
Vienna University of Technology
Vienna, Austria
email: richard.kidd (at) geo.tuwien.ac.atStefan Kern
University of Hamburg
email: stefan.kern (at) uni-hamburg.de
References
Literature:
- Product User Guide for v09.1
- Product Validation and Intercomparison Report for v09.1
- Algorithm Theoretical Baseline Document (ATBD), v09.0
- Gruber, A., et al., 2017, Triple Collocation-Based Merging of Satellite Soil Moisture Retrievals, Transactions on Geoscience and Remote Sensing, 55(12), 1-13. doi:10.1109/TGRS.2017.2734070. https://doi.org/10.1109/TGRS.2017.2734070
- Gruber, A., et al., 2019, Evolution of the ESA CCI soil moisture climate data records and their underlying merging methodology, Earth System Science Data, 11, 717-739, https://doi.org/10.5194/essd-11-717-2019.
- Dorigo, W. A., et al., 2017, ESA CCI Soil Moisture for improved Earth system understanding: State-of-the art and future directions, Remote Sensing of Environment, 203, 185-215, 2017, doi:10.1016/j.rse.2017.07.001., https://doi.org/10.1016/j.rse.2017.07.001
- Dorigo, W. A., et al., 2015, Evaluation of the ESA CCI soil moisture product using ground-based observations, Remote Sensing of Environment, 162, 380-395, doi:10.1016/j.rse.2014.07.023. https://doi.org/10.1016/j.rse.2014.07.023
- Zeng, J., et al., 2015, Evaluation of Remotely Sensed and Reanalysis Soil Moisture Products over the Tibetan Plateau using in situ Observations, Remote Sensing of Environment, 163, 91-110, doi:10.1016/j.rse.2015.03.008. https://doi.org/10.1016/j.rse.2015.03.008
- Jing, W., et al., 2018, A comparison of ECV and SMOS soil moisture products based on OzNet monitoring network, Remote Sensing, 10(5), 703, doi:10.3390/rs10050703, https://doi.org/10.3390/rs10050703
Websites:
- ESA CCI Soil Moisture website, http://www.esa-soilmoisture-cci.org/
- Terms and Conditions at the ESA CCI Soil Moisture Website: https://www.esa-soilmoisture-cci.org/node/236
Data citation
Please cite the data as follows:
Dorigo, W.; Preimesberger, W.; Hahn, S.; Van der Schalie, R.; De Jeu, R.; Kidd, R.; Rodriguez-Fernandez, N.; Hirschi, M.; Stradiotti, P.; Frederikse, T.; Gruber, A.; Duchemin, D. (2024): ESA Soil Moisture Climate Change Initiative (Soil_Moisture_cci): Version 09.1 data collection. NERC EDS Centre for Environmental Data Analysis, date of citation. http://catalogue.ceda.ac.uk/uuid/779f116d0477439db1874592add5848c
And the data set should be cited using the complete three references as follows:
Last data accessed by ICDC from ftp.geo.tuwien.ac.at on July 14, 2025.
- Gruber, A., et al., 2019, Evolution of the ESA CCI soil moisture climate data records and their underlying merging methodology, Earth System Science Data, 11, 717-739, http://doi.org/10.5194/essd-11-717-2019.
- Dorigo, W. A., et al., 2017, ESA CCI Soil Moisture for improved Earth system understanding: State-of-the art and future directions, Remote Sensing of Environment, 203, 185-215, 2017, doi:10.1016/j.rse.2017.07.001.
- Preimesberger, W., Scanlon, T., Su, C. -H., Gruber, A. and Dorigo, W., "Homogenization of Structural Breaks in the Global ESA CCI Soil Moisture Multisatellite Climate Data Record," in IEEE Transactions on Geoscience and Remote Sensing, vol. 59, no. 4, pp. 2845-2862, April 2021, doi: 10.1109/TGRS.2020.3012896.