Datasets - Data to be validated

The following datasets can be validated within the QA4SM tool. These datasets are available in the "data" section of the validate page.

Dataset Details Versions supported Time Range Covered Data availability Citation Filters
C3S SM The C3S long-term data record provides active, passive and combined (active+passive) soil moisture data on a daily, dekadal and monthly basis. Observations are provided on a quarter degree grid. For more information, please visit the Climate Data Store. The QA4SM tool supports version v201706 and v201812 of the C3S product. Currently, the COMBINED product (combination of active and passive sensors) is supported. 1978 - 2018 (both versions) The data can be downloaded from the Climate Data Store. See Climate Data Store
  • Valid range:
    Filter soil moisture values to ensure they are within the valid range (between 0 and 1 for the COMBINED product).
  • Use data where flag=0:
    Only use satellite observations where no inconsistencies were detected.
  • Frozen soil or snow-cover:
    Only use soil moisture data from grids cells without no snow cover or frozen soil (flag != 1).
  • Dense vegetation:
    Only use soil moisture data from grids cells without dense vegetation (flag != 2).
  • Ascending mode only:
    Only use satellite observations in ascending mode.
  • Descending mode only:
    Only use satellite observations from descending mode.
ESA CCI SM COMBINED The ESA CCI SM long-term data record provides active, passive and combined (active+passive) on a daily basis. Observations are provided on a quarter degree grid. For more information on the ESA CCI SM product, please see the product homepage. v04.4 1978 - 2018 Register at ESA CCI, then download through FTP. http://www.esa-soilmoisture-cci.org;
Liu, Y.Y., Dorigo, W.A., Parinussa, R.M., de Jeu, R.A.M. , Wagner, W., McCabe, M.F., Evans, J.P., van Dijk, A.I.J.M. (2012). Trend-preserving blending of passive and active microwave soil moisture retrievals, Remote Sensing of Environment, 123, 280-297, doi: 10.1016/j.rse.2012.03.014.;
Liu, Y.Y., Parinussa, R.M., Dorigo, W.A., De Jeu, R.A.M., Wagner, W., van Dijk, A.I.J.M., McCabe, M.F., & Evans, J.P. (2011). Developing an improved soil moisture dataset by blending passive and active microwave satellite based retrievals. Hydrology and Earth System Sciences, 15, 425-436.;
Wagner, W., W. Dorigo, R. de Jeu, D. Fernandez, J. Benveniste, E. Haas, M. Ertl (2012). Fusion of active and passive microwave observations to create an Essential Climate Variable data record on soil moisture. ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume I-7, 2012. XXII ISPRS Congress, 25 August - 01 September 2012, Melbourne, Australia.;
Gruber, A., Dorigo, W. Crow, W., & Wagner, W. (2017). Triple collocation-based merging of satellite soil moisture retrievals. IEEE Transactions on Geoscience and Remote Sensing, 1-13.;
Dorigo, W.A., Wagner, W., Albergel, C., Albrecht, F., Balsamo, G., Brocca, L., Chung, D., Ertl, M., Forkel, M., Gruber, A., Haas, E., Hamer, P. D., Hirschi, M., Ikonen, J., de Jeu, R., Kidd, R., Lahoz, W., Liu, Y. Y.,Miralles, D., Mistelbauer, T., Nicolai-Shaw, N., Parinussa, R., Pratola, C., Reimer, C., van der Schalie, R., Seneviratne, S. I. Smolander, T., Lecomte, P. (2017). ESA CCI Soil Moisture for improved Earth system understanding: State-of-the art and future directions, Remote Sensing of Environment. https://doi.org/10.1016/j.rse.2017.07.001.
See filters specified for the C3S dataset.
SMAP Level 3 SM The NASA SMAP level 3 data set provides global daily soil moisture observations at a 36 km resolution from the SMAP sensor (more information). The QA4SM tool supports version 5 of the SMAP L3 Soil moisture product. 2015 - 2018 The data can be downloaded from the product homepage here. Click here
  • Valid range:
    Observations are filtered to ensure they are within the valid range (between 0 and 1)
H-SAF ASCAT SSM CDR The ASCAT dataset from the EUMETSAT H-SAF portal provides global daily soil moisture observations on a discrete global grid (DGG) with a spatial resolution of 25 km. Observations are provided from the ASCAT instrument on-board both Metop-A and Metop-B (more information). The QA4SM tool supports version H113 of the H-SAF ASCAT SSM CDR product. 2007 - 2017 The data can be downloaded from the product homepage. See section 5.2 of this document
  • Valid range: Filter soil moisture values to ensure they are between 0 and 100.
  • Metop-A observations: Use only observations retrieved using ASCAT on-board Metop-A.
  • Metop-B observations: Use only observations retrieved using ASCAT on-board Metop-B.
  • Soil not frozen (or state not known):
  • No confidence flags raised:
  • No processing flags raised:
SMOS IC The SMOS IC product generated by INRA and CESBIO provides global soil moisture and VOD based on the two parameter inversion of the L-MEB model. The QA4SM tool supports version 105 ascending. 2010 - 2018 The data can be downloaded from the product homepage. See this page.
  • Valid range: Filter soil moisture values to ensure they are between 0 and 1 m3 / m3.
  • Soil moisture values are retrieved and recommended (Quality_Flag == 0)

Datasets - Reference Data

The following datasets can be used as a reference within the QA4SM tool. These datasets are available in the "reference" section of the validate page.

Dataset Details Versions supported Time Range Covered Data availability Citation Filters
ISMN The ISMN provides in-situ soil moisture data from over 2600 monitoring stations worldwide. The data is harmonised and quality controlled to ensure the highest quality data is provided through the portal. Data is provided from 1952 to present day (more information). The ISMN data is downloaded periodically for use in the QA4SM portal, therefore the version number (and data) will change over time. There are currently two versions available within QA4SM: v20180830 and v20190222. Station dependent Data is freely available after registration here. Terms and conditions, readme (v20180830), and readme (v20190222)
  • Quality flag is "good" (G):
    More information on the ISMN quality flags can be found here.
GLDAS GLDAS is a land surface model (LSM) which provides soil moisture data at different depths. Different versions are available for different time periods. For more information, visit the LDAS website: NASA Land Data Assimilation Systems Website Version 2.1 is supported within the QA4SM tool. This dataset covers the period from the start of 2000 to the end of 2017. 2000-2017 Data is freely available after registration here for version 2.1 Click here
  • Frozen soil or snow-cover:
    Only use soil moisture data from grids cells where there is no snow cover or frozen soil.
ERA5 ERA5 is a global reanalysis product provided by ECMWF. It provides global, sub-daily simulations of variables for land, atmosphere and ocean waves. The downloaded original 6-hourly (starting at 0:00 UTC) images of ERA5 Volumetric Soil Moisture with a spatial resolution of 0.25° Lat. * 0.25° Lon were converted into a time series format via daily averages. The ERA5 dataset starts in 1979. The version number used in QA4SM indicates the date when the original data was downloaded. For more details about ERA5 please see ECMWF Confluence - ERA5 Documentation Version 20190613 is a snapshot of the reanalysis dataset from this point in time 1979 - 2018 Data is freely available with a CDS account. See ECMWF Confluence - ERA5 Download Click here
  • Frozen soil:
    Only use soil moisture data from grids cells where there is no frozen soil.