DESCRIPTION: SM-DAS-2
Profile Index in the roots region by scatterometer data assimilation

SM-DAS-2 is the H-SAF root zone soil moisture index product, retrieved by scatterometer assimilation in a the ECMWF Land Data Assimilation System.

SM-DAS-2 production chain based on ASCAT surface soil moisture data assimilation in the ECMWF Land Data Assimilation System:

Product description

In the soil moisture assimilation system, the surface observation from ASCAT is propagated towards the roots region down to 2.89 m below surface, providing estimates for 4 layers (thicknesses 0.07, 0.21, 0.72 and 1.89 m). The ECMWF model generates soil moisture profile information according to the Hydrology Tiled ECMWF Scheme for Surface Exchanges over Land (HTESSEL). SM-DAS-2 is available at a 24-hour time step, with a global daily coverage at 00:00 UTC. SM-DAS-2 is produced in a continuous way in order to ensure the time series consistency of the product (and also to provide values when there is no satellite data, from the model propagation). The SM-DAS-2 product is the first global product of consistent surface and root zone soil moisture available NRT for the NWP, climate and hydrological communities. It has been produced in Near Real Time since 01 January 2012 (Contact H-SAF or ECMWF to get the SM-DAS-2 product) and will be declared as an operational H-SAF product by the end of 2012. August 2010.

  • Coverage: SM-DAS-2 is a Global Product
  • Cycle: 24 hours regular: daily at 0000 UTC
  • Resolution: Horizontal: 25 km (T799) Vertical (below surface): 4 layers: 0-7 cm, 7-28 cm, 28-100 cm, 100-289 cm
  • Accuracy: The H-SAF global soil moisture products SM-OBS-1 and SM-DAS-2 are evaluated and compared with the SMOS level 2 soil moisture product in "Comparison between H-SAF large scale surface soil moisture, H-SAF assimilated soil moisture and SMOS level 2 soil moisture", by Gruhier et al. (2011). Evaluation of the three products against ground data from more than 200 stations accross the world was conducted in Albergel et al (2011).
  • Timeliness: 36 h
  • Dissemination: Initially by ftp to ZAMG. Available on H-SAF ftp site
  • Formats: Grib-1

Satellites and instruments to be used pre-operationally during the Development Phase

  • MetOp ASCAT : 5.3 GHz (C-band), resolution 50 and 25 km, basic sampling 12.5 km

Satellites and instruments used experimentally during the Development Phase

  • ERS-1/2 AMI-SCAT : 5.3 GHz (C-band), resolution 50 and 25 km (after reprocessing)

Satellites and instruments to be used during the Operational Phase

  • MetOp ASCAT : 5.3 GHz (C-band), resolution 50 and 25 km, basic sampling 12.5 km

Non-satellite supporting information (ancillary/auxiliary for processing, or used for verification)

Soil, land cover and vegetation maps, Orography, Atmospheric analyses from ECMWF's operational Integrated Forecast System Conventional SYNOP station data, soil moisture observations from regional networks