A unique 38-year long soil moisture data set, version 4.2, has been generated in the framework of the ESA-CCI Soil Moisture ECV project. For this purpose C-band scatterometer data (ERS-1/2 AMI scatterometer, MetOp Advanced Scatterometer) and multi-frequency radiometer data (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) (ATBD for SM retrieval from active MW sensors); the second strand comprises soil moisture retrieved using satellite microwave radiometry (ATBD for SM retrieval from passive MW sensors). Data products from each strand are first merged separately together with a sophisticated uncertainty characterization, before finally the active and the passive microwave data products are merged (ATBD of the merging process). The approach makes best use of already established Level 2 services of ESA, EUMETSAT, NASA, JAXA, etc. for the different satellites and sensors. The most important differences between v04.2 and earlier versions can be found in the Executive Summary.
For more information regarding retrieval schemes we refer to our 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: http://www.esa-soilmoisture-cci.org/).
We DEFINITELY recommend all interested users to register at the respective ESA web site http://www.esa-soilmoisture-cci.org/ to not miss information about updates of the data set.
We are offering the daily "COMBINED" data set v04.2. Currently data sets "ACTIVE" and "PASSIVE" are only available on request.
Last data set update at ICDC: April 5, 2018.