A unique 40-year long soil moisture data set, version 4.5, 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); 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). 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. The most important differences between v4.4 and earlier versions like v4.2 and v3.2 can be found in the Executive Summary. Version v4.5 is identical to v4.4 with respect to the processing used.
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 v4.5. Currently data sets "ACTIVE" and "PASSIVE" are only available on request.
Last data set update at ICDC: February 14, 2020.