PO.DAAC is pleased to announce the publication of new CYGNSS Level 3 Soil Moisture Version 1.0 data. The product originally covered the period from 18 March 2017 to 16 August 2020, but it is now covering data up to the present with an approximate forward production latency of 1 to 6 days (nominally under 2 days).
The CYGNSS soil moisture dataset provides daily and sub-daily estimates of surface soil moisture in netCDF-4 format at a 6-hour discretization for most of the subtropics. It was derived from the CYGNSS L1 SDR v2.1 by investigators at the University Corporation for Atmospheric Research (UCAR) and the University of Colorado at Boulder (CU). Their algorithm uses collocated soil moisture retrievals from SMAP to calibrate CYGNSS observations from the same day. For a given location, a linear relationship between the SMAP soil moisture and CYGNSS reflectivity is determined and used to transform all the CYGNSS observations into soil moisture.
Within this dataset are two soil moisture variables that report the volumetric water content in units of cm3/cm3. The variable SM_subdaily includes up to four soil moisture estimates per day, and SM_daily provides a daily average. The data producers (Chew and Small, 2020) have provided these data as a preliminary release on behalf of the CYGNSS Science Team, and as such, data users are advised to use caution when interpreting these data.
Citation: CYGNSS. 2020. CYGNSS Level 3 Soil Moisture from UCAR/CU Version 1.0. Ver. 1.0. PO.DAAC, CA, USA. Dataset accessed [YYYY-MM-DD] at https://doi.org/10.5067/CYGNU-L3SM1
Reference: Chew, C. C. and E. E. Small. 'Description of the UCAR/CU Soil Moisture Product'. Remote Sens. 2020, 12, 1558. https://doi.org/10.3390/rs12101558.
Access: Users are encouraged to use the PO.DAAC Data Downloader/Subscriber (https://github.com/podaac/data-subscriber) to download the data.