SMOS-IC includes both a product of soil moisture (SM) and L-band vegetation optical depth (L-VOD) at a resolution of 25 x 25 km
The SMOS-IC algorithm corresponds to the SMOS “original algorithm” i.e. the two parameter (SM and L-VOD) inversion of the L-MEB model that was proposed in the SMOS project submitted to ESA and was already described back in Wigneron et al. (2000, 2007).Model parameter optimisation was evaluated in Fernandez Moran et al., 2017b; First version (V105) was presented and evaluated at global scale by Fernandez Moran et al., 2017a. The most recent version (V2) was developed by the INRAE-Bordeaux (IB) Remote Sensing Lab, Wigneron, J.-P., Li, X., Frappart F., Fan L., Al-Yaari A., De Lannoy G., Liu X., Wang M., Le Masson E., Moisy C., SMOS-IC data record of soil moisture and L-VOD: historical development, applications and perspectives, Remote Sens. Env., 254, 112238, https://doi.org/10.1016/j.rse.2020.112238, 2021.
Key Features: -SMOS-IC is independent of modelled SM data (ECMWF and NOAH mdoel) and vegetation optical indices (LAI, NDVI, EVI), thus avoiding circular evaluation/validation and making it indepedent and robust in (i) evaluation against modelled SM data and RS-derived biomass/height data base (ii) analysis of long term trends, (iii) model assimilation -The SMOS-IC L-VOD / SM products have been recently used, within the framework of many international collaborations, in studies investigating the water and carbon cycles at continental scales and published in Nature Ecology Evolution, Nature Plants, Nature Communications, SCience Advances, etc.
Performances: past and ongoing studies showed that the IC product compares very well with/or outperforms, the other microwave products for both SM (Fernandez-Moran et al., 2017, A. Al-Yaari et al., 2019, Quets et al., 2017, Ma et al., 2020, Dong et al., 2020, etc.) and L-VOD (Fernandez-Rodriguez et al., 2018).
Product. SMOS-IC provides global gridded (EASE grid 2) daily SM (m3/m3) and VOD in the NetCDF format with a ~25 km cylindrical projection (ascending and descending overpasss at 0600 a.m. and 0.600 p.m. Local Solar Time, respectively). The current version is V200 (processed end of 2020) and has a global coverage. The version V105 of SMOS-IC SM is no longer available.
All data available after registration are public, according to the CC-BY 4.0 license.
SMOS-IC V2 product Documentation
- ASCAT IB VOD
ASCAT IB VOD was developed by the INRAE-Bordeaux (IB) Remote Sensing Lab (Liu et al., 2021, in review). ASCAT IB VOD is the active C-band vegetation optical depth (C-VOD) retrieved from ASCAT at a resolution of 25 x 25 km. The data was retrieved based on the Water Cloud Model (WCM) coupled with the Ulaby linear model.
ASCAT IB VOD product documentation
- AMSR2 IB XVOD
AMSR2 IB X-VOD is a passive X-band vegetation optical depth (X-VOD) product retrieved from AMSR2 (the Advanced Microwave Scanning Radiometer 2) brightness temperature observations. It was developed by the INRAE-Bordeaux (IB) Remote Sensing Lab and based on the inversion of the X-MEB model (X-band microwave emission of the biosphere) (Wang et al., 2021). The X-MEB model is an extension of the L-MEB model (Wigneron et al., 2007; Fernandez-Moran et al., 2017) to the X-band.