SMOS-IC data record of soil moisture and L-VOD: Historical development, applications and perspectives

Passive microwave remote sensing observations at L-band provide key and global information on surface soil moisture and vegetation water content, which are related to the Earth water and carbon cycles. Only two space-borne L-band sensors are currently operating: SMOS, launched end of 2009 and thus providing now a 10-year global data set and SMAP, launched beginning of 2015. This study provides a state-of-the-art scientific overview of the SMOS-IC retrieval data set based on the SMOS L-band observations. This SMOS product aims at improved performance and independence of auxiliary data, key features for robust applications. The SMOS-IC product includes both a soil moisture (SM) and a L-band vegetation optical depth (L-VOD) data set which are currently at the basis of several studies evaluating the impact of climate and anthropogenic activities on aboveground carbon stocks. Since the release of the first version, the algorithm has been significantly changed in support to key applications, but no document is available to report these changes. This paper fills this gap by analyzing key science questions related to the product development, reviewing application results and presenting an extensive description of the last version of the product (version 2) considering changes in comparison to the previous version (V105). For the future it is planned to merge the SMOS and SMAP L-VOD data sets to ensure L-VOD data continuity in the event of failure of one of the space-borne SMOS or SMAP sensors.

Automated summary

This study provides an overview of the SMOS-IC retrieval data set, discussing its importance in research and applications, introducing the latest version of the product and its improvements. It also outlines the plan to merge the SMOS and SMAP L-VOD data sets for data continuity in the future.