This session highlights advances in development and applications of land data assimilation systems (LDAS), which merge ground- or satellite-based land surface observations with estimates from coupled or “off-line” land surface models, and can be used to initialize weather and seasonal climate forecasts, monitor and predict extreme events, provide improved background information for atmospheric data assimilation, improve process understanding, and support model development. Contributions may include studies that evaluate or improve land DA methods, assess LDAS impact on state estimates, or use LDAS for the above-mentioned applications. Contributions may address the simultaneous assimilation of multiple observation types, and use of current and planned hydrology satellite missions (e.g. SMOS, SMAP and SWOT). Contact(s): Mike Ek (Michael.Ek@noaa.gov), Youlong Xia (Youlong.Xia@noaa.gov), Rolf Reichle (Rolf.Reichle@nasa.gov), and Susan Steele-Dunne (s.c.steele-dunne@tudelft.nl)