2012 Annual Report 1a.Objectives (from AD-416): Project seeks to gain membership on the NASA SMAP mission science definition team. The science definition team will provide science feedback on SMAP mission design issues. 1b.Approach (from AD-416): We will run a series of data assimilation experiments to aid in SMAP algorithm development and inform SMAP mission trade-offs. 3.Progress Report: Work is continuing on the development of long-term (8-year) observing system simulation experiment over North America (using the Soil Moisture Active/Passive (SMAP) algorithm test bed). This experiment has led to the generation of a synthetic SMAP Level 3 soil moisture product which is currently being used to clarify the relationship between various soil moisture evaluation metrics and expected error sources in SMAP surface soil moisture retrievals. This work will aid in the development of viable agricultural and hydrologic applications for SMAP soil moisture products following its anticipated launch in October 2014.