Looking for the perfect soil moisture raster GIS layer? The SMAP project stands for Soil Moisture Active/Passive. This satellite will produce global maps of soil moisture spatial data within the top 5 cm of soil, rather than deriving this data from precipitation and temp data. This satellite will also show specific dates & duration of freeze thaw cycles (a dream for niche modelling of many plants). Launched January 31st 2015, data will probably not be available for some time, but still something to get excited about.
more info here.