 

Field
CLM/WFDEI soil moisture 010cm
CLM output
X axis: whole world in 720 0.50° steps, first point at 0.25° E, last point at 359.75° E Y axis: regular grid with 360 0.50° steps, first point at 89.75° S, last point at 89.75° N Z at 1.00 level Monthly data available from Jan1979 to Dec2013 ( 420 months) Variable SOILLIQ (soil liquid water 010cm) in kg/m^2 Full metadata. Construct a statistical forecast model from this field Compute anomalies
Compute zonal mean
If you really want to get it here, CLM/WFDEI soil moisture 010cm is available as a netcdf file (size 109.414 MB). 
© KNMI
