now scaling covariance matrix

da/ctgridded/statevector.py

@@ -80,6 +80,8 @@ class CtGriddedStateVector(StateVector):
                 cov         = 0.16 *np.dot(cov_ocn,cov_ocn)
             else: 
                 cov         = f.GetVariable('covariance')
+                cov_sf      = 1./np.sqrt(cov.diagonal().sum())  # this scaling factor makes the total variance close to the value of a single ecoregion
+                cov         = cov*cov_sf
 
             dummy   = f.close()