Added noise reduction scheme developed by Remco to the NH gridded statevector

da/statevectors/statevectorNHgridded_cteco2.py

@@ -101,6 +101,9 @@ class CO2GriddedStateVector(StateVector):
                 cov = f.get_variable('covariance')
                 parnr = f.get_variable('parameternumber')
                 cov_sf = 90.0 / np.sqrt(cov.diagonal().sum())  # this scaling factor makes the total variance close to the value of a single ecoregion
+                covlim = 15.    # limit covariances for small ecoregions, which otherwise give very large uncertainties		
+                if cov_sf > covlim:
+                    cov_sf = covlim
                 cov = cov * cov_sf
 
             f.close()