diff --git a/src/gsi-ncdiag/gsi_ncdiag.py b/src/gsi-ncdiag/gsi_ncdiag.py
index d0effe983..21e0e7662 100644
--- a/src/gsi-ncdiag/gsi_ncdiag.py
+++ b/src/gsi-ncdiag/gsi_ncdiag.py
@@ -1245,7 +1245,7 @@ def toIODAobs(self, OutDir, ObsBias, QCVars, TestRefs, clobber=True):
         try:
             obserr = self.var('Input_Observation_Error')
         except IndexError:
-            obserr = 1./self.var('Inverse_Observation_Error')
+            obserr = np.repeat(self.var('error_variance'), nlocs, axis=0)
         obsqc = self.var('QC_Flag').astype(np.int32)
         if (ObsBias):
             nametbc = [