diff --git a/src/ich/args_in.py b/src/ich/args_in.py
index 7c2989de3ad5f85d3011191972960f38cd7c144a..767776e5b1e58ba3b938059a0efa6eb757eff9e7 100644
--- a/src/ich/args_in.py
+++ b/src/ich/args_in.py
@@ -204,7 +204,8 @@ def rvog_inverse(args):
             ht_ = unblockshaped(np.array(ht_), rows,cols)
             count = unblockshaped(np.array(count), rows,cols)            
             temp_cor = unblockshaped(temp_cor, rows,cols)
-
+            
+            temp_mask[temp_mask==0]=np.nan
             s = s*temp_mask
             c = c*temp_mask