diff --git a/modules/util/viirs_surfrad.py b/modules/util/viirs_surfrad.py
index 8652a820ac9964a64e6dd766baff78c91d81e2b7..0f8b0b76ca4c7070dda315c23c08bfb024059089 100644
--- a/modules/util/viirs_surfrad.py
+++ b/modules/util/viirs_surfrad.py
@@ -40,7 +40,7 @@ solzen_name = group_name_m + 'solar_zenith'
 label_params = [group_name_i+target_param]
 data_params = [group_name_m+'temp_11_0um', group_name_m+'refl_0_65um', group_name_m+target_param]
 param_idx_m = data_params.index(group_name_m + target_param)
-param_idx_i = data_params.index(group_name_i + target_param)
+param_idx_i = label_params.index(group_name_i + target_param)
 
 
 def is_missing(p_idx, tile):