diff --git a/modules/util/acspo_validate.py b/modules/util/acspo_validate.py
index f58923f4e091945f2184898721f0d9d5f123849e..bf0446d6fdbcbfaaf1c1ad95b1dcf4f00e58e2c3 100644
--- a/modules/util/acspo_validate.py
+++ b/modules/util/acspo_validate.py
@@ -28,17 +28,15 @@ def acspo_validate(oper_file, cspp_file, rel_tol=0.001, outfile_nc=None):
     sst_oper = get_grid_values_all(h5f_oper, 'sea_surface_temperature')[0, ]
     l2p_flags_oper = get_grid_values_all(h5f_oper, 'l2p_flags')[0, ]
 
-    # generate a ndarray of boolean
+    # generate a ndarray of boolean, True: clear or probably clear
     cspp_clear = (l2p_flags_cspp & (1 << 15)) == 0
     oper_clear = (l2p_flags_oper & (1 << 15)) == 0
 
-    start_idx_oper = -1
-    stop_idx_oper = -1
-    start_idx_cspp = -1
-    stop_idx_cspp = -1
+    start_idx_oper, stop_idx_oper = -1, -1
+    start_idx_cspp, stop_idx_cspp = -1, -1
 
     for k in range(len(cntr_lat_oper)):
-        c_a = np.isclose(cntr_lat_oper[k], cntr_lat_cspp)
+        c_a = np.logical_and(np.isclose(cntr_lat_oper[k], cntr_lat_cspp), np.isclose(cntr_lon_oper[k], cntr_lon_cspp))
         if np.size(np.nonzero(c_a)[0]) == 1:
             if start_idx_oper == -1:
                 start_idx_oper = k