diff --git a/modules/amv/caliop_clavrx_amv.py b/modules/amv/caliop_clavrx_amv.py
index e4cda1c2f3876f67f7d18c263e2ac9bf987575a5..be450bf0325013e63cf814b563f64149ed8edb5e 100644
--- a/modules/amv/caliop_clavrx_amv.py
+++ b/modules/amv/caliop_clavrx_amv.py
@@ -109,8 +109,11 @@ def match_calipso_clavrx_to_amvs(calipso_clavrx_ds, calipso_clavrx_file, amv_fil
         calipso_clavrx_data.append(calipso_clavrx_nc4[pname][:])
     lat_s = calipso_clavrx_nc4['latitude'][:]
     lon_s = calipso_clavrx_nc4['longitude'][:]
-    xs = calipso_clavrx_nc4['x'][:]
-    ys = calipso_clavrx_nc4['y'][:]
+    if calipso_clavrx_ds.variables.get('x') is None:
+        xs, yx = nav.earth_to_lc_s(amv_lons, amv_lats)
+    else:
+        xs = calipso_clavrx_nc4['x'][:]
+        ys = calipso_clavrx_nc4['y'][:]
     clvr_xy_s = zip(xs, ys)
 
     for idx, clvr_xy in enumerate(clvr_xy_s):