diff --git a/definitions/mars/grib.eefo.pfc.def b/definitions/mars/grib.eefo.pfc.def
index 04adb5a22..c1bc2b6bd 100644
--- a/definitions/mars/grib.eefo.pfc.def
+++ b/definitions/mars/grib.eefo.pfc.def
@@ -1,5 +1,3 @@
-alias mars.number = perturbationNumber;
-
 alias mars.step = stepRange;
 
 # We need this because 'postProcessing' is defined later
diff --git a/definitions/mars/grib.eefo.ppm.def b/definitions/mars/grib.eefo.ppm.def
index 9129cbcd8..a8c09a96e 100644
--- a/definitions/mars/grib.eefo.ppm.def
+++ b/definitions/mars/grib.eefo.ppm.def
@@ -1,5 +1,3 @@
-alias mars.number = perturbationNumber;
-
 alias mars.step = stepRange;
 
 # We need this because 'postProcessing' is defined later
diff --git a/definitions/mars/grib.enfo.pfc.def b/definitions/mars/grib.enfo.pfc.def
index 04adb5a22..c1bc2b6bd 100644
--- a/definitions/mars/grib.enfo.pfc.def
+++ b/definitions/mars/grib.enfo.pfc.def
@@ -1,5 +1,3 @@
-alias mars.number = perturbationNumber;
-
 alias mars.step = stepRange;
 
 # We need this because 'postProcessing' is defined later
diff --git a/definitions/mars/grib.enfo.ppm.def b/definitions/mars/grib.enfo.ppm.def
index 9129cbcd8..a8c09a96e 100644
--- a/definitions/mars/grib.enfo.ppm.def
+++ b/definitions/mars/grib.enfo.ppm.def
@@ -1,5 +1,3 @@
-alias mars.number = perturbationNumber;
-
 alias mars.step = stepRange;
 
 # We need this because 'postProcessing' is defined later