diff --git a/definitions/mars/grib.lwda.gai.def b/definitions/mars/grib.lwda.gai.def
new file mode 100644
index 000000000..66e453379
--- /dev/null
+++ b/definitions/mars/grib.lwda.gai.def
@@ -0,0 +1,2 @@
+alias mars.anoffset=offsetToEndOf4DvarWindow;
+
diff --git a/definitions/mars/grib.oper.gai.def b/definitions/mars/grib.oper.gai.def
new file mode 120000
index 000000000..a720ff713
--- /dev/null
+++ b/definitions/mars/grib.oper.gai.def
@@ -0,0 +1 @@
+base.def
\ No newline at end of file