diff --git a/definitions/grib2/localConcepts/ecmf/unstructuredGridSubtype.def b/definitions/grib2/localConcepts/ecmf/unstructuredGridSubtype.def
index 0f9911a54..2a1d885eb 100644
--- a/definitions/grib2/localConcepts/ecmf/unstructuredGridSubtype.def
+++ b/definitions/grib2/localConcepts/ecmf/unstructuredGridSubtype.def
@@ -6,3 +6,4 @@
 'F' = { numberOfGridInReference = 5; }
 'C' = { numberOfGridInReference = 6; }
 'N' = { numberOfGridInReference = 7; }
+'D' = { numberOfGridInReference = 8; }
diff --git a/definitions/grib2/localConcepts/ecmf/unstructuredGridType.def b/definitions/grib2/localConcepts/ecmf/unstructuredGridType.def
index dfcc93e2f..8264d8121 100644
--- a/definitions/grib2/localConcepts/ecmf/unstructuredGridType.def
+++ b/definitions/grib2/localConcepts/ecmf/unstructuredGridType.def
@@ -8,3 +8,4 @@
 'eORCA12'   = { numberOfGridUsed = 7; }
 'CORE2'     = { numberOfGridUsed = 8; }
 'NG5'       = { numberOfGridUsed = 9; }
+'DART'      = { numberOfGridUsed = 10; }