diff --git a/src/mptrac.c b/src/mptrac.c
index a274a527e..f8553ea2c 100644
--- a/src/mptrac.c
+++ b/src/mptrac.c
@@ -12139,7 +12139,6 @@ void dd_communicate_particles(
 
   /* Wait for all signals to be send... */
   MPI_Barrier(MPI_COMM_WORLD);
-
   /* Recieving... */
   for (int isourc = 0; isourc < ndestinations; isourc++) {
   
diff --git a/src/mptrac.h b/src/mptrac.h
index e2e01a615..e7c52db5d 100644
--- a/src/mptrac.h
+++ b/src/mptrac.h
@@ -3235,6 +3235,27 @@ typedef struct {
   
 } particle_t;
 
+typedef struct {
+
+  /*! Time [s]. */
+  double* time;
+
+  /*! Pressure [hPa]. */
+  double* p;
+
+  /*! Longitude [deg]. */
+  double* lon;
+
+  /*! Latitude [deg]. */
+  double* lat;
+
+  /*! Quantity data (for various, user-defined attributes). */
+  double* q[NQ];
+
+} particle_ptr_t;
+
+
+
 /**
  * @brief Cache data structure.
  *