diff --git a/src/MNH/ini_aircraft_balloon.f90 b/src/MNH/ini_aircraft_balloon.f90
index 6191e60d53b4158b0e065c67a48f1540720c3126..7509894df862663f1e2458cc01f8a2a7e142c671 100644
--- a/src/MNH/ini_aircraft_balloon.f90
+++ b/src/MNH/ini_aircraft_balloon.f90
@@ -177,6 +177,7 @@ CONTAINS
 !----------------------------------------------------------------------------
 SUBROUTINE ALLOCATE_FLYER(TPFLYER)
 !
+USE MODD_SURF_PAR, ONLY: XUNDEF_SFX => XUNDEF
 !
 CLASS(TFLYERDATA), INTENT(INOUT) :: TPFLYER
 !
@@ -262,7 +263,7 @@ TPFLYER%XCRARE_ATT = XUNDEF
 TPFLYER%XWZ        = XUNDEF
 TPFLYER%XZZ        = XUNDEF
 TPFLYER%XTKE       = XUNDEF
-TPFLYER%XTSRAD     = XUNDEF
+TPFLYER%XTSRAD     = XUNDEF_SFX
 TPFLYER%XZS        = XUNDEF
 TPFLYER%XTKE_DISS  = XUNDEF
 !
diff --git a/src/MNH/ini_modeln.f90 b/src/MNH/ini_modeln.f90
index 258172aeb40c59870159e6086c11a546bdeed831..81161434af7b10dc1228883a77aa714133e53f7e 100644
--- a/src/MNH/ini_modeln.f90
+++ b/src/MNH/ini_modeln.f90
@@ -394,6 +394,7 @@ use MODD_SALT_OPT_LKT,      only: NMAX_RADIUS_LKT_SALT=>NMAX_RADIUS_LKT, NMAX_SI
 USE MODD_SERIES,            only: LSERIES
 USE MODD_SHADOWS_n
 USE MODD_STAND_ATM,         only: XSTROATM, XSMLSATM, XSMLWATM, XSPOSATM, XSPOWATM
+USE MODD_SURF_PAR,          only: XUNDEF_SFX => XUNDEF
 USE MODD_TIME
 USE MODD_TIME_n
 USE MODD_TURB_CLOUD,        only: NMODEL_CLOUD, CTURBLEN_CLOUD,XCEI
@@ -1494,7 +1495,7 @@ IF (CRAD /= 'NONE') THEN
   ALLOCATE(XDIR_ALB(IIU,IJU,NSWB_MNH))
   ALLOCATE(XSCA_ALB(IIU,IJU,NSWB_MNH))
   ALLOCATE(XEMIS  (IIU,IJU,NLWB_MNH))
-  ALLOCATE(XTSRAD (IIU,IJU))    ; XTSRAD = 0.0
+  ALLOCATE(XTSRAD (IIU,IJU))    ; XTSRAD = XUNDEF_SFX
   ALLOCATE(XSEA (IIU,IJU))
   ALLOCATE(XZS_XY (IIU,IJU))
   ALLOCATE(NCLEARCOL_TM1(IIU,IJU))