diff --git a/extern/stim b/extern/stim
index 23271344..fbfd52cd 160000
--- a/extern/stim
+++ b/extern/stim
@@ -1 +1 @@
-Subproject commit 23271344190d4b9a12c8737a69fdad6e25c3db3c
+Subproject commit fbfd52cdc350c3ff8f8a78aa20978e84d4999a3c
diff --git a/src/gotm/register_all_variables.F90 b/src/gotm/register_all_variables.F90
index 8ed31244..dbe05fb5 100644
--- a/src/gotm/register_all_variables.F90
+++ b/src/gotm/register_all_variables.F90
@@ -198,6 +198,7 @@ subroutine register_stim_variables(nlev)
    use stim_variables, only: albice_f, albmelt, albsnow_f, albice_m, albsnow_m 
    use stim_variables, only: transsf, transsm, transif, transim, transm 
    use stim_variables, only: swkappasm, swkappasf, swkappaim, swkappaif
+   use stim_variables, only: epsilon,kelvin,sigma,theta
    
    IMPLICIT NONE
 !
@@ -235,16 +236,16 @@ subroutine register_stim_variables(nlev)
    !call fm%register('rCpmix', '', 'rCpmix', standard_name='', data0d=rCpmix, category='ice')
    !call fm%register('Hfi', '', 'Hfi', standard_name='', data0d=Hfi, category='ice')
    call fm%register('hsmin', 'm', 'minimum snow thickness required for separate snow layer', standard_name='', data0d=hsmin, category='ice')
-   !call fm%register('theta ', '', 'a parameter between 0.5 and 1. which determines how implicit the scheme is', standard_name='', data0d=theta, category='ice')
-   !call fm%register('sigma ', 'W m-2 K-4)', 'Stefan-Boltzmann constant', standard_name='', data0d=sigma, category='ice')
-   !call fm%register('epsilon', 'dimensionless', 'emissivity of ice', standard_name='', data0d=epsilon, category='ice')
+   call fm%register('theta ', '', 'a parameter between 0.5 and 1. which determines how implicit the scheme is', standard_name='', data0d=theta, category='ice')
+   call fm%register('sigma ', 'W m-2 K-4)', 'Stefan-Boltzmann constant', standard_name='', data0d=sigma, category='ice')
+   call fm%register('epsilon', 'dimensionless', 'emissivity of ice', standard_name='', data0d=epsilon, category='ice')
    call fm%register('PenFrac', '', 'fraction of incoming short wave radiation that penetrates  the surface', standard_name='', data0d=PenFrac, category='ice')
    call fm%register('hlaymin', 'm', 'thickness below which a linear temperature profile is assumed', standard_name='', data0d=hlaymin, category='ice')
    call fm%register('rhoscold', 'kg m-3', 'specified cold snow density', standard_name='', data0d=rhoscold, category='ice')
    call fm%register('rhoswarm', 'kg m-3', 'specified warm snow density', standard_name='', data0d=rhoswarm, category='ice')
    call fm%register('rhowaterfresh', 'kg m-3', 'fresh water density', standard_name='', data0d=rhowaterfresh, category='ice')
    call fm%register('rhoice', 'kg m-3', 'ice density', standard_name='', data0d=rhoice, category='ice')
-   !call fm%register('kelvin', 'K', 'zero deg Celsius', standard_name='', data0d=kelvin, category='ice')
+   call fm%register('kelvin', 'K', 'zero deg Celsius', standard_name='', data0d=kelvin, category='ice')
    call fm%register('Tmelts', 'K', 'melting temperature of snow (fresh water)', standard_name='', data0d=Tmelts, category='ice')
    call fm%register('Tmelti', 'K', 'melting temperature of sea ice', standard_name='', data0d=Tmelti, category='ice')
    call fm%register('Condfi', 'W m-1 K-1', 'conductivity of pure ice', standard_name='', data0d=Condfi, category='ice')