Nullify all the gradient pointer setup for k-kL model
subroutine destroy_lctm2015_grad()
!< Nullify all the gradient pointer setup for k-kL model
implicit none
DebugCall('destroy_sst_grad')
select case(trim(transition))
case('lctm2015')
nullify(gradtgm_x)
nullify(gradtgm_y)
nullify(gradtgm_z)
case('bc', 'none')
!do nothing
continue
case DEFAULT
Fatal_error
end Select
end subroutine destroy_lctm2015_grad