Add warning for FSD without waves, clarify documentation (#409)

* Clarifications to documentation

* Edit documentation

* Update docs

* Add space

* Add warning for waves=F and FSD=T

* Clarify documentation on wave forcing

configuration/driver/icedrv_init.F90

@@ -650,6 +650,9 @@ subroutine input_data
 
       wave_spec = .false.
       if (tr_fsd .and. (trim(wave_spec_type) /= 'none')) wave_spec = .true.
+      if (tr_fsd .and. (trim(wave_spec_type) == 'none')) then
+         write (nu_diag,*) 'WARNING: tr_fsd=T but wave_spec=F - not recommended' 
+      end if
 
       !-----------------------------------------------------------------
       ! spew

doc/source/user_guide/ug_case_settings.rst

@@ -372,10 +372,10 @@ forcing_nml
    "``update_ocn_f``", "``.false.``", "do not include frazil water/salt fluxes in ocn fluxes", "``.false.``"
    "", "``true``", "include frazil water/salt fluxes in ocn fluxes", ""
    "``ustar_min``", "real", "minimum value of ocean friction velocity in m/s", "0.005"
-   "``wave_spec_type``", "``constant``", "wave data file is provided, constant wave spectrum, for testing", "``none``"
+   "``wave_spec_type``", "``constant``", "wave data file is provided, sea surface height generated using constant phase (1 iteration of wave fracture)", "``none``"
    "", "``none``", "no wave data provided, no wave-ice interactions (not recommended when using the FSD)", ""
-   "", "``profile``", "no wave data file is provided, use fixed dummy wave spectrum, for testing", ""
-   "", "``random``", "wave data file is provided, wave spectrum generated using random number", ""
+   "", "``profile``", "no wave data file is provided, use fixed dummy wave spectrum, for testing, sea surface height generated using constant phase (1 iteration of wave fracture)", ""
+   "", "``random``", "wave data file is provided, sea surface height generated using random number (multiple iterations of wave fracture)", ""
    "``ycycle``", "integer", "number of years in forcing data cycle", "1"
    "", "", "", ""