Rofi spread

[anton-seaice]

This change allows for spreading of the iceberg melt field according to a climatological pattern.

A new configuration parameter is added, rof2ocn_ice_spread - which is the filename for a netcdf file with a 12-monthly climatological spreading pattern. If this parameter is not set - there is no change to existing behaviour (see repro test)

When a file is provided, the incoming Forr_rofi field is spread according to the pattern supplied in the climatology of spreading.

e.g., for January:

and for June:

Water volume is maintained between that coming from drof and ficeberg in MOM:

See example OM3 100km configuration:

ACCESS-NRI/access-om3-configs@3169a38

[anton-seaice]

mediator timestamps are a bit strange, hence the minor difference in mediator vs mom runoff plots:

[aekiss]

Thanks @anton-seaice - do you think this is ready for the next 25km IAF test run?

[anton-seaice]

Ready from my perspective.

1. Do we want to seperate the impact of changing the land mask in the poles to support b-grid advection from this change ?
2. Needs review and deployment - would take a few days at least

[anton-seaice]

I did some cleanup, but have finished that for now

[dougiesquire]

Nice work @anton-seaice. Sorry for taking so long to get to this.

My main worry is the lack of time interpolation and the resulting step changes in the pattern between months. But, as we've discussed, we probably can't address that here.

[anton-seaice]

I think I got all the comments @dougiesquire - should be good to go

[anton-seaice]

Example output in /g/data/tm70/as2285/payu/om3-rofi-spread/dev-MC_100km_jra_ryf/archive/output000

[dougiesquire]

Thanks @anton-seaice - just this comment remaining

[dougiesquire]

Do we want to abort or just not apply the normalisation when the sum is zero? What if one wanted to spread one hemi and not the other? Am I overthinking this?

[anton-seaice]

Oh yeah, will be a problem for panant

[anton-seaice]

Possibly good now @dougiesquire

[dougiesquire]

This will enter the else for SH cells if spread_rofi_sh=.false. and spread_rofi_nh=.true., so SH cells will get incorrectly divided by the NH sum (I don't think the incorrect rof2ocn_spread would actually be used in this case but still good to correct to avoid confusion).

Suggested change

	if (lats(i) < 0.0_r8 .and. spread_rofi_sh) then
	rof2ocn_spread(i,month) = rof2ocn_spread(i,month) / global_sum(1)
	else if ( spread_rofi_nh ) then
	rof2ocn_spread(i,month) = rof2ocn_spread(i,month) / global_sum(2)
	end if
	if (lats(i) < 0.0_r8 .and. spread_rofi_sh) then
	rof2ocn_spread(i,month) = rof2ocn_spread(i,month) / global_sum(1)
	else if (lats(i) >= 0.0_r8 .and. spread_rofi_nh) then
	rof2ocn_spread(i,month) = rof2ocn_spread(i,month) / global_sum(2)
	end if

[anton-seaice]

Should be fixed now

[dougiesquire]

Thanks @anton-seaice