[MITgcm-devel] seaice_budget_ice

[Martin Losch]

Hi Jinlun, Dimitris,

Please forgive me, if I am confused about all these constants:
I am currently trying to implement some radiation-bulk formulae that  
estimate lwdown from air and ocean temperature, humidity, because  
apparently for the Arctic the reanalysis fields for lwdown (and  
swdown) are not very good (this is what my Arctic specialists Gerdes,  
Karcher, Kauker, Koeberle tell me). The seaice-pkg has some remains  
of the original Parkinson&Washington bulk formulae in it, which is  
close to what we want to have for the Arctic (for comparison  
reasons), so I want to understand what the individual contributions are.
So: What is the 0.97? ice emissivity? why then have .97*lwdown, if  
lwdown is not affected by the surface? Or is it some sort of albedo  
for long wave radiation? What variable name should I give to this  
number?

Martin

On 27 Dec 2006, at 07:23, Dimitris Menemenlis wrote:

> Martin, why do you think that emissivity is already part of  
> lwdown?  My understanding of the NCEP and ERA fields is that lwdown  
> and swdown are radiation fields prior to any interaction with sea  
> surface, as opposed to lwnet and swnet, which include interaction  
> with sea surface.  A more serious issue is potentially the lack of  
> realism of the representation of atmospheric boundary layer  
> processes, especially in NCEP reanalysis, which is the older of the  
> two.
>
> A second comment is that by default we bypass the  
> seaice_budget_ocean bulk formulae and instead use that of pkg/exf.
>
> Dimitris
>
>> Whatever forcing one uses, make sure 0.97 is not used twice. Jinlun
>> Martin Losch wrote:
>>> Hi there,
>>> why is lwdown (now lwdownLoc) mulitplied by 0.97 in  
>>> seaice_budget_ice
>>> (formerly budget)? This looks awfully like some ocean surface   
>>> emissivity,
>>> which is already part of lwdown if I am not mistaken.  (the same  
>>> is true
>>> for seaice_budget_ocean, also formerly budget.)
>>> I think that this is wrong.
>>> Martin
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