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Hi Martin,</div>
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I do what you do and extrapolate my boundary fields into land, and there is no salinity < 33 in any of the boundary files (including all masked areas) which is why I am so confused that such low values show up in the output. The same is true for the temperature
fields. So independently of any mistakes I make in the masking, there should be no values in the salinity < 33. It seems like something must introduce zero salinities independently of the boundary files I use...and this happens, as you can see in the attached
figure, at every ocean-land transition along the boundary. I guess I could only create open boundaries where I actually have ocean, but I would have thought this shouldn't make a difference... What do you think?</div>
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<span style="color: rgb(0, 0, 0); font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;">Andreas</span></div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> MITgcm-support <mitgcm-support-bounces@mitgcm.org> on behalf of Martin Losch <Martin.Losch@awi.de><br>
<b>Sent:</b> Friday, 19 June 2020 3:50 PM<br>
<b>To:</b> MITgcm Support <mitgcm-support@mitgcm.org><br>
<b>Subject:</b> Re: [MITgcm-support] [EXTERNAL] topography with OBCS</font>
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<div>Hi Andreas,<br>
<br>
check the masks. <br>
You should be able to specify salinity everywhere and the masks should take care of this, i.e. if you specify salinity over land points, they will be masked.<br>
In your case it looks like your mask and obcs file disagree and a land point is not masked but interpreted as zero salinity (but you knew that). I usually extrapolate my boundary field into land to avoid this.<br>
<br>
Martin<br>
<br>
> On 19. Jun 2020, at 05:12, Dimitris Menemenlis <dmenemenlis@gmail.com> wrote:<br>
> <br>
> Hi Andreas, are you sure that you are extracting your boundary conditions at the correct location?<br>
> You could be off by one grid cell, which could cause this problem. Dimitris<br>
> <br>
> <br>
>> On Jun 18, 2020, at 6:21 PM, Andreas Klocker <andreas.klocker@utas.edu.au> wrote:<br>
>> <br>
>> Hi,<br>
>> <br>
>> I am trying to set up a regional model configuration with OBCS. For some reason the model seems to introduce salinities where I actually have bathymetry (see attached figure; bathymetry left, salinities right). Salinities this low definitely do not exist
in the files containing the bounday conditions. Is it necessary to set the open boundary exactly to where I have ocean, or should the bathymetry file take care of this by telling the model there should be nothing happening in case of zero water depth?<br>
>> <br>
>> Here's my data.obcs file:<br>
>> <br>
>> # Open-boundaries<br>
>> &OBCS_PARM01<br>
>> <br>
>> OB_Iwest = 600*1,<br>
>> OB_Ieast = 600*-1,<br>
>> OB_Jsouth = 2600*1,<br>
>> OB_Jnorth = 2600*-1,<br>
>> <br>
>> useOBCSsponge = .TRUE.,<br>
>> useOBCSbalance = .TRUE.,<br>
>> useOBCSprescribe = .TRUE.,<br>
>> <br>
>> useOrlanskiWest = .FALSE.,<br>
>> useOrlanskiEast = .FALSE.,<br>
>> useOrlanskiSouth = .FALSE.,<br>
>> useOrlanskiNorth = .FALSE.,<br>
>> <br>
>> OBWuFile = 'OWU',<br>
>> OBWvFile = 'OWV',<br>
>> OBWtFile = 'OWT',<br>
>> OBWsFile = 'OWS',<br>
>> <br>
>> OBEuFile = 'OEU',<br>
>> OBEvFile = 'OEV',<br>
>> OBEtFile = 'OET',<br>
>> OBEsFile = 'OES',<br>
>> <br>
>> OBSuFile = 'OSU',<br>
>> OBSvFile = 'OSV',<br>
>> OBStFile = 'OST',<br>
>> OBSsFile = 'OSS',<br>
>> <br>
>> OBNuFile = 'ONU',<br>
>> OBNvFile = 'ONV',<br>
>> OBNtFile = 'ONT',<br>
>> OBNsFile = 'ONS',<br>
>> <br>
>> # OBCS_monitorFreq= 86400.,<br>
>> # OBCS_monSelect = 1,<br>
>> &<br>
>> <br>
>> # Orlanski parameters<br>
>> &OBCS_PARM02<br>
>> # Cmax=0.45,<br>
>> # cVelTimeScale=1000.,<br>
>> &<br>
>> <br>
>> &OBCS_PARM03<br>
>> Urelaxobcsinner=864000.,<br>
>> Urelaxobcsbound=86400.,<br>
>> Vrelaxobcsinner=864000.,<br>
>> Vrelaxobcsbound=86400.,<br>
>> spongeThickness=40.,<br>
>> &<br>
>> <br>
>> Thanks in advance!<br>
>> Andreas<br>
>> <br>
>> <br>
>> University of Tasmania Electronic Communications Policy (December, 2014). <br>
>> This email is confidential, and is for the intended recipient only. Access, disclosure, copying, distribution, or reliance on any of it by anyone outside the intended recipient organisation is prohibited and may be a criminal offence. Please delete if obtained
in error and email confirmation to the sender. The views expressed in this email are not necessarily the views of the University of Tasmania, unless clearly intended otherwise.<br>
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