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<p>Hi there,</p>
<p><br>
</p>
<p>I am running a simple 2d oceanic model with surface tide with diurnal frequency propagating up and down a slope. There is noise near the bottom of the slope, especially the shelf break area. I have attached a snap shot of the noise near the shelf break,
where the y-axis is the horizontal velocity right above the slope and x-axis is the number of points.</p>
<p>The noise seems unphysical(?), though its not too bad, I wonder is there any way I can do to remove the noise?</p>
<p><br>
</p>
<p>Here is my set-up:</p>
<p>My deep water depth H=2km and shallow water depth h=200m. I have 80 points in the shallow water region and 400 points in the whole water column. <span style="font-size: 12pt;">The horizontal resolution dx=46m. I am using pp81 for the vertical viscosity and
diffusion and </span>Smagorinsky for the horizontal viscosity.</p>
<p>I have tried increasing the resolution both x and z direction, reducing dt, smoothing out the slope more, increasing the viscosity etc. None of these will reduce the noise except reducing hfacMin from 0.1 to 0.01. My data file is attached.</p>
<p><br>
</p>
<p># ====================</p>
<p># | Model parameters |</p>
<p># ====================</p>
<p>#</p>
<p># Continuous equation parameters</p>
<p> &PARM01</p>
<p></p>
<p> tRef=0.,</p>
<p> sRef= 0.,</p>
<p> viscAz=1.E-5,</p>
<p> viscAh=0.,</p>
<p> no_slip_sides=.FALSE.,</p>
<p> no_slip_bottom=.FALSE.,</p>
<p> diffKhT=2.E-1,</p>
<p> diffKzT=1.E-5,</p>
<p>#new parameters for smag</p>
<p> viscC2Smag=2.0,</p>
<p> f0=6.5E-5,</p>
<p> beta=0.,</p>
<p> eosType='LINEAR',</p>
<p> tAlpha=2.E-4,</p>
<p> sBeta =0.,</p>
<p> rhonil=1028.0,</p>
<p> rhoConst=1028.0,</p>
<p> gravity=9.81,</p>
<p> rigidLid=.TRUE.,</p>
<p> implicitFreeSurface=.FALSE.,</p>
<p># exactConserv=.TRUE.</p>
<p> nonHydrostatic=.FALSE.,</p>
<p># minimum cell fraction. This reduces steppiness</p>
<p> hFacMin=0.01,</p>
<p></p>
<p>#- not safe to use globalFiles in multi-processors runs</p>
<p> globalFiles=.TRUE.,</p>
<p> readBinaryPrec=64,</p>
<p> writeBinaryPrec=64,</p>
<p> writeStatePrec=64,</p>
<p> saltStepping=.FALSE.,</p>
<p>#parameters for kl10</p>
<p> implicitDiffusion=.TRUE.,</p>
<p> implicitViscosity=.TRUE.,</p>
<p>#change advection shceme</p>
<p> tempAdvScheme=33,</p>
<p> staggerTimeStep=.TRUE.,</p>
<p> &</p>
<p><br>
</p>
<p># Elliptic solver parameters</p>
<p> &PARM02</p>
<p> cg2dMaxIters=1000,</p>
<p> cg2dTargetResidual=1.E-13,</p>
<p> cg3dMaxIters=400,</p>
<p> cg3dTargetResidual=1.E-13,</p>
<p> &</p>
<p><br>
</p>
<p># Time stepping parameters</p>
<p> &PARM03</p>
<p> nIter0=0,</p>
<p> nTimeSteps=447121,</p>
<p> deltaT=12.,</p>
<p> abEps=0.1,</p>
<p> pChkptFreq=5365440.,</p>
<p> chkptFreq=0.,</p>
<p> dumpFreq=5365440.,</p>
<p> monitorFreq=2500.,</p>
<p> monitorSelect=2,</p>
<p>#obcs forcing</p>
<p> periodicExternalForcing=.TRUE.,</p>
<p> externForcingPeriod=486.,</p>
<p> externForcingCycle=89424.,</p>
<p> &</p>
<p><br>
</p>
<p># Gridding parameters</p>
<p> &PARM04</p>
<p> usingCartesianGrid=.TRUE.,</p>
<p> delXfile='delXvar',</p>
<p># delX=2000*500.,</p>
<p> delY=100.E3,</p>
<p> delRfile='delZvar',</p>
<p> &</p>
<p><br>
</p>
<p># Input datasets</p>
<p> &PARM05</p>
<p> hydrogThetaFile='T.init',</p>
<p> bathyFile='topog.slope',</p>
<p> vVelInitFile='vgeo.bin',</p>
<p> &</p>
<p><br>
</p>
<p>Thanks</p>
<p><br>
</p>
<p>Yangxin</p>
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