<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css" style="display:none;"><!-- P {margin-top:0;margin-bottom:0;} --></style>
</head>
<body dir="ltr">
<div id="divtagdefaultwrapper" style="font-size:12pt;color:#000000;font-family:Calibri,Helvetica,sans-serif;" dir="ltr">
<p style="margin-top:0;margin-bottom:0">Hi all,</p>
<p style="margin-top:0;margin-bottom:0"> I am some questions about prescribing winds through the 'exf' package. My initial condition is a shallow mixed layer in geostrophic balance (based on the 'MLAdjust' test case) with a zonal jet whose peak value
at the surface is initially 0.24 m/s. <br>
</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">When I turn off the 'exf' package, and prescribe a wind stress = 0.05 N/m2 through the '<span>zonalWindFile</span>' variable in 'data', the model runs without problems for 50 days.<br>
</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">When I turn on the 'exf' package with a constant wind of 3 m/ the zonal velocities in the domain keep increasing with time until I get NaN values around day 30. I am not sure why this is happening as the wind stress in
the second case is much weaker. Winds of 3 m/s, assuming an exchange coefficient (Cd) of 1.2e-3, and rho_air=1.22 kg/m3, correspond to a wind stress of
<span>0.013</span> N/m2. <br>
</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">For the simulation with 'exf' turned on, I have enabled the following three options in EXF_OPTIONS.h:</p>
<p style="margin-top:0;margin-bottom:0"></p>
<div>#define ALLOW_ATM_TEMP<br>
#define ALLOW_ATM_WIND<br>
#define ALLOW_DOWNWARD_RADIATION</div>
<br>
<p></p>
<p style="margin-top:0;margin-bottom:0">I am pasting below the relevant parameters from some of the data files for the simulation with 'exf' turned on. Any pointers on where I might be erring would be greatly appreciated.
<br>
</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">--------------------------data.pkg---------------------------------------------<br>
</p>
<p style="margin-top:0;margin-bottom:0"></p>
<div># Packages<br>
&PACKAGES<br>
useEXF = .TRUE.,<br>
useCAL = .TRUE.,<br>
useMNC = .TRUE.,<br>
useKPP = .TRUE.,<br>
useDiagnostics=.TRUE.,<br>
&<br>
----------------------------data.kpp---------------------------------------------<br>
<div># KPP parameters<br>
&KPP_PARM01<br>
KPPmixingMaps = .FALSE.,<br>
KPPwriteState = .TRUE.,<br>
KPP_ghatUseTotalDiffus=.TRUE.,<br>
kpp_dumpFreq = 2160000., <br>
&</div>
---------------------------data.exf------------------------------------------------<br>
</div>
<p></p>
<p style="margin-top:0;margin-bottom:0"></p>
<div> &EXF_NML_01<br>
# useExfCheckRange = .TRUE.,<br>
useAtmWind=.TRUE.,<br>
readStressOnCgrid=.TRUE.,<br>
# repeatPeriod = 2678400.0,<br>
# exf_iprec = 32,<br>
#<br>
&<br>
<br>
<span>&EXF_NML_02</span><br>
<div> hfluxfile = ' ',<br>
sfluxfile = ' ',<br>
ustressfile = ' ',<br>
vstressfile = ' ',<br>
atempfile = ' ',<br>
aqhfile = ' ',<br>
uwindfile = ' ',<br>
vwindfile = ' ',<br>
evapfile = ' ',<br>
precipfile = ' ',<br>
lwfluxfile = ' ',<br>
swfluxfile = ' ',<br>
lwdownfile = ' ',<br>
swdownfile = ' ',<br>
runoffFile = ' ',<br>
climsstfile = ' ',<br>
climsssfile = ' ',<br>
&<br>
<br>
<div> &EXF_NML_03<br>
uwindconst = -3.0,<br>
atempconst = 298.0, # approx. 0.5 degree cooler than the SST<br>
swfluxconst= 0.0, # zeroed out for debugging<br>
lwdownconst = 0.0, # zeroed out for debugging<br>
&</div>
<br>
----------------------------------------data-------------------------------------<br>
<div> &PARM01<br>
viscAr=1.E-5,</div>
<span> viscC4leith = 1.85,</span><br>
<span> viscC4leithD = 1.85,</span><span> <br>
viscC4smag = 1.,<br>
<span> viscA4GridMax = 1.,</span><br>
<span> useFullLeith=.TRUE.,</span><br>
<div> no_slip_sides=.FALSE.,<br>
no_slip_bottom=.FALSE.,<br>
vectorInvariantMomentum=.TRUE.,<br>
ivdc_kappa=0.,<br>
implicitDiffusion=.TRUE.,<br>
implicitViscosity=.TRUE.,<br>
f0=4.E-5, # corresponds to lat. = 16 N<br>
beta=1.E-11,<br>
</div>
<div> useJamartWetPoints=.TRUE.,<br>
eosType='LINEAR',<br>
# Temperature <br>
tAlpha=3.16E-4,<br>
# Salinity <br>
sBeta =6.32E-4,<br>
gravity=9.81,<br>
rhoNil=1027.,<br>
rigidLid=.FALSE.,<br>
implicitFreeSurface=.TRUE.,<br>
staggerTimeStep=.TRUE.,<br>
tempAdvScheme=33,<br>
saltAdvScheme=33,<br>
readBinaryPrec=64,<br>
writeBinaryPrec=64,<br>
nonHydrostatic=.FALSE.,<br>
&<br>
<br>
<div> &PARM02<br>
cg2dMaxIters=1000,<br>
cg2dTargetResidual=1.E-11,<br>
cg3dMaxIters=40,<br>
cg3dTargetResidual=1.E-9,<br>
&</div>
<br>
<span> &PARM03</span><span> <br>
cAdjFreq=0.,<br>
&<br>
<br>
---------------------------------------------------------<br>
<br>
Thanks,<br>
Sanjiv<br>
</span></div>
<br>
</span></div>
<br>
</div>
<br>
<p></p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
</div>
</body>
</html>