Abiotic-HOWTO J. Orr, R. Najjar, C. Sabine, and F. Joos Revision: 1.16, Date: 2000/01/08 18:46:21 This document provides step-by-step guidelines to make the so-called solubility pump runs for CO2 and C-14 according to the standard OCMIP-2 protocols. No biological effects are included. The ocean model carries only DIC and DIC14. We describe five types of abiotic simulations: (1) Equilibrium run, (2) Historical run for 1765-2000, (3) Future runs (IPCC S650 and CIS92A) for DIC only, (4) a 1000-yr Pulse Input run for DIC only, and (5) three Control runs needed for drift correction for the Abiotic transient runs (i.e., the Historical, Future, and Pulse simulations). Contents 1 Recuperation of OCMIP-2 files by ftp: 3 2 Model runs 4 2.1 Conservation equations .......................................... 4 2.2 Virtual flux (Fv) .............................................. 5 2.3 Air-sea gas exchange fluxes (F and F14) ................................. 5 2.4 The Piston Velocity Kw .......................................... 6 2.5 Oceanic and Atmospheric Components .................................. 7 2.5.1 Ocean ............................................... 8 2.5.2 Atmosphere ............................................ 8 3 Initialization and duration of simulations 9 4 Output type and frequency 11 5 Output Format 14 5.1 Output routines .............................................. 14 5.2 Downloading the output routines ..................................... 18 5.3 Compiling the output routines ...................................... 19 5.4 Using the output routines ......................................... 19 5.4.1 Equilibrium Output ........................................ 19 5.4.2 Historical Output ......................................... 20 5.4.3 Future Output ........................................... 22 5.4.4 Pulse Output ........................................... 23
Transcript
Abiotic-HOWTOJ. Orr, R. Najjar, C. Sabine, and F. Joos Revision: 1.16,Date:2000/01/0818:46:21
This document provides step-by-step guidelines to make the so-called solubility pump runs for CO2 andC-14 according to the standard OCMIP-2 protocols. No biological effects are included. The ocean modelcarries only DIC and DIC14. We describe five types of abiotic simulations: (1) Equilibrium run, (2)Historical run for 1765-2000, (3) Futur e runs (IPCC S650 and CIS92A) for DIC only, (4) a 1000-yr PulseInput run for DIC only, and (5) three Control runs needed for drift correction for the Abiotic transient runs(i.e., the Historical , Futur e, and Pulsesimulations).
To complywith OCMIP-2guidelines,all modelersmustmakesimulationsaccordingto OCMIP-2standardboundaryconditions.To doso,onemustfirst recuperatethefollowing filesvia thisWebpage.(youcansavea file to diskbyclicking on its link while holdingdown theShift key)
� Filesconcerninggasexchange(samefor all OCMIP-2runs)
� Jv14 is the”virtual” source-sinktermfor changesin surface[DIC14]dueto evaporationandprecipitation(E-Pchangesin backgroundconcentrationsareof thesameorderasobservedvariability);
� J is thethesource-sinktermdueto air-seaexchangeof CO2;and
� J14 is thesource-sinktermdueto air-seaexchangeof 14CO2.
Thesource-sinktermsJv, Jv14, J, andJ14 areaddedonly assurfaceboundaryconditions.Thatis they areequaltozeroin all subsurfacelayers.Thesesource-sinktermsareequivalentto thefluxes,describedbelow, dividedby thesurfacelayerthicknessdz1.
Jv = Fv/dz1
Jv14= Fv14/dz1
J = F/dz1
J14= F14/dz1
2. Model runs 5
2.2 Virtual flux (Fv)
In modelswheresurfacesalinity is restoredto observedvalues,this resultsin a surfaceflux of salt,notasurfacefluxof waterasin therealworld. Suchsurfacesaltfluxesaretypically foundin modelswith a rigid lid, andevenin somemodelswith a freesurface(e.g.,theOGCMfrom Louvain-la-Neuve).For simplicity, wecategorizebothclassesofmodelsas”rigid-lid-lik e”. Conversely, non-rigid-lid-likemodelshavea freesurfaceandrestoresurfacesalinityby anequivalentflux of waterleadingto dilution or concentration(e.g.,theMPI LSGmodel).Salinity in thelattertypeoffree-surfacemodelis conserved;E-Pfluxesaretakeninto accountby thevelocityfieldsandthusdonotneedto beexplicitly formulatedin thetransportmodel.
Yet for all rigid-lid-lik emodels,wemustexplicitly take into accounttheconcentration-dilutioneffectof E-P(EvaporationminusPrecipitation),whichchangessurface[DIC] and[Alk] . Thusweaddthevirtual flux to thesurfacelayer, eachtimestepaccordingto
(2a) Fv = DICg * (E-P)
(2b) Fv14= DIC14g * (E-P)
whereDICg andDIC14garethemodel’sgloballyaveragedsurfaceconcentrationsof DIC andDIC14,respectively.Bothglobalaveragesmustbecomputedat leastonceperyear. For rigid-lid-lik emodelswith only salinity restoring,wesuggestthat(P - E) becomputedas
(3) P - E =����������� ���
* dz1 /Tau
whereS’ is theobservedlocalsalinity to whichmodeledlocalsalinityS is beingrestored,Sg is themodel’sgloballyaveragedsurfacesalinity, dz1 is thetop layerthickness,andTau is therestoringtimescalefor salinity. Forrigid-lid-lik emodelswhich in additionincludeexplicit P - E waterfluxes,thattermmustof coursealsobeaddedtoeq(3).
2.3 Air -seagasexchangefluxes(F and F14)
For simulationsof DIC andDIC14,OCMIP-2simulationswill directlymodelthefinite air-seafluxesF andF14,respectively. Modelersmustusetheformulationfor thestandardOCMIP-2air-to-seaflux,
(4a) F = Kw (Csat - Csurf)
(4b) F14= Kw (14Csat- 14Csurf)
with
(5a) Csat= alphaC * pCO2atm * P/Po
(5b) 14Csat= Csat * Ratm
where
� Kw is theCO2gastransfer(piston)velocity [m/s] ;
� Csurf is thesurfaceaqueous[CO2] concentration[mol/mˆ3], which is computedfrom themodel’ssurface[DIC], T, S,and[Alk] (seesection2.5);
� 14Csurf is thesurfaceocean[14CO2](seesection2.5);
2. Model runs 6
� alphaC is theC solubility for water-vaporsaturatedair [mol/(mˆ3* uatm)];
� pCO2atm is thepartialpressureof CO2in dry air atoneatmospheretotalpressure[in microatm],which is thesameasthedry air mixing ratioof CO2multipliedby 10ˆ6;
� P is thetotal air pressureat sealevel [atm], locally;
� Po is 1 atm;and
� Ratm is thenormalizedatmosphericratioof C-14/C-12,which for ourpurposeswedivideby theanalogousratio for thestandardRstd
(6) Ratm = (1 + D14Catm/1000)
whereD14Catm is theatmosphericDeltaC-14,thefractionationcorrectedratioof C-14/C-12,givenin permil (seebelow).
Thosefamiliarwith C-14,maybesurprisedthatin equation(6) wedefineRatm, withoutmultiplying theright handtermby Rstd (1.176e-12).Instead,wepreferto beableto compare[DIC14] to [DIC] , directly, in orderto simplifyearlyinterpretationandcodeverification.With theaboveformulationfor theOCMIPequilibriumruns(wherepCO2atm=278ppmandD14Catm=0� ), if bothtracersareinitialized identically, theonly differencebetweenunitsfor the[DIC] and[DIC14] tracerswill bedueto radioactivedecay. For theanthropogenicruns,therewill alsobecontributionsdueto differencesbetweenatmosphericrecordsfor pCO2atm andD14Catm.
2.4 The PistonVelocity Kw
For simulationsof DIC andDIC14,modelersmustusethestandardOCMIP-2formulationfor thepistonvelocityKwfor CO2.Themonthlyclimatologyof Kw , to beinterpolatedlinearly in timeby eachmodelinggroup,is computedwith thefollowing equationadaptedfrom Wanninkhof(1992,eq.3):
� u2 is theinstantaneousSSMIwind speed,averagedfor eachmonth,thensquared,andsubsequentlyaveragedoverth esamemonthof all yearsto givethemonthlyclimatology. (seetheOCMIP-1README.satdatforfurtherdetails);
� v is thevarianceof theinstantaneousSSMIwind speedcomputedoveronemonthtemporalresolutionAnd 2.5degreespatialresolution,andsubsequentlyaveragedover thesamemonthof all yearsto give themonthlyclimatology. Again,seetheOCMIP-1README.satdatfor furtherdetails.
� a is thecoefficientof 0.337,consistentwith apistonvelocity in cm/hr. We adjustedthecoefficienta forOCMIP-2,in orderto obtainBroeckeretal.’s (1986)radiocarbon-calibrated,globalCO2gasexchangeof0.061mol CO2/(mˆ2* yr * uatm),whenusingthesatelliteSSMIwind information(u2 + v) from Boutinand
2. Model runs 7
Etcheto(pers.comm.).Ourcomputedvaluefor a is similar to thatdeterminedby Wanninkhof(a = 0.31),whouseda differentwind speeddatasetandassumptionsaboutwind speedvariance;weusetheobservedvariance.
� Xconv = 1/3.6e+05,is a constantfactorto convert thepistonvelocity from [cm/hr] to [m/s]. Thisconversionfactoris alreadyincludedin theforcingfield xKw, providedbelow.
� Sc is theSchmidtnumberwhich is to becomputedusingmodeledSST, usingtheformulationfromWanninkhof(1992).Thefunctionscco2.fcomputestheSc(unit-less)for CO2.
Practicallyspeaking,to useequation(2) eachgroupwill interpolatetheOCMIP-2standardinformationto theirownmodelgrid. Thestandardinformationis providedby IPSL/LSCEasa monthlyclimatologyon the1 x 1 degreegridof Levitus (1982)in netCDFformat(in file gasxocmip2.nc).Griddedvariablesin thatfile include
� thevariableFice,
� thesecondterm,[Xconv * a * (u2 + v)], denotedasxKw [m/s]
� themaskTmask (1 if ocean;0 if land),
� thetotalatmosphericpressureat sealevel P [atm]
� thelongitudeLon at thecenterof each1 x 1 degreegrid box,
� thelatitudeLat at thecenterof each1 x 1 degreegrid box.
For thevariablesFiceandxKw , continentson the1 x 1 degreestandardgrid havebeenfloodedwith adjacentoceanvalues.Suchanapproachavoidsdiscontinuitiesat land-seaboundariesduringinterpolation.SeetheFortranprogramrgasxocmip2.ffor anexampleof how to readtheinformationin gasxocmip2.nc.gzinto your interpolationroutines.After compilation,to link andusergasxocmip2.f,onemusthavealreadyinstallednetCDF.
Following equation(4), wedonot includeRstd whencalculatingD14Cocnin themodel.
2.5.2 Atmosphere
TheatmosphericcomponentsCsat and14Csatin equations(4a)and(4b)arespecifieda priori via four remainingterms:
1. alphaC: TheCO2solubility alphaC is to becomputedusingmodeledSSTandSSS,bothof whichvary intimeateachgrid point. For OCMIP-2weusethesolubility formulationof Weiss(1974),correctedfor thecontributionof watervaporto thetotalpressure(WeissandPrice,1980,TableIV for solubility in [mol/(l *atm)]). Thesolubility alphaC is calculatedwithin theroutineco2calc.f.
integrateduntil theendof 1999,following theobservedrecorduntil 1990.5(splco2.dat)andIPCCscenarioS650(stab.dat)until 2000.0(Enting,1994).Thatsamescenario,Future run S650, will becontinuedfrom2000.0to 2300.0.Similarly, a secondFuture run CIS92A (seealsocis92a.dat)will berun from 1990.0to2100.0,afterinitializing with modeloutputfrom theHistorical run in 1990.0.Additionally a Pulse run will bemade,wherepreindustrialatmosphericCO2is doubledandallowedto declinefor 1000years.Finally toeliminateeffectsdueto modeldrift, wewill makeessentiallytwo Control runs: (1) thefirst will beheldto thesameatmosphericboundaryconditionsastheEquilibrium run , carryingbothDIC andDIC14during1765-2000but only DIC from 2000-2300;(2) thesecondwill beanalogousto thePulserun,madein forwardmodefor 1000years,exceptthatatmosphericCO2will notbedoubledon thefirst timestep.
3. D14Catm: is atmosphericDeltaC-14[in permil]. For theEquilibrium run, D14Catmis heldconstantat0� .For theHistorical run, wedefinetheequilibriumstateasyear1765.0.Thenthemodelmustbeintegrateduntiltheendof year1999following theobservedrecord(Enting,1994).TheobservedatmosphericC-14recordisgivenfor threelatitudinalbands:
� 90S-20S� 20S-20N� 20N-90N
Therewill beNO futureor pulsesimulationsfor C-14.
4. P: Is thetotalatmosphericpressure[atm] from themonthlymeanclimatologyof EsbensenandKushnir(1981).Thelatter, givenoriginally ona4 x 5 degreegrid (latitudex longitude)in bars,is convertedto atmbymultiplying by (1/1.101325).Landandseaicevaluesin theoriginaldatasetwerefilled with averagevaluesfrom adjacentoceanpoints.Thesemonthlymeanarrayswerethenlinearly interpolatedto the1 x 1 degreegridof Levitus (seenetCDFfile gasxocmip2.nc).
� Initial Conditions: Thesedon’t reallymatterfor theAbiotic Equilibriumrun. Thatis, thefinalsteady-statedistributionsfor DIC andDIC14donotdependon theinitial conditionsbecauseexchangewith theatmospherewill ultimatelydeterminetheir final steady-stateinventories.However, a judiciouschoiceof initial conditionscanreducetheintegrationtime requiredto reachsteady-state.Unfortunately,initial conditionsmustbequitecloseindeedto thesteady-statesolutionif thereis to bea significantreductionin computingtime. Thechoiceof initial conditionsis left to thediscretionof eachof themodelinggroups.For initial debugging,groupsmaypreferto initialize DIC14 to thesame3-D field asusedfor DIC. Thatway theonly differencebetweenthetwo tracersis drivenby radioactivedecay.
� Duration: TheEquilibriumrun for abioticDIC andDIC14shouldbecontinueduntil at leastboththefollowing criteriaarereached:
– For DIC, werecommendthattheglobally integratedair-seaflux shouldbelessthan0.01PgC/yr
– For C-14,we recommendthat98%of theoceanvolumeshouldhaveadrift of lessthan0.001� /year(Aumontetal., 1998,p. 105). In termsof C-14age,thisdrift is equivalentto a changeof 8.27yr per1000yearsof simulation.
For mostmodels,thesecriteriacanbereachedonly afterintegrationsof at leastfew thousandmodelyears.
2. Historical run :
� Initial Conditions: Thehistoricalabioticsimulationfor bothDIC andDIC14will beinitializedwith finaloutput(onDec.31) from theEquilibrium run or ”steady-state”simulation.
� Duration: Thehistoricalsimulationwill begin at thebeginningof 1765(Jan1, i.e.,1765.0).Theanthropogenicsimulationwill becontinueduntil theyear2000.0.
– Duration: to becontinuedusingatmosphericCO2from IPCCScenarioS650until theyear2300.0
4. Pulseinput responsefunction (DIC only):
� Initial Conditions: OceanDIC is to beinitializedwith final outputfrom theEquilibriumrun;AtmosphericCO2is to bedoubled(556ppm,where1 ppm= 2.123PgC) at t=0, andthenbecontrolledonly via air-seafluxes.Thusthemodelis thento berun in forwardmode(atmosphericCO2iscalculated).TheInjectionHOWTO describesotherforwardsimulationsin moredetail.
� Historical Control (DIC andDIC14);andFuture Control (DIC only)/:
– Initial Conditions: OceanDIC is to beinitializedwith final outputfrom theEquilibriumrun;AtmosphericCO2andC-14areto beheldatpreindustrialconditions(278ppm,0� ) throughoutthedurationof thesimulation.
– Duration: Thetotal integrationfor DIC will befor 535years(1765.0- 2300.0).HowevertheintegrationincludingDIC14 is only necessaryfor thefirst 235years(Historical Control run1765.0-2000.0).
– Historical-Future transistion: If runseparately, theFuture Control runshouldbeinitializedwith the3-D DIC fieldsAND the2-D CumulativeFluxes(i.e.,bothair-seagascumulativeflux andvirtualcumulativeflux) from thelasttimestepof 1999(endof Historical Control run).
� Pulse Control (DIC only):
– Initial Conditions: OceanDIC is to beinitializedwith final outputfrom theEquilibriumrun;AtmosphericCO2is to beinitializedwith thequantityof CO2equivalentto 278ppm(1 ppm= 2.123PgC) at t=0, andthenbecontrolledonly via air-seafluxes.Thusthemodelis to berun in forwardmode(atmosphericCO2is calculated).TheInjectionHOWTO describesotherforwardsimulationsin moredetail.
2. Historical Output : for anthropogenicrun for CO2andC-14(1765.0-2000.0)
� Type: Sameasfor theEquilibriumrun (exceptAlk, which is thesame),plus
2-D fields
(a) SurfaceDIC concentration(mol/mˆ3);
(b) SurfaceDC14ocn(permil),seeequation(11);
(c) VerticalInventoryof DIC (mol/mˆ2),i.e., theverticalintegralof its concentrationwith depth,throughoutthewatercolumn.
(d) VerticalInventoryof DC14ocn(permil * m), i.e., theverticalintegralof its level with depth,throughoutthewatercolumn(permil*m arestrangebut usefulunits).
Eachmodelinggroupmustprovidetheiroutputin thestandardOCMIP-2format.Modeloutputthatdoesnot followtheseformattingconventionscannotbeincludedfor analysisduringOCMIP-2.Modelgroupsmustusethestandardroutinesthatwehavedevelopedspecificallyfor writing outputin standardform for OCMIP-2.
If this is thefirst OCMIP-2simulationyou havemade,you will needto recuperatetheroutinewrite nc MaskAreaBathy.f to write outcharacteristicsof yourmodelgrid, mask,andbathymetryusingthestandardOCMIP-2format.Useof this routineis detailedin theCFCHOWTO (section5.1).
Otherwiseif you havesubmittedOCMIP-2modeloutputpreviously, you will only needto resubmittheoutputfileproducedby write nc MaskAreaBathy.f undertwo conditions:
For example,aftercompilingandlinking theOCMIP-2outputroutines,weaddthefollowing codeto theIPSLroutinesto storeoutputin standardOCMIP-2form
call write_nc_Abiotic_equil("IPSL","NG L46_SI",
& imt, jmt, kmt,
& 60*60*24*365, 1200,
& MDIC, MDIC14, Alk,
& MpCO2surf, MdpCO2,
& MF, MF14,
& MFv, MFv14)
By line, theargumentsinclude
1. theOCMIP-2model code AND yourown model version indicator(in GDT 1.2terminology, these2 variablesreferto the institution andproduction, respectively);
When do I call the aboveEquilibrium output routine? It shouldbecalledonly once,at theendof thesimulationafterbuilding monthlyarrays(12members)for eachof the2-D and3-D spatialfieldsgivenasarguments.
Notethatwehavealsoaddedthedimensionnt on line 2. Youmustusent to signalif you arepassingannualmeans(nt=1)or monthlymeans(nt=12).Theargumentnt is usedin thesamefashionfor routinesthatfollow. The3-D inputarraysMDIC andMDIC14 areasdescribedfor theEquilibriumrun.
When do I call the above3-D Historical output routine? It shouldbecalledfor eachof thefollowing times:
� with nt=12 (monthlymeans,12 recordsperyear)for eachof theyears1838,1953,1954,1957,1965,1972,1973,1974,1977,1978,1981,1982,1983,1985,1986,1987,1988,1989,1991,1993,1995,1997,1999.
� with nt=1 (annualmeans,1 recordperyear)for eachof theyears1838,1839,1900,andeveryyearfor1953-1999(inclusive).
For 2-D output,weno longerneedthedimensionkmt, formerly in line 2. Conversely, weneedsupplemental2-Dmodeloutputfor theHistoricalrunwhichwasnot includedin theequilibriumoutput.Thissupplemental2-D outputis neededto dueto theHistoricalrun’s transientnatureandourasynchronoussaving of its 2-D and3-D output.Supplemental2-D Historicaloutputincludes
5. Output Format 21
� line 7: themeansurfaceDIC (mol/mˆ3)andDC14ocn(permil),seeeq.(11);
� line 8: themeanverticalinventoryof DIC (mol/mˆ2)andDC14ocn(permil * m);
� line 9: theend-of-year2-D cumulativeflux for F (mol/mˆ2)andF14(mol/mˆ2);
� line 10: theend-of-year2-D cumulativeflux for Fv andFv14(bothin mol/mˆ2)
Cumulativefluxes(lines9 and10above)mustbeinitialized to zeroandintegratedwith respectto time(i.e.,eachtimestep)from year=1765.0.Notethatthesevaluesshouldbeoutputonly at theendof eachyear, regardlessofwhethernt=12or nt=1.
When do I call the above2-D Historical output routine? It shouldbecalledwith nt=12 for eachof thefollowingyears:1838,1839,1900,andeveryyearfor 1948-1999(inclusive).
1. theOCMIP-2model code AND yourown model version indicator(in GDT 1.2terminology, these2 variablesreferto the institution andproduction, respectively);
2. thenumberof recordssavedandthearrayof thetimes(in decimalyears)atwhich they weresaved–formonthlymeans,times shouldbesetto thecorrespondingtimeatmid-month(seebelow for exactvalues).
10. thehistoryof theglobalmeancumulativefluxesF andF14(in mol/mˆ2,integratedsince1765.0)at theendofeachmonth,with eachmonthindicatedby its mid-monthtimegivenin line 2; and
11. thehistoryof theglobalmeancumulativefluxesFv andFv14(in mol/mˆ2,integratedsince1765.0)at theendof eachmonth,with eachmonthindicatedby its mid-monthtimegivenin line 2.
When do I call the above0-D Historical output routine? It shouldbecalledonly once,afterconstructing1-D (intime)arraysfrom all of yourmodeloutput.Thetimestoragefrequency is regular:everymonththroughouttheentirerun(i.e.,all years1765-1999,inclusive). Thusmodelersmustusenrec = 2820,andfill the1-D temporalarraytimeswith theappropriatevalues(i.e.,1765.04167,1765.125,1765.2083,1765.29167,1765.375,... 1999.875,1999.9583).
When do I call the above0-D Futur eoutput routine? It shouldbecalledonly once,afterconstructing1-D (intime)arraysfrom all of yourmodeloutput.Thetimestoragefrequency is regular:everymonththroughouttheentirerun(i.e.,all years1990-2299,inclusive). Thusmodelersmustusenrec = 3720,andthey mustfill the1-D temporalarraytimes) with appropriatecorrespondingvalues(i.e.,1990.04167,1990.125,1990.2083,1990.29167,1990.375,..., 2299.875,2299.9583).
5.4.4 PulseOutput
Anothersetof 2 routinesis neededfor storingthe2-D and0-D resultsfrom thePulserun; for thatrun thereis NO3-D output.Differencesrelative to thePulseoutputroutinesare
� thescenariospecificationhasbeenremoved(only 1 pulserun is to bemade);and
� thent termhasbeenremovedfrom the2-D routinesince2-D outputis to besavedonly for annualmeans,notmonthlymeans.
When do I call the above2-D Pulseoutput routine? It shouldbecalledusingannualmeans,for eachof thefollowing years:0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,20,30,40,50,60,70,80,90,100,200,300,400,500,600,700,800,900,and999.Thesedetailsaregivenin astructuredway in theprevioussection(OutputtypeandFrequency).
When do I call the above0-D Pulseoutput routine? It shouldbecalledonly once,afterconstructing1-D (in time)arraysfrom all of yourmodeloutput.Thetimestoragefrequency (spacingbetweenindividualmembersof thearraytimes) is NOT regularlyspacedin time. For the0-D Pulse run,outputasspecifiedby times mustbegivenfor
� everymonthfrom years0.0to 10.0(i.e.,12x 10= 120records),with correspondingmonthlymeansprovidedatmid-month(i.e., for times = 0.04167,0.1250,0.2083,0.29167,0.3750,... 9.875,9.9583);
� everyyearfrom years10.0to 100.0(i.e.,90records),with correspondingannualmeansprovidedatmid-year(i.e., for times = 10.5,11.5,12.5,... 99.5);
� every10yearsfrom years100.0-991.0(i.e.,90 records),with correspondingannualmeansprovidedatmid-year(i.e., for times = 100.5,110.5,120.5,130.5,... 990.5);and
� thefinal year(i.e.,1 record),with its correspondingannualmeansprovidedatmid-year(i.e., for times = 999.5).
Thuswith this irregularspacing,modelsmustusenrec = 301(i.e.,120+ 90+ 90+ 1).
5.4.5 Control Output
Finally weneedto storeoutputfor thecontrolrun. Thecontrolrun is necessarybecause3-D tracerfieldsandassociatedfluxesin ourEquilibrium runnever reachperfectequilibrium.Theassociateddrift affectsresultsfor thetransientruns.Correctingfor drift maybeimportantwhencomparingmodeldifferences,particularlyintegratedquantities,over long timeperiods.Thecontrolrun is neededto drift-correctmodels,beforecomparison.It isdesirablethatall groupsmakeall threecontrolruns,but thismaynotbepossiblefor some,dueto CPUrequirements.Below area few guidelinesto helpyou decidewhentheControlrunsarenecessaryandwhatshortcutscanbetaken:
5. Output Format 25
1. If youwill make thePulse run,youMUST alsomake theequivalentPulse Control run.
2. If youhaveNOT respectedtheEquilibriumdrift criteriayouMUST make theHistorical Control andFutureControl runs.
3. If youhaverespectedtherecommendedEquilibriumdrift criteria,you mayskip makingtheHistorical ControlandFuture Control runs.However, wedoHIGHLY RECOMMENDthatyou makethesesimulations,if youcanafford them,i.e., if they donot representa largeproportionof yourannualCPUbudget.Having thisoutputwill simplify analysisandeliminateguesswork.
4. If youhaverespectedtheEquilibriumdrift criteriaandchoosenot to submitHistorical Control andFutureControl output,youMUST still provideanindicationof thedrift of yourmodel.In otherwords,you mustusethethree*ctrlH* routines(seebelow) to provideyouroutputfor anotheryear. For instance,youcouldprovideoutputfrom the0-D, 2-D, and3-D *ctrlH* routinesfor theyear1775.We would thencomputeyourmodeldrift andtreatit asconstant.
Thosewhowill bemakingall theCO2Injectionsimulationscaneconomizea little. Thatis, with thoseruns,oneautomaticallymakesmakeboththeLate Control andthePulse Control runs,simultaneoulsy. Thefirst of thetenInjectiontracersis thecontroltracer. Unfortunately, theInjection runsdoNOT offer anopportunityto skip theHistorical Control run. For moredetails,seethefinal versionof theInjectionHOWTO.
1. Historical Control output(for 1765-1999,inclusive): We saveboththeDIC andDIC14relatedcomponents.We use3 routines,with thesameargumentsasthe0-D, 2-D, and3-D Historical output routines.
� When do I call the above3-D Historical Control output routine (write nc Abiotic ctrlH 3D.f)? Itshouldbecalledwith Annual means (nt=1) for 1765,1838,1839,1900,andeveryyearfrom 1953-1999(inclusive).
� When do I call the above2-D Historical Control output routine (write nc Abiotic ctrlH 2D.f)? Itshouldbecalledwith Annual means (nt=1) for 1765,1838,1839,1900,andeveryyearfrom 1948-1999(inclusive).
� When do I call the above0-D Historical Control output routine (write nc Abiotic ctrlH 0D.f)? Itshouldbecalledonly once,afterconstructing1-D (in time)arraysfrom all of yourmodeloutput.Thetimestoragefrequency is regular:everymonththroughouttheentirerun (i.e.,all years1765-1999,inclusive). Thusmodelersmustusenrec = 2820,andfill thethe1-D temporalarraytimes with theappropriatevalues(i.e.,1765.04167,1765.125,1765.2083,1765.29167,1765.375,... 1999.875,1999.9583).TheHistorical Control Runusesthesamenrec andtimes arrayasdoestheHistorical run.
2. Future Control output(for 2000-2764,inclusive): We saveonly theDIC-relatedcomponent.We use3 routineswith thesameargumentsasthe0-D, 2-D, and3-D Future output routines.
� When do I call the above3-D Future Control output routine (write nc Abiotic ctrlF 3D.f)? It shouldbecalledwith Annual means (nt=1) for years2000,2010,2020,2040,2060,2080,2099,2100,2120,2140,2160,2180,2200,2220,2240,2260,2280,2299.
5. Output Format 26
� When do I call the above2-D Future Control output routine (write nc Abiotic ctrlF 2D.f)? It shouldbecalledwith Annual means (nt=1) for years2000,2010,2020,2040,2060,2065,2080,2099,2100,2120,2140,2160,2165,2180,2200,2220,2240,2260,2265,2280,2299.
� When do I call the above0-D Future Control output routine (write nc Abiotic ctrlF 0D.f)? It shouldbecalledonly once,afterconstructing1-D (in time)arraysfrom all of yourmodeloutput.Thetimestoragefrequency is regular:everymonththroughouttheentirerun(i.e.,all years2000-2300,inclusive).Thusmodelersmustusenrec = 3600,andthey mustfill the1-D temporalarraytimes) with appropriatecorrespondingmid-monthvalues(i.e.,2000.04167,2000.125,2000.2083,2000.29167,2000.375,...,2299.875,2299.9583).Notethatnrec andtimes areNOT identicalto thoseusedwhencalling theanalogous0-D routineto saveFutureoutput(i.e.,nrec is smaller;times starts10yearslater).
3. Pulse Control output(for 2000-2764,inclusive): We save only theDIC-relatedcomponent.We use2 routineswith thesameargumentsasthe0-D and2-D Pulse output routines.
� When do I call the above2-D Pulse Control output routine (write nc Abiotic ctrlP 2D.f)? It shouldbecalledwith Annual means (nt=1) for years0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,20,30,40,50,60,70,80,90,100,200,300,400,500,600,700,800,900,and999.
� When do I call the above0-D Pulse Control output routine (write nc Abiotic ctrlP 0D.f)? It shouldbecalledonly once,afterconstructing1-D (in time)arraysfrom all of yourmodeloutput.Thetimestoragefrequency is NOT regularlyspacedin time. For the0-D Pulse Control run,outputasspecifiedbytimes mustbegivenfor
– everymonthfrom years0.0to 10.0(i.e.,12x 10= 120records),with correspondingmonthlymeansprovidedatmid-month(i.e., for times = 0.04167,0.1250,0.2083,0.29167,0.3750,... 9.875,9.9583);
– everyyearfrom years10.0to 100.0(i.e.,90records),with correspondingannualmeansprovidedatmid-year(i.e., for times = 10.5,11.5,12.5,... 99.5);
– every10yearsfrom years100.0-991.0(i.e.,90records),with correspondingannualmeansprovidedatmid-year(i.e., for times = 100.5,110.5,120.5,130.5,... 990.5);and
– thefinal year(i.e.,1 record),with its correspondingannualmeansprovidedatmid-year(i.e., fortimes = 999.5).
Thuswith this irregularspacing,modelsmustusenrec = 301(i.e.,120+ 90+ 90+ 1).
5.4.6 Namesof Output files
All argumentsof theAbiotic routinesareinput;noneareoutput.With theargumentsaslistedin thenineroutinesabove,ThecorrespondingoutputnetCDFfiles are
Thesefilesalongwith all othersproducedby theAbiotic routinesshouldbetrasferredto IPSL(seesectionTransferof output).FilenamesshouldNOT bechanged.Subsequently, at IPSL,fileswill be(1) testedfor consistency, (2)includedin theOCMIP-2database,and(3) processedfor baseanalysis.
5.5 Needmoredetails?
See <http://www.ipsl.jussieu.fr/OCMIP/tec h>. for additionalinformationabouttheformatnetCDFandotherconventions(COARDS,GDT) chosenfor storingOCMIP-2modeloutput.
We providedetailsonly for transferringEquilibriumOutput.Outputfrom theotherAbiotic simulations(HistoricalOutput,FutureOutput,PulseOutput,andControlOutput)shouldbetransferredin ananalogousfashion.
If gzip is notavailableonyourmachine,thealternative is to usecompress . After compression,youshouldftp yourfiles to LSCEfor processingandanalysis.Yourmodeloutputcouldbequitelargedependinguponmodelresolution.Fearnot though,becausewehave thediskspaceto accommodateoutputfrom all OCMIPmodels.Contactusif theftp transferrateis inadequate.In thatcase,you’ll needto write youroutputto tape(DDS,DDS2,Exabyte,or DLT)andmail it to
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