MARS CLIMATE DATABASE v5.0 USER MANUAL - The Mars ...

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Table 2: CALL MCD output arguments (continued)ier integer Status code: When an error occurs in call mcd, all the outputsarguments (pres, dens, temp, zonwind, merwind,all elements of meanvar and extvar)are set to −999 and amessage is written to the standard output. The value of iersummarises the status of call mcd :0: OK (no error)1: Wrong vertical coordinate flag zkey2: Wrong choice of dust scenarion scena3: Wrong value for perturbation flag perturkey4: Wrong value for high resolution flag hireskey5: Wrong value for date flag datekey6: Wrong value for extra variables output flag extvarkey7: Wrong value for latitude xlat8: Inadequate value for gravity wave wavelengthgwlength9: Wrong value of input solar longitude (xdate must be in[0:360], in the datekey=1 case)10: Given Julian date xdate (in the datekey=0 case) impliesan Earth date outside of [1800:2200] range11: Wrong value of local time (in the datekey=1 case),which should be in [0:24]12: Incompatible localtime≠0 and datekey=013: Unresonable value of seedin (in perturkey=5 case)14: No dust storm scenario available at such date15: Could not open a database file (dset is probably wrong)16: Failed loading data from a database file17: Sought altitude is underground18: adding (perturkey=5) perturbation yields unphysicaldensity19: adding (perturkey=5) perturbation yields unphysicaltemperature20: adding (perturkey=5) perturbation yields unphysicalpressure5.5 The right use of the CALL MCD subroutine5.5.1 Perturbed atmospheresIn addition to the mean atmospheric state, the user may obtain a realisticly perturbed (using inputflag perturkey) atmosphere.The perturbation consisting of adding n times the standard deviation to the mean value(the perturkey = 5 case) must not be used to create randomly perturbed atmospheres, but onlyas a mean to globally overestimate or underestimate the profiles of the meteorological variables. To20
Table 3: Example of Fortran code to illustrate the use of (re-)setting perturbations! build a density profile at a given time and location! with EOF and GW perturbationsperturkey=4seedin=100 ! seed perturbationszkey=3 ! work in "altitude above local surface" coordinatedo i=1,100xz=(i-1)*2000.0 ! go from surface to 200kmcall_mcd(zkey,xz,xlon,xlat,hireskey,&datekey,xdate,localtime,dset,scena,&perturkey,seedin,gwlength,extvarkeys,&&pres,dens,temp,zonwind,merwind,meanvar,extvar,seedout,ier)profile(1,i)=dens ! store densityenddo!! ... some code here...! ... moved on to a different time or place ’far’ from previous one! ... such that perturbations should be reset!&&&&seedin=seedout! build the new density profiledo i=1,100xz=(i-1)*2000.0 ! go from surface to 200kmcall_mcd(zkey,xz,xlon,xlat,hireskey,! change seedin to regenerate perturbationsdatekey,xdate,localtime,dset,scena,perturkey,seedin,gwlength,extvarkeys,pres,dens,temp,zonwind,merwind,meanvar,extvar,seedout,ier)profile(2,i)=dens ! store densityenddogenerate randomly perturbed atmospheres you must use small or large scale perturbations whichtake into account some correlation of perturbations in the space and between variables. Then whenyou use the perturkey = 5 perturbation, you have to keep the same seedin (ie: multiplyingfactor) along the whole trajectory to avoid introducing unrealistic gradients between consecutivevalues.When generating a randomly perturbed atmosphere using the large scale perturbations (perturkey= 2 or 4) to simulate a trajectory, the value of seedin should be kept constant in order to workwith the same correlated perturbed atmosphere.Reseting the large scale perturbations (by modifying the value of seedin between calls to call mcd)to build profiles at a given location should only be done in the context of generating a range of differentpossibilities (an example is given in table 3).When using the perturbation due to gravity wave propagation (small scale perturbation)(preturkey = 3 or 4), to generate a vertical profile, the phase (ie: the value of seedin), aswell as the associated wavelength gwlength should remain fixed.Note that if computing a group of trajectories clustered over a small horizontal distance (andat a given martian time), then perturbations should not be reset between the computation of eachtrajectory in order to retain the underlying correlation of the perturbations.21
Page 1 and 2: MARS CLIMATE DATABASE v5.0USER MANU
Page 3 and 4: 1 IntroductionThe Mars Climate Data
Page 5 and 6: - Detailed Design Document (detaile
Page 7 and 8: e used. The Fortran subroutines use
Page 9 and 10: • The compile file which contains
Page 11 and 12: Table 1: CALL MCD Input argumentsNa
Page 13 and 14: Table 1: CALL MCD Input arguments (
Page 15 and 16: Table 2: CALL MCD output arguments
Page 17 and 18: Table 2: CALL MCD output arguments
Page 19: Table 2: CALL MCD output arguments
Page 23 and 24: set the path (the dset variable) to
Page 25 and 26: storm; data corresponding to the Cl
Page 27 and 28: ADifferences Between Version 5.0 an
Page 29: • The main difference between ver

MARS CLIMATE DATABASE v5.0 USER MANUAL - The Mars ...

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