NAM_BALLOONS

This namelist allows to add virtual balloons to the simulation. Before using this namelist, the total number of balloons must be set in the NAM_FLYERS namelist.

Balloons are advected by the wind of the model. They can crash. All the prognostic fields (zonal and meridian wind (from U and V components), vertical velocity, potential temperature, pression, mixing ratios, tke, radiative surface temperature…) are recorded along the trajectories of the balloons, as well as their trajectories themselves (positions in X, Y and Z directions and orography). All records are stored in the diachronic file (.000).

NAM_BALLOONS content

Fortran name

Fortran type

Default value

CMODEL

CHARACTER(LEN=3)(:)

‘FIX’

CTITLE

CHARACTER(LEN=10)(:)

CTYPE//nnn

CTYPE

CHARACTER(LEN=6)(:)

‘’

NMODEL

INTEGER(:)

0

TLAUNCH

TYPE(DATE_TIME)(:)

default value of type(date_time)

XTSTEP

REAL(:)

60.0

XLATLAUNCH

REAL(:)

XUNDEF

XLONLAUNCH

REAL(:)

XUNDEF

XALTLAUNCH

REAL(:)

XNEGUNDEF

XPRES

REAL(:)

XNEGUNDEF

XWASCENT

REAL(:)

XNEGUNDEF

XDIAMETER

REAL(:)

XNEGUNDEF

XVOLUME

REAL(:)

XNEGUNDEF

XMASS

REAL(:)

XNEGUNDEF

XAERODRAG

REAL(:)

XNEGUNDEF

XINDDRAG

REAL(:)

XNEGUNDEF

  • CMODEL : ‘FIX’ if the balloon stays on the same grid model, ‘MOB’ if the balloon may change of grid model (always the finest depending on the horizontal position). ‘FIX’ by default

  • CTITLE : name of the balloon. If not provided, it is set to CTYPE//nnn with $nnn$ the number of the balloon

  • CTYPE : ‘CVBALL’ for constant volume balloon, ‘ISODEN’ for iso-density balloon, ‘RADIOS’ for radiosounding balloon. Mandatory

  • NMODEL : number of the grid model where the balloon flies. If CMODEL=’FIX’, it may be any grid model number (forced to 1 if NMODEL not set). If CMODEL=’MOB’, NMODEL is forced to 1 at simulation start but will change during flight to always fly on the finest model at a given horizontal position.

  • TLAUNCH : instant of launch. Mandatory. This type has 4 fields (nyear, nmonth, nday and xtime).

    Note

    For example:

    TLAUNCH(1)%nyear  =  2023
TLAUNCH(1)%nmonth =     1
TLAUNCH(1)%nday   =    16
TLAUNCH(1)%xtime  = 21600.

  • XTSTEP : data storage frequency. If not set, it is forced to 60s. The frequency must be a multiple of the timestep of the chosen model NMODEL if CMODEL=’FIX’ or of the main model 1 if CMODEL=’MOB’. It will be enforced at run. Balloon positions are not computed with this timestep but with the model one.

  • XLATLAUNCH : latitude of the launching site. Mandatory

  • XLONLAUNCH : longitude of the launching site. Mandatory

  • XALTLAUNCH : altitude of the launching site (mandatory if CTYPE=’RADIOS’; if not set for ‘CVBALL’ or ‘ISODEN’, XPRES must be provided)

  • XPRES : pressure at the launching site (in Pascal). Must be provided for ‘CVBALL’ or ‘ISODEN’ if XALTLAUNCH is not set. Ignored for ‘RADIOS’

  • XWASCENT : ascentional vertical speed of the ballon (in m/s). Speed in calm air for ‘RADIOS’ (added to air vertical speed, default 5 m/s), initial value for ‘CVBALL’ (default 0 m/s), not used for ‘ISODEN’

  • XDIAMETER : diameter of the balloon (for ‘CVBALL’) (in m). If not provided, XVOLUME must be set.

  • XVOLUME : volume of the balloon (for ‘CVBALL’) (in \(m^3\)). If not provided, XDIAMETER must be set.

  • XMASS : mass of the balloon (for ‘CVBALL’) (in kg). Mandatory

  • XAERODRAG : aerodynamic drag coefficient of the balloon (for ‘CVBALL’). Default: 0.44

  • XINDDRAG : induced drag coefficient (i.e. air shifted by the balloon, only for ‘CVBALL’). Default: 0.014