#284 closed Support (fixed)
Strange big bouncing of particles when hitting ground
Reported by: | fcheng | Owned by: | pesei |
---|---|---|---|
Priority: | major | Milestone: | |
Component: | FP other | Version: | FLEXPART 10.4 |
Keywords: | Cc: |
Description
Dear FLEXPART community,
I observe that the particles released by FLEXPART have seemingly overexaggerated bouncing behavior when they are hitting the ground, sometimes they can be reflected by a few km or even up to 10km in just one hour. This really confuses me since it just does not make sense.
I think the source code that controls the bouncing of particles is related to advance.f90, and maybe also the default setting of SPECIES 24. But I just could not really identify where the problem comes from.
For your information, here is my RELEASES file
&RELEASES_CTRL NSPEC = 1, ! Total number of species SPECNUM_REL= 24, ! Species numbers in directory SPECIES / &RELEASE ! For each release IDATE1 = 20080601, ! Release start date, YYYYMMDD: YYYY=year, MM=month, DD=day ITIME1 = 00000, ! Release start time in UTC HHMISS: HH hours, MI=minutes, SS=seconds IDATE2 = 20080601, ! Release end date, same as IDATE1 ITIME2 = 00000, ! Release end time, same as ITIME1 LON1 = -179.000, ! Left longitude of release box -180 < LON1 <180 LON2 = 179.000, ! Right longitude of release box, same as LON1 LAT1 = -89.000, ! Lower latitude of release box, -90 < LAT1 < 90 LAT2 = 89.000, ! Upper latitude of release box same format as LAT1 Z1 = 0.000, ! Lower height of release box meters/hPa above reference level Z2 = 5000.000, ! Upper height of release box meters/hPa above reference level ZKIND = 1, ! Reference level 1=above ground, 2=above sea level, 3 for pressure in hPa MASS = 1.0000E0, ! Total mass emitted, only relevant for fwd simulations PARTS = 6000000, ! Total number of particles to be released COMMENT = "RELEASE 1 test, particles released in an hour.", ! Comment, written in the outputfile /
And my COMMAND
&COMMAND LDIRECT= 1, ! Simulation direction in time ; 1 (forward) or -1 (backward) IBDATE= 20080601, ! Start date of the simulation ; YYYYMMDD: YYYY=year, MM=month, DD=day IBTIME= 00000, ! Start time of the simulation ; HHMISS: HH=hours, MI=min, SS=sec; UTC IEDATE= 20080601, ! End date of the simulation ; same format as IBDATE IETIME= 210000, ! End time of the simulation ; same format as IBTIME LOUTSTEP= 3600, ! Interval of model output; average concentrations calculated every LOUTSTEP (s) LOUTAVER= 3600, ! Interval of output averaging (s) LOUTSAMPLE= 900, ! Interval of output sampling (s), higher stat. accuracy with shorter intervals ITSPLIT= 99999999, ! Interval of particle splitting (s) LSYNCTIME= 900, ! All processes are synchronized to this time interval (s) CTL= -5.0000000, ! CTL>1, ABL time step = (Lagrangian timescale (TL))/CTL, uses LSYNCTIME if CTL<0 IFINE= 4, ! Reduction for time step in vertical transport, used only if CTL>1 IOUT= 1, ! Output type: [1]mass 2]pptv 3]1&2 4]plume 5]1&4, +8 for NetCDF output IPOUT= 1, ! Particle position output: 0]no 1]every output 2]only at end 3]time averaged LSUBGRID= 0, ! Increase of ABL heights due to sub-grid scale orographic variations;[0]off 1]on LCONVECTION= 1, ! Switch for convection parameterization;0]off [1]on LAGESPECTRA= 0, ! Switch for calculation of age spectra (needs AGECLASSES);[0]off 1]on IPIN= 0, ! Warm start from particle dump (needs previous partposit_end file); [0]no 1]yes IOUTPUTFOREACHRELEASE= 0, ! Separate output fields for each location in the RELEASE file; [0]no 1]yes IFLUX= 0, ! Output of mass fluxes through output grid box boundaries MDOMAINFILL= 1, ! Switch for domain-filling, if limited-area particles generated at boundary IND_SOURCE= 1, ! Unit to be used at the source ; [1]mass 2]mass mixing ratio IND_RECEPTOR= 1, ! Unit to be used at the receptor; [1]mass 2]mass mixing ratio 3]wet depo. 4]dry depo. MQUASILAG= 1, ! Quasi-Lagrangian mode to track individual numbered particles NESTED_OUTPUT= 0, ! Output also for a nested domain LINIT_COND= 0, ! Output sensitivity to initial conditions (bkw mode only) [0]off 1]conc 2]mmr SURF_ONLY= 0, ! Output only for the lowest model layer, used w/ LINIT_COND=1 or 2 CBLFLAG= 0, ! Skewed, not Gaussian turbulence in the convective ABL, need large CTL and IFINE OHFIELDS_PATH= "../../flexin/", ! Default path for OH file /
And, here is the hourly altitude (meters a.g.l.) of a particle that had a big bounce (and there are many particles with such a behavior)
397.4110413 40.72389984 537.1908569 289.5689392 937.1464233 323.7579346 98.35718536 138.9232025 74.352005 155.2883759 11351.6709 11257.2832 11149.76074 11025.70117 10902.66504 10848.78516 10827.65918 10822.45605 10803.74316 10752.75 10698.94824
Is such a big bouncing behavior normal? Any hints and help are much appreciated. Thanks a lot!
Warm regards,
Fandy
Change History (4)
comment:1 Changed 3 years ago by pesei
- Owner set to pesei
- Status changed from new to accepted
comment:2 Changed 3 years ago by fcheng
Thank you for the reply. From my experience analyzing the particle's position, I found that such an abrupt jump often occurred near the ground level, that was why I thought the particle might hit the ground and somehow trigger the bouncing motion.
I think for a particle that travels vertically by 10km in just one hour seems a bit strange. I will check the results again by turning the convection scheme off. Thanks a lot for the hint.
Cheers,
Fandy
comment:3 Changed 3 years ago by pesei
- Resolution set to fixed
- Status changed from accepted to closed
It is not strange, it is how convection works. And penetrating convection starts near the surface. However, if you think that too many particles are affected, and if you see this happen even if you turn convection off, then please reopen the ticket.
comment:4 Changed 3 years ago by fcheng
Well understood. Thanks a lot for the comment. I really appreciate it.
Best,
Fandy
I see that you have convection activated. Therefore I assume that what you see is a particle lifted in convection from 155 m to 11351 m. I do not see "bouncing" in your data.