Opened 8 years ago

Closed 7 years ago

#1092 closed help (answered)

Radiation diagnostics on different timestep to other variables?

Reported by: Emma_Turner Owned by: um_support
Component: UM Model Keywords: timestep radiation
Cc: Platform: HECToR
UM Version: 6.6.3



I am confused as to what has happened with my radiation timesteps appearing at different times to all other variables. I am using a 15 hour timestep with the 30 day month so in Atmosphere - Scientific Parameters and Sections - Time-stepping, the 'Number of timesteps per 'period' I have is 48, and 'Number of days per 'period is 1. At the bottom the 'Convection calling frequency (Timesteps)' is 3, and both the 'Number of calculations of SW/LW radiation increments per day' are 8.

As my timestep is every 15 hours some daily .pp files contain 2 timesteps (time0) and some contain 1. The radiation outputs I have now asked for (e.g. section 2, item 205 outgoing LW rad flux (TOA)) are appearing with a separate time coordinate time1, whose values are very similar to time0 but about 0.02 days out (time is in days since 1970-01-01). Also sometimes the timestep is in the next file along.


Day 1 time0 13259.38, 13260
Day 1 time1 13259.4
Day 2 time0 13260.62
Day 2 time1 13260.02, 13260.65

I thought I was for filling all the requirements for frequency of radiation calls being integer multiples of the timestep. But I must have missed something.

Can you help?
Many thanks

Change History (7)

comment:1 Changed 8 years ago by jeff

Hi Emma

I'm a bit confused with your explanation here, maybe if you could give the jobid things would be clearer. One thing to note is the radiation diagnostics are always output 1 time step later than the other diagnostics.


comment:2 Changed 8 years ago by Emma_Turner

Hi Jeff,

The job id is xihtfa I don't know if you can see the files at /home/d43/d43-geos-climate/eturner/work/um/xihtf/M ? You might not have access rights.

OK by timestep do you mean the one I set, in this case 15 hours? Maybe it is a rounding problem if that is the case, where the 2 times, time0 and time1, are rounded to different values as they are very close.


comment:3 Changed 8 years ago by jeff

I take it you mean job xihtf? I don't know what you mean by a 15 hour timestep, the timestep for this job is 30 minutes.


comment:4 Changed 8 years ago by Emma_Turner

Yes that is right. By 15 hour timestep I mean that we are only obtaining output every 15 hours.


comment:5 Changed 8 years ago by Emma_Turner

I have looked at the data and am I right in thinking that the LW radiation timestep is also 1 timestep after the SW timestep? Looking at my data I have time0 (most variables), time1 (SW variables) and time2 (LW variables). However there is some confusion as the variable: Outgoing LW radiation flux (TOA) which is STASH section 2, item 205 is a LW radiation variable, but has time1 (SW radiation) as its time coordinate? Can you help?


comment:6 Changed 8 years ago by jeff

I really need to see some of the UM output files, if they aren't too big can you copy a couple of files to puma, the original data and your converted data if you still have them.


comment:7 Changed 7 years ago by annette

  • Resolution set to answered
  • Status changed from new to closed


I'm assuming we can close this ticket as there hasn't been a response in a while. You can reopen the ticket or create a new one if you further issues.


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