Hi Iain, Please give us the input files you used as well as the command line and the error message. I will look at it and answer your question.
Thank you Julie for the answer regarding Iain's questions. Miguel Iain Russell wrote: > Hi Julie > > Thanks for sending along this information. I have read the information > on coupling and it seems that at least 3 hrs of observation/forecast > data overlap is required in order for METRo to produce good forecasts in > the first few hours. We are in fact attempting to provide 8 hours of > overlap, but sometimes as I said in my original post this can result in > the first timesteps in the forecast and observations files being the > same. When this happens the model crashes. > > Our workaround is to have 12 hours of historical forecast data, 8 hours > of historical observed data, prior to the first desired forecast > timestep in the output file. This way we get 8 hours of coupling (good > for data quality), and no crashing of the model because the first > forecast timestep and first obs timestep in the input data never line > up. That's our workaround ; I'm just a bit surprised that no-one else > has come across this issue at some point. > > Regards > Iain > > -----Original Message----- > From: Julie Prestopnik [mailto:[EMAIL PROTECTED] > Sent: November 12, 2007 12:54 PM > To: Iain Russell > Cc: [email protected] > Subject: Re: [Metro-developers] METRo crashes when obs and forecast > start times are the same > > Hi Iain. > > I'll have to defer to the developers of METRo regarding your coupling > question, because I don't know the details of how all of that works (I'm > a software engineer). But, here is a link to an article on METRo that > was published in the Journal of Applied Meteorology which may be able to > answer your question: > http://ams.allenpress.com/perlserv/?request=get-document&doi=10.1175%2F1 > 520-0450%282001%29040%3C2026%3AMANMFR%3E2.0.CO%3B2 > > In the example I gave, there was actually one hour of overlap: > 2006-07-12T12:00Z. > > For most all of the cases I've run, I've given METRo only one hour of > overlap in the observation and forecast data, and METRo has continued to > produce reliable results. > > Also, looking at the Input observation QA/QC page on the wiki: > http://documentation.wikia.com/wiki/Input_observation_QA/QC_%28METRo%29 > > it says under "Time constraints": > "3. Let H, the first hour when METRo provided a road forecast. All > observations after the H time are not be used." > > In my example, the first time for the input forecast data was > 2006-07-12T12:00Z, which means that the first time for output roadcast > data would be 20 minutes later at 2006-07-12T12:20Z. The text above > indicates that any observations after this time would not be used; > another indicator that you want to have observations prior to the first > time in your input forecast file. > > I'm sorry I'm not able to provide more detailed/technical information. > I hope this helps. > > Thanks, > Julie > > > Iain Russell wrote: > >> Hi Julie >> >> I will get some example input files for this situation when the model >> crashes, but I won't have the output roadcast file because...er...well >> the model crashes :) >> >> Regarding your comment that the input obs file end timestep should be >> the same as the input forecast start timestep ; how does the coupling >> stage of the model work in this case ... i.e. in the example you gave, >> there's no overlap of obs and forecast and so there's no way for the >> model to learn from the forecast biases. Maybe I'm missing something. >> >> Regards >> Iain >> >> -----Original Message----- >> From: Julie Prestopnik [mailto:[EMAIL PROTECTED] >> Sent: November 12, 2007 12:19 PM >> To: Iain Russell >> Cc: [email protected] >> Subject: Re: [Metro-developers] METRo crashes when obs and forecast >> start times are the same >> >> Hi Iain. >> >> I'm not sure if I'm interpreting your message correctly or not. It >> sounds like you want the input observation file and the input forecast >> file to start at the same time. For example, having them both start >> > at: > >> 2006-07-12T00:00Z >> >> But instead, METRo wants to have the first input forecast time the >> > same > >> as the last input observation time. So, for example, my observation >> file would start at 2006-07-12T00:00Z and end at 2006-07-12T12:00Z. >> And, my forecast file would start at 2006-07-12T12:00Z and end at >> 2006-07-15T23:00Z. >> >> METRo wants to get the model going by using input observations to >> > start > >> with and then use the forecast information following the observations >> > to > >> help determine the roadcast. >> >> The issue that I reported back on April 6th, was a different >> > situation. > >> We only had one hour of forecast data, but METRo requires at least >> > two > >> hours of forecast data. >> >> I hope this has helped. Also, if you want help in reproducing >> behaviour, it's always helpful to attach all of your I/O files >> (observation file, atmospheric forecast file, station configuration >> file, output roadcast file) and the command line that you're using. >> That way we can test the exact problem that you're having without >> > having > >> major differences. >> >> Let us know if you have any further questions or need any assistance. >> >> Thanks, >> Julie >> >> Iain Russell wrote: >> >>> Hi >>> >>> We have found that METRo crashes when both the input observation file >>> and the input forecast file start at the same timestep. >>> >>> Operationally we are running version 2.1.1, but we also did a test >>> >> with >> >>> the latest stable release and got the same result. In order to >>> circumvent the problem we are capturing more historical forecast data >>> than observation data so that our 2 input files never start at the >>> >> same >> >>> time. >>> >>> A similar-looking issue was reported on April 6th 2007 by Julie >>> Prestopnik ; but I'm unsure if the case that Julie reported and the >>> >> one >> >>> I'm reporting here are related in any way. >>> >>> Can someone do a test to see if you can reproduce the behaviour I'm >>> reporting here ; make the first timestep in the input observation >>> > file > >>> and the forecast file the same times. >>> >>> Thanks >>> Iain >>> >>> >>> >>> >>> >>> > ------------------------------------------------------------------------ > >>> _______________________________________________ >>> METRo-developers mailing list >>> [email protected] >>> https://mail.gna.org/listinfo/metro-developers >>> > > > _______________________________________________ > METRo-developers mailing list > [email protected] > https://mail.gna.org/listinfo/metro-developers > _______________________________________________ METRo-developers mailing list [email protected] https://mail.gna.org/listinfo/metro-developers
