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[IDV #QEL-679004]: Use case for time matching, HRRR, etc...

> IDVers:
> 
> I have something I would like to do with IDV and I don't know if it
> can be done with the current IDV.  Perhaps it can, but it is not
> immediately obvious.

Jim,
      Yes, it can be done in the current IDV.
> 
> What I would like is a loop extending from 12 hours into the past
> to 12 (or 18) hours into the future that seemlessly blends *observed*
> radar reflectivity, HRRR *analyzed* surface wind vectors (and possibly
> other fields), and HRRR forecasts of radar reflectivity and surface wind
> vectors.  The idea is to have a real-time short-range forecast tool for
> precipitation the blends the observed/analyzed past with the future
> forecast.  The bundle would need to grab past HRRR analyses and the
> latest HRRR forecast.  It would probably be best if it were done with
> hourly increments for performance reasons.
> 
> Of course, we need the HRRR for this and I don't think it is
> presently available on motherlode (hopefully it is coming).  In it's
> place, we could use the RAP as a test case.

HRRR is available in this catalog:

http://thredds.ucar.edu/thredds/catalog.xml

There may be some minor changes in the catalog, but the best time series should 
be consistent.

> 
> So, I sat down to do this today with the RAP and it wasn't
> immediately obvious how to do it and it highlights, potentially, some of
> the limitations of the IDV, the need for more user friendliness with
> regards to time matching, or the need for some improvements with THREDDS.
> 
> For example, I thought I might be able to specify the from 12 hours
> into the past to 12 hours into the future using the time animation
> properties widget, but I don't think this is possible. Either the start
> or end time needs to be Current time for a real-time bundle.  An
> alternative would be to use the maximum time for all data and grab the
> latest HRRR/RAP, but if one does that, you need to use the somewhat
> obtuse "reverse times" options with the best time series option.  This
> gets messy very quickly.  I've done it for many of my bundles, but it's
> very hard to setup right.  We need to do better.  BTW, whatever happened
> to the latest model run option on the motherload THREDDS?  All there is
> now seems to be best time series.
> 

The only possible way is to use the time animation widget to set the driver 
time, you can specify past 12 hours
to future 18 hours by selecting both start and end time as current, and then 
set the offset values
to be -12 for past and 18 for future.

> I've been thinking of making this capability in most of my
> bundles.  It would be cool to have analyses and forecasts blended
> together.  Presumably there is an easy way to do this, but I'm not sure
> how if one starts mixing in model forecasts, satellite data, radar data,
> etc.
> 

Time driver feature is the best fit for this kind of requirement.

> Let me know if I'm clueless or if we have a topic worth of
> addressing.  Oh yeah, to beat a dead horse, this brings up the
> omniprescent need to be able to identify forecast vs. analysis hours
> with the model grids.
> 
> Jim
> 

Let me know if you need more help.


Yuan
> 
> 
> 

Ticket Details
===================
Ticket ID: QEL-679004
Department: Support IDV
Priority: Normal
Status: Open