This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.
> > Hi Guys, > > Can you give me a quick ABC on how to do back trajectories in the > IDV? > > One group of students here at the PASI will be working on transport > of Saharan dust to the Caribbean, and it would be very useful to > be able to illustrate the likely origins of air parcels sampled. > > This will be used Friday afternoon in a computer lab. > > Thanks in advance... > > Cheers, > > Tom Tom, It is very easy to do. 1)Open a globe view window. 2)Load a dataset, gfs 1 degree, you may need more than one dataset since it takes pretty long time to move dust from Saharan to Caribbean, if so, aggregate them. 3)In the field Selector, select momentum > derived > Grid 3D trajectory, click create display, when a window popup, select the colored by parameter. Note: it would be good to use property window to subset the time, use every other, or something, otherwise, it is too big to load every time step. 4)In the trajectory control, select level to 85000, inital area as "Rectangle", and check the "Backward trajectory" box, and draw a rectangle in the globe view window around the Caribbean region, and click "Create Trajectory" The only thing I worry about is the internet speed if you are getting data from remote server. Yuan > -- > +----------------------------------------------------------------------------+ > * Tom Yoksas UCAR Unidata Program * > * (303) 497-8642 (last resort) P.O. Box 3000 * > * address@hidden Boulder, CO 80307 * > * Unidata WWW Service http://www.unidata.ucar.edu/ * > +----------------------------------------------------------------------------+ > > Ticket Details =================== Ticket ID: HVX-641068 Department: Support IDV Priority: Normal Status: Closed