faq

Questions about data

  • Where can I download the PF data?
    Please referer to the data download page here.
  • Why cann't I find some orbits?
    TRMM satellite has to adjust its orbit now and then to keep its orbit height. The measurements are not well calibrated during these manuevers. So we did not process these orbits.
  • Why are there about 0.5% of the PFs have a negative minimum 37/85 GHz PCT (MIN37PCT)? The value is -999.
    Yes, there are many cases when TMI does not return valid values due to the instrument calibration or some other reasons. When that happens, we do not throw all the data away because other instruments work OK. So we mark -999 for such cases. Fortunately, this happens randomly. So the climatology is right if you just filter that data out for calculating the statistics.
  • Sometimes the figure show no VIRS data, why?
    There were periods when VIRS were turned off for various reasons. No VIRS data are available for these times.
  • Why are there zero rainfall over northern Australian from 2A25?
    Due to the complains of the PR interference to the ground devices from the Australian Government, TRMM PR automatically shutdown whenever passes that area. Thus no rainfall is retrieved there.
  • How to calculate flash rates from flashcounts?
    Using the viewtime of features in the level-2 data. flashrate=flashcount/viewtime*60, units in #/minute.
  • How to remove the sample biases?
    Use the total sampled PR or TMI pixels in 1x1 grid summarized in level-3 10 years data (download ).

Questions about software

  • How do I read the PF data?
    Please use the software described here.
  • Are there software in Fortran, Matlab or C to read the data?
    Sorry, at the moment we have no plans to write the code in other languages besides IDL. Since all data are written in HDF4 format, IDL is the easiest software to access them. If you have interest developing software in other programming languages, we are glad to link to your software from here.
  • Are there plotting software available for these data?
    Yes, there are quite a few IDL programs generating most of the plots shown in this website. Because these programs are poorly documented, I am hesitated to just post them online. But I am glad to share them, please contact me for details.

Other Questions

  • Can I use figures from this website in somewhere else?
    We reserve the copyright of the figures generated from this website. Please let us know before you use them in the publications.
  • Can I redistribute the data from this website?
    The data is free to public, please feel free to pass the data and the software to your colleagues. We are grateful if you can acknowledge the data source in your publications if you use the data here.
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