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Getting and Using SSUSI Data f rom the SSUSI Website, and Website Features

Learn how to analyze SSUSI data and utilize the features of the SSUSI website. Identify the time period, data products, retrieve and access the data, and analyze variables and data quality. Discover various perspectives and features in the SSUSI Summary image gallery.

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Getting and Using SSUSI Data f rom the SSUSI Website, and Website Features

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  1. Getting and Using SSUSI Data from the SSUSI Website, and Website Features Robert Schaefer and Giuseppe Romeo for the SSUSI team Robert Schaefer Giuseppe Romeo Robert.Schaefer@jhuapl.eduGiuseppe.Romeo@jhuapl.edu 240-228-2740 240-228-5905

  2. Overview • How to do analysis with SSUSI data • SSUSI Web and features

  3. How to Analyze SSUSI data • So you have an idea to investigate some upper atmospheric phenomenon – what do you do now? • First, Identify time period of the data you want. • Second, identify the appropriate data product(s) you need. • Third, Retrieve the data • Fourth, identify Variables that have the information you want • Fifth, identify any quality issues • Sixth, Read and access the data

  4. 1. Identify the Time Period • If you have a pre-defined time period, see discussion of data availability page coming up later to determine what data exist for the period • If not, the SSUSI Website can help • L1B Daily Summaries – found in the SSUSI Gallery • http://ssusi.jhuapl.edu/images_daily_l1b • 3 color images to represent 3 UV color images • Red = LBH Short • Green = 1356 Å • Blue = 1304 Å • Variety of perspectives

  5. SSUSI L1B daily Summary Gallery • Time frame, satellite, date • Slideshow • Perspective • GUVI web site will soon look like this, too. • Can see many features of interest

  6. Features in Summary image • Brightness of color corresponds to UV color intensity • Equatorial Ionosphere • White means all three colors are bright.

  7. Other perspectives available in Summary • Stacked Limb Plots • Stacked Disk Plots • Polar view plots • Orthographic perspectives • Can go browsing for features Stacked Limb Plot Equatorial ionosphere Aurora Dayglow Aurora Polar Perspective Plot

  8. If you need want higher time resolution browse Google Earth galleries • Require Google Earth plugin (freely downloadable from Google)

  9. 2. Identify Data Products You need • Electron Density • Low Latitude Electron Density Profiles • Nightside • 3D density cube: EDR-IONO • Bubbles and Characteristics: EDR-IONO • Mutual neutralization corrected profile: EDR-NIGHT-LIMB • Dayside • Topside density (only above 400 km): EDR-DAY-LIMB • Disk F-region NmF2, HmF2 is an unvalidated product – use at your own risk: EDR-DAY-DISK • High Latitude Electron Density Profiles • E-Region densities: EDR-AURORAL • Dayside Neutral Densities: • O/N2: EDR-DAY-DISK • Solar Extreme UV Flux • Qeuv: EDR-DAY-DISK

  10. Identify Products (for the polar region analysis) • Auroral Zone products - All are in the: EDR-AURORAL • Precipitating electron energy flux (Q) and mean energy (E0) (conductances!) • Hemispheric Power • Regions of proton precipitation • Auroral boundaries (poleward, equatorward),(global/pixelated) • Discrete arc locations • Magnetic field lines from the auroral boundary • Auroral Oval predition –EDR-AURORA-PRED • New product (not validated) gives predicted auroral energy flux, mean energy and boundary

  11. 3 Retrieve the Data • Single files are clickable • Case where you want more than one file will be discussed later

  12. Data Availability – for the future • DMSP program is winding down – one more SSUSI to launch (2016?) • Long term data support> • NASA: Space Physics Data Facility – http://spdf.gsfc.nasa.gov • CDAwebhttp://cdaweb.gsfc.nasa.gov/istp_public/ • Virtual ITM Observatory – http://vitmo.jhuapl.edu

  13. 4. Identify Variables Needed • Separate Document discusses this - Here we give an overview • Coordinates • Low latitude Disk – PiercepointLatitude, Longitude at • Night Altitude 350 km • Day Altitude: 150 km • Auroral Altitude: 110 km • Low Latitude Limb – Tangentpoint Latitude, Longitude, and Altitude • Auroral Zone – Geographic and Magnetic Coordinates available • Magnetic Latitude and Magnetic Local Time • Time • Year, DOY, and Seconds of the day • Note seconds of the day called “TIME” in all files except AURORAL files where it is called UT (actually UT_N for northern hemisphere magnetic coordinates and UT_S for southern hemisphere coordinates) • Other variables more specific to the product and type of analysis

  14. Example DQI • EDR-NIGHT-LIMB • DATA_QUALITY variable is an array – 1 per pixel Bit # Meaning if set to true (1) 0 VER fit unsuccessful (chi squared test: rchi2v>10) • Chapman fit unsuccessful (chi squared test: rchi2c>10) • NmF2 uncertainty > 50% • HmF2 < 0 km • HmF2 > 500 km • HmF2 uncertainty > 50% • NRP < 7 • SZA < 105 degrees • MeV contamination 9-15 Spare

  15. 5. Data Quality Issues • Data Quality Indices – Integers used as bit fields • Individual bits have meaning for different failure conditions • Designed so that 0=good, 1=bad • Simplest thing to do: • Evaluate as integers • Throw away anything that is not 0 • Other Data indicators • Aurora – sometimes files only cover one hemisphere • SOUTH_DATA, NORTH_DATA are set to 1 if Data exists for the SOUTH, NORTH hemispheres, 0 if no data. • Variables can be checked to see if any useful data exists • Also Pixels with no data are set to IEEE NaN value to prevent accidental use in averages • no problem for IDL programmers • Good_data_indices= where(finite(variable_arrary))

  16. 6. Read and Access Data • IDL Software tools available (http://ssusi.jhuapl.edu/software_tools) • These allow you to read and plot data • Libraries in many computer language for reading NetCDF available from Unidata UCAR web site (http://www.unidata.ucar.edu/software/netcdf/index.html) • Most useful utility we have found: read_ncdf.pro • Reads in everything in the file and populates an idl structure with a single call • Variable names become tags in the structure • Reads in all global header information, including geophysical indices supplied by the Air Force in realtime • Plotting routines show examples of reading and manipulating most useful variables

  17. SSUSI and GUVI Websites

  18. SSUSI Website • Most of the content is available to the general public, some is restricted to registered users • New interface/New tools

  19. New Features for SSUSI website • Data Availability • Data Retriever • Image Galleries (including Google Earth KMZ file) • Enhanced Data Retriever (registered users ONLY) • Software tools

  20. SSUSI Data Availability(http://ssusi.jhuapl.edu/data_availability)

  21. Data Retriever (http://ssusi.jhuapl.edu/data_retriver)

  22. Data Products (http://ssusi.jhuapl.edu/data_products)

  23. Daily Data Retriever (http://ssusi.jhuapl.edu/daily_data_retriever) • To prevent abuse by robots, only registered users can retrieve data for periods longer than 1 orbit. • For Longer Periods than a day, need to request them by e-mail to one of us on the SSUSI team • Compressed files covering a range of dates can be downloaded by registered users.

  24. User Requested Data Archive(http://ssusi.jhuapl.edu/data_archive)

  25. Daily Summary Images(http://ssusi.jhuapl.edu/images_daily_l1b)

  26. EDR-AURORAL KMZ gallery(http://ssusi.jhuapl.edu/gal_edr-aur)

  27. EDR-IONOSPEHERE (http://ssusi.jhuapl.edu/gal_edr-iono)

  28. GUVI New Data Products • Thermospheric O/N2 Gallery • Level 1B Spectrograph Gallery • Thermospheric O/N2 Gallery and Total Electron Control • SSUSI-Like EDR-AURORAL, EDR-IONOSPHERE, SDR

  29. GUVI Thermospheric O/N2 Gallery(http://guvi.jhuapl.edu/site/gallery/guvi-galleryl3on2.shtml)

  30. GUVI Level 1B Spectrograph Gallery(http://guvi.jhuapl.edu/site/gallery/guvi-galleryl1bspec.shtml)

  31. GUVI Thermospheric O/N2 Gallery and TEC(http://guvi.jhuapl.edu/site/gallery/guvi-galleryl3on2tec.shtml)

  32. SSUSI Like EDR-AURORAL(http://guvi.jhuapl.edu/site/gallery/NewProduct/edr-aur/guvi-gallery.shtml)

  33. SSUSI Like EDR-IONOSPHERE(http://guvi.jhuapl.edu/site/gallery/NewProduct/edr-iono/guvi-gallery.shtml)

  34. SSUSI Like SDR(http://guvi.jhuapl.edu/site/gallery/NewProduct/sdr/guvi-gallery.shtml)

  35. What’s to come, funding permitting! • New web interface for GUVI • NetCDF 4 (compressed and browseable format) • Simpler Filenaming scheme • Solar Storm alert based on Auroral SSUSI data

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