IONOSPHERIC DIGITAL DATABASE
WORLDWIDE VERTICAL INCIDENCE
CD-ROM DATASET
The National Geophysical Data Center (NGDC) (now the National Centers for Environmental Information - NCEI) wishes to announce the July 1994 release of the Ionospheric Digital Database of Worldwide Vertical Incidence Parameters on two compact discs (CDs) with custom-designed access and display software.
The CDs contain 40,000 station months (1350 megabytes) of digitized vertical incidence parameters from 130 sites around the world. These data have been contributed through a major effort among the World Data Centers and many ionosonde network organizations.
The User Documentation Manual included with the CD dataset package details instructions for equipment set up and installation of the software as well as information about the ionosphere and ionograms, vertical incidence parameters, data collection, quality control, format descriptions, and user instructions for the software. Instructions and navigation commands are also provided on-line as context-sensitive help windows inside the IDD display software.
With the Ionospheric Digital Database software, the user may browse and display any data on the CD database. In the individual mode a graph of the diurnal distribution for up to one month is displayed along with the monthly median values. Comparative or composite modes display up to six datasets of any combination of station, date, and ionospheric parameter data available. The browse mode allows the user to search through the numerical values in any one of the selected datasets.
The graphs that you create can be saved as PCX files for display at a later time or for creating your own series of computerized images for visual reproduction.
A world map with both Geographic Longitudes and Latitudes as well as corrected Geomagnetic Latitudes displays the catalog of all ionosonde stations and stations with digital data contained on the CD database. The catalog of digital stations may be searched by any geographic area, date, or ionospheric parameter ascertain availability of data. The map and a list of the stations containing digital data for the selection can be saved.
All the data contributed come from 1957 through 1990. They have been digitized, reformatted, converted to universal time (the software also can display the data in local meridian time), and passed through quality control filters. In November 1993, the Ionospheric Informatic Working Group (IIWG) format was adopted. Corrections, data to fill existing gaps, and data from before and after the 1957 through 1990 period of this release will be added to this continuing database. These data can be obtained from NCEI and will be issued on CDs in the future.
Corrections, data to fill existing gaps, and data from before and after the 1957 through 1990 period of this release will be added to this continuing database. These data can be obtained from NCEI and will be issued on CDs in the future.