SWIPPA Products COMMENTS

Transcription

1 PRODUCT SWIPPA-DLR-CNF-PRO-DAT-TEC SWIPPA-DLR-RST-PRO-MAP-TEC COMMENTS TEC : Total Electron Content Vertical Source: GNSS measurements; SWIPPA-DLR-CNF-PRO-DAT-TMP SWIPPA-DLR-RST-PRO-MAP-TMP TEC-TMP : Total Electron Content Rate of TEC (ROT ) SWIPPA-DLR-CNF-PRO-DAT-LON SWIPPA-DLR-RST-PRO-MAP-LON TEC-LAT : Total Electron Content Longitudinal Gradient SWIPPA-DLR-CNF-PRO-DAT-LAT SWIPPA-DLR-RST-PRO-MAP-LAT TEC-LON : Total Electron Content Latitudinal Gradient SWIPPA-DLR-CNF-PRO-DAT-FOR TEC-FOR : Total Electron Content Forecast Source: NTCM2 model + space weather observations ; Update: ~ 15 min ; Format: data files ; SWIPPA-DLR-OPN-PRO-DAT-WRN WRN : Warning geophysical message Source: space weather observations ; Update: ~ 15 min ; Format: data files ;

2 PRODUCT MAP No Parameter Description Update Format Size Comments 1. TEC Total Electron Content 2. TEC-TMP Rate of TEC 3. TEC-LAT Total Electron Content Latitude Gradient 4. TEC-LON Total Electron Content Longitude Gradient

3 PRODUCT - MAP DATA The rtf file format is used to archive and exchange maps of ionospheric data; such files contain only ascii -character data. An rtf file contains one map. Note: it is considered in future to accommodate several consecutive maps in one file covering 24 hour period). Each map file starts with a header followed by several lines of data. Here is the description of the header and the data lines: SWIPPA-DLR-CNF-PRO-DAT-TEC The header starts with a product tag identifying the type of map; thus, the product tag makes it possible to identify the data independent of the file name. At the moment, the following product tags are defined: "SWIPPA-DLR-CNF-PRO-DAT-TEC" for TEC values "SWIPPA-DLR-CNF-PRO-DAT-TECERR" for TEC error values "SWIPPA-DLR-CNF-PRO-DAT-TMP" for temporal TEC gradient values "SWIPPA-DLR-CNF-PRO-DAT-LAT" for latitudinal TEC gradient values "SWIPPA-DLR-CNF- PRO-DAT-LON" for longitudinal TEC gradient values The 8 numbers after the product tag provide the associated time (coded) for the current map in the following sequence: <day> <month> <year> <hour> <minute> <second> <GPS week> <GPSweek-second>. After the associated time, the geographic coordinates of the grid are given: <lowest latitude> <highest latitude> <latitude stepping size> <lowest longitude> <highest longitude> <longitude stepping size>. Then the data scaling factor follows. To reconstruct a value at a grid point the given value has to be multiplied by the scaling factor: <scaling-factor>. After the scaling factor, the header ends with the number of longitudinal grid points and the number of latitudinal grid points: <lon-gridpoints> <lat-gridpoints>. After the header, from the beginning of the next row, a block of data values follow. The values in a given block are ordered from lowest latitude to highest latitude and from lowest longitude to highest longitude. One line contains the values for one longitude and all latitudes. After all data lines, the data block ends with a separate empty line. Note: If the rtf file contains more than one map, the next map starts with a new header line.

4 PRODUCT TEC FORECAST The TEC forecast is based on a prediction of the TEC quite-time behaviour using the NTCM model (Jakowski, 1996; Jakowski et al., 1998) and a sub-sequent correction deduced from measured TEC relative deviations from its quiet-time values (Stankov, 2002; Stankov et al., 2002). The predicted TEC values are provided at the grid points in the SWIPPA area (-5 E < long < 25 E and 35 N < lat < 60 N). The file header (first line) contains description of the data columns (LON longitude, LAT latitude, TECF forecasted TEC value in TECU [10^16/m^2]), year (e.g. 2005), month (e.g. 03), day (e.g. 22), and UT time (hour, minute, second). References: Jakowski, N. (1996): TEC Monitoring by Using Satellite Positioning Systems, in: Modern Ionospheric Science (Eds. H. Kohl, R. Ruester, K. Schlegel), EGS, Jakowski, N., Sardon, E., Schlüter, S. (1998): GPS-Based TEC Observations in Comparison With IRI95 and the European TEC Model NTCM2, Advances in Space Research, 22, Stankov, S. M. (2002): Ionosphere-plasmasphere system behaviour at disturbed and extreme magnetic conditions. OSTC Final Scientific Report, Royal Meteorological Institute of Belgium, Brussels, Belgium. Stankov, S.M., N. Jakowski, A. Wehrenpfennig, R. Warnant (2002): Index of local response to geomagnetic activity for use in the short-term ionospheric forecast. in: COST 271 Products for ITU-R and other radiocommunication applications (Proceedings of the EU COST-271 workshop, 1-5 October 2002, Faro, Portugal).

5 PRODUCT WARNING MESSAGE Notes: The first row contains the predicted estimate of the space weather conditions according to the scale: SEVERE, STRONG, DISTURBED, UNSETTLED, QUIET. For convenience, the SWIPPA disturbance scale is linked to the geomagnetic index Kp, but not only. Further explanation is provided below. Each warning (if source data are available) is issued about minutes in advance. The warning is valid for the time and date given on the second and third row. A file contains only the recent warning text. The warning message has ASCII characters only. After analysing and synthesising the incoming geophysical information, short messages are forwarded to users, warning them about on-going ionosphere disturbances. The warning message is kept simple so it can be conveniently used by programmers for derivative services via the ftp protocol. The warning is mostly based on the geomagnetic index Kp estimations/predictions using solar wind observations. Additional data are also considered such as measurements of the geomagnetic field's horizontal component and the percentage deviation of the ionospheric critical frequency from its monthly medians.