This data set consists of six coefficients sets and a FORTRAN program to generate global foF2 maps for different universal times (UT: 0, 1, 2, . . . 23). The model is based on measurements by the topside sounder aboard the Japanese ISS-b. Data were sampled into two-hour UT bins. Measurements from four consecutive months had to be combined to obtain a homogeneous global coverage. The exact sampling periods for the six sets of coefficients are 8/11-12/12/78, 10/10/78-2/11/79, 11/9/78-3/13/79, 1/10-5/14/79, 2/9-6/13/79, and 8/8- 12/13/79. About 2,000 globally distributed data points are found for each of the periods in each of the UT bins. Spherical harmonics analysis is applied to these data points up to order 9 in modified dip latitude and to 4 in geographic longitude. The analysis method is explained in six reports of the Communications Research Laboratory for the six time periods. These reports also include global contour plots for different UTs and LTs. The ISS-b maps are for high solar activity, whereas the CCIR and URSI maps cover the whole solar activity range. Rush et al. (1989) showed that the new URSI model represents the ISS-b maps better than the older CCIR model.
Availability: On tape or networks from NSSDC's Request Office.
NSSDC ID: 78-018A-01A)
Atlas of Ionospheric Critical Frequency (foF2) Obtained from Ionospheric Sounding Satellite-b Observation, Part 1, August to December 1978 (1979); Part 2, October 1978 to March 1979 (1980); Part 3, January to June 1979 (1981); Part 4, August to December 1979 (1983), Communications Research Laboratory, Ministry of Posts and Telecommunications, Tokyo, Japan.
N. Wakai and N. Matuura, Operation and Experimental Results of the Ionosphere Sounding Satellite-b, Acta Astronautica 7, 999, 1980.
N. Matuura, M. Kotaki, S. Miyazaki, E. Sagawa, and I. Iwamoto, ISS-b Experimental Results on Global Distributions of Ionospheric Parameters and Thunderstorm Activity, Acta Astronautica 8, 527, 1981.
C. M. Rush, M. Fox, D. Bilitza, K. Davies, L. McNamara, F. Stewart, and M. PoKempner, Ionospheric Mapping-An Update of foF2 Coefficients, Telecomm. J. 56, 179, 1989.
NASA Official: Dr. Robert McGuire, Head of the Space Physics Data Facility