The influence of varying solar activity on ionospheric electron and ion 
temperatures using SROSS-C2 RPA data 
 
 
P K Sharma and D K Sharma 
 
Department of Applied Sciences & Humanities 
Manav Rachna College of Engineering, Faridabad 121001 (INDIA) 
 ssem_2002@yahoo.com, Fax: 0129-4198111 
 
 
ABSTRACT 
Ionospheric F-region is very dynamic and highly depends on the solar cycle. In 
the present study almost half of the solar cycle from January 1995 to December 
2000 (from solar minimum to solar maximum) satellite data were used. The data 
were recorded with the help of Retarded Potential Analyzer (RPA) payload aboard 
Indian SROSS-C2 satellite at an average altitude of 500 km over the Indian 
region. The data analysis shows that the nighttime average ionospheric electron 
and ion temperatures show a positive correlation with solar activity. However, 
the sunrise peak values show anti-correlation with solar activity. Further the 
ratio of sunrise average peak value and nighttime average show a negative 
correlation with the solar activity both for electron and ion temperatures. A 
sudden enhancement at sunrise has been observed during all seasons, in both 
electron and ion temperatures. Comparison of the measured ionospheric electron 
and ion temperatures with the predicted values from th 
 e international reference ionosphere (IRI) reveals that the peak during sunrise 
hours is slightly underestimated by the IRI model. 
 
Key words: F2 region; Ionospheric temperature; Solar activity; PRA payload