2. Data Analysis

[3]  The morphological analysis was made for Huancayo ( j = 12.0 ^oS; l = 284.7 ^oE; I=1.3 ) and Kodaikanal ( j = 10.2 ^oN; l = 77.5 ^oW; I=2.6 ) over all available years of observations, (1957-1989) and (1957-1987) for the two stations, respectively. Following to the method by MDL a 27-day N_mF2 running median centered to the day in question rather than usual monthly median was used for the Q disturbances analysis. The advantages of using the 27-day median were discussed by MDL. In our analysis, Q disturbances were referred to hourly ( N_mF2/N_mF2 _med -1 ) deviations more than 40% if all 3-hour ap indices were 7 for 24 previous hours. Normally, this provides a selection of quiet time periods (MDL). Three levels of solar activity were considered using 12-month running mean sunspot number: solar minimum R₁₂ < 50, medium R₁₂ = 50-100, and maximum R₁₂ > 100.