No abstract

No abstract

No abstract

No abstract

No abstract

accurate in each data system to better than 1 s during the period of the measurements. The time during which the cable measurements were made was relatively quiet geomagneticallyB. Five of the most quiet days were selected to represent the Sq variation measured at Green Hill. These days, and their daily sum global geomagnetic activity indices 'i.Kp were: 3 May,-6; 4 May,-9; 5 May,-14; 17 May, +5; 18 May,-8. The averages ofthese five quiet days in the three magnetic field components measured at Green Hill are shown as solid lines in Fig. 2. These averages are obtained from the hourly mean values. The time dependences during a day show typical Sq patterns for this geomagnetic latitude, except for the local morning intervals in the Hand Z-components. The dashed lines in Fig. 2 show the computed Sq curves expected on the basis of the spherical harmonic analysis of the potential for the daily variation by Chapman and Bartels 9 • We used the harmonic coefficients of Matsushita lO for location B on the model cable path in Fig. 1. The fit of the calculated Sq patterns using location B is quite good in the east-west component but is not good for the local morning observations in either the north-south or the vertical components. In addition, the magnitude of the Sq variation observed in the local afternoon in the north-south component is about a factor of two larger than that predicted by the model Sq calculations. These disagreements in the north-south and vertical components are

No abstract

No abstract