The horizontal east-west drift velocity VE of ionisation irregularities in E region, and the vertical drift velocity VF of electrons in F region over Jicamarca (dip latitude?1¿N) are used to estimate the average diurnal variation of the east-west components of the electric fields in these two regions. The F region field is estimated from VF by using the relationship derived earlier by Woodman. The E region field is estimated from VE by using a relationship different from the one used earlier by Balsley and Woodman and is derived by using more realistic electrojet and conductivity models. The E region electric field thus obtained is found to be weaker at least by a factor of 3 than that estimated by Balsley and Woodman. A comparitive study shows that the east-west electric field in the F region is, most of the time, stronger than that in the E region, and also that the ratio of the E region field to the F region field systematically increases from forenoon to afternoon hours, and from pre-midnight to post-midnight hours. |