At magnetic equator, total intensity of Earth’s magnetic field is I_E and at poles it is I_P. They are related as

$\text{ Total intensity of Earth's magnetic field}$

$\mathrm{in} \mathrm{terms} \mathrm{of} \mathrm{\lambda }\text{ is }\mathrm{I}={\mathrm{I}}_0\sqrt{1+3{\sin }^2\mathrm{\lambda }}$

At poles, ${\mathrm{I}}_{\mathrm{P}}={\mathrm{I}}_0\sqrt{1+3·{\sin }^{2}90°}={\mathrm{I}}_0\sqrt{1+3}==2{\mathrm{I}}_0$

At equator, ${\mathrm{I}}_{\mathrm{E}}={\mathrm{I}}_0=\sqrt{1+3·{\sin }^2\mathrm{\theta }}={\mathrm{I}}_0$

$\therefore {\mathrm{I}}_{\mathrm{p}}=2{\mathrm{I}}_{\mathrm{E}}$