میدان مغناطیسی
type: Concept
preferred label: magnetic field @en
related: وردش سالانه

وردش فصلی
type: Concept
preferred label: seasonal variation @en
related: وردش سالانه

وردش سالانه
type: Concept
preferred label: annual variation @en
related: وردش دیرپا
related: وردش فصلی
related: وردش
related: میدان مغناطیسی

وردش دیرپا
type: Concept
preferred label: secular variation @en
related: وردش سالانه

وردش
type: Concept
preferred label: variation @en
related: وردش سالانه