Эрдэмтэд Номхон далайн экваторын бүс дэх хайлмал төмрийн урсгалын чиглэл өөрчлөгдсөнийг газрын болон сансрын соронзон орны хэмжилтүүдэд үндэслэн тогтоожээ.
“Journal of Studies of Earth’s Deep Interior” сэтгүүлд 2026 оны тавдугаар сарын 6-нд нийтлэгдсэн судалгаагаар Дэлхийн гадаргуугаас 2200 км-ийн гүнд орших хайлмал гадна цөмд томоохон өөрчлөлт гарсныг илрүүлжээ. Фредерик Дал Мадсен болон түүний багийнхан 1997-2025 оны хоорондох соронзон орны хэмжилтүүдэд дүн шинжилгээ хийхдээ, 2010 онд Номхон далайн экваторын бүсэд шингэн төмрийн урсгал баруун зүг рүү чиглэсэн сул урсгалаас хүчтэй зүүн зүг рүү чиглэсэн урсгал болон өөрчлөгдсөнийг тогтоосон байна.
Судлаачид соронзон орны “secular variation” буюу цаг хугацааны явцад өөрчлөгдөх үзэгдлийг ашиглан цөмийн дээд хэсгийн шингэний хөдөлгөөнийг загварчилжээ. Энэхүү судалгаанд ESA-ийн Swarm, CryoSat, Германы CHAMP болон Ørsted сансрын хөлгүүдийн өндөр нарийвчлалтай мэдээллийг ашигласан нь уламжлалт газрын станцуудын мэдээлэл дээр суурилсан загварыг илүү баяжуулсан байна. Энэхүү өөрчлөлт нь цөмийн эргэлт урт хугацаанд тогтвортой байдаг гэх таамаглалыг сорьж байгаа юм.
Урсгалын чиглэл өөрчлөгдсөн шалтгаан нь одоогоор тодорхойгүй байгаа бөгөөд судлаачид үүнийг газар хөдлөл зүй болон геодезийн аргаар илрүүлсэн дотоод цөмийн үйл ажиллагааны өөрчлөлттэй холбоотой байж болзошгүй хэмээн таамаглаж байна. Гэсэн хэдий ч энэхүү холбоо хамаарал нь одоогоор батлагдсан онол бус, судалгааны явцад дэвшүүлсэн таамаглал юм.
Загварын тооцооллоор 2020 оноос хойш зүүн зүг рүү чиглэсэн энэхүү хүчтэй урсгал дахин суларч эхэлсэн байна. Энэ нь уг үзэгдэл түр зуурын хэлбэлзэл үү, эсвэл цөмийн эргэлтийн илүү тогтвортой өөрчлөлт үү гэдгийг тодорхойлохын тулд цаашид үргэлжлүүлэн хянах шаардлагатай гэж судлаачид үзэж байна.
Дэлгэрэнгүйг эх сурвалжаас харах
↓Эх сурвалжийг нээх ↓
A broad region of liquid iron beneath the equatorial Pacific reversed direction in 2010, switching from a weak westward flow to a strong eastward one. Researchers still do not know what caused the change, and their model suggests the eastward flow has been weakening again since 2020.
The finding comes from an analysis of ground-based magnetic observations and satellite measurements covering 1997 to 2025. The peer-reviewed study, published May 6, 2026, in the Journal of Studies of Earth’s Deep Interior, was written by Frederik Dahl Madsen, Isobel Howard, William Brown and Kathryn Whaler.
Earth’s molten outer core lies about 2,200 kilometres below the surface. Its electrically conducting liquid iron moves around the solid inner core, generating the geomagnetic field. Changes in that magnetic field allow scientists to reconstruct how material near the top of the outer core is moving, even though the region itself cannot be observed directly from the surface.
Equatorial Pacific Flow Shifts Eastward
Core-surface flow has historically been predominantly westward. The study connects that pattern with a large planetary-scale gyre of westward flow that is offset from Earth’s rotation axis. The equatorial Pacific sits outside the influence of that gyre, giving the researchers a region where the flow can behave differently.
That difference became pronounced in 2010. The analysis found that a broad area of iron-rich fluid beneath the equatorial Pacific changed from moving weakly westward to moving strongly eastward. ESA describes the reversal as unexplained and says it challenges the idea that large-scale outer-core circulation necessarily remains comparatively stable over long periods.
The research does not treat the 2010 change as a complete reversal of the entire outer core. It identifies a regional change beneath the Pacific against a wider background in which westward flow has historically been dominant. That distinction is central to the study’s description of what happened.
To build their flow models, the researchers used observations of secular variation, the change in Earth’s geomagnetic field over time. Their analysis assumes that magnetic diffusion can be neglected on timescales shorter than 100 years, allowing those magnetic-field changes to be inverted into models of fluid motion at the top of the core.
The dataset combines observations from ground-based magnetic stations with measurements from ESA’s Swarm and CryoSat missions, Germany’s CHAMP mission and the Ørsted mission. Together, those records allowed the researchers to examine how the inferred core-surface flow evolved over nearly three decades.
Swarm Measurements Track Changes After the Reversal
ESA launched the three Swarm satellites in 2013, three years after the Pacific reversal. Each satellite carries sensitive magnetometers that map Earth’s magnetic field, while their coordinated orbits help researchers distinguish magnetic signals originating in the core from signals produced by the crust, oceans, ionosphere and magnetosphere.
That separation is important because measurements taken above Earth contain magnetic contributions from several sources at once. Swarm’s long-running global observations provided high-precision measurements of the period after the reversal and helped researchers reconstruct changes in flow near the core–mantle boundary.
The satellite data also exposed more than the broad eastward shift. Researchers identified wave-like accelerations and rapidly changing flow structures that might otherwise have been obscured in noisier datasets. ESA also links the observations to sudden changes associated with the Pacific reversal and a 2017 geomagnetic jerk.
The measurements matter because the geodynamo is not static. Motion in the liquid outer core continuously changes, and those changes alter the magnetic field generated by the moving iron. Many large-scale flow patterns had nevertheless appeared relatively persistent across decades of observation, making the rapid regional change beneath the Pacific notable within the dataset.
Researchers Examine a Possible Inner-Core Connection
The cause of the Pacific reversal remains unresolved, but its timing gives researchers one possible line of investigation. The rise of the strong eastward flow occurred at about the same time as a change in inner-core behaviour inferred from geodesy and seismology.
Madsen and his co-authors hypothesise that changes in Earth’s deeper interior triggered the inferred flow changes beneath the Pacific. The study does not establish that relationship as a confirmed cause, and the coincidence in timing remains part of the researchers’ hypothesis rather than a settled explanation.
The model adds another complication: the strong eastward flow has apparently been weakening since 2020. That leaves several possibilities open. The reversal could represent a relatively short-lived fluctuation, part of an oscillating pattern or a more persistent change in core circulation.
Madsen said continued observation would be needed to distinguish between those possibilities: “Continued monitoring will be essential to determine how the flow evolves over the coming years.”
Magnetic Measurements Reveal Motion Deep Inside Earth
The processes described in the study occur thousands of kilometres below Earth’s surface and do not pose a danger to people or the climate. Their scientific importance comes from the role of outer-core motion in generating Earth’s magnetic field.
That field changes as core flow evolves. ESA notes that such changes are relevant to navigation systems, spacecraft operations and models of near-Earth space weather. The field also shields Earth from charged particles streaming from the Sun.
The Pacific reversal gives researchers a measurable example of how quickly a regional flow pattern can change. The study covers observations through 2025, providing a record that extends well beyond the original 2010 switch and into the period when the eastward movement began to weaken.
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