Imagine a giant, invisible force field protecting Earth—that’s our planet’s magnetic field. It guides the compass, produces the dazzling aurora, and, critically, guides directional drillers deep beneath the surface. This field is complex and constantly changing, and we need precise models to navigate it.

The High Definition Geomagnetic Model (HDGM) is a global, high-resolution model of Earth’s geomagnetic field. The model provides magnetic field values (total field, dip, and declination) at any point above or below the Earth’s surface. The HDGM is updated annually to correctly model changes in the geomagnetic field.

NOAA’s National Centers for Environmental Information (NCEI) and the University of Colorado Boulder’s Cooperative Institute for Research In Environmental Science (CIRES) have released the upgraded HDGM for 2026.

What is the HDGM?

Scientists measure the geomagnetic field in the air (satellites and aircrafts) and on land (ground observatories) because they capture different parts of the field—from the vast, stable core-generated field to smaller crustal variations—all crucial for understanding space weather, navigation, resource exploration, and Earth’s deep processes. Satellites offer broad global coverage, while ground stations and low-flying aircraft map localized, detailed magnetic anomalies in the crust, providing complementary data.

NOAA and CIRES scientists combine satellite and ground-based data with airborne and marine magnetic data, which are compiled into the Earth Magnetic Anomaly Grid (EMAG2). This combination allows scientists to create the HDGM, which provides highly accurate estimates of the Earth’s magnetic field and its fluctuations over time. Consequently, the HDGM is recognized as the most advanced model for tracking changes in the global magnetic field.

As the data center for NOAA’s marine trackline geophysical data, NCEI is in a unique position to continuously enhance the resolution of the crustal magnetic field. The HDGM 2026 release signifies a major advancement in both resolution and real-time capabilities.

What’s New

More Accurate Subsurface Mapping: The new model has a 20% increase in resolution. It can now "see" magnetic variations caused by the Earth’s crust down to about 19 kilometers (12 miles) of detail. For the oil and gas industry, this means ultra-precise guidance for drilling complex, billion-dollar wellbores, making operations safer and more efficient.

Safer Drilling in the Northern Polar Region: The Northern Lights (Aurora Borealis) are beautiful, but the powerful electric currents that cause them (the auroral electrojet) can severely disrupt magnetic measurements, throwing off drill guidance in places like Alaska and the North Sea. The 2026 update includes real-time disturbance correction for these high-altitude regions, protecting operators from magnetic storms.

Accuracy Everywhere: The model is not just better near the poles. Updates to the ionospheric modeling mean better accuracy in low and mid-latitude regions around the world. Plus, the core field model has been updated with the very latest satellite data to ensure it remains precise through the end of 2026.

Validated by the Industry

The model has been rigorously validated, with its core, crustal and external field components carefully tested to ensure accuracy. Additionally, NCEI and CIRES scientists partnered with the directional drilling industry to validate the new HDGM against their own data. Industry partners in directional drilling confirmed that the new HDGM 2026 matches local, high-resolution surveys "significantly better," reducing the margin of error for wellbore placement.