NGDC-720V4QT: A revised model of the global lithospheric magnetic field to fill the data gap in the Qinghai-Tibet Plateau

Existing magnetic anomaly datasets, such as EMAG2, suffer from significant data gaps that hinder the accuracy of high-resolution lithospheric field modeling in certain regions. For instance, the NGDC-720 model has limited spatial resolution for wavelengths shorter than 330 km over the Qinghai-Tibet Plateau, as it relies primarily on satellite-derived data due to the incomplete coverage in EMAG2. Updating this model with newly available near-surface magnetic measurements is essential to address these shortcomings. However, developing an updated model requires substantial computational resources and time, which likely explains the lack of revisions to the NGDC-720 model since the release of its third version more than two decades ago.

To overcome this challenge, we propose an innovative methodology for efficiently updating the spherical harmonic representation of the lithospheric magnetic field. By incorporating high-precision aeromagnetic data from the Qinghai-Tibet Plateau, we enhance the spatial resolution of the NGDC-720 model from a 330 km wavelength to a 56 km wavelength in this region. The updated model not only provides high-resolution regional magnetic anomaly data, but it also maintains consistency with the original NGDC-720 model, revealing key tectonic structures. Our results suggest that this approach holds significant potential for refining global lithospheric magnetic field models through localized updates.

The new model is provided in Schmidt semi-normalized spherical harmonic coefficients, with degrees 1–120 replaced by the satellite-based crustal field model MF6. It has a maximum internal field degree of 740 and uses a reference radius of 6371.2 km.

This dataset is publicly available for scientific research. Please cite the corresponding publication: