GEOMAGNETIC MODELS

HDGM2022-RT

At mid- and low-latitudes and during quiet geomagnetic times, electrical currents flowing in the ionosphere generate magnetic variations of a few tens of nT on the ground and at low-Earth orbit altitudes. The Sq ("solar quiet") current system takes the form of two large-scale vortices on the dayside of the Earth, one in each hemisphere. Due to a local enhancement of conductivity, a stronger current, the equatorial electrojet (EEJ), flows along the dip equator and generates magnetic signatures that can reach up to 150 nT at some locations.

HDGM2021-RT

At mid- and low-latitudes and during quiet geomagnetic times, electrical currents flowing in the ionosphere generate magnetic variations of a few tens of nT on the ground and at low-Earth orbit altitudes. The Sq ("solar quiet") current system takes the form of two large-scale vortices on the dayside of the Earth, one in each hemisphere. Due to a local enhancement of conductivity, a stronger current, the equatorial electrojet (EEJ), flows along the dip equator and generates magnetic signatures that can reach up to 150 nT at some locations.

HDGM2020-RT

HDGM2019-RT

At mid- and low-latitudes and during quiet geomagnetic times, electrical currents flowing in the ionosphere generate magnetic variations of a few tens of nT on the ground and at low-Earth orbit altitudes. The Sq ("solar quiet") current system takes the form of two large-scale vortices on the dayside of the Earth, one in each hemisphere. Due to a local enhancement of conductivity, a stronger current, the equatorial electrojet (EEJ), flows along the dip equator and generates magnetic signatures that can reach up to 150 nT at some locations.

HDGM2018-RT

At mid- and low-latitudes and during quiet geomagnetic times, electrical currents flowing in the ionosphere generate magnetic variations of a few tens of nT on the ground and at low-Earth orbit altitudes. The Sq ("solar quiet") current system takes the form of two large-scale vortices on the dayside of the Earth, one in each hemisphere. Due to a local enhancement of conductivity, a stronger current, the equatorial electrojet (EEJ), flows along the dip equator and generates magnetic signatures that can reach up to 150 nT at some locations.

HDGM2017-RT

At mid- and low-latitudes and during quiet geomagnetic times, electrical currents flowing in the ionosphere generate magnetic variations of a few tens of nT on the ground and at low-Earth orbit altitudes. The Sq ("solar quiet") current system takes the form of two large-scale vortices on the dayside of the Earth, one in each hemisphere. Due to a local enhancement of conductivity, a stronger current, the equatorial electrojet (EEJ), flows along the dip equator and generates magnetic signatures that can reach up to 150 nT at some locations.

POMME is a scientific main field model representing the geomagnetic field in the region from the Earth's surface to an altitude of a couple of thousand kilometers. The time variations of the internal field are given by a piece-wise linear representation of the spherical harmonic (Gauss) coefficients of the magnetic potential.

POMME is a scientific main field model representing the geomagnetic field in the region from the Earth's surface to an altitude of a couple of thousand kilometers. The time variations of the internal field are given by a piece-wise linear representation of the spherical harmonic (Gauss) coefficients of the magnetic potential.

POMME is a main field model providing the geomagnetic field in the region from the Earth's surface to an altitude of a couple of thousand kilometers. The time variations of the field are represented by a Taylor series of the spherical harmonic (Gauss) coefficients of the magnetic potential. We provide the static coefficients for 2005.0 and the first and second time derivatives (secular variation and secular acceleration).

POMME is a main field model providing the geomagnetic field in the region from the Earth's surface to an altitude of a couple of thousand kilometers. The time variations of the field are represented by a Taylor series of the spherical harmonic (Gauss) coefficients of the magnetic potential. We provide the static coefficients for 2005.0 and the first and second time derivatives (secular variation and secular acceleration). The corresponding geomagnetic power spectrum is shown in Figure 1.

rint map (paper and digital download) of EMAG2 available at BGR Geoshop

GIS GeoTIFF versions of EMAG2 included in the product table at the bottom of this page

Satellites in low-Earth orbit (LEO) provide the most effective means of mapping the long wavelengths of the magnetic field caused by the magnetization of the Earth's crust. The first global magnetic anomaly maps were produced from POGO (1960s) and Magsat (1979) satellite measurements. A breakthrough in resolution and accuracy was achieved with the CHAMP satellite, launched in July 2000. Apart from an order of magnitude improvement in magnetometer accuracy, CHAMP was designed to remain in LEO for many years, leading to excellent spatial coverage.

POMME is a main field model providing the geomagnetic field in the region from the Earth's surface to an altitude of a couple of thousand kilometers. Seven years of highly accurate CHAMP satellite magnetic measurements offer an unprecedented opportunity to track the time variations of the field originating in the Earth's core. An interesting question is whether we can start to see changes in the secualar acceleration (2nd time derivative) of the geomagnetic field.

Marine and airborne magnetic anomaly data have been collected for more than half a century, providing global coverage of the Earth. Due to the changing main field from the Earth's core, and due to differences in quality and coverage, combining these data to a consistent global magnetic grid is challenging. The World Digital Magnetic Anomaly Map (WDMAM) project is an international effort to integrate all available near-surface and satellite magnetic anomaly data.

Six years of low-orbit CHAMP satellite magnetic measurements have provided an exceptionally high-quality data resource for lithospheric magnetic field modeling. Our fifth generation satellite-only magnetic field model MF5 extends to spherical harmonic degree 100. As a result of careful data selection, extensive corrections, filtering and line-leveling, the model has low noise levels and can be safely evaluated at the Earth’s surface. The model is particularly suited for inferring large-scale structure and composition of the lithosphere.

POMME is a main field model providing the geomagnetic field in the region from the Earth's surface to an altitude of a couple of thousand kilometers. POMME-3.1 includes the time varying core field, crustal field, the ring current field modulated by the Dst/Est/Ist Indices, a time averaged magnetospheric field, the penetration of the horizontal part of the Interplanetary magnetic field (IMF), and the fields induced by Earth rotation in the external fields.

POMME is a main field model providing the geomagnetic field in the region from the Earth's surface to an altitude of a couple of thousand kilometers. POMME-2.5 includes the time varying core field, crustal field, the ring current field modulated by the Dst/Est/Ist Indices, a time averaged magnetospheric field, the penetration of the horizontal part of the Interplanetary magnetic field (IMF), and the fields induced by Earth rotation in the external fields.

MF4x is a lithospheric field model from CHAMP satellite data, estimated by a new algorithm from the same cleaned data set which was used for MF4. By using linear combinations of spherical harmonics (SH), we defined localized functions which are band-limited to a given maximum degree. Using these localized basis functions, a model's SH resolution can be varied over the globe.