Scientific Theme: Advanced Modeling and Observing Systems

Scientific Theme: Geodynamics
This research also directly supported the International Association of Geomagnetism and Aeronomy World Digital
Magnetic Anomaly Map Project (IAGA/WDMAM) and studies of crustal magnetism contributing to geodynamic
models of the lithosphere, geologic mapping, and natural resource exploration. Inferences from crustal magnetic
field maps, such as the WDMAM, interpreted in conjunction with other information, can help delineate geologic
provinces, locate impact structures, dikes, faults, and other geologic entities that have a magnetic contrast with their
surroundings. The Magnetic Anomaly Map of the World, based on the NGDC-720 model, will be published in July
2007 by UNESCO and the Commission for the Geological Map of the World.
Products include:
The Extended Magnetic Field Model (EMM-06), including software and the main field, secular variation,
NGDC-720-V1 crustal field, magnetospheric field, and induced field is now available via on-line access
(http://www.ngdc.noaa.gov/seg/EMM/).
Candidate model for the World Digital Magnetic Anomaly Map Project
(http://geomag.org/models/wdmam.html).
MILESTONE NGDC05.2:
Produce a climatological model of the equatorial electrojet by analyzing CHAMP, Ørsted, and
SAC-C satellite magnetic data.
ACCOMPLISHMENTS FOR NGDC05.2:
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The Earth‘s equatorial ionosphere is a
region of complex electrodynamics
resulting from solar-driven pondermotive
forces and ionospheric
conductivity gradients. Understanding
the physics of these interactions is
important for specifying the
morphology of currents flowing in
the upper atmosphere and for
predicting the occurrence of
ionospheric scintillation that can have
a deleterious effect on communications.
Recent satellite missions have
provided measurements of the
geomagnetic field with unprecedented
accuracy and resolution,
which are now used to infer the
electrodynamics of the equatorial
ionosphere. Deviations from the main
geomagnetic results are used to
model height-integrated current
densities within the ionosphere from
which local electric fields and plasma
motions can be inferred.
CIRES scientists working at NGDC developed the Equatorial ElectroJet Model (EEJM1) climatological model using
high-quality magnetic measurements from recent satellite missions. The EEJM1 is composed of three models of the
equatorial electrojet that were constructed based on six years of satellite magnetic measurements from each of the
CHAMP, Ørsted, and SAC-C satellites. The models are based on data that comprise half of a solar cycle (from solar
maximum to solar minimum). The Equatorial Electrojet Model—coefficients and driver program—is available
online at http://www.earthref.org and at http://models.geomag.us/EEJ.html.
MILESTONE NGDC05.3:
Produce the 2006/2007 CIRES/NGDC scientific geomagnetic field model, accounting for recent
changes of the Earth's magnetic field.