Data Services Products: EMC-GlobalEM-2009-10x10 Global electrical conductivity model

Summary

GlobalEM-2009-10×10 is a global 3D inverse model of electrical conductivity of the Earth’s mantle based on C-responses at ground geomagnetic observatories using the global electromagnetic inversion technique of Kelbert, Egbert and Schultz (2008). Uses a 10×10 degree grid and a degree and order 9 spherical harmonics parameterization at a discrete set of layers with layer boundaries (km) [100 250 410 520 670 900 1200 1600 2000 2400 2900 3500].

Description

Name GlobalEM-2009-10×10
Title Global electromagnetic induction constraints on transition-zone water content variations
Type 3-D Electrical Conductivity Model
Sub Type Global
Units Siemens/meter
Year 2009
 
Short Description   Kelbert, Schultz, & Egbert (2009) inverted C-responses with the global electromagnetic inversion technique of Kelbert, Egbert and Schultz (2008). Uses a 10×10 degree grid and a degree and order 9 parameterization at a discrete set of layers with layer boundaries (km)[100 250 410 520 670 900 1200 1600 2000 2400 2900 3500]. Prior model was discretized from Kuvshinov and Olsen (2006): in log(10) resistivity, [2.2 2.2 2.2 1.4 1.4 0.4 -0.3 0 -0.6 -0.6 -0.6 -5]. Fits 52 ground magnetic observatories from Fujii and Schultz (2002) data set + 6 obs from Schultz and Larsen (1987) data set, 59 observatories total. The C-responses were corrected for auroral sources using a 1D + thinsheet at a 1×1 degree resolution; P10 source was assumption was employed for the inversion.
Authors:  
A. Kelbert
Geomagnetism Program
U.S. Geological Survey
Golden, CO 80401, USA
 
A. Schultz
College of Earth, Ocean and Atmospheric Sciences
Oregon State University
Corvallis, Oregon 97331, USA
 
G. D. Egbert
College of Earth, Ocean and Atmospheric Sciences
Oregon State University
Corvallis, Oregon 97331, USA
 
Previous Model
Reference Model
Prior Model
Inversion Software inversion3d/earth3d by Anna Kelbert
Model Download GlobalEM-2009-10×10.nc (see metadata ), is the netCDF file for the model
Model Homepage
Depth Coverage 0 to 3500 km (can be considered adequately well resolved 410 to 1200 km)
Areal Coverage latitude: -80° to 80°, longitude: 0° to 360°
 
Data Set Description Obtained from Fujii+6-TSU_C_prior_by_1×1_28_g001_9.rho using global2netcdf.m

Plot of sigma at the depth of 520 km
Plot of log10 electrical conductivity at the depth of 410 to 520 km. The observatory locations used in the inversion
are plotted as gray dots.

Plot of sigma at the depth of 670 km.
Plot of log10 electrical conductivity at the depth of 520 to 670 km. The observatory locations used in the inversion
are plotted as gray dots.

Plot of sigma at the depth of 670 to 900 km
Plot of log10 electrical conductivity at the depth of 670 to 900 km. The observatory locations used in the inversion
are plotted as gray dots.

Plot of sigma at the depth of 900 to 1200 km
Plot of log10 electrical conductivity at the depth of 900 to 1200 km. The observatory locations used in the inversion
are plotted as gray dots.

Citations and DOIs

To cite the original work behind this Earth model:

  • Kelbert, A., Schultz, A. and Egbert, G., 2009. Global electromagnetic induction constraints on transition-zone water content variations. Nature, 460(7258), p.1003.

To cite IRIS DMC Data Products effort:

  • Trabant, C., A. R. Hutko, M. Bahavar, R. Karstens, T. Ahern, and R. Aster (2012), Data Products at the IRIS DMC: Stepping Stones for Research and Other Applications, Seismological Research Letters, 83(5), 846–854, https://doi.org/10.1785/0220120032.

DOI for this EMC webpage:
https://doi.org/10.17611/DP/GLOBALEM200910X10

References:

  • Fujii, I. and Schultz, A., 2002. The 3D electromagnetic response of the Earth to ring current and auroral oval excitation. Geophysical Journal International, 151(3), pp.689-709.
  • Kelbert, A., Egbert, G.D. and Schultz, A., 2008. Non-linear conjugate gradient inversion for global EM induction: resolution studies. Geophysical Journal International, 173(2), pp.365-381.
  • Kuvshinov, A. and Olsen, N., 2006. A global model of mantle conductivity derived from 5 years of CHAMP, Ørsted, and SAC‐C magnetic data. Geophysical Research Letters, 33(18).
  • Schultz, A. and Larsen, J.C., 1987. On the electrical conductivity of the mid-mantle-I. Calculation of equivalent scalar magnetotelluric response functions. Geophysical Journal International, 88(3), pp.733-761.

Credits

  • Anna Kelbert

Timeline

2019-05-14
online

Categories

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