Publications
Geomagnetism publications.
Filter Total Items: 414
An empirical model of the quiet daily geomagnetic field variation
An empirical model of the quiet daily geomagnetic field variation has been constructed based on geomagnetic data obtained from 21 stations along the 210 Magnetic Meridian of the Circum‐pan Pacific Magnetometer Network (CPMN) from 1996 to 2007. Using the least squares fitting method for geomagnetically quiet days (Kp ≤ 2+), the quiet daily geomagnetic field variation at each station was described
Authors
Y. Yamazaki, K. Yumoto, M.G. Cardinal, B.J. Fraser, P. Hattori, Y. Kakinami, J.Y. Liu, K.J.W. Lynn, R. Marshall, D. McNamara, T. Nagatsuma, V.M. Nikiforov, R.E. Otadoy, M. Ruhimat, B.M. Shevtsov, K. Shiokawa, S. Abe, T. Uozumi, A. Yoshikawa
Are secular correlations between sunspots, geomagnetic activity, and global temperature significant?
Recent studies have led to speculation that solar‐terrestrial interaction, measured by sunspot number and geomagnetic activity, has played an important role in global temperature change over the past century or so. We treat this possibility as an hypothesis for testing. We examine the statistical significance of cross‐correlations between sunspot number, geomagnetic activity, and global surface te
Authors
Jeffrey J. Love, K. Mursula, V.C. Tsai, D. M. Perkins
Long-term biases in geomagnetic K and aa indices
Analysis is made of the geomagnetic-activity aa index and its source K-index data from groups of ground-based observatories in Britain, and Australia, 1868.0–2009.0, solar cycles 11–23. The K data show persistent biases, especially for high (low) K-activity levels at British (Australian) observatories. From examination of multiple subsets of the K data we infer that the biases are not predominantl
Authors
Jeffrey J. Love
Geomagnetic referencing in the arctic environment
Geomagnetic referencing is becoming an increasingly attractive alternative to north-seeking gyroscopic surveys to achieve the precise wellbore positioning essential for success in today's complex drilling programs. However, the greater magnitude of variations in the geomagnetic environment at higher latitudes makes the application of geomagnetic referencing in those areas more challenging. Precise
Authors
Benny Podjono, Nathan Beck, Andrew Buchanan, Jason Brink, Joseph Longo, Carol A. Finn, E. William Worthington
East Antarctic rifting triggers uplift of the Gamburtsev Mountains
The Gamburtsev Subglacial Mountains are the least understood tectonic feature on Earth, because they are completely hidden beneath the East Antarctic Ice Sheet. Their high elevation and youthful Alpine topography, combined with their location on the East Antarctic craton, creates a paradox that has puzzled researchers since the mountains were discovered in 1958. The preservation of Alpine topograp
Authors
Fausto Ferraccioli, Carol A. Finn, Tom A. Jordan, Robin E. Bell, Lester M. Anderson, Detlef Damaske
Widespread inclination shallowing in Permian and Triassic paleomagnetic data from Laurentia: Support from new paleomagnetic data from Middle Permian shallow intrusions in southern Illinois (USA) and virtual geomagnetic pole distributions
Recent paleomagnetic work has highlighted a common and shallow inclination bias in continental redbeds. The Permian and Triassic paleomagnetic records from Laurentia are almost entirely derived from such sedimentary rocks, so a pervasive inclination error will expectedly bias the apparent polar wander path of Laurentia in a significant way. The long-standing discrepancy between the apparent polar
Authors
M. Domeier, R. Van Der Voo, F.B. Denny
Spring-fall asymmetry of substorm strength, geomagnetic activity and solar wind: Implications for semiannual variation and solar hemispheric asymmetry
We study the seasonal variation of substorms, geomagnetic activity and their solar wind drivers in 1993–2008. The number of substorms and substorm mean duration depict an annual variation with maxima in Winter and Summer, respectively, reflecting the annual change of the local ionosphere. In contradiction, substorm mean amplitude, substorm total efficiency and global geomagnetic activity show a do
Authors
K. Mursula, E. Tanskanen, J.J. Love
Correlation of the Miocene Peach Spring Tuff with the geomagnetic polarity time scale and new constraints on tectonic rotations in the Mojave Desert, California
We report new paleomagnetic results and 40Ar/39Ar ages from the Peach Spring Tuff (PST), a key marker bed that occurs in the desert region between Barstow, California, and Peach Springs, Arizona. The 40Ar/39Ar ages were determined using individual hand-picked sanidine crystals from ash-flow specimens used in previous paleomagnetic studies at eight sites correlated by mineralogy, stratigraphic posi
Authors
John W. Hillhouse, David M. Miller, Brent D. Turrin
By
Energy and Minerals Mission Area, Natural Hazards Mission Area, Energy Resources Program, Geomagnetism Program, Groundwater and Streamflow Information Program, Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Geologic Hazards Science Center, Geology, Minerals, Energy, and Geophysics Science Center
Averaging and sampling for magnetic-observatory hourly data
A time and frequency-domain analysis is made of the effects of averaging and sampling methods used for constructing magnetic-observatory hourly data values. Using 1-min data as a proxy for continuous, geomagnetic variation, we construct synthetic hourly values of two standard types: instantaneous "spot" measurements and simple 1-h "boxcar" averages. We compare these average-sample types with other
Authors
Jeffrey J. Love, V.C. Tsai, Jennifer L. Gannon
Movie‐maps of low‐latitude magnetic storm disturbance
We present 29 movie‐maps of low‐latitude horizontal‐intensity magnetic disturbance for the years 1999–2006: 28 recording magnetic storms and 1 magnetically quiescent period. The movie‐maps are derived from magnetic vector time series data collected at up to 25 ground‐based observatories. Using a technique similar to that used in the calculation of Dst, a quiet time baseline is subtracted from the
Authors
Jeffrey J. Love, Jennifer L. Gannon
Proceedings of the XIIIth IAGA Workshop on Geomagnetic Observatory Instruments, Data Acquisition, and Processing
The thirteenth biennial International Association of Geomagnetism and Aeronomy (IAGA) Workshop on Geomagnetic Observatory Instruments, Data Acquisition and Processing was held in the United States for the first time on June 9-18, 2008. Hosted by the U.S. Geological Survey's (USGS) Geomagnetism Program, the workshop's measurement session was held at the Boulder Observatory and the scientific sessio
Authors
Jeffrey J. Love