Geology topics

J.M. Quinn

Publications and source records attributed to J.M. Quinn.

4 recordsLinked to original sources

USGS2014

The 2000 revision of the joint UK/US geomagnetic field models and an IGRF 2000 candidate model

The method of derivation of the joint UK/US spherical harmonic geomagnetic main-field and secular-variation models is presented. Early versions of these models, with the main field truncated at degree 10, are the UK/US candidates for the IGRF 2000 model. The main-field model describes the Earth’s magnetic field at the 2000.0 epoch, while the secular-variation model predicts the evolution of this field between 2000.0 and 2005.0. A revised 1995.0 main-field model was also generated. Regional models for the continental US, Alaska and Hawaii were also produced as a by-product of the UK/US global modelling effort.

Earth, Planets and Space↗

USGS1997

The 1995 revision of the joint US/UK geomagnetic field models. II: Main field

This paper presents the 1995 main-field revision of the World Magnetic Model (WMM-95). It is based on Project MAGNET high-level (??? 15,000 ft.) vector aeromagnetic survey data collected between 1988 and 1994 and on scalar total intensity data collected by the Polar Orbiting Geomagnetic Survey (POGS) satellite during the period 1991 through 1993. The spherical harmonic model produced from these data describes that portion of the Earth's magnetic field generated internal to the Earth's surface at the 1995.0 Epoch. When combined with the spherical harmonic model of the Earth's secular variation described in paper I, the Earth's main magnetic field is fully characterized between the years 1995 and 2000. Regional magnetic field models for the conterminous United States, Alaska and, Hawaii were generated as by-products of the global modeling process.

Earth, Planets and Space↗

USGS1997

The 1995 revision of the joint US/UK geomagnetic field models - I. Secular variation

We present the methods used to derive mathematical models of global secular variation of the main geomagnetic field for the period 1985 to 2000. These secular-variation models are used in the construction of the candidate US/UK models for the Definitive Geomagnetic Reference Field at 1990, the International Geomagnetic Reference Field for 1995 to 2000, and the World Magnetic Model for 1995 to 2000 (see paper II, Quinn et al., 1997). The main sources of data for the secular-variation models are geomagnetic observatories and repeat stations. Over the areas devoid of these data secular-variation information is extracted from aeromagnetic and satellite data. We describe how secular variation is predicted up to the year 2000 at the observatories and repeat stations, how the aeromagnetic and satellite data are used, and how all the data are combined to produce the required models.

Earth, Planets and Space↗

USGS1996

Rationale and preliminary operational plan for a high-altitude magnetic survey over the United States

A proposed high-altitude survey of the U.S. with an ER-2 to collect radar data offers an exciting and cost-effective opportunity to collect magnetic anomaly data. At this workshop, a group of magnetic specialists addressed this opportunity by discussing the need for high-altitude magnetic data and by formulating a preliminary operational plan to acquire such data. The high-altitude aeromagnetic survey would provide critical data needed to expand our knowledge of the geomagnetic field, with applications to a variety of earth science issues including geology, tectonics, core-processes, and rock-magnetism. Test flights with a cesium magnetometer indicate that the ER-2 has the potential to measure the magnetic field at an accuracy of 2 nT or better along flight lines. If the national ER-2 survey is carried out, the successful collection of high-altitude magnetic data hinges on establishing a consortium of federal and state agencies, private industry, and academic institutions to provide the identified resources.

Open-File Report↗