John M. Brozena

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[1] A global Earth Magnetic Anomaly Grid (EMAG2) has been compiled from satellite, ship, and airborne magnetic measurements. EMAG2 is a significant update of our previous candidate grid for the World Digital Magnetic Anomaly Map. The resolution has been improved from 3 arc min to 2 arc min, and the altitude has been reduced from 5 km to 4 km above the(More)
Age-depth relations from internal layering reveal a large region of rapid basal melting in Greenland. Melt is localized at the onset of rapid ice flow in the large ice stream that drains north off the summit dome and other areas in the northeast quadrant of the ice sheet. Locally, high melt rates indicate geothermal fluxes 15 to 30 times continental(More)
Amulti-sensor, multidisciplinary aerogeophysical survey over much of Afghanistan was recently conducted by investigators from NRL and the U.S. Geological Survey. The survey was flown aboard an NP-3D Orion aircraft operated by VXS-1. Sensor systems installed on the P-3 included dual gravimeters, scalar and vector magnetometers, a digital photogrammetric(More)
This letter demonstrates the detection of a man-made structure hidden beneath a forest canopy through exploitation of the joint spatial/aspect-angle variation exhibited by the structure’s ultrahigh-resolution synthetic aperture radar signature. The variation produced by the structure alone is first determined from the signature of an unobscured copy of the(More)
An enhanced simulated annealing algorithm is used to invert sparsely sampled seismic data collected with sonobuoys to obtain seafloor geoacoustic properties at two littoral marine environments as well as for a synthetic data set. Inversion of field data from a 750-m water-depth site using a water-gun sound source found a good solution which included a(More)
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