Joel Brown

Geophysics PhD Student

Phone: (406) 370-1775
email: jbrown@cgiss.boisestate.edu

Education:

- B.A. in Physics/Astronomy from The University of Montana-2003
- M.S. in Geology from The University of Montana-2006
CV

Research: 

My current projects include (1) measuring the density gradient of the upper 80 m of snow in the percolation zone of Greenland with GPR (2) using multi-offest radar to accurately estimate Snow Water Equvalent of seasonal snowpack in the Intermountain Northwest (3) using 10 m firn cores in conjunction with a simple 1-D densification model to determine variations of melt induced densification in the percolation zone of Western Greenland (4) Impedance inversion of georadar data acquired on the Greenland Icesheet (5) Using 1-D full waveform inversion to invert zero-ffset radar data for snow/firn density.

Past/ongoing Research:

Identifying and tracking the time variability of a radar transparent layer within a temperate valley glacier

I am working on a project focusing on a the time variability of a radar-transparent layer within Bench Glacier, Chugach Mtns., A.K.  I have spent two seperate field seasons on Bench collecting radar traces.  This project is an extension of my master's thesis project.
Poster for Fall 06 AGU

Measuring the densification rate of snow and firn in the percolation zone of Greenland

I conducted radar surveys along the EGIG line in Western Greenland. The results of these data is to determine the density of the upper 80 m of the percolation zone of Greenland. I collected multiple sets of CMP gathers from which I determine the EM propagation velocity in the subsurface for various layers. I use the EM propagation velocities to invert for density variation with depth. Further details of this project are in the following presentations:
Poster for Fall 07 AGU
Greenland percolation zone presentation
Poster for Fall 08 AGU

Mapping the spatial variations of the magnetic field intensity of an archeological site

I mapped the spatial variabiliy of the intensity of the magnetic field of a 118 acre archeological site in Southwestern Montana (0.5 - 1 m transects!).  The information I gathered, processed, and interpreted is currently being used by the BLM to determine the proto-historical relevance of the site in order to determine if it will be considered a national historical site and be federally protected. 

Peer reviewed publications:

Bradford, J.H., Harper, J.T., and Brown, J., 2009, Complex dielectric permittivity measurements from ground-penetrating radar data to measure liquid water content in snow in the pendular regime: Water Resources Research, 45, W08403, doi:10.1029/2008WR007341

Brown, J.M., Harper, J.T., Bradford, J.H., 2009, A radar transparent layer in a temperate valley glacier: Bench Glacier, Alaska: Earth Surface Processes and Landforms, 34, 1497-1506.

Brown, J., Nichols, J., Steinbronn, L., and Bradford, J., 2009, Improved GPR interpretation through resolution of lateral velocity heterogeneity: Example from an archaeological site investigation: Journal of Applied Geophysics, 68, 3-8, doi:10.1016/j.jappgeo.2008.08.014.