Premium
Complex dielectric permittivity measurements from ground‐penetrating radar data to estimate snow liquid water content in the pendular regime
Author(s) -
Bradford John H.,
Harper Joel T.,
Brown Joel
Publication year - 2009
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2008wr007341
Subject(s) - snowpack , ground penetrating radar , snow , liquid water content , permittivity , water content , liquid water , soil science , dielectric , terrain , geology , radar , remote sensing , environmental science , hydrology (agriculture) , geotechnical engineering , materials science , geomorphology , geography , engineering , cloud computing , telecommunications , earth science , optoelectronics , cartography , computer science , operating system
Monitoring the snow water equivalent (SWE) is critical to effective management of water resources in many parts of the world that depend on the mountain snowpack for water storage. There are currently no methods to remotely sense SWE with accuracy over large lateral distances in the steep and often forested terrain of mountain basins. Previous studies have shown that measurements of ground‐penetrating radar (GPR) velocity can provide accurate estimates of SWE in dry snow. Introduction of liquid water into the snowpack results in a three‐phase system that cannot be accurately characterized with GPR velocity alone. We show that measuring the frequency‐dependent GPR signal attenuation and velocity provides a direct estimate of the complex dielectric permittivity. Because the imaginary component is a function only of liquid water content, we can utilize both the real and imaginary components of the permittivity to estimate liquid water content, snow density, and SWE using existing empirical relationships that are valid in the pendular regime. We tested this new method at two field sites and found that the estimates were accurate to within 12% of gravimetric methods in both a moist and a dry snowpack. GPR has the potential to provide SWE estimates across large lateral distances over a broad range of snow conditions.