Skip to main content

Radio-echo probing of Black Rapids Glacier, Alaska, USA, during onset of melting and spring speed-up

Buy Article:

$35.11 plus tax (Refund Policy)


Radio-echo soundings were collected on Black Rapids Glacier, Alaska, USA, from mid-May to mid-July 1993 to investigate spring speed-up and summer slowdown including high-speed events associated with three lake drainages. Temporal changes in echo power from all depths were highly correlated, indicating a strong effect from varying amounts of near-surface water. Evaluation of bed reflectivity was corrected for this effect based on the time variation of spatially stable patterns of internal scattering identified using principal component analysis. Hourly time series collected at two fixed locations over the deepest part of two valley cross sections showed no detectable change in bed reflection power (<5%) or phase (<0.05 rad). Reoccupation of fixed locations toward the margins at several-day intervals revealed changes in bed power reflectivity up to 50%, but with no definable relation to lake drainages. Theoretical analyses indicate that changes in reflectivity of <5% from a rock bed constrain basal water thickness changes to centimeter scale or less. Conductive basal till degrades the constraint to decimeter scale or more. Changes in bed reflectivity of 50% indicate probable absence of thick conductive till at such locations, and that the changes were caused by centimeter to decimeter changes in equivalent water thickness.

Document Type: Research Article


Publication date: August 1, 2012

More about this publication?
  • The Journal of Glaciology is published six times per year. It accepts submissions from any discipline related to the study of snow and ice. All articles are peer reviewed. The Journal is included in the ISI Science Citation Index.
  • Editorial Board
  • Information for Authors
  • Ingenta Connect is not responsible for the content or availability of external websites

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Partial Open Access Content
Partial Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more