North Pole Environmental Observatory


Polar Science Center,

Applied Physics Laboratory, University of Washington, Seattle WA

Principal contact

Dr. Richard Moritz, email: dickm at

Data web site


Upward Looking Sonar on bottom anchored moorings


North Pole

Time interval


Data processing notes

Data were processed and calibrated by R. Moritz. Statistical summaries were computed and reformatted by R. Lindsay, from the point data.

Additional details on the ULS instrument, calibration procedures, are presented in

Drucker, R., S. Martin and R. Moritz. Observations of ice thickness and frazil ice in the St. Lawrence Island polynya from satellite imagery, upward looking sonar, and salinity/temperature moorings. J. Geophys. Res., 108 (C5), 2003, 18-1 - 18-18.

V20140415: removed ULS 60, 2006-2008 due to unreliable data.

Number of samples

369490 point samples, 65 total months


Point data

2001-2002, 10 min, 2002-2003, 5 min, 2004-2005, 7 min, 2005-2006, 5 min preliminary, 2008-2010, 8 min




ULS concept picture      NPEO mooring design

npeo box plots

Box plots show the median (black bar) and the 5th, 25th, 75th, and 95th percentile values for each month. The colors show the month of the year. A * marks the mode.