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North Pole Environmental Observatory (NPEO) Oceanographic Mooring Data, 2001-2002

Entry ID: ARCSS156

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Summary

Abstract: This data set, acquired with an oceanographic bottom-anchored mooring, includes sea-ice draft and depth data, conductivity, temperature, pressure, salinity, and ocean current measurements such as speed and direction. Each mooring contains vertically distributed instruments, which measure ocean properties at fixed depths and record data internally. These data are retrieved annually when the mooring ...

Related URL

Link: VIEW PROJECT HOME PAGE

Description: NPEO Home Page

Link: VIEW RELATED INFORMATION

Description: North Pole Environmental Observatory Aerial CTD Survey

Link: VIEW RELATED INFORMATION

Description: Seawater Chemistry from the North Pole Environmental Observatory, 2000-2004

Link: VIEW RELATED INFORMATION

Description: North Pole Environmental Observatory (NPEO) Weather and Radiation Buoy Data, 2002-2004

Geographic Coverage

(Click for Interactive Map)

Spatial coordinates

N: 89.56

S: 89.56

E: 66.65

W: 66.65

Data Set Citation

Dataset Originator/Creator: Morison, J., K. Aagaard, R. Moritz, M. McPhee, A. Heiberg, M. Steele, and R. Andersen

Dataset Title: North Pole Environmental Observatory (NPEO) oceanographic mooring data, 2001-2002

Dataset Series Name: NPEO

Dataset Release Date: 2005-11-21

Dataset Release Place: Boulder, CO

Dataset Publisher: National Snow and Ice Data Center (NSIDC)

Online Resource: http://nsidc.org/data/arcss156.html

Temporal Coverage

Start Date: 2001-04-01

Stop Date: 2002-04-27

Location Keywords

OCEAN > ARCTIC OCEAN

GEOGRAPHIC REGION > ARCTIC

GEOGRAPHIC REGION > POLAR

Science Keywords

CRYOSPHERE > SEA ICE > SEA ICE MOTION

OCEANS > OCEAN CIRCULATION > OCEAN CURRENTS

ISO Topic Category

CLIMATOLOGY/METEOROLOGY/ATMOSPHERE

Platform

GROUND-BASED OBSERVATIONS

MOORINGS

Instrument

CONDUCTIVITY METERS

CURRENT METERS

Project

ARCSS > Arctic System Science

NSF/OPP > Office of Polar Programs, National Science Foundation

ARCSS/NPEO > Arctic System Science/North Pole Environmental Observatory

Quality Pressure is readily checked for consistency between different instruments, noting. However, investigators noted that precise ocean depth is difficult to determine and that line length errors are possible. The 2001-2002 mooring was well positioned with respect to depth. Four pressure sensors near the top of the mooring report instrument depths within 2 m of design depths. One sensor on RCM-7, ... serial number 11455, the only current meter recording pressure, reported itself some 7 m deeper than designed. The investigators accept as correct those four pressure measurements, located both above and below the suspect RCM, suggesting an erroneous offset in the one RCM pressure sensor. Consequently, a constant pressure was assigned to the 84 m design depth and used in the salinity calculation for that RCM. However, for completeness the pressure as measured is reported in the data file, and those measurements provide information on pull-down of the RCM. The deep Sea-Bird instruments, SBE-37s with serial numbers 1772, 1773, and 1774, unfortunately suffered from the failure of a new pressure sensor, which was subsequently confirmed by the manufacturer as flawed. These three instruments do report temperature and conductivity with good accuracy, and constant pressures inferred from the design depths are used in the calculation of salinity at those levels. Note that no pressure correction has been made for pull-down of these instruments, as is also the case for RCM serial number 11455. A stuck vane or malfunctioning compass afflicted RCM serial number 6545 at 600 m, constraining the direction to one-third of its full arc, while current speed appears reasonable. Both speed and direction are reported as measured. General information about the North Pole Environmental Observatory, the NPEO mooring, and various data extracts and summaries may be viewed on the NPEO website. See Bottom-Anchored Mooring (http://psc.apl.washington.edu/northpole/Mooring.html). Potentially important sources of error in the sea-ice draft computed as described above include the following: *Systematic and random errors in density rhow *Systematic and random errors in sound speed cbar *Random errors in sea-level air pressure Ps *Errors in the local value of earth's gravitational acceleration g *Timing variations in the sonar hardware/software system *Target identification errors for first-return echoes from targets not directly above the ULS, or from targets intervening between the ULS and the intended target (ice bottom or sea surface) *Non-hydrostatic (short) waves during open water intervals Extensive analysis, as reported in Moritz (2005) yields a net systematic error of approximately +0.3 meters, a standard deviation of random errors of approximately 0.05 meters during the summer, and an annual variation of systematic error on the order of 0.10 meters for ULS 22 at NPEO 2001-2002. The summertime random errors show some persistence over intervals of at least several hours. An offset correction was applied to both the 5-minute and 10-second time series, by identifying occurrence of open water based on a combined analysis of the ULS and ADCP data. The offset correction eliminates most of the net systematic error, and greatly reduces the random errors in summer. The offset has been applied to the data set provided here. Once the offsets are applied, summer (June-August) sea-ice drafts between -0.10 m and +0.10 m are reset to 0 m, consistent with the range of error variability for open water episodes and with the model that ice thinner than 10 cm is rare during these months. For all other months, sea-ice drafts between -0.05m and 0 m are reset to zero. Sea-ice drafts outside the range -0.05 m < draft < 20 m are replaced by the bad data value -999. This results in data with all sea-ice drafts in the interval 0 m to 20 m. The ULS is programmed to look for sea-ice drafts in a window that opens approximately 20 meters below sea level.

Ancillary Keywords

ARCSS

ARCSS Data Coordination Center

Data Set Progress

IN WORK

Originating Center

NSIDC_ARCSS

Data Center

National Snow and Ice Data Center

Data Center URL: http://nsidc.org

Data Center Personnel
Name: NSIDC USER SERVICES Phone: +1 (303) 492-6199 Fax: +1 (303) 492-2468 Email: nsidc at nsidc.org Contact Address: National Snow and Ice Data Center CIRES, 449 UCB University of Colorado City: Boulder Province or State: CO Postal Code: 80309-0449 Country: USA

Arctic System Science Data Coordination Center

Data Center URL: http://nsidc.org/arcss/
Dataset ID: arcss156

Data Center Personnel
Name: NSIDC ARCSS USER SERVICES Phone: +1 (303) 492-6199 Fax: +1 (303) 492-2468 Email: nsidc at nsidc.org Contact Address: National Snow and Ice Data Center CIRES, 449 UCB University of Colorado City: Boulder Province or State: CO Postal Code: 80309-0449 Country: USA

Distribution

Distribution Media: FTP

Distribution Size: 28 MB uncompressed, 6.2 MB compressed

Distribution Format: ASCII text

Personnel

JAMES H. MORISON

Role: INVESTIGATOR

Phone: +1 (206) 543-1394

Fax: 1+206-616-3142

Email: morison at apl.washington.edu

Contact Address:

University of Washington

Polar Science Center, Applied Physics Laboratory

Polar Science Center

Applied Physics Laboratory

University of Washington

1013 NE 40th Street

City: Seattle

Province or State: WA

Postal Code: 98105

Creation and Review Dates

DIF Creation Date: 2005-09-22

Last DIF Revision Date: 2012-05-11

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