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TITLE: CEOP EOP-3 and EOP-4 ARM NSA Surface Meteorological and Radiation Data Set

CONTACT:

Raymond McCord
Building 1507
PO Box 2008, MS 6407
Oak Ridge, TN 37831-6407

Telephone: (865) 574-7827
Fax: (865) 574-4665

E-Mail: mccordra@ornl.gov

1.0 DATA SET OVERVIEW

This data set contains 30-minute resolution surface meteorological and
radiation data from the Coordinated Enhanced Observing Period (CEOP) Reference
Site operated by the Atmospheric Radiation Measurement (ARM) Program at its
North Slope of Alaska (NSA) facility in Alaska. This data set
includes observations from two locations. This data set covers the
time period 1 October 2002 through 31 December 2004. Further information
about the ARM NSA site is available at the
following URL: http://www.arm.gov

1.1 Station Locations

Site Elev (m) Latitude Longitude
-------------------------------------------------
C1_Barrow AK 8.0 71.32300 -156.60900
C2_Atqasuk AK 20.0 70.47180 -157.40660

1.2 Time Period Covered by Data

All stations cover the complete EOP-3 and EOP-4 period (1 October 2002
to 31 December 2004).

1.3 Temporal Resolution

All data are 30-minute resolution. See the instrumentation section for
further information.

Both stations have observations of air temperature, relative humidity,
dew point, specific humidity, wind speed, wind direction, U wind
component, V wind component, station pressure, precipitation, snow
depth, skin temperature, incoming longwave, incoming shortwave, outgoing
longwave, outgoing shortwave and net radiation.

Neither station provides observations of incoming or outgoing PAR.

2.0 INSTRUMENTATION DESCRIPTION

The ARM NSA meteorological tower measurements at the Barrow site are
from their Barrow Meteorology (BMET) tower. At the Atqasuk site the
meteorological tower measurements are from their Atqasuk Meteorology
(AMET) tower. Starting on 6 November 2003 C2_Atqasuk changed
instrumentation to the METTWR2H and on 31 October 2003 C1_Barrow
changed instrumentation to the METTWR4H. The radiation data
come from the GNDRAD and SKYRAD instrumentation at both sites.

2.1 BMET Sensors (Barrow site)

Full descriptions of the instruments used at the Barrow site prior
to 31 October 2003 are available in the pdf file Other_NSA_BMET.pdf
included with your order.
ARM NSA BMET Handbook.

2.2 AMET (Atqasuk) Sensors

Full descriptions of the instruments used at the Atqasuk site prior
to 6 November 2003 are available in the pdf file Other_NSA_AMET.pdf
included with your order.
ARM NSA AMET Handbook.

2.3 METTWR2H (Atqasuk) Sensors

Full descriptions of the instruments used at the Atqasuk site starting
6 November 2003 and ending 8 September 2008 are available in the pdf file Other_NSA_METTWR2H.pdf
included with your order.
ARM NSA METTWR2H Handbook.

2.4 METTWR4H (Barrow) Sensors

Full descriptions of the instruments used at the Barrow site starting
31 October 2003 and ending 11 September 2008 are available in the pdf file Other_NSA_METTWR4H.pdf
included with your order.
ARM NSA METTWR4H Handbook.

2.5 MET (Barrow and Atqasuk) Sensors

Full descriptions of the instruments used at the Barrow site starting 18 September 2008 and at the Atqasuk site
starting 9 September 2008 are available in the pdf file Other_NSA_MET.pdf
included with your order.
ARM NSA MET Handbook.

2.6 TWR (Barrow and Atqasuk) Sensors

Full descriptions of the instruments used at the Barrow site starting 18 September 2008 and at the Atqasuk site
starting 9 September 2008 are available in the pdf file Other_NSA_TWR.pdf
included with your order.
ARM NSA TWR Handbook.

2.7 GNDRAD and SKYRAD Sensors

Full descriptions of the radiation instruments used at both sites
are available in the pdf file Other_GNDRAD.pdf and Other_SKYRAD.pdf included
with your order.
ARM NSA GNDRAD Handbook and
ARM NSA SKYRAD Handbook.

3.0 DATA COLLECTION AND PROCESSING

3.1 ARM Data Collection and Processing

For complete information on the SKYRAD instrumentation see the
ARM NSA SKYRAD Handbook.

For complete information on the GNDRAD instrumentation see the
ARM NSA GNDRAD Handbook.

For complete information on the METTWR4H instrumentation see the
ARM NSA METTWR4H Handbook.

For complete information on the METTWR2H instrumentation see the
ARM NSA METTWR2H Handbook.

For complete information on the AMET instrumentation see the
ARM NSA AMET Handbook.

For complete information on the BMET instrumentation see the
ARM NSA BMET Handbook.

For complete information on the MET instrumentation see the
ARM NSA MET Handbook.

For complete information on the TWR instrumentation see the
ARM NSA TWR Handbook.

3.2 NCAR/EOL Data Processing

The National Center for Atmospheric Research/Earth Observing
Laboratory (NCAR/EOL) converted the data from the raw format
provided by ARM into the CEOP EOP-3 data format agreed to by
the CEOP Scientific Steering Committee. This format is described
in detail as part of the CEOP Reference Site Data Set Procedures
Report which is available at the following URL:

http://www.eol.ucar.edu/projects/ceop/dm/documents/refdata_report

The METTWR4H, METTWR2H, AMET, BMET , GNDRAD and SKYRAD provide
1 minute measurements, the observations at the 00 and 30 minute
marks of every hour are included in the final data set.

4.0 QUALITY CONTROL PROCEDURES

4.1 ARM Quality Control Procedures

For futher information on ARM QC Procudures see the instrument
handbooks mentioned above and in the references below.

4.2 NCAR/EOL Quality Control Procedures

NCAR/EOL converted the ARM QC flags into the CEOP QC flags in the
following manner. If a parameter failed one of the ARM QC checks it was
flagged as Questionable/Dubious ("D") and if it failed two or more ARM
QC checks it was flagged as Bad ("B").

Additionally, NCAR/EOL conducted two primary quality assurrance/control
procedures on the reference site data. First the data has
been evaluated by a detailed QA algorithm that verifies the format is
correct, examines any QC flags, and conducts basic checks on data
values. Second, NCAR/EOL conducts a manual inspection of time series
plots of each parameter.

5.0 GAP FILLING PROCEDURES

No gap filling procedures were applied to these data by either
ARM or NCAR/EOL.

6.0 DATA REMARKS

6.1 ARM Data Quality Report for station C2 (Atqasuk) All Parameters

Missing data from 0029 UTC on 22 September 2002 to 1935 UTC on
21 November 2002:

Due to unknown wiring differences and pin changes by Vaisala to their
Wind Speed and Direction sensors, a power feedback into the QLI data
collector occurred. This caused an overload which shut the QLI data
collector down. Once trouble shooting pinpointed the power feedback,
wiring diagrams were created and the differences were found. Wiring
was changed to prevent and remove the power feedback.

6.2 ARM Data Quality Report for station C2 (Atqasuk) All parameters

From 1430 UTC on 25 November 2002 to 2229 UTC on 26 March 2003:

Missing met, present weather, and snow depth data due to comm error

An error in the communication sub-routine of the Bridgeview collection
software occurred resulting in data loss from the Snow Depth sensor,
Present Weather Sensor and the Barometer.

7.0 REFERENCE REQUIREMENTS

To support the continuation of this program, please include the
following 'credit line' in the acknowledgments of your
publication:

"Data were obtained from the Atmospheric Radiation Measurement
(ARM) Program sponsored by the U.S. Department of Energy, Office
of Science, Office of Biological and Environmental Research,
Environmental Sciences Division."

8.0 REFERENCES