LAKE BONNEY SNOWFENCE STATION MEASUREMENTS

Photo taken by Thomas Nylen - 2002-2003 Season All Rights Reserved. Reproduced with permission.

• The Principal Investigator be sent a notice stating reasons for acquiring any data and a description of the publication intentions.
• The Principal Investigator be sent a copy of the report or manuscript prior to submission and be adequately cited in any resultant publications.
• A copy of any resultant publications should be sent to the McMurdo data manager.
  

MCM LTER Data Manager:	Chi Yang
Address:	Institute of Arctic and Alpine Research, Campus Box 450, University of Colorado Boulder, Colorado 80309-0450
Phone:	(303) 492-4639
E-Mail:	Chi.Yang@colorado.edu

PRINCIPAL INVESTIGATOR:	Andrew G. Fountain
Address:	Department of Geology, Portland State University, Portland OR, 97207-0751
Phone:	(503)725-3022
E-Mail:	fountaina@pdx.edu

OTHERS:	Thomas Nylen
Address:	Department of Geology, Portland State University, Portland OR, 97207-0751
Phone:	(503)725-3355
E-Mail:	nylent@pdx.edu

• To query air temperature, precipitation, relative humidity, radiation and soil temperature of any station, click here.


• To query AVERAGE (DAILY and MONTHLY) air temperature, precipitation, relative humidity, radiation and soil temperature of any station, click here.


• Descriptions of previous adjustments to the data files can be found in the log page.

ABSTRACT: As part of the Long Term Ecological Research in the McMurdo Dry Valleys of Antarctica, meteorological data was collected from various locations throughout Taylor, Wright and Victoria Valleys. These files contain data for the Lake Bonney Snowfence station (in Taylor Valley).

VARIABLES: Samples are represented using the following variable names:

Variable Name	Description
Dataset Code	Code for given set of information from Lake Bonney Snowfence station
MetLocID	Location code for Lake Bonney Snowfence station
Date / time	Date/time of sample (McMurdo time)
PAR_Soil+3.6m	Photosynthetically active radiation 3.6 m east of snowfence
Flag	Radiation measurements (PARs) flag (see below for details of flag)
PAR_Soil+1.8m	Photosynthetically active radiation 1.8 m east of snowfence
Flag	Radiation measurements (PARs) flag
PAR_Air+1.5m	Photosynthetically active radiation at 1.5 m above ground
Flag	Radiation measurements (PARs) flag
AirT1m	Average air temperature at 1 m above ground
Flag	Air temperature flag
SoilT_-1.8m	Surface soil temperature at 1.8 m west of snowfence
Flag	Soil temperature flag
SoilT_+0.9m	Surface soil temperature at 0.9 m east of snowfence
Flag	Soil temperature flag
SoilT_+1.8m	Surface soil temperature at 1.8 m east of snowfence
Flag	Soil temperature flag
SoilT_+3.6m	Surface soil temperature at 3.6 m east of snowfence
Flag	Soil temperature flag
Snow Height	Height of snow from soil
Flag	Soil temperature flag

RESEARCH LOCATION: The Lake Bonney Snowfence station is located at a latitude of S, a longitude of E, and an elevation of ; meters above sea level. Descriptions of this and other McMurdo Dry Valley meteorology stations can be found at http://huey.colorado.edu/LTER/datasets/meteorology/metlocs.html.

METHODS: During the 2000-2001 field season, the McMurdo LTER established a snowfence above (south) of the west lobe of Lake Bonney in western Taylor Valley. The station was set up to sample sensors every 30 seconds, except the sonic range which samples every 15 minutes, and send summary statistics (for example, averages and maximums) to solid-state storage modules every 15 minutes. This has resulted in approximately 20 values being recorded for final storage in every output interval. Primary measurements made on the Lake Bonney Snowfence station, instrumentation used, and time of initiation are shown in the following table:

Measurement	Starting Season	Ending Season	Instrument Used
Air temperature 3 m	2000/2001	---	Campbell Scientific 107 temperature probe
Soil temperature -1.8 m	2000/2001	---	Campbell Scientific 107 temperature probe
Soil temperature +0.9 m	2000/2001	---	Campbell Scientific 107 temperature probe
Soil temperature +1.8 m	2000/2001	---	Campbell Scientific 107 temperature probe
Soil temperature +3.6 m	2000/2001	---	Campbell Scientific 107 temperature probe
PAR +3.6 m	2000/2001	---	LI-COR model 190SB quantum sensor
PAR +1.8 m	2000/2001	---	LI-COR model 190SB quantum sensor
Air PAR +1.5 m	2000/2001	---	LI-COR model 190SB quantum sensor
Snow Height	2002/2003	---	Campbell Scientific SR50 Sonic Ranging Sensor

TIMING: Data was gathered from the Lake Bonney Snow Fence on the dates and frequencies listed in the link below. Due to regular station maintenance, occasional short gaps (hours) with missing data occurs. Longer intervals (several months) with missing data have occasionally occurred due to storage module problems, but this is minimized through the regular station upkeep every austral summer. Click here to see the dates and frequencies.

CITATIONS: Doran, Peter T., Gayle L. Dana, Jordan T. Hastings and Robert A. Wharton, Jr. 1995. McMurdo Dry Valleys Long-Term Ecological Research (LTER): LTER automatic weather network (LAWN). Antarctic Journal of the U.S. 30(5): 276-280.

COMMENTS: Meteorological data is collected year-round at each of the stations in the McMurdo Dry Valleys of Antarctica. After retrieving this data (usually every January), the parameters that are recorded are processed from level 0 (raw) to level 1 (processed, provided on the web). The raw data file descriptions and task lists summarize what was done to get from level 0 to level 1.

STATUS: Public Access (Type 1).

VARIABLE DESCRIPTION:

variable	type	description	units	missing value indicator	minimum	maximum	precision
Dataset code	Text	Code for given set of information for Lake Bonney Snowfence station	None	Required entry	n/a	n/a	n/a
MetLocID	Text	Location code for Lake Bonney Snowfence station	None	Required entry	n/a	n/a	n/a
Date / Time	Date	Date/time of sample (McMurdo time)	MM/DD/YY HH24:MM	Required entry	01/01/01 00:00	12/31/04 23:59	MM (minutes)
PAR_Soil+3.6m	Number	Photosynthetically active radiation	µmols/second/meter2	Null	n/a	n/a	0.1
PAR_Soil+1.8m	Number	Photosynthetically active radiation	µmols/second/meter2	Null	n/a	n/a	0.1
PAR_Air+1.5m	Number	Photosynthetically active radiation	µmols/second/meter2	Null	n/a	n/a	0.1
PAR Comments	Text	Helpful hints on PAR measurements	None	Null	n/a	n/a	n/a
AirT1m	Number	Average air temperature at 3 m above ground	degrees celcius	Null	n/a	n/a	0.01
AirT1m Comments	Text	Helpful hints on air temperatures	None	Null	n/a	n/a	n/a
SoilT_-1.8m	Number	Soil temperature -1.8 m	degrees celcius	Null	n/a	n/a	0.01
SoilT_+0.9m	Number	Soil temperature +0.9 m	degrees celcius	Null	n/a	n/a	0.01
SoilT_+1.8m	Number	Soil temperature +1.8 m	degrees celcius	Null	n/a	n/a	0.01
SoilT_+3.6m	Number	Soil temperature @ +3.6 m	degrees celcius	Null	n/a	n/a	0.01
Soil Temp Comments	Text	Helpful hints on soil temperatures	None	Null	n/a	n/a	n/a
Snow Height	Number	Sonic ranger measurement of surface	cm	Null	n/a	n/a	0.1
Snow Height Comments	Text	Helpful hints on snow depth	None	Null	n/a	n/a	n/a

FLAGS: Flags used during data processing:

"#": Bogus value, initialized but never calculated
"B": Recorded by instrument,but known to be "bad data"
"F": Recorded by instrument, but apparently flawed
"M": Supposedly recorded by instrument, but missing
"N": Not available/applicable (e.g. WDir when WSpd=0)
"R": Out of Range (user-adjustable limits)
"*": Subjectively voided

In addition, flags were found that were not included in the list above. Peter Doran was therefore contacted to find out how to translate the flags for "S", "U" and "V". He advised to use the following:

"S": Negative value generated by noise in the system zeroed out (eg. incoming shortwave radiation level should not be negative, so convert negative value to zero)
"U": Constant ice surface ablation on the glaciers causes the 20-centimeter ice temperature probe to continually become shallower. The probe depth is therefore not well known.
"V": Constant ice surfaceablation on the glaciers causes the 1-meter ice temperature probe to continually become shallower. The probe depth is therefore not wellknown.

Since the flags in the data files were added to values that were recorded, rather than appearing as a separate variable (eg. 0.0N, as opposed to 0.0, N), it was necessary for the data manager to revise these files so that the measurements were represented in numeric format & the flags would be in text format. Denise Steigerwald therefore imported the data into Microsoft Access, created comment fields for categories such as air temperature, humidity, wind, radiation, and soil temperature, and moved the suffixes described above to these comments fields. The comments were then expanded from the single letter codes to short descriptions of what was occurring.