LAKE FRYXELL METEOROLOGICAL STATION

Photo taken by Thomas Nylen - 2002/2003 Season All Rights Reserved. Reproduced with permission. For a panoramic view of the valley near the station, click here

• 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 Fryxell meteorology 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 Fryxell Met Station
MetLocID	Location code for Lake Fryxell meteorology station
Date	Date/time of sample (McMurdo time)
AirT3m	Average air temperature at 3 m above ground
AirTMax	Maximum air temperature at 2.5 - 3 m above ground
AirTMin	Minimum air temperature at 2.5 - 3 m above ground
AirTdel3m1	Air temperature at 3 m above ground minus air temperature at 1 m above ground
AirT Comments	Comments about air temperature
RichNo	Bulk richardson number
RichNo Comments	Comments about bulk richardson number
RH	Relative humidity
RH Comments	Comments about relative humidity
SoilT0cm	Soil temperature at 0 cm depth
SoilT5cm	Soil temperature at 5 cm depth
SoilT10cm	Soil temperature at 10 cm depth
SoilT Comments	Comments about soil temperature
PAR	Photosynthetically active radiation
SwRadIn	Incoming shortwave radiation
SwRadOut	Outgoing shortwave radiation
Radiation Comments	Comments about radiation measurements (PAR, shortwave)
WDir	Average wind direction
WDirStD	Standard deviation of wind direction
WSpd	Wind speed
WSpdMax	Maximum wind speed
WSpdMin	Minimum wind speed
Wind Comments	Comments about wind speed
WVapD	Water vapor density
WVapD Comments	Comments about water vapor density
Snow Height	Depth of snow
Snow Height Comments	Comments about depth of snow

RESEARCH LOCATION: The Lake Fryxell meteorology station is located at a latitude of 77 10.6 S, a longitude of 163 10.1766 E, and an elevation of 19 meters above sea level. As of 8-Dec-1998, the station was 1 meter above Lake Fryxell. Descriptions of this and other McMurdo Dry Valley meteorology stations can be found at http://huey.colorado.edu/LTER/datasets/meteorology/metlocs.html.

METHODS: When the McMurdo Dry Valley LTER project began in December, 1993, a lake-ice meteorology station was already set up at Lake Fryxell. It was a 6 foot tower built by Rich Harnish in ~1989, but had not collected data for at least a year. Peter Doran, noting that the problem was power related (since the battery was under water and the voltage was less than 5), righted the station, and rebuilt it with new power supply, a new wind monitor, new CR10, new solar panel, and added a quantum sensor. The under water light sensors were not hooked up again nor was the barometric pressure sensor.

The lake-ice station was operated from 7 December 1993 to 6 January 1994. At that time, it was decided that maintenance of the records at the site of the old Fryxell land station was more important than the ice station so the ice station was cannibalized to re-establish the Lake Fryxell shore station, (which had been destroyed by wind the previous winter). The station was based on a 6 foot tripod which set it apart from the other Taylor Valley stations, but a 10 foot tower was subsequently installed in year 2. The land station is located a few meters above the old site to avoid rising lake levels.

On June 25, 2001 @ 0230 the station mast broke and blew over, breaking the wind monitor. Station was taken apart on November 16, 2001, with the sensors except wind temporally set up on what was left of the station. On November 27, 2001 the station was reconstructed and was made operational again. Mark all values from June to November as bad or questionable except the soil temperatures

The station was set up to sample sensors every 30 seconds and send summary statistics (for example, averages and maximums) to solid-state storage modules every:

• 10 minutes from December 7, 1993 to January 6, 1994 and January 7, 1994 to January 12, 1994,
• three hours from January 6, 1994 to January 7, 1994 and January 12, 1994 to November 28, 1994,
• 20 minutes between November 28, 1994 and November 21, 1995, and
• 15 minutes thereafter.

Measurement	Starting Season	Ending Season	Instrument Used
Air temperature @ 3 m	1993/1994 1999/2000	1999/2000 ---	Campbell Scientific 207 temp/rh probe Campbell Scientific 107 temp probe
Air temperature difference between 1 m & 3 m heights	1993/1994	1995/1996	Chromel-constantan thermocouple wire
Relative humidity @ 3 m	1993/1994 1999/2000	1999/2000 ---	Campbell Scientific 207 temp/rh probe Vaisala HMP45C RH probe
Soil temperature @ 0 cm	1994/1995	---	Campbell Scientific 107B temperature probe
Soil temperature @ 5 cm	1994/1995	---	Campbell Scientific 107B temperature probe
Soil temperature @ 10 cm	1994/1995	---	Campbell Scientific 107B temperature probe
Wind speed	1993/1994	---	R.M. Young model 05103 wind monitor
Wind direction	1993/1994	---	R.M. Young model 05103 wind monitor
Solar Flux (incoming)	1993/1994	---	LI-COR model L1200S silicon pyranometer
Solar Flux (outgoing)	1993/1994	---	LI-COR model L1200S silicon pyranometer
PAR	1993/1994	---	LI-COR model 190SB quantum sensor
Snow Height	2002/2003	---	Campbell Scientific SR50 Sonic Ranging Sensor

TIMING: Data was gathered from the Lake Fryxell meteorology station 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 Fryxell meteorology station	None	Required entry	n/a	n/a	n/a
MetLocID	Text	Location code for Lake Fryxell meteorology station	None	Required entry	n/a	n/a	n/a
Date	Date	Date/time of sample (McMurdo time)	MM/DD/YY HH24:MM	Required entry	12/01/94 00:00	12/31/04 23:59	MM (minutes)
AirT3m	Number	Average air temperature at 3 m above ground	degrees celcius	Null	-70	15	0.01
AirTMax	Number	Maximum air temperature at 2.5 - 3 m above ground	degrees celcius	Null	-70	15	0.01
AirTMin	Number	Minimum air temperature at 2.5 - 3 m above ground	degrees celcius	Null	-70	15	0.01
AirTdel3m1	Number	Air temperature at 3 m minus air temperature at 1 m	degrees celcius	Null	n/a	n/a	0.01
AirT Comments	Text	Helpful hints on air temperatures	None	Null	n/a	n/a	n/a
RichNo	Number	Bulk Richardson Number		Null	n/a	n/a	0.1
RichNo Comments	Text	Helpful hints on Bulk Richardson number	None	Null	n/a	n/a	n/a
RH	Number	Relative humidity	percent	Null	0	100	0.1
RH Comments	Text	Helpful hints on relative humidity	None	Null	n/a	n/a	n/a
SoilT0cm	Number	Soil temperature at 0 cm depth	degrees celcius	Null	-70	25	0.01
SoilT5cm	Number	Soil temperature at 5 cm depth	degrees celcius	Null	-70	25	0.01
SoilT10cm	Number	Soil temperature at 10 cm depth	degrees celcius	Null	-70	25	0.01
SoilT Comments	Text	Helpful hints on soil temperatures	None	Null	n/a	n/a	n/a
PAR	Number	Photosynthetically active radiation	µmols/second/meter2	Null	0	2000	0.1
SwRadIn	Number	Incoming shortwave radiation/solar flux	W/m2	Null	0	900	0.1
SwRadOut	Number	Outgoing shortwave radiation/solar flux	W/m2	Null	0	900	0.1
Radiation Comments	Text	Helpful hints on photosynthetically active, shortwave & longwave radiation/solar flux measurements	None	Null	n/a	n/a	n/a
WDir	Number	Average wind direction	degrees from north	Null	0	360	0.1
WDirStD	Number	Standard deviation of wind direction	degrees from north	Null	0	n/a	0.1
WSpd	Number	Wind speed	meters per second	Null	0	n/a	0.1
WSpdMax	Number	Maximum wind speed	meters per second	Null	0	n/a	0.1
WSpdMin	Number	Minimum wind speed	meters per second	Null	0	n/a	0.1
Wind Comments	Text	Helpful hints on wind measurements	None	Null	n/a	n/a	n/a
WVapD	Number	Water Vapor Density		Null	n/a	n/a	0.1
WVapD Comments	Text	Helpful hints on water vapor density measurements	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.