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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).
This is part of a multi-part data set.
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 for all station found at the following address:
http://www.mcmlter.org/data/meteorology/tasks/task_lists.htm
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.
Notes Data contained in these files has been subjected to quality
control standards imposed by the investigator. The user of this data should be
aware that, while efforts have been taken to ensure that these data are of the
highest quality, there is no guarantee of perfection for the data contained
herein and the possibility of errors exists. If you encounter questionable data,
please contact the MCM LTER data manager (telephone: 303-492-4639) so that the
data can be corrected or qualified. Thus, these data may be modified and future
data will be appended.
she did some fine-tuning of the data, which included:
1. Removal and flagging of WDirStd values between Nov 28, 1994 @ 15:40 and Nov 30,
1994 @ 14:00. The task sheet in frl94501.dat and frl94502.dat both indicated the
WDirStD should be flagged, but only the data covering frl94502.dat had been flagged.
2. Removal of all RichNo and RichNo Comments from 11/21/1995 12:40:00 to
1/24/1996 12:15:00, since data was not collected after 11/21/95.
3. addition of PAR values for the entire portion of 1997. This data was accidently dropped
and needed to be added back.
4. removal of all commas from the comments fields, since commas cause spreadsheet
software packages to add additional columns.
In May 2000, the 1999-2000 data was posted. In the process, Denise Steigerwald changed the
layout of the files so that they were sorted by category (air temperatures, humidity, radiation,
wind etc.) rather than by year. Files containing monthly and daily averages were generated and
minor adjustments were made to the metadata.
On May 24, 2000, relative humidity (RH) values were corrected for a systematic error in the
measurement created by an instrument manufacturer error. All RH data with air temperatures
below freezing were corrected using the vapor pressure over ice (rather than over water which
was used initially). The error became quite large for very cold temperatures (the correction could
grow to around 30%). The formula used for the correction was:
RH_corr=RH_orig/((A*temp*temp)+(B*temp)+C) where
RH_corr = corrected relative humidity
RH_orig = original relative humidity
temp = air temperature
A = 4.165E-5
B = 9.7E-3
C = 1.0
For example, with an air temperature of -2.3 and RH_orig of 50.6, the RH_corr will be 51.7.
Records that showed corrected RH values greater than or equal to 100 were changed to 99.99
and flagged.
In June 2000, summary files were added to the web containing daily and monthly statistics.
These were generated by creating "views" of daily and monthly means, minimums, maximums
and counts of the records represented in the Oracle database's meteorology tables.
On May 6, 2003, radiation values were omitted between June 25, 2001 @ 0230 to Nov 27, 2001
because station was blown over.
In 2007, it was realized that the RH error was still present in parts of the dataset. Hasan Basagic made
the above corrections to the FRLM dataset for the date range 1/23/2004 11:15 - 12/21/2006 13:30 (102,058 records).
In September, 2007 the information manager (Chris Gardner) removed all old RH data and re-inserted then newly
calculated values and associated comments. The original files are archive in the 'submitted data' section of the
mcmlter server.
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://www.mcmlter.org/data/meteorology/locations/metlocs.html
Allow read to users: public
Basagic, Hassan
position name:Associated Researcher
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 (this
lake-ice station is located in the same table as the Lake Fryxell shore station and
is noted with the METLOCID=FRIM).
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 (METLOCID=FRLM)). 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. This has resulted in approximately 20
values being recorded for final storage in every output interval. Primary
measurements made on Lake Fryxell meteorology station, instrumentation used, and
time of initiation are shown in the following table: