PAR

High frequency measurements from Taylor Glacier Meteorological Station (TARM) in Taylor Valley, Antarctica from 1994 to present

Abstract: 

As part of the McMurdo Dry Valleys Long Term Ecological Research program, meteorological data are collected from various locations throughout the McMurdo Dry Valleys of Antarctica. This data package contains 15-minute data from the Taylor Glacier Meteorological Station (TARM), located in Taylor Valley. TARM was established in 1994, during the 94/95 field season.

Dataset ID: 

7013

Associated Personnel: 

848
847
234
7
233
235

Short name: 

TARM

Purpose: 

Meteorological data is collected year-round at each of MCM LTER stations. Data is manually downloaded from the meteorological stations during the austral summer. Raw 15 minute data (Level 0) is processed and provided as Level 1 data on the MCM LTER website. Field notes, sensor information, processing procedures, QA/QC, and metadata is provided in the Meteorological Post Processing Documentation and Task Lists for each field season at the following address: http://www.mcmlter.org/data/meteorology/tasks/task_lists.htm 

Methods: 

During the 1994-1995 field season, the Taylor Glacier meteorological station was constructed at a latitude of 77 42.15845 S, longitude of 162 7.70264 E, and elevation of 334.1 meters above sea level. 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 20 minutes between November 21, 1994 and November 17, 1995 and every 15 minutes thereafter. This has resulted in approximately 20 values being recorded for final storage in every output interval.

Sampling and Averaging Intervals For Sampling frequency and Data Logger output and averaging intervals please visit: http://mcmlter.lternet.edu/data/meteorology/methods/Interval_Dates.pdf
Seasonal Task Summary To view the data post-processing steps for each season please visit: http://mcmlter.lternet.edu/data/meteorology/tasks/task_lists.htm

Data sources: 

TARM_AIRT
TARM_DEPTH
TARM_ICESURF
TARM_ICET
TARM_RADN
TARM_RH
TARM_WIND
TARM_WVAPD

Maintenance: 

On September 8, 1999, at the request of Thomas Nylen, the data manager did some fine-tuning of the data. This included:

  1. Removal and flagging of WDirStD values between Nov 21, 1994 @ 15:20 and Jan 23, 1995 @ 9:20. Wind speed had already been flagged for this period, and it was determined that WDirStD values needed a similar approach.
  2. Revision of LwRadIn values between Dec 19, 1995 @ 19:15 and Jan 25, 1996 @ 9:30. The initial LwRadIn values were zero, or close to zero. During the same period, LwRadIn2 had values consistent with the operation of the instrument. Since LwRadIn2 modifies the LwRadIn values, it was concluded that the values for LwRadIn must have been lost. Thomas therefore resubmitted the correct values to use.

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 31, 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 June 29, 2004, Thomas Nylen flagged the incoming and outgoing shortwave radiation data between 11/21/1994 @ 1520 to 12/01/1995 @ 0945 as questionable because the values are significantly higher than L. Bonney during the time period. During this time period, two Licor pyranometers were used, but were wired similar to the Eppley Pyranometers and used the same lines in the program. It is suspected that the incorrect wiring and/or program caused the higher output. After two Eppley Pyranometers were installed on the station on December 1, 1995 @ 1045, the values matched the measurements made at Lake Bonney. In 2006, metadata was standardized by Chris Gardner and Inigo San Gil using the EML. 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 TARM dataset for the date range 1/24/2004 11:30 - 1/20/2007 13:00 (104,827 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. In 2013, ice depth/sonic was revised to account for discontinuities arising at the maintenance downtime In 2014, this metadata was enhanced using the Drupal Ecological Information Management System (Inigo San Gil)

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