shortwave radiation

High frequency measurements from Lake Bonney Meteorological Station (BOYM) in Taylor Valley, Antarctica from 1993 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 package contains 15-minute data from the Lake Bonney Meteorological Station (BOYM), located in Taylor Valley. BOYM was established in 1993, during the 93/94 field season.

Dataset ID: 

7003

Associated Personnel: 

825
824
223
225
224
226

Short name: 

BOYM

Purpose: 

Meteorological data are collected year-round at each of MCM LTER stations. Data are 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: 

 The Lake Bonney meteorology station was initially built on the lake's ice cover in November, 1993. Shortly thereafter the station was listed to the point where it was decided to move it to shore. Some attempt was made to right the station during this period. The move of the station was done using the ATV with the station still running. The move began at 14:50 and ended at 15:06 on December 17, 1993. Data collected after 15:06 was done so with the station in it's final position. The clock synchronized with John Priscu's logger measuring light on Nov 26 in afternoon. 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 November 24, 1993 to January 12, 1994, 
  three hours from January 12, 1994 to November 12, 1994, 
  20 minutes from November 12, 1994 to November 22, 1995 
  15 minutes thereafter. 
  
This has resulted in approximately 28 values being recorded for final storage in every output interval.
 

Data sources: 

BOYM_AIRT
BOYM_PPT
BOYM_RADN
BOYM_RH
BOYM_SNOWHT
BOYM_SOILT
BOYM_WIND
BOYM_WVAPD

Maintenance: 

  On August 24, 1999, the data manager did some fine-tuning of the data, as requested by Thomas  Nylen. This included:
 
  1. Placement of flags for WDir and WDirStD between Jan 6, 1998 @ 17:15 and Jan 15,  1998 @ 9:00. It was assumed the data was deleted because the wind direction values = 0.  This needed to be indicated in the notes portion of the file.
 
  2. Deletion of SoilT5cm, SoilT10cm, SwRadIn, SwRadOut, PAR, LwRadIn and  LwRadOut2 values on 1/15/98 @ 9:15. They all appeared suspect are regarded as bad  data.
 
  3. Deletion of precipitation values between 1/15/98 @ 10:15 and 1/15/98 @ 10:45. The  values were zero and are regarded as bad data.
 
  4. Removal and flagging of the WDirStd data from Nov 12, 1994 @ 17:20 to Jan 20, 1995  @ 10:20.
 
  5. Addition of precipitation values between Dec 5, 1994 @ 11:20 Jan 20, 1995 @ 10:20. At  the request of Thomas Nylen, the first value for precipitation in this group was  subjectively voided, and the 3 values right after this file were deleted (01/20/1995  10:20:00 AM to 11:00 AM).
 
  6. Addition of WSpd, WSpdMax and WSpdMin values between Dec 5, 1994 @ 11:20 Jan 20, 1995 @ 10:20. In addition, WDir and WDirStd on 12/26/1994 4:00:00 was voided because the wind speed = 0.
 
  7. Addition of records taken between Nov 9, 1995 @ 19:20 and Nov 22, 1995 @ 16:20.  These records were not among the file provided on the web to that point.
 
 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 16, 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.
  
In May 2003, PAR values between 11/20/01 10:30 AM and 1/24/02 11:45 AM were changed because the wrong multiplier was used the first time it was processed. The values were divided  by 1.37283 (old multiplier) and multiplied by 1.64249 (correct multiplier).
  
In Apr 2004, LwRadIn data between 11/17/2000 @ 1130 am and 01/09/2002 @ 08:45 am were delete and flagged as "LwRadIn value recorded by instrument but known to be bad data". The  sensor values were considerably lower than the tempeature corrected LwRadIn2 value. The battery in the Eppley Pyrgeometer was probably left in, which affects the output voltage.
  
On June 4, 2004, the relative humidity (RH) values after January 15, 2000 @ 1300 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 polynomials used for the correction is based on Lowe (1977). The original RH value is multiplied by the saturation vapor pressure over water and divided by the the saturation vapor pressure over ice
 
  RH3m_corr=[RH3m]*(6.107799961 + [AirT3m] * (0.4436518521 + [AirT3m] *  (0.01428945805 + [AirT3m] * (0.0002650648471 + [AirT3m] *(0.000003031240396 +  [AirT3m] * (0.00000002034080948 + 0.00000000006136820929 * [AirT3m])))))) /  (6.109177956 + [AirT3m] * (0.503469897 + [AirT3m] * (0.01886013408 + [AirT3m] *  (0.0004176223716 + [AirT3m] * (0.00000582472028 + [AirT3m] * (0.00000004838803174 +  0.0000000001838826904 * [AirT3m])))))))
 
  Records that showed corrected RH values greater than or equal to 100 were changed to 99.99  and flagged.
  
  In March 2006, Chris Gardner consolidated the SnowHt and SoilSurfChange tables, as they are actually the same measurement.  The Data in BOYM_SNOWHT from 1/24/2003 4:00PM through 1/24/2004 1:30PM were  taken from  BOYM_SOILSURFCHANGE
 
 Metadata was standardized using EML in 2006 (Gardner, San Gil) and enhance using DEIMS in 2014
 
  
 

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