net radiation

Daily measurement summaries from Canada Glacier Meteorological Station (CAAM) 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 package contains daily measurement summaries derived from 15-minute data generated by the Canada Glacier Meteorological Station (CAAM), located in Taylor Valley (Latitude: -77.61334, Longitude: 162.96437, Elevation: 264 meters above sea level). CAAM was established in 1994, during the 94/95 field season.

Dataset ID: 

7106

Associated Personnel: 

861
809
141
142
143
144

Short name: 

CAAM_DAILY

Data sources: 

CAAM_AIRT_DAILY
CAAM_ICET_DAILY
CAAM_PRESSTA_DAILY
CAAM_RADN_DAILY
CAAM_RH_DAILY
CAAM_SURFTEMP_DAILY
CAAM_WSPD_DAILY

Methods: 

On December 1, 1994, Gayle Dana established a summer-only eddy correlation station on Canada Glacier. The station and program both  belonged to Scott Tyler at the Desert Research Institute (DRI) so they were slightly different than the LTER standard. However, the station was set up to  monitor all of the standard meteorological parameters, as well as net radiation and sensible and latent heat fluxes with the use of the eddy correlation sensors  during the summer. Information was gathered with a sampling frequency of every 1 second and averaging & output interval of every 20 minutes using this  setup from December 1, 1994 to January 21, 1995. 
 
On November 20, 1995, Karen Lewis established a permanent meteorology station  on Canada Glacier with eddy sensors. It was set up to sample sensors regularly 
and send summary statistics (for example, averages and maximums) to solid-state storage modules every: 
 
 
  15 minutes between November 20, 1995 and January 16, 1997, 
  15 minutes between January 12, 1998 and January 16, 1998, 
  10 minutes between January 16, 1998 and January 30, 1998, 
  15 minutes thereafter. 
 
  
This has resulted in approximately 20 values being recorded for final storage in every output interval. 
 
(NOTE: Between Jan 16, 1997 @ 09:30 and Jan 12, 1998 @ 21:15 the  station was taken down and brought to the U.S. It was taken back to Antarctica for the 1997-98 season andamp; set up on January 12, 1998). 

Maintenance: 

Daily data packaged for LTER NIS export in 2016 - San Gil.
 
Files were submitted by Karen Lewis to the McMurdo LTER data manager in October, 1997 and  March, 1999. In order to get the dates and times in the proper format, Denise Steigerwald
 changed any times marked as 24:00 to 0:00, and added 1 to the corresponding julian date. Julian dates and times were then converted to a format with mm/dd/yy hh24:mm in order to make this file more compatible with other McMurdo LTER files. Variables were renamed to match with corresponding measurements at other meteorology stations. A column was also added for
 location code in order to identify the station of these measurements. Updates were done using Microsoft Excel and Access software. Comma delimited ascii files were then generated to make the data files available on the web page.
 
In June, 1999, it was determined that the transformations used to get records from level 0 to level 1 did not occur for the data sets submitted by Karen Lewis. Denise Steigerwald, the data
 manager, therefore replaced what she could with data sets that originated at the Desert Research Institute and had undergone these transformations. This included records between November 10, 1995 and August 21, 1996. The remaining records were downloaded by Thomas Nylen to allow him to get the records to level 1. On September 29, 1999, the level 1 records on the web replaced the level 0 records.
 
 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 17, 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 4, 2004, the relative humidity (RH) values after January 16, 2000 @ 1600 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.

Additional information: 

Meteorological data are 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.  These 15-min values are averaged to compute the daily averages, maximum, minimum and standard deviation

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