Daily measurement summaries from Lake Vida Meteorological Station (VIAM) in Victoria Valley, Antarctica from 1995 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 daily measurement summaries derived from 15-minute data generated by the Lake Vida Meteorological Station (VIAM), located in Victoria Valley.

Dataset ID:

7116

Associated Personnel:

908

909

179

181

180

182

Short name:

VIAM_DAILY

Data sources:

VIAM_AIRT_DAILY

VIAM_RADN_DAILY

VIAM_RH_DAILY

VIAM_SOILT_DAILY

VIAM_WSPD_DAILY

VIAM_SURFCHANGE_DAILY

Methods:

The Lake Vida meteorological station was added to the McMurdo Dry Valley network in the 1995-1996 field season. It was established on the shore of Lake Vida in Victoria Valley, one of the largest lakes in the dry valleys, recently discovered to have a 19 m ice cover over a hypersaline brine of undetermined depth. 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 15 minutes. 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 this link : Meteorological task Lists

Maintenance:

On September 6, 1999, the data manager added the 1998-1999 data to this dataset. In the process,she did some fine-tuning of the data, which included:

1. Addition of PAR values between Nov 24, 1997 @ 11:30 and Jan 13, 1998 @ 12:00. This was done at the request of Thomas Nylen.

On June 1, 2000, the 1999-2000 data was posted. In the process, Denise Steigerwald changed thelayout of the files so that they were sorted by category (ait temperatures, humidity, radiation,wind etc.) rather than by year. Files containing monthly and daily averages were generated andminor adjustments were made to the metadata.

On June 1, 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 whichwas used initially). The error became quite large for very cold temperatures (the correction couldgrow 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 99.99and 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.

Additional information:

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 for all station found at the following address:

Meteorological Task Lists