DELIVERED JULY 2008
TRANSMISSOMETER DATA README FILE - JULY 2008
This CD contains level-1 hourly transmissometer-based visibility data from the 4
transmissometer sites (listed below) in the IMPROVE visibility monitoring network. The data
included are from 1/1/07 through 12/31/07. There is a total of 16 transmissometer level-1 data
files included on this CD. As with all level-1 transmissometer data, careful attention should be
paid to the validity interference codes, which indicate a variety of uncertainties in the processed
measurements.
DATA FILE FORMAT KEY
The data file format key for all transmissometer data files is included in this folder and is
available in:



MS Word format
Adobe Acrobat format
Text only
(transkeyNov2003.doc)
(transkeyNov2003.pdf)
(transkeyNov2003.txt)
FILE NAMING CONVENTIONS
Quarterly data files are named XXXXX_T1W.YYS, where XXXXX is the site abbreviation, YY
is the year, and S is the calendar season:
1.
2.
3.
4.
=
=
=
=
Winter
Spring
Summer
Fall
(January, February, and March)
(April, May, and June)
(July, August, and September)
(October, November, and December)
For example, GRCA1_T1W.071 contains Grand Canyon (South Rim) National Park
transmissometer data for the period January 1, 2007 through March 31, 2007. The average size
of a quarterly transmissometer file is 202 Kb.
SITE SPECIFIC NOTES FOR TRANSMISSOMETER DATA (1/1/2007 – 12/31/2007)
BRID1 – Extinction readings possibly too low and not matching actual conditions with lamp
#3851 from 2/27/07 – 5/08/07. Smoke from local fires affecting extinction readings periodically
from early July through mid September .
GRCA1 - Extinction readings affected by fires in and around the park from mid July through late
September. NPS directed shutdown of transmissometer 10/01/07.
SITE SPECIFIC NOTES FOR TRANSMISSOMETER DATA (1/1/2007 – 12/31/2007)
GRCW1 - Extinction readings possibly too high and not matching actual conditions with lamp
#3536 from 2/22/07 – 5/04/07. Smoke from fires in and around the park affecting extinction
readings periodically from early April through late August. Transmitter control box/chopper
frequency malfunction from 9/3/07 – 9/30/07. NPS directed shutdown of transmissometer
10/01/07.
*SAGO1 - USFS directed shutdown of transmissometer 6/01/06. Site reactivated 3/08/07.
Smoke from nearby fire affected extinction readings from 10/24/07 – 10/30/07.
* Included on this data CD are two files (SAGO1_T1W.063 & SAGO1_T1W.064) that are
blankfilled to make a complete data set for SAGO1 during the time when site was deactivated.
TRANSMISSOMETER SITES IN THE IMPROVE VISIBILITY MONITORING
NETWORK:
1) BRID1 – Bridger Wilderness, WY
2) GRCA1 – Grand Canyon National Park (South Rim), AZ
3) GRCW1 – Grand Canyon National Park (In-Canyon), AZ
4) SAGO1 – San Gorgonio Wilderness, CA