                    TRANSMISSOMETER CD-ROM README FILE - OCTOBER 2002  

This CD contains level-1 hourly transmissometer-based visibility data from all sites in the
IMPROVE visibility monitoring network. Previously reported transmissometer data went through
Fall 2000, but were in seasonal format. All previously reported transmissometer data
have been reformatted into calendar quarters (see file naming conventions section below) and
are included on this CD with the addition of newly processed data through Fall 2001.
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 the "Readme"
folder on this CD and is available in:

	-  MS Word format 	  (transkeyOct2002.doc)

	-  Adobe Acrobat format   (transkeyOct2002.pdf)

	-  Text only		  (transkeyOct2002.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 =	Winter   (January, February, and March)
	-  2 =	Spring   (April, May, and June)
	-  3 =	Summer   (July, August, and September)
	-  4 =	Fall     (October, November, and December)

For example, BRID1_T1W.961 contains Bridger Wilderness transmissometer data for the period 
January 1, 1996 through March 31, 1996.  The average size of a quarterly transmissometer
file is 202 Kb.

-  At several sites, the transmissometer was moved to a new location due to site
 	   related operational problems.  Data collected while the instrument was at the
	   initial location has a "1" in the site abbreviation code.  Data collected after 
           relocation has a "2" in the site abbreviation code. At Chiricahua NM the receiver
           and transmitter swapped locations (receiver instrumentation installed at transmitter
           site and vice versa) on July 12, 2001. The new site was designated "CHIR3". Two (2)
           transmissometers are curently operating over adjacent sight paths at Big Bend NP. 
           The original sight path is designated "BIBE1" and the adjacent sight path is 
           designated "BIBE2". Data collection over the adjacent sight path (BIBE2) began
           January 29, 2000. 

**********************************************************************************************
LIST OF SITE NAMES AND DATES OF OPERATION



   ----------------------------------------- IMPROVE -------------------------------------------
 
      Location		        	Abbr.	     First Data	         Last Data   Files	
	
   Acadia NP		        	ACAD1*	     Fall   1987	Spring 1993   23		
   Badlands NP				BADL1	     Winter 1988	Fall   2001   56
   Bandelier NM				BAND1        Fall   1988	Fall   2001   53	
   Big Bend NP				BIBE1	     Fall   1988	Fall   2001   53
   Big Bend NP (Grapevine Hills)	BIBE2	     Spring 2000	Fall   2001    7
   Bridger W		       		BRID1	     Fall   1988	Fall   2001   53 
   Canyonlands NP			CANY1	     Fall   1986	Fall   2001   61	
   Chiricahua NM			CHIR1	     Winter 1989	Fall   1998   40	
      (Relocated January 23, 1999)	CHIR2	     Winter 1999	Spring 2001   10
      (Relocated July 12, 2001) 	CHIR3	     Summer 2001	Fall   2001    2
   Crater Lake NP			CRLA1*	     Summer 1989	Fall   1990    4#
      (Relocated June 26, 1991)		CRLA2*	     Summer 1991	Summer 1991    1
   Glacier NP		       		GLAC1	     Winter 1989	Fall   2001   52 	
   Great Basin NP			GRBA1	     Summer 1992	Fall   2001   38	
   Grand Canyon NP (South Rim)		GRCA1	     Fall   1986	Fall   2001   61	
   Grand Canyon NP (In-Canyon)		GRCW1	     Fall   1989	Fall   2001   49	
   Guadalupe Mountains NP		GUMO1	     Fall   1988	Fall   2001   53	
   Mesa Verde NP			MEVE1*	     Summer 1988	Spring 1990    8+
     (Relocated July 19, 1991)		MEVE2*	     Summer 1991	Summer 1993    9
   Petrified Forest NP			PEFO1	     Spring 1987	Summer 1987    2	
     (Relocated July 6, 1987)		PEFO2	     Summer 1987	Fall   2001   58
   Pinnacles NM				PINN1*	     Winter 1988	Summer 1993   23	
   Rocky Mountain NP	        	ROMO1	     Fall   1987	Summer 1997   40$	
     (Relocated October 3, 1998)	ROMO2	     Fall   1998 	Fall   2001   13
   San Gorgonio W			SAGO1	     Spring 1988	Fall   2001   55	
   Shenandoah NP			SHEN1	     Fall   1988	Spring 1991   11	
     (Relocated September 15, 1991)	SHEN2	     Summer 1991	Fall   2001   42
   Tonto NM			        TONT1*	     Spring 1989	Summer 1991   10+	 
   Yellowstone NP			YELL1*	     Summer 1989	Summer 1993   17	
   Yosemite NP				YOSE1	     Fall  1988 	Fall   1994   25	
     (Relocated December 12, 1994)	YOSE2	     Fall   1994	Fall   2001   29
                                                                                    -----
                                                                        Total files = 958   
  ---------------------------------------------------------------------------------------------


      Notes:  1)  During the period June 1999 - October 2000, all IMPROVE transmissometers were
		  retrofit with a re-designed transmissometer feed-back block (see IMPROVE 
		  Newsletter for Fall 1999).  Instruments with the new feed-back block
		  modification were phased into the network during annual servicing site visits.
		  
		
	      2)  * - Identifies transmissometer sites that are no longer in operation.

              3)  # - Summer and Fall quarter only for 1989 & 1990.

              4)  + - Transmissometer removed 7/90 for site relocation.
 
              5)  $ - Transmissometer removed 7/97 for site relocation.             	

	      6)  Refer to Site Specific Notes section in Word document.		     