Document title: Description of processing done at NSSDC for the NDADS DE 
datatype WATS_2S_ASCII.
Project: DE
NDADS Datatype: WATS_2S_ASCII
EID: DOCUMENT
Super-EID: DOCUMENTS
There may be other documents also identified by this super-EID.
NDADS filename: wats_nssdc_pro_de.doc
TRF entry: b47608.txt in NSSDC's controlled digital document library, Dec. 1998.
Document text follows:
----------------------

			DE-2 Dynamics Explorer 2 
		WATS Wind and Temperature Spectrometer


The Original WATS High-Resolution Data and Software:
----------------------------------------------------
The original PI-provided WATS high-resolution data were in VAX/VMS binary
format with one file per orbit. This data are archived at NSSDC on magnetic
tape (81-070B-04C). In addition the PI team had provided a FORTRAN program 
WATSCOR to correct the WATS data. WATSCOR makes the following corrections
that are recommended by the PI team:
	(1) Temperature measurements following a RPA-mode measurements are not
reliable and are therefore set equal to the fillvalue 9999.
	(2) Increases the temperature measured during horizontal baffle postion 
by 1% and during vertical position by 5%.
	(3) Decreases oxygen temperature by 3%.
	(4) Averages out the sweep assymetry for the horizontal or vertical
neutral winds in geographic coordinates.
 

Processing Done at NSSDC:
-------------------------

I. As recommended by the PI, we first corrected the data with the WATSCOR
program, and include the corrected and uncorrected temperatures and velocities
in the output file. To run the WATSCOR program the following changes were 
necessary and were implemented before creating the WATSCOR-corrected orbit 
files:	(1) Some of the array sizes had to be increased so that the program 
could handle the files from the whole DE-2 mission.
	(2) It was found that what is described as varibale 9 in FORMAT.SFD is 
really variable 10 and vice versa. The decoding of the packed variables 9 and 
10 was done with the FORTRAN routine IBITS.
	(3) In subroutine VELCOR the last two 'IF ...'AND' statements contain 
the uninitialized variable IE, which should be really II.

II. The following additional data processing was done at NSSDC (program 
OAWATSREAD.FOR):
	(1) The corrected and uncorrected temperatures (new words 8 and 9) and 
velocities (new words 15 and 16) were included in the ASCII output file.
	(2) Several of the instrument mode and status parameters were stored
as bits packed into the original VAX/VMS binary words. To make access to these
parameters easier we have decoded all of these parameters and included them
as separate words in the output file:

	  parameter	packed in old word		new word
	  SLOT		10 (NOT 9 as indicated		4
	    		    in the SFDU docs)
	  TIME1		10				13	
	  TIME2		10				14
	  COUNTS1	 9 (NOT 10 as indicated		11	
			    in the SFDU docs)
	  COUNTS2	 9				12

	(3) Variable values outside the valid range for the specific 
variable were replaced by the following fill values:

	  word(s)	description		valid range	  fill value
          ------------------------------------------------------------------
	  4		slot position		1,2,3,4			  9
	  5		baffle direction	0,1			  9
	  6		mass in AMU		0 < mass < 100		 -9
	  8,9		temperature [K]		200  <= Tn <= 4000	 -9
	  10,15,16	velocity [m/s]		4000 <= v <= 4000      9999
	  11,12		counts			0 <= counts < 100000	 -9
	  13,14		baffle times		0 <= counts < 100000	 -9
	  23(o/a)	L-value			0 < L < 100		 -9

There were also two records that had an invalid date (a date of 1183894048
during 82255 and a date of 0 during 82351) and were discarded.

	(5) The following orbit parameters were added using the OAREAD Fortran 
subroutine and the OABASE binary o/a data base:

		word	description		units
		-----------------------------------------
		17 	Orbit number 
		18 	Altitude   		[km]
		19 	Geographic latitude   	[degree]  
		20 	Geographic longitude  	[degree]  
		21  	Local Solar Time        [hours]   
		22 	Local Magnetic Time     [hours]   
		23 	McIllwain L value
		24 	Invariant latitude 	[degree] 
		25 	Solar Zenith Angle 	[degree] 

	(3) The orbit files (one per orbit) were combined to daily files for 
easy access to all the data for a specific day of year.