can be displayed and retrieved.

tovpre - Performs limb-corrections and transforms calibrated and earth-located HIRS/MSU data produced by INGTOV into data sets

SYNOPSIS

tovpre

Parameters are Letter, HIRS_LIMB-CORRECTION_FLAG, MSU_LIMB-CORRECTION_FLAG.

DESCRIPTION

Tovpre does limb-corrections and transforms calibrated and earth-located HIRS/MSU data produced by INGTOV into data sets that can be displayed and retrieved. If the MSU 'LIMB-CORRECTION' flag is on, MSU data are corrected for antenna pattern (transform antenna temp. to brightness temp.), limb effects (normalize to theta = 0), surface reflectivity (normalize to sfc.emis. = 1), and liquid water (precipitating cloud) attenuation. If the HIRS 'LIMB-CORRECTION' flag is on, HIRS data are corrected for limb effects, and water vapor attenuation in the window channels. In addition, HIRS channels 17 and 18 are corrected, in daylight, for fluorescence and reflected sunlight, respectively, regardless of the state of the limb-correction flag. MSU and HIRS are colocated by interpolating the MSU observations to the HIRS scan pattern.

Input file:       TOVSINGO.DAT
Output files:     TOVSORB?.DAT
                  TOVSND?.DAT

The question mark (?) should be replaced by the response to the ENTER LETTER OF FILE FOR OUTPUT parameter. TOVSORB?.DAT has all data for one parameter contiguous on disk, and thus is optimized for imaging. TOVSND?.DAT has all data for one scan spot contiguous on disk, and thus is optimized for sounding.



STRUCTURE OF THE 'TOVORB' AND 'TOVSND' FILES

*** TOVORB
      ACCESS ROUTINE: TSNIO
      RECORD LENGTH = 112 INTEGER*4 WORDS
CONTENTS OF FIRST RECORD ('DOCUMENTATION' OR 'HEADER'):

      IBUF( 1) = YYDDD AT START OF PASS
      IBUF( 2) = HHMMSS AT START OF PASS
      IBUF( 3) = HHMMSS AT END OF PASS
      IBUF( 4) = NUMBER OF HIRS LINES IN PASS
      IBUF( 5) = SATELLITE IDENTIFICATION (NOAA-NUMBER)
      IBUF( 6) = STATUS (TO IDENTIFY USER, ETC.)
      IBUF( 7) = DIRECTION (1=ASCENDING, 2=DESCENDING)
      IBUF(50) = START TIME OF PASS IN MILLISECONDS
      IBUF(51) = HIRS LIMB-CORRECTION FLAG
      IBUF(52) = MSU  LIMB-CORRECTION FLAG
      IBUF(53:112) = NOT USED

ORGANIZATION OF DATA IN SUBSEQUENT RECORDS:

There are 30 parameters, each of which is allotted 50 records on disk, providing for 100 HIRS scan lines (stored two lines per record). If the 'IMAGE' or orbital pass contains less than 100 lines, the unused portion of each 'LOGICAL (PARAMETER) FILE' is filled with 999999 tO serve as a 'MISSING' indicator to software that accesses the file.

      THE PARAMETERS ARE AS FOLLOWS:

       1     LATITUDE  (DEG X 100,+N,-S)
       2     LONGITUDE (DEG X 100,+E,-W)
       3     SOLAR ZENITH ANGLE (DEG X 100; 9000 IF NIGHT)
       4     BRIGHTNESS TEMPERATURE (DEG X 100), HIRS CHANNEL  1
       5     BRIGHTNESS TEMPERATURE (DEG X 100), HIRS CHANNEL  2
       .     ...
      22     BRIGHTNESS TEMPERATURE (DEG X 100), HIRS CHANNEL 19
      23     BRIGHTNESS TEMPERATURE (DEG X 100), MSU CHANNEL 1A
      24     BRIGHTNESS TEMPERATURE (DEG X 100), MSU CHANNEL 1
      25     BRIGHTNESS TEMPERATURE (DEG X 100), MSU CHANNEL 2
      26     BRIGHTNESS TEMPERATURE (DEG X 100), MSU CHANNEL 3
      27     BRIGHTNESS TEMPERATURE (DEG X 100), MSU CHANNEL 4
      28     TOTAL OUTGOING LONGWAVE FLUX (WATT/SQ-METER, X 100)
      29     BIDIRECTIONAL REFLECTANCE DERIVED FROM HIRS CHANNEL 20(VIS)
      30     BRIGHTNESS TEMPERATURE (DEG X 100), HIRS CHANNEL 18A

      EXPLANATION OF EXTRA BRIGHTNESS TEMPERATURES:

      ITEM 23 ... If MSU data are limb-corrected, this is channel 1 with
            surface effects retained; if not limb-corrected, this is
            indexing information and not mappable.
      ITEM 30 ... If daytime, this is channel 18 (4 micron window) with
            a first-order approximate correction for reflected sunlight.

The access routine 'TSNIO' does the internal calculations to locate the data on disk, given parameter number, initial line, initial element, number of lines, and number of elements.

*** TOVSND
      ACCESS ROUTINE: SNDIO
      RECORD LENGTH = 112 INTEGER*4 WORDS
      FIRST RECORD IS 'HEADER', AND IS IDENTICAL TO THAT FOR 'TOVORB'

ORGANIZATION OF DATA IN SUBSEQUENT RECORDS:

Parameters 1 through 28 (see 'TOVORB' description above for contents) are stored as a vector with coordinates of line and element (or spot). Thus each 112-word record contains data for four HIRS fields-of-view. The access routine 'SNDIO' does the internal calculations to locate the data on disk, given line and element.

PARAMETERS

The recommended parameter responses are shown in the example.

NOTE: Even though the questions given in the example imply that they have default values, the DO NOT! Each value must be entered.

EXAMPLES

[ 4] % tovpre
ENTER LETTER OF FILE FOR OUTPUT:
1
ENTER HIRS LIMB-CORRECTION FLAG (1=ON,0=OFF):
0
ENTER  MSU LIMB-CORRECTION FLAG (1=ON,0=OFF):
0

FILES