LOCALG

                                                                                
----+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
LOCALG                                                                          
----+----0----+----0----+----0----+----0----+----0----+----0----+----0----+----0
                                                                                
                                                                                
COLUMNS FORMAT         DESCRIPTION                         DEFAULT VALUE & UNITS
                                                                                
1-6     A6     LOCALG - Requests appliation and possibly
               estimation of gravity anomalies. Gravity 
	       anomalies [1] are regional (local) departures 
	       from the gravity field implied by the
	       input set of spherical harmonics.
	       The location of the gravity anomaly is
	       specified on a second card [2]. 

7-14    I8     Gravity Anomaly number. This is a unique number
	       specified by the user to identify the gravity
	       anomaly parameter. No two gravity anomaly parameters
	       may use the same gravity anomaly number. Information
	       about the area of the gravity anomaly parameter is
	       input on a grid [3]. The gravity anomaly number
	       helps link up information from the grid to the
               gravity anomaly parameter.

18-24   I7     Grid Number [3]. Information about the gravity
               anomaly area is given on an external grid.
	       The grid number identifies the grid which is
               being used. All gravity anomaly parameters in
               the same run must use the same grid.kk

25-44   D20.8  A priori value of the gravity anomaly at                  mgals  
               the center of the master block. [2]                              
                                                                                
73-80   D8.3   Standard deviation of gravity anomaly.  A                        
               value > 0 results in estimation of gravity  
               anomalies.                                                       

Note [1]       The parameters are free air anomalies on the surface of
	       a sphere with radius (a*a*b)**(1/3) where a is the semi
	       major axis and b is the semi minor axis of the central
	       body.

Note [2]       A card which is blank in COLs 1-6 must follow each
               LOCALG card. This second card contains information
               in COLs 7-66 about the location of the gravity anomaly.

Note [3]       When LOCALG parameters are present, IIS searches for
               a data set called SUBBLK. SUBBLK contains points which
               are assigned to the LOCALG parameters. The points represent
	       subdivision areas of the LOCALG parameters and are used
               to numerically integrate the equations which upward continue
	       the gravity anomaly to the satellite location.
                                                                                
SUBBLK is a formatted data set as follows:


7-14    I8    Gravity Anomaly number. This is a unique number
              for LOCALG parameters. At least one (preferably
	      more than one) grid point will match each LOCALG
              parameter's gravity anomaly number.

18-24   I7    Grid Number. This is a number which uniquely
              identified the grid (all points on the grid have
              the same grid number.

25-49  D25.16 Geocentric latitude of grid point (degrees)

50-74  D25.16 Longitude of grid point (degrees)

75-99  D25.16 Area on unit sphere represented by the grid point
                                                                                
                                                                                
IF CARD OMITTED: Gravity anomalies will not be applied.
FEB 2003

0302.0

GLOBAL SET

LOCALG (cont)

                                                                                
                                                                                
SECOND CARD                                                                     
___________                                                                     
                                                                                
                                                                                
----+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
                                                                                
----+----0----+----0----+----0----+----0----+----0----+----0----+----0----+----0
                                                                                
COLUMNS FORMAT         DESCRIPTION                         DEFAULT VALUE & UNITS
                                                                                
1-6     A6         Contains information about master                            
                   block and its subdivisions.                                  
                                                                                
 7-21   D15.2      Latitude of the center of the master                  deg    
                   block.                                                       
                                                                                
22-36   D15.2      East longitude at the center of the                   deg    
                   master block.                                                
                                                                                
37-51   D15.2      Size of the master block in the direction             deg    
                   of latitude.                                                 
                                                                                
52-66   D15.2      Size of the master block in the direction             deg    
                   of longitude.                                                

IF CARD OMITTED:   And LOCALG was requested the program will                    
                   terminate abnormally.

FEB 2003

0302.0

GLOBAL SET - Option Cards



Despina Pavlis
2003-02-24