********************************************************************************
*                                                                              *
*    Input file for the trajectory model FLEXTRA: Please select your options   *
*                                                                              *
********************************************************************************

1. __________________________________________________ 3X, A50
   Test run #1
   LABEL FOR THE MODEL RUN
   
2. __                3X, I2  
   1   
   DIRECTION         1 FORWARD, -1 BACKWARD TRAJECTORIES
   
3. _______           3X, I7
   2400000
   HHHMISS           LENGTH OF AN INDIVIDUAL TRAJECTORY

4. ________ ______   3X, I8, 1X, I6
   20100828 223000
   YYYYMMDD HHMISS   BEGINNING DATE

5. ________ ______   3X, I8, 1X, I6
   20100828 223000
   YYYYMMDD HHMISS   ENDING DATE

6. _______           3X, I7
   0060000
   HHHMISS           TIME INTERVAL BETWEEN STARTING TIMES OF TRAJECTORIES

7. _  _____          3X, I1, 2X, I5
   1  10800 
   i  SSSSS          i>0: INTERPOLATED OUTPUT OF TRAJECTORY EVERY SSSSS SECONDS

8. _____  ___.___  _.___  _.___  _.___  _.___ 3X, I5, 2X, F7.3 4(2X,F5.3)
   00000  000.500  2.000  0.080  0.080  0.200 
   NUMBER            NUMBER, DISTANCE (GRID UNITS), TIME CONSTANT (WIND FIELD INTERVAL UNITS) AND INTERPOLATION ERRORS (IN U, V AND W) OF UNCERTAINTY TRAJECT.

9. _                 3X, I1
   1 
   INTERPOLATION     1 = IDEAL INTERPOLATION   >1 = LINEAR INTERPOLATION

10. ---.--           4X, F6.4
      5.0
    CFL              TIMESTEP CRITERION HORIZONTAL AND VERTICAL

11. ---.--           4X, F6.4
      5.0
    CFLT             TIMESTEP CRITERION TIME GAP BETWEEN INPUT WIND FIELDS

12. -                4X, I1  
    1              
    MODE             1 NORMAL MODE, 2 CET MODE, 3 FLIGHT MODE
===================================================================
1. Comment to identify the current model run

2. Direction of trajectories (1 means forward trajectories, -1 backward)

3. Temporal lengths of the trajectories in the format HHHMISS, where HHH is 
   HOUR, MI is MINUTE and SS is SECOND

4. Beginning date and time of trajectory calculation. Must be given in format
   YYYYMMDD HHMISS, where YYYY is YEAR, MM is MONTH, DD is DAY, HH is HOUR,
   MI is MINUTE and SS is SECOND. All times are in UTC.

5. Ending date and time of trajectory calculation. Same format as 4.

6. Time interval between two trajectory calculations. Same format as 3.

7. Options for the trajectory output:     
   0 = original data in irregular time intervals
   1 = constant time intervals, interpolated output every SSSSS seconds
   2 = 0 plus 1

8. Six parameters have to be inputted. The first is the number of
   uncertainty trajectories. They are starting in a distance from
   the starting point of the reference trajectory as given by the
   second parameter (in grid units).
   Additionally, random errors may be added at each time step of the
   trajectory calculation. Using a Langevin equation, they are relaxed 
   with a time constant (in units of the wind field interval, third
   parameter) specified by the user. These random errors are
   thought to reflect typical wind errors caused, for instance, by
   interpolation. The magnitude of these errors (in relative units,
   relative to the wind velocity) must be specified by the user for
   the three wind components u, v and w (last three parameters).

9. Kind of interpolation
   1  - horizontal interpolation bicubic
        vertical interpolation polynomial
        temporal interpolation linear
   >1 - horizontal interpolation bilinear         
        vertical interpolation linear
        temporal interpolation linear
 
10.cfl criterion horizontal/vertical
   factor by which time step must be shorter than that determined
   from the CFL criterion, i.e.

                delta_t1=delta x/u/cfl
                delta_t2=delta y/v/cfl
                delta_t3=delta z/w/cfl

                delta_t(space) = min(delta_t1,delta_t2,delta_t3)

11. cfl criterion time
    factor by wich time is shorter than time interval of the wind
    fields

                delta_t(time) = delta_T(input wind)/cflt

     The time step used for trajectory calculation is the minimum of
     delta_t(space) and delta_t(time)

     cfl and cflt must not be less than 1!

12.  1 NORMAL mode -> read file STARTPOINTS and calculate a time
     series of trajectories starting all from the same starting
     points
     2 CET mode -> read file STARTCET and calculate trajectories
     starting uniformly spaced from a user-defined domain
     (for a single starting time)
     3 FLIGHT mode -> read file STARTFLIGHT and calculate
     trajectories starting neither uniformly spaced nor with
     constant time intervals (as needed, for instance, to start
     trajectories along an aircraft leg)
