HYSPLIT4 TRAJECTORY INFORMATION
Also see the list of Frequently Asked Questions
Select the trajectory direction (forward or backward) This is direction of trajectory calculation. Note that you must change the default starting time when computing forecast backward trajectories because the default time is the start of the meteorological forecast, and thus the model cannot calculate backward prior to the initial forecast time. Select the vertical motion method This indicates the vertical motion calculation method. Model Vertical Velocity uses the meteorological model's vertical velocity fields; other options include isentropic and isobaric (usefull for balloon flight calculations). Most applications should use Model Vertical Velocity. Enter starting time (year, month, day, hour) The default of 0's will cause the model to start at the beginning or end of the forecast dataset according to the direction of the calculation (a backward calculation will start at the end of the forecast dataset, while a forward calculation will start at the beginning or initialization time of the forecast dataset). For a time other than the beginning or end of the dataset, enter the two digit values for the UTC time that the calculation is to start. The default time is the time of the first record in the meteorological data set. Enter starting location (lat, lon, m-agl) Simultaneous trajectories can be calculated at multiple levels. The maximum number that can be accomodated depends upon the compilation parameters. The WEB menu can accomodate up to 3 simultaneous starting heights. Position in degrees and fraction (West and South are negative). Height is entered as meters above ground. Enter trajectory duration or total run time (hours) Specify the duration of the calculation in hours. A maximum of 240 hours can be specified for archive datasets on the web. If the model runs out of meteorological data it will terminate. Graphic Size Select the size (in pixels) of the trajectory plot. Save the NCAR Graphics metafile? This options allows users of NCAR Graphics to save the vector graphics to a file. Trajectory output file format (ASCII) Record #1 I6 - Number of meteorological grids used in calculation Loop Records #2 == > number of grids A8 - Meteorological Model identification 5I6 - Data file starting Year, Month, Day, Hour, Forecast Hour Record #3 I6 - number of different trajectories in file A8 - direction of trajectory calculation (FORWARD/BACKWARD) A8 - vertical motion calculation method (OMEGA,THETA,...) Loop Record #4 ==> number of different trajectories in file 4I6 - starting year, month, day, hour 2F8.3 - starting latitude, longitude F8.3 - starting level above ground (meters) Record #5 I6 - number of diagnostic output variables nA8 - label identification of each variable (PRESSURE,THETA,...) Loop Record #6 ==> through end of all endpoints I6 - trajectory number I6 - meteorological grid number 5I6 - time of point: year month day hour minute I6 - forecast hour at point F8.1 - age of the trajectory in hours 2F8.3 - position latitude and longitude F8.1 - position height in meters above ground nF8.1 - n diagnostic output variables (1st output is always pressure) |