DYCOMS-II Model:  NOAA/ARL Eta Model Backward Trajectory Imagery (GIF)


1.0  General Information


The NOAA/ARL Eta Model Backward Trajectory Imagery (GIF) is one of 
several model products collected as part of the Dynamics and 
Chemistry of Marine Stratocumulus Phase II: Entrainment Studies
(DYCOMS-II) project field catalog operated by the University 
Corporation for Atmospheric Research/Joint Office for Science Support 
(UCAR/JOSS; http://www.joss.ucar.edu/dycoms/catalog/).
The images were produced utilizing the National Oceanic and Atmospheric
Administration (NOAA)/Air Resources Laboratory (ARL) HYbrid Single-Particle 
Lagrangian Integrated Trajectory (HYSPLIT) Model
(http://www.arl.noaa.gov/ready/hysplit4.html).  Backward 
trajectories were produced daily ending at 12 UTC and running 48
hrs.  Three different source locations were used at points in the
DYCOMS-II region.  Each location had source heights at 250 and 
1500 m.  The products cover the period from 1 - 31 July 2001 and 
cover the DYCOMS-II region.  All images are in GIF format.


2.0  Data Contact


Bjorn Stevens, UCLA (bstevens@atmos.ucla.edu)


3.0  Product Information


The images were produced utilizing the HYbrid Single-Particle
Lagrangian Integrated Trajectory (HYSPLIT) Model
(http://www.arl.noaa.gov/ready/hysplit4.html).

3.1  Referencing Requirement

Use of the HYSPLIT4 results in a publication requires the
following citation: 

HYSPLIT4 (HYbrid Single-Particle Lagrangian Integrated Trajectory)
Model, 1997. Web address: 
http://www.arl.noaa.gov/ready/hysplit4.html, NOAA Air Resources
Laboratory, Silver Spring, MD. 

4.0  Quality Control Procedures


     UCAR/JOSS conducted no quality checks on these data.


5.0  File Naming Convention


The file names are structured as follows:

arl_backward_traj.yyyymmddhhmm.31p23N_123p05W_lev1500.gif

Where arl_backward_traj is the data type
      yyyy is the four digit year
      mm is the two digit month
      dd is the two digit day
      hh is the hour (UTC)
      mm is the minute 
      yyyymmddhhmm is the ending point of the backward
        trajectory
      31p23N_123p05W represents the source location of the backward
        trajectory.  31.23 deg N and 123.05 deg W.  The source
        locations used for DYCOMS-II included:
        31p23N_123p05W
        31p23N_121p64W
        31p23N_120p23W
      lev1500 represents the source height in m above ground
        level.  Two levels were used for DYCOMS-II, 250 and 1500
        m.


6.0  References


Trajectory Verification - Draxler, R.R. 1996, Trajectory
   Optimization for Balloon Flight Planning, Weather and 
   Forecasting, Vol 11, March, pp. 111-114. 

Kinematic and Isentropic Trajectories - Draxler, R.R. 1996,
   Boundary layer isentropic and kinematic trajectories duing the
   August 1993 North Atlantic Regional Experiment Intensive, J. 
   Geophys. Res., Vol 101, No. D22, pp. 29255-29268. 

Hysplit Ozone Calculations - Draxler, R.R. 2000, Meteorological
   Factors of Ozone Predictability at Houston, Texas, J. Air and
   Waste Management Assoc., 50: 259-271. 

Emergency Response Applications - Draxler, R.R., Jean, M., Hicks,
   B., and Randerson, D. 1997, Emergency Preparedness, Regional
   Specialized Meteorological Centers at Washington and Montreal,
   Radiation Protection Dosimetry, Vol 73, pp. 27-30. 

Technical Information - Draxler, R.R. and G.D. Hess, 1997,
   Description of the Hysplit_4 modeling system, NOAA Tech Memo ERL
   ARL-224, Dec, 24p. 

Verification and Examples - Draxler, R.R. and G.D. Hess, 1998, An
   Overview of the Hysplit_4 Modeling System for Trajectories,
   Dispersion, and Deposition, Aust. Met. Mag., 47, 295-308. 

Hysplit User's Guide - An essential document if you will be using
   the Windows PC version of the model. The document provides
   complete information about file formats, command line prompts,
   and descriptions of each input line for the Hysplit model's
   control file that is used to set up the simulation (NOAA Tech
   Memo ERL ARL-230, June 1999, 35p - Last Revised April 2001).