Creating Rotation Tracks using WDSS-II

How do you go about creating rotation tracks starting from Level-II radar data from NCDC?


The entire process is described in M. Miller, V. Lakshmanan, and T. Smith, “An automated method for depicting mesocyclone paths and intensities,” Wea. Forecasting, vol. 28, pp. 570-585, 2013

If you use Rotation Tracks in your research, please cite the above paper and also cite the papers for each of the following steps.

  1. Untar the Level-II data and place it somewhere. Let’s call this directory RAWDIR
  2. Get terrain netcdf data for your radar. You can get terrain files for US radars from   Untar this, and let’s call this directory TERRAIN
  3. Decide where you want your output products to go. Let’s call this DATADIR.
  4. Define a variable RADAR to hold your radar identifier (e.g. KBMX)
  5. Run ldm2netcdf to convert the Level-II data into NetCDF
  6. QC the radar reflectivity data.  Note that I am assuming that you have don’t have dualpol (if you do have dualpol, you should w2qcnndp) and that you do have super-resolution (if you have 1km resolution, change -R accordingly)
  7. Dealias the velocity data
  8. Compute Azimuthal Shear
  9. Run w2merger to put the data on a LatLonGrid
  10. Run w2accumulator with QC to create the rotation tracks

Here’s a script that will carry out the entire process. Edit as needed.



# Overall reference about the entire process
# M. Miller, V. Lakshmanan, and T. Smith, ``An automated method for depicting mesocyclone paths and intensities,'' Wea. Forecasting, vol. 28, pp. 570-585, 2013. 


# (5) convert Level-II to netcdf
# V. Lakshmanan, T. Smith, G. J. Stumpf, and K. Hondl, ``The warning decision support system - integrated information,'' Wea. Forecasting, vol. 22, no. 3, pp. 596-612, 2007.
ldm2netcdf -i $RAWDIR -o $DATADIR -s $RADAR -p $RADAR -a -1 --verbose
replaceIndex -i $DATADIR/code_index.fam -o $DATADIR/code_index.xml

# (6) note: if you have dualpol data, use w2qcnndp instead of w2qccn. The rest of the command-line is the same
# V. Lakshmanan, A. Fritz, T. Smith, K. Hondl, and G. J. Stumpf, ``An automated technique to quality control radar reflectivity data,'' J. Applied Meteorology, vol. 46, pp. 288-305, Mar 2007
# V. Lakshmanan, C. Karstens, J. Krause, and L. Tang, ``Quality control of weather radar data using polarimetric variables,'' J. Atm. Ocea. Tech., vol. 0, p. 0, 2013. 
w2qcnn -i $DATADIR/code_index.xml -o $DATADIR -R 0.25x0.5x460 -s $RADAR -E $TERRAIN -u --verbose
replaceIndex -i $DATADIR/code_index.fam -o $DATADIR/code_index.xml

# (7) note: if you have sounding information, provide it. the results will be better
# Jing and Wiener 1993
dealias2d -i $DATADIR/code_index.xml -o $DATADIR --verbose
replaceIndex -i $DATADIR/code_index.fam -o $DATADIR/code_index.xml

# (8) run LLSD
# Smith and Elmore 2004 
w2circ -i $DATADIR/code_index.xml -o $DATADIR -a -w -z ReflectivityQC -Z 20 -D -t -c -L "0:2:1.0:7.5:AGL  3:6:0:90:AGL" -V "0.5 250 920" -G $RADAR -g $TERRAIN --verbose
replaceIndex -i $DATADIR/code_index.fam -o $DATADIR/code_index.xml

# (9) run w2merger to put the data on a cartesian grid
# V. Lakshmanan, T. Smith, K. Hondl, G. J. Stumpf, and A. Witt, ``A real-time, three dimensional, rapidly updating, heterogeneous radar merger technique for reflectivity, velocity and derived products,'' Wea. Forecasting, vol. 21, no. 5, pp. 802-823, 2006. 
# V. Lakshmanan and T. W. Humphrey, ``A MapReduce technique to mosaic continental-scale weather radar data in real-time,'' IEEE J. of Select Topics in Appl. Earth Obs. and Remote Sensing, vol. 0, no. 0, 2013.
TOP=`grep -A 2 $RADAR ~/WDSS2/src/w2/w2config/misc/radarinfo.xml | head -2 | tail -1 | sed 's/[=\"]/ /g' | awk '{print $3+4,$5-4}'`
BOT=`grep -A 2 $RADAR ~/WDSS2/src/w2/w2config/misc/radarinfo.xml | head -2 | tail -1 | sed 's/[=\"]/ /g' | awk '{print $3-4,$5+4}'`
echo "$TOP to $BOT"
w2merger -i $DATADIR/code_index.xml -o $DATADIR -I AzShear_0-2kmAGL -p 0.001 -e 60 -C 1 -R 230 -t "$TOP 1" -b "$BOT 0" -s "0.005 0.005 1" --verbose
replaceIndex -i $DATADIR/code_index.fam -o $DATADIR/code_index.xml

# (10) run w2accumulator with QC
# V. Lakshmanan, M. Miller, and T. Smith, ``Quality control of accumulated fields by applying spatial and temporal constraints,'' J. Atmos. Ocean. Tech., vol. 30, pp. 745-757, 2013. 
w2accumulator -i $DATADIR/code_index.xml -o $DATADIR -R -s -t "60 120 360" -C 1 -O RotationTrack -t 120 -Q blob:0.002:0.005:25:azshear,mht:1:2:1800:5:1 -g MergedAzShear_0-2kmAGL --verbose
replaceIndex -i $DATADIR/code_index.fam -o $DATADIR/code_index.xml