© 2003 University of Essex Progress of Dual Doppler Radar Visualisation Software DARWIn ( Doppler...
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Transcript of © 2003 University of Essex Progress of Dual Doppler Radar Visualisation Software DARWIn ( Doppler...
© 2003 University of Essex
Progress of Dual Doppler Radar
Visualisation SoftwareDARWIn
( Doppler Analysis and Retrieval of Wind Information )
Yong Kheng [email protected]
http://prswww.essex.ac.uk15-16 December 2003
© 2003 University of Essex
Status of Software
- Reading SMR data (Bologna & Gattatico)
- Graphics generation: 2-D Visualisation: PPI, RHI, VAD 3-D Visualisation: Velocity vectors
- Data Conversion: polar -> Cartesian
- Construction of wind velocity vectors
- Saving retrieved wind vectors in ASCII file
© 2003 University of Essex
Reading SMR data sets
- Available data set:15 Aug 2003 (1400 - 1857)
17 Dec 2002 (1800 - 2357)
- Data Quality:Weak Z in region of interest
SPC Radar Scan problems (Aug 2003 case)
GAT Radar Time problems (both cases)
© 2003 University of Essex
Coordinates conversion I
- Grid resolution:0.5 km x 0.5 km (x ~1 km)
- Ray resolution:Spacing 0.25 km
beam width 0.9 deg
approx. 1 km width
- Algorithm:
trap and average
© 2003 University of Essex
Wind Extraction : Algorithm
- Horizontal componentsdata: radial velocity from 2 radarsVr = u sin(az) cos(el) + v cos(az) cos(el) + W sin(el)W = Wt + w, Wt = 2.6 Z0.107
- Vertical componentMass continuity equation Boundary conditions
© 2003 University of Essex
Wind Extraction : boundary conditions
- Currently using V = 0, on ground
- What boundary condition do we want to use?
- Any other information available? Wind vector at 10 m
© 2003 University of Essex
Wind Field Data Structure
- Header lines:location of grid center
date/time
data files name
- Data:6 columns
x, y, z, Vx, Vy, Vz
© 2003 University of Essex
Case Studies
- Case I : (17 Dec 2002) 1915hr
- Case II : (15 Aug 2003) 1815 hr
© 2003 University of Essex
What next ... ?
- More data for analysis
- Extracting vertical wind component
- Testing + verifying DARWIn (Cedric)
- Extraction of clear- air wind
- Comparison with NWP
- Triple Doppler?
© 2003 University of Essex
Summary
●DD-VAD Analysis -- RHIs show Bologna Radar can have problems.
●Conversion -- demonstrates the quality of the polar->cartesian conversion.
●3-D wind field -- examples of retrieved data and problems with boundary conditions.
●Verifying results -- any other info available?