© 2003 University of Essex Progress of Dual Doppler Radar Visualisation Software DARWIn ( Doppler Analysis and Retrieval of Wind Information ) Yong Kheng Goh December 2003
© 2003 University of Essex Contents Part I : - Status of DARWIn Part II : - Case studies
© 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 ( ) 17 Dec 2002 ( ) - 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 Visualisation I
© 2003 University of Essex Visualisation II
© 2003 University of Essex Visualisation III
© 2003 University of Essex Visualisation IV
© 2003 University of Essex Visualisation V
© 2003 University of Essex Visualisation VI
© 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 Coordinates conversion II
© 2003 University of Essex Wind Extraction : Algorithm - Horizontal components data: radial velocity from 2 radars Vr = u sin(az) cos(el) + v cos(az) cos(el) + W sin(el) W = Wt + w, Wt = 2.6 Z Vertical component Mass 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 Case I (17 Dec 2002) 1915hr : Gattatico Reflectivity
© 2003 University of Essex Case I (17 Dec 2002) 1915hr : Bologna Reflectivity
© 2003 University of Essex Case I (17 Dec 2002) 1915hr : Gattatico Doppler Velocity
© 2003 University of Essex Case I (17 Dec 2002) 1915hr : Dual-Doppler Wind Field
© 2003 University of Essex Case I (17 Dec 2002) 1915hr : RHI along Radar-to-Radar line
© 2003 University of Essex Case I (17 Dec 2002) 1915hr : Dual-Doppler Wind vs. VAD
© 2003 University of Essex Case II (15 Aug 2003) 1815hr : Bologna Reflectivity
© 2003 University of Essex Case II (15 Aug 2003) 1815hr : Bologna Reflectivity
© 2003 University of Essex Case II (15 Aug 03) 1815hr : Gattatico Reflectivity
© 2003 University of Essex Case II (15 Aug 2003) 1815hr : Bologna Doppler Velocity
© 2003 University of Essex Case II (15 Aug 2003) 1815hr : Dual Doppler Wind Field
© 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?