Progress of Dual Doppler Radar Visualisation Software DARWIn

Progress of Dual Doppler Radar Visualisation Software DARWIn ( Doppler Analysis and Retrieval of Wind Information ) Yong Kheng Goh kygoh@essex. ac. uk http: //prswww. essex. ac. uk 15 -16 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 (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 © 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 0. 107 - 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) 1915 hr - Case II : (15 Aug 2003) 1815 hr © 2003 University of Essex

Case I (17 Dec 2002) 1915 hr : Gattatico Reflectivity © 2003 University of Essex

Case I (17 Dec 2002) 1915 hr : Bologna Reflectivity © 2003 University of Essex

Case I (17 Dec 2002) 1915 hr : Gattatico Doppler Velocity © 2003 University of Essex

Case I (17 Dec 2002) 1915 hr : Dual-Doppler Wind Field © 2003 University of Essex

Case I (17 Dec 2002) 1915 hr : RHI along Radar-to-Radar line © 2003 University of Essex

Case I (17 Dec 2002) 1915 hr : Dual-Doppler Wind vs. VAD © 2003 University of Essex

Case II (15 Aug 2003) 1815 hr : Bologna Reflectivity © 2003 University of Essex

Case II (15 Aug 2003) 1815 hr : Bologna Reflectivity © 2003 University of Essex

Case II (15 Aug 03) 1815 hr : Gattatico Reflectivity © 2003 University of Essex

Case II (15 Aug 2003) 1815 hr : Bologna Doppler Velocity © 2003 University of Essex

Case II (15 Aug 2003) 1815 hr : 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? © 2003 University of Essex