Radar Observations During NAME 2004 EOP Timothy Lang Steve Rutledge Steve Nesbitt Rob Cifelli Lee Nelson Dave Lerach Gustavo Pereira Dave Ahijevych Rit Carbone Photo courtesy of Brenda Dolan CSU NCAR

NAME Radar Network Planned ● S-Pol ● 4 SMN Radars ● SMN radars run in full-volume 360s ● 15-min resolution Actual ● S-Pol (7/8-8/21) ● Cabo (7/15-Fall) ● Guasave (6/10-Fall) ● SMN radars single low-level sweep (high temporal resolution)

SMN Upgrade Issues Guasave Upgrade completed 6/10 PRF increased 7/29 – Best Doppler data afterward Software problems prevented full-volume 360s Data recording outage 7/22-29 Los Cabos Upgrade completed 7/15 PRF increased 7/20 – Best Doppler data afterward Mechanical problems prevented full-volume 360s No solar gain calibrations Obregon Transmitter power supply failed Palmito Lightning strike and fuel/shipping delays ● Highest priority radars upgraded (Guasave & Cabo) ● Can use low-level sweeps to map rainfall and characterize horizontal structure of storms

S-Pol Operations 24-h Ops started 7/8, continued through 8/21 Occasional downtime for Ka-band work in preparation for RICO – Usually mid-morning precipitation minimum Two Modes of Scanning: “Climatology” Used most frequently 200-km range Full-volume 360s, completed in 15-min Includes rain-mapping angles (0.8,1.3,1.8-deg) & 0.0-deg “Storm Microphysics” hours total spread over ~35 cases Usually 150-km range 2-3 sector PPI volumes with 0-1 sets of RHIs in 15 min Includes rain-mapping angles (0.8,1.3,1.8-deg)

Radar Data Quality Control S-Pol Radar Mostly automated Threshold away non-meteorological echo (clutter, insects, etc.) Filter differential phase (PHI DP ) and calculate K DP Blockage & attenuation correction Currently working to improve the K DP algorithm SMN Radars Apply calibration – Intercomparison with S-Pol & TRMM Can threshold away most non-meteorological echo Some hand-editing needed for insects and leftover clutter Rainfall & attenuation correction based on Z-R – Tune using S-Pol

S-Pol Blockage Mean Power Clear-Air 0.8 deg Elevation Little to No Blocakge above 2 deg Elevation Minor Block Major Blocks Much of Low-Elevation Sweeps over Land Blocked at S-Pol But We Can Recover Using Phase! Mountain Clutter Ocean

Regional Composites Example – 0200 UTC on 8/6/04 Cabo Guasave S-Pol “Near-surface” reflectivity and rainfall every 15 minutes – 0.01, 0.02, & 0.05-deg grids Use low-level sweep – For S-Pol, use higher sweeps to fill in gaps caused by clutter and complete blocks S-Pol uses polarimetric rainfall estimates; SMNs will use Z-R based on polarimetric tuning – Constrain with gauges Will create smaller grid containing vertical information from S-Pol (0.5-km vert res); Grid will include hydrometeor ID Priority is EOP coverage by S-Pol (7/9-8/21)

05 Aug '04 Case Study Mesoscale Convective System Developed Over SMO and Propagated to the NW (“Proof of Concept” for Regional Composites) GOES IR 2230 UTC (5 Aug) GOES IR 0324 UTC (6 Aug)

Altair Sounding Time-Height 05 Aug '04 Case Study During IOP #7 (MCS & poss. Gulf Surge) - No Gulf Surge Inverted Trough Passed Thru Region Late on 8/05 UTC Midnight,8/6

2130 UTC 2230 UTC Regional Composites of Reflectivity

2330 UTC 0030 UTC Regional Composites of Reflectivity

0130 UTC 0230 UTC Regional Composites of Reflectivity

ZHZH RHO HV Z DR PHI DP Power LDR K DP Large Hail Aloft (D > 2 cm) Attenuation Melting hail causing large phase shifts Melt Level 05 Aug ' UTC Large Hail High Z Neg Zdr Low RHO High LDR Very Intense Convection!

Regional Composites of Rainfall Rain 2330 UTC 6-h Total ( UTC) Blocks

Hydrological Applications

Choix Presidio Piaxtla Tamazula Badiraguato Best Radar-Covered Hydrological Basins Basin-Averaged Rainfall For 6-h Event ( UTC, 5-6 Aug) Choix0.1 mm Badiraguato 14.8 mm Tamazula 5.1 mm Piaxtla 3.8 mm Presidio 0.4 mm

Future Work – Climatological Statistics Diurnal cycle of precipitation Principal physical processes controlling diurnal cycle Spatial variability Convective echo fraction Vertical structure of convection Effects of easterly waves and Gulf surges on precipitation Relative importance of MCS rainfall, stratiform rainfall, etc. Intercomparison with NERN Evaluate radar estimates of rainfall Evaluate gauge-based estimates of diurnal cycle Merged radar-gauge rainfall product

Future Work – Microphysical Case Studies 7/20-21 MCS (Vertically Intense) During IOP #3 (Monsoon ridge breakdown) 7/29 Sea breeze (Shallower) During IOP #4 (Monoon break & sea breeze)

Future Work -Intercomparison with Profilers S-Pol Images Collaboration with NOAA

Future Work – Radar/Lightning Analyses Meridional Propagation: Standard Anomalies 3-5 day BP Filtered Zonal Propagation: Standard Anomalies (Flash Count – Mean)/  Collaboration w/ Walt Petersen of U of Alabama and w/ Vaisala CG Flash Hovmollers from the Long-Range NLDN

Providing Products to the Community Estimate delivery starting this summer – Study of subset for J. Clim NetCDF for regional and S-Pol-centric grids – various resolutions Will tailor to specific community needs Model initialization & verification Microphysical parameterization verification Verification of satellite rainfall estimates For More Information