Radar Observations During NAME 2004 EOP

Timothy LangSteve RutledgeSteve NesbittRob CifelliLee NelsonDave LerachGustavo Pereira

Dave AhijevychRit 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 IssuesGuasaveUpgrade completed 6/10PRF increased 7/29 – Best Doppler data afterwardSoftware problems prevented full-volume 360sData recording outage 7/22-29

Los CabosUpgrade completed 7/15PRF increased 7/20 – Best Doppler data afterwardMechanical problems prevented full-volume 360sNo solar gain calibrations

ObregonTransmitter power supply failed

PalmitoLightning strike and fuel/shippingdelays

●Highest priority radars upgraded (Guasave & Cabo)

●Can use low-level sweeps to map rainfall and characterize horizontal structure of storms

S-Pol Operations24-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 frequently200-km rangeFull-volume 360s, completed in 15-minIncludes rain-mapping angles (0.8,1.3,1.8-deg) & 0.0-deg

“Storm Microphysics”70-80 hours total spread over ~35 casesUsually 150-km range2-3 sector PPI volumes with 0-1 sets of RHIs in 15 minIncludes 360s @ rain-mapping angles (0.8,1.3,1.8-deg)

Radar Data Quality Control

S-Pol RadarMostly automatedThreshold away non-meteorological echo (clutter, insects, etc.)Filter differential phase (PHI

DP) and calculate K

DP

Blockage & attenuation correction

Currently working to improve the KDP

algorithm

SMN RadarsApply calibration – Intercomparison with S-Pol & TRMMCan threshold away most non-meteorological echoSome hand-editing needed for insects and leftover clutterRainfall & attenuation correction based on Z-R – Tune using S-Pol

S-Pol Blockage

Mean PowerClear-Air0.8 degElevation

Little to No Blocakgeabove 2 deg Elevation

MinorBlock

Major Blocks

Much of Low-Elevation Sweeps over Land Blocked at S-PolBut We Can Recover Using Phase!

MountainClutter

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 DevelopedOver 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 SurgeInverted 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

ZH

RHOHV

ZDR

PHIDPPower LDR

KDPLargeHailAloft(D > 2 cm)

Attenuation

Melting hailcausing largephase shifts

Melt Level

05 Aug '04 2123 UTC

Large HailHigh ZNeg ZdrLow RHOHigh LDR

Very IntenseConvection!

Regional Composites of Rainfall

Rain Rate @ 2330 UTC6-h Total

(2100-0300 UTC) Blocks

Hydrological Applications

Choix

Presidio

Piaxtla

Tamazula

Badiraguato

Best Radar-Covered Hydrological Basins

Basin-Averaged RainfallFor 6-h Event(2100-0300 UTC, 5-6 Aug)

Choix 0.1 mmBadiraguato 14.8 mmTamazula 5.1 mm Piaxtla 3.8 mmPresidio 0.4 mm

Future Work – Climatological Statistics

Diurnal cycle of precipitationPrincipal physical processes controlling diurnal cycleSpatial variabilityConvective echo fractionVertical structure of convection

Effects of easterly waves and Gulf surges on precipitation

Relative importance of MCS rainfall, stratiform rainfall, etc.

Intercomparison with NERNEvaluate radar estimates of rainfall Evaluate gauge-based estimates of diurnal cycleMerged 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 AnalysesMeridional Propagation: Standard Anomalies 3-5 day BP Filtered

Zonal Propagation: Standard Anomalies (Flash Count – Mean)/

Collaboration w/ Walt Petersen ofU of Alabamaand w/ Vaisala

CG FlashHovmollersfrom theLong-RangeNLDN

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 needsModel initialization & verificationMicrophysical parameterization verificationVerification of satellite rainfall estimates

For More Informationhttp://radarmet.atmos.colostate.edu/name

tlang@atmos.colostate.edu