NCAR Activities Using TAMDAR Icing Data

Marcia K. Politovich, Jamie Braid

Scott Landolt and Cory WolffNCAR Research Applications Laboratory

Projects

• Impacts on Current Icing Potential product– What: Determine the impact of TAMDAR icing reports

(positive and negative) on icing diagnoses– Why: Do results support FAA/NWS funding of

TAMDAR data stream?– Funded by: AIRDAT

• Description of icing data set– What: Compile “climo” of TAMDAR icing data using

RUC and CIP outputs – Why: Will help QC efforts – what are these reports,

are they consistent with expected icing conditions, are we seeing inconsistencies?

– Funded by: FAA

Laser senses 0.020” ice accreted here

Yes: activates heating cycle to melt and start over again

No: no ice detected

Uncertain: Ttot >0C,

Tstat <0C(ice won’t freeze

onto probe)

CIP impact: progress

• Converted TAMDAR data sets to pseudo PIREP NetCDF data

• Determined HRCIP run times for study

• Completed baseline verification using voice PIREPs and standard QAPDT methods

CIP concept

LightningDeep Convection

High-res (5 km) CIP

PIREPs in CIP

• Used as a boosting factor for icing potential (along with RUC SLW and VV)

• Currently, only positive icing PIREPs are used: icepotfinal = icepotini(0.35*PIREPmap + .4*SLWmap + .25*VVmap)

severity = 1-8 scale (T=1, H=8, etc.),

PIREPmap = severity/8

and weigh by proximity in space and time

Need to determine how to use negative TAMDAR icing data – decrease potential

CIP Comparison

• Three-way comparison– Baseline: no TAMDAR– Add TAMDAR positive icing reports– Add TAMDAR negative icing reports– Compare PODy, PODn, area and volume

covered

• What is the effect on the statistics? On the look and feel?

TAMDAR Icing “Climo”

• Use ASCII files for location of positive icing reports

• Form climatology – time of day, location, by month, etc. Where is icing being reported?

• Use matching hourly 20-km RUC forecasts to pull info on temperatures, RH, condensate– Can use positive TAMDAR icing data to “verify” RUC

condensate fields

• Use matching CIP icing potential to check our expectations on icing – positive and negative

Ice Accretion?

• New icing severity definitions are accretion-rate based– Updated CIP severity

• Accretion rate depends on object shape, airspeed, etc…

• We’re interested in working with AIRDAT on this

More ideas?