DOW Observations in IHOP and Analyses of CI Yvette Richardson, Nettie Arnott and Joshua Wurman.

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DOW Observations in IHOP and Analyses of CI

Yvette Richardson, Nettie Arnott

and Joshua Wurman

Outline

• Data Navigation Issues

• Summary of DOW cases

• Examination of two CI cases

• Quicklook at boundary layer cases

Navigation of Data

• Multiple Doppler analyses require synthesis of radial velocity wind fields

• Winds must be put on a common grid before synthesis– Requires accurate ‘navigation’ of the data– Need location of trucks (gps) and pointing

angle of the radar

Radar1 Radar2

Determination of Pointing Angle

• Possible Methods – Use clutter targets

• Have to have targets to use

– Use reflectivity features and align• Tedious

• Accuracy is questionable

– Use the sun as a target – solar calibration• Do very slow scans across the sun

• Sub-beam accuracy

• Usually Possible – not good at noon

Solar Calibrations

Find the azimuth of max average power and compare to known sun location for your time and location

Available for all IHOP cases where a solar calibration scan was performed

• http://met.psu.edu/~narnott/SolarCals.html

• Agree very well with other techniques

DOW Missions

• All CI

• 3 BLH (20 and 29 May, 7 June)– Looking for collaborators

• 4 QPF (16 May, 23 May, 26 May, 4 June)– Collaborating with Anagnostou

• Three ABLE – Collaborating with Weckwerth

CI Cases

• 10 June

• 19 June

• 24 May (collaborating with Ziegler and others)

10 June

Quasi-stationary cold front

Great coordinationCells initiated all along

the front – just outside the IOR but within overdetermined dual-Doppler coverage

DOW2 20:55 UTC – 1.5 degree tilt

XPOL 20:57 UTC – 1.3 degree tilt

Scientific Questions

• What controls the difference in convective modes on either side of the boundary?

• Why did the growing cumulus field suddenly cease its growth? Is this related to changes in the boundary?

• Role of the thin line which intersected the boundary. – unable to result in initiation – why?

• Role of the circulations along the boundary play? Related to preferred locations for clouds even though not initiation?

• What caused the initiation outside the box?

19 June 2002

• Boundary near Colby, KS

• Very interesting vortices along boundary

• Very well coordinated• CI occurred – possibly

within dual-Doppler coverage

• Satellite loop

19:08 20:08 21:08

22:08 23:08

DOW3 19:30

Dual-Doppler AnalysisAt 19:30At z=0

Deployment #2 – 21:20+ UTC

2nd Deployment Sequence• DOW2 begins moving around

21:00 And gets in position at 21:20

• XPOL stays in position to provide DD with DOW3 over original triangle until 21:20 – breaks down on way to next deployment

• DOW3 switches to new sector at 21:20

• Initiation occurs at approximately 21:22

• Loop

DOW3 21:23

DOW2 21:22 – 8.4 degree tilt N

DOW2 21:25 – 14.3 degree tilt N

DOW2 21:25 – 2.1 degree tiltN

DOW3 21:30 – 3.5 degree tiltN

Scientific Questions

• What role did the misocyclones play in the initiation of convection?

• Was water vapor enhanced near the misocyclones? Collaboration with lidar?

• What determined the locations of the misocyclones (intersections?)? Did these deepen the moisture field?

5/29 BLH Mission

0.5 degree

1.0 degree

1.4 degree

2.1 degree

Future Work

• Finish dual-Doppler analyses

• Combine wind analyses with water vapor measurements (lidar)

• Continue QPF and BLE collaborations

• Many thanks to all collaborators

My Favorite IHOP Project

CompletedNew Year’s Eve, 2002

DOW Observations in IHOP and Analyses of CI Yvette Richardson, Nettie Arnott and Joshua Wurman.

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