1. Observations of ClearAir Boundaries
Made By the UMass “Tornado Radar” During the International H2O Project (IHOP)
Scientific Goals
Christopher Weiss & Howard Bluestein
University of Oklahoma
Norman, Oklahoma

2. Operations During IHOP_2002
June 9
(dryline)
June 10
(dryline)
June 3
(cold front)
Deployments:
3 rolling RHI
2 stationary RHI
2 VAD
Deployments:
2 rolling RHI
2 VAD
Deployments:
1 stationary RHI
May 22
(dryline)
Deployments:
4 rolling RHI
2 stationary RHI
2 VAD
1 vertical antenna X-sect

3. Scientific Goals Goal with UMass mm-wave data:
Resolve the kinematics of the dryline secondary circulation (DSC) and dryline convergence zone (DCZ)
Each mode of data collection has a different objective

4. Data Collection Strategies Mode #1 - VAD
5/22/02 – moist side VAD W
Obtain high spatial resolution depiction of boundary layer wind profile on both sides of the dryline (e.g., inflection points?)

5. Data Collection Strategies Mode #2 – Vertical Antenna
Spatial distribution of upward and downward motion in and near the DCZ
Convective rolls

6. Data Collection Strategies Mode #3 – Stationary RHIDZ E VE
Temporal evolution of the dryline.
Support/refute theories of advancement, retrogression.

7. Data Collection Strategies Mode #4 – Rolling RHI
Once suitable analysis method found, can resolve full two-dimensional wind field (u/w) in cross-dryline plane.
Potentially the most useful data collection method

8. Complications Subtraction of truck velocity is delicate.
Accurate GPS position, velocity important
Pitch of truck
Uncertainty of GPS elevation data
Translation and development of feature
“Stationarity assumption”
Sensitivity and range
Irregular weave pattern (i.e., varying angle of intersection between two radar looks)

9. Atkins et al. 1998 Weiss and Bluestein 2002
Compare high-resolution ground based data to recent airborne pseudo dual-Doppler studies.
Descent west of DCZ? Acceleration of westerly inflow?
Magnitude of descent east of DCZ?
Contribution of air parcels in DCZ (e.g., trajectory analysis)
Tilt of DCZ

10. 6/10/02
1959 UTC DZ W VE
(uncorrected)

11. Scientific Goals Goal with UMass mm-wave data:
Resolve the kinematics of the dryline secondary circulation (DSC) and dryline convergence zone (DCZ)
But…need collaboration for the full picture!
Surface thermodynamic data [MM – (Rasmussen)]
cm-wave radar [DOW/XPOW – (Richardson,
Wurman), SR-1 (Ziegler, Markowski)]
Airborne radar [ELDORA, Wyoming - Geerts, others?]