The Simultaneous Observation of the Near-Dryline Environment (SONDE-

2008/2009?) Experiment

Objectives and HypothesesNew Developments

Talking Points

Dr. Chris WeissNCAR mtg

7 September 2006

Objectives (2005 proposal)1) Variations in dryline vertical structure and cumulus development

Participating Ground-Based Facilities

2) Vertical transport of heat and momentum

3) Ancillary dryline formation and along-dryline variability

4) Misovortices

GOAL

To determine fine-scale dryline controls:- Genesis- Morphology- Motion- Convective initiation

•Secondary circulation, interaction with ambient shear•Vertical slope of convergence zone• v, density current dynamics•Buoyancy of parcels in DCZ•Buoyancy below cumulus cloud base•Detrainment of condensate into dry free troposphere

•Cross-dryline variations in vertical heat, momentum flux•Relation to weaknesses in capping inversion, gradients in land-use properties•Effects on vertical profile of convergence in the DCZ•Inversion height, relation to easternmost reach of dryline

•Ancillary dryline prominence•Mechanisms for formation•Magnitude of v

•Solenoidal circulation•Potential origin as horizontal convective rolls•Ancillary/primary dryline intersection points

•Relation of w to •Role of tilting/stretching in budget•Buoyancy of parcels within misovortices•Size spectrum•Water vapor transport•Evolution / propagation

Typical deployment:

WTM = West Texas MesonetMM = Mobile mesonet200T = 200 m towerVWP = Vertical wind profilerSONDE = Rawinsonde systemSR = SMART-R

SMART-Radar

Mobilemesonet

West TXMesonet

Radar profiler

Rawinsondesystem

Some of my areas of interest…

1) Relating meso- variations in vertical heat and momentum transport to dryline propagation and convergence/CI in dryline convergence zone

Atkins et al. 1998 Weiss and Bluestein 2002

- Local variations in vertical momentum flux help determine strength of convergence in DCZ?- What would explain these variations? Variability in sensible heating? Weaknesses in CBL-top inversion?- Can some meso- “bulges” in drylines be explained in such a manner?

Some of my areas of interest…

2) Along-dryline variability

Hane et al. 1997

- Can land-use gradients force solenoidal circulations, on which cumulus clouds can develop? Intersection points with dryline often favored for CI!

Some of my areas of interest…

2) Along-dryline variability

- Can land-use gradients force solenoidal circulations, on which cumulus clouds can develop? Intersection points with dryline often favored for CI!

Reflectivity

Dryline (s)

warm/dry

cool/moist

Refractivity

dryline

Courtesy B. Demoz (NASA/GSFC)

u

qSE NW

Some of my areas of interest…

2) Along-dryline variability

Reflectivity

Dryline (s)

Ancillary Drylines

- Related to land-use gradients?- Solenoidal circulation?- How often do they occur? (Likely more often than commonly thought, but more subtle in most cases)- In WTM and 88D, often have boundaries of unknown origin, esp. in dry air.- A key for CI?

Some of my areas of interest…

2) Along-dryline variability

Misocyclones

- Prevalence- Relation to CI? (phase lag between w and )- Generation

Arnott et al. 2004

What has changed since last fall…

1) Texas Tech Vice President of Research awards grant for the development of a wind power testbed at TTU.

• Key item = Two Ka-band mobile Doppler radars (should have partial seed funding for 2008 and possibly 2009). Will need to propose more though… RFP has been issued for completion date of December 2007.

• Also, funds available for mobilization of TTU sounding platform

2) In conjunction with Wind Science and Engineering Research Center, 10 “Stick-Net” platforms have been developed as of August 2006. Plans are in place for the development of 10-20 more by spring 2007.

Some Talking Points

1) Distinguishing ourselves from IHOP2) Data Assimilation

- Improvement of dryline forecasts (motion, CI) due to proper capture of sensible heat flux?

- Instruments? ISFF? Any others from LOAF?- Model (WRF & HRLDAS)?

2) The proposal- Timeline? 15 Dec deadline for facility request, proposals due

about the same time- Scope same as before, with addition of others?

3) Role of TTU Ka-band radars, mobile sounding unit4) Same location / time period (WCR conflict again) ?

- Lubbock area, 1-May to 1-June 2008, maybe 15-May to 15-June, with option for 2009?

- Would like to avoid April if at all possible.