Unstable Science Question 2

John Hanesiak

CEOS, U. Manitoba

Unstable Workshop, Edmonton, AB

April 18-19, 2007

Science Question 2

• What are the contributions of surface processes to the initiation of deep moist convection and the development of severe thunderstorms in the Alberta Foothills region?

Equipment• Radiometrics WVR-1100

– Total column vapor and liquid water– Temporal resolution depends on scanning cycle

• Acoustic Doppler sodar– 3-component winds & standard deviations– Up to 1km, 50m resolution, 15-30 min averages

• AERI– Vertical profiles of temperature & vapor– Up to 3km, 100-200m resolution, every 15 min– Limitation = clouds & low level saturation

• Radiometrics 3000A– Vertical profiles of temperature & vapor, cloud base, & total column– Up to 10km, 100-250m resolution, less than 5 min– Limitation = precipitation

• MARS (Mobile Atmospheric Research System)• Portable rawinsonde• 2 Campbell Sci weather stations• Laser precipitation sensor• Mobile vehicle (T, RH, wind)

• Mobile Atmospheric Research System (MARS)• UofM URGP & NSERC

sodar AERI AMR

weatherstation

portable rawinsonde

Sub-Questions & Methods

• (a) Is there a noticeable difference in storm initiation and evolution between wet and dry areas over the cropped region (as defined by a crop model) over the duration of the project?

• (b) Are there noticeable gradients of surface and boundary layer water vapour across the major wet/dry areas and how do these evolve over the project?

• J. Brimelow

Sub-Questions & Methods

• (c) Are mesoscale circulations detectable in the vicinity of boundaries between wet and dry areas? If so, how do they appear to influence storm initiation and evolution?

Methods:• Mobile observations (surface vehicle & sodar on MARS)• Mesonet• Array of rawinsondes• Aircraft• Radar?• Satellite & radar for initiation zones in association with these

observations

Sub-Questions & Methods

• (d) What are the latent and sensible heat fluxes over the region, especially across any wet/dry areas that may exist? How do they influence temperature and water vapor stratification?

Methods:• Aircraft• Any available eddy correlation or bulk profile measurements• Rawinsondes, MARS, radiometers, boundary layer models

Sub-Questions & Methods

• (e) How does the orientation of synoptic (background) flows modify (b) - (d) on a day-to-day basis?

Methods:• Synoptic analysis fields in relation to field measurements (i.e. are

there detectable spatial 3D variations in thermodynamic and dynamic fields … transient boundaries)

• Perpendicular versus angled synoptic flows in relation to surface wet/dry boundaries

Sub-Questions & Methods

• (f) Can the surface contributions to total boundary layer moisture be quantified?

Methods:• Aircraft flux measurements• Water balance exercise• Estimated as a residual in the water balance equations?• How do we deal with storage?

Sub-Questions & Methods

• (g) How can the existing observational network be improved to better represent surface processes that contribute to the initiation and development of severe thunderstorms?

Methods:• Soil moisture / flux measurement sensor array (strategic areas)• Make better use of satellite surface products (validation)• “enhance” confidence in crop model and/or CLASS output

Break-Outs

• Refinement of the UNSTABLE science questions• Data, instrumentation and deployment strategies

necessary to answer the science questions• Who plans to be directly involved in the

UNSTABLE field campaign and how• Funding strategies and opportunities for in-kind

support• Others as suggested by discussion groups