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Neil Taylor 1 , Dave Sills 2 , John Hanesiak 3 , Jason Milbrandt 4

UNSTABLE The UN derstanding S evere T hunderstorms and A lberta B oundary L ayers E xperiment. Neil Taylor 1 , Dave Sills 2 , John Hanesiak 3 , Jason Milbrandt 4 1 Hydrometeorology and Arctic Lab, Environment Canada (EC) 2 Cloud Physics and Severe Weather Research Section, EC

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Neil Taylor 1 , Dave Sills 2 , John Hanesiak 3 , Jason Milbrandt 4

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  1. UNSTABLEThe UNderstanding Severe Thunderstorms and Alberta Boundary Layers Experiment Neil Taylor1, Dave Sills2, John Hanesiak3, Jason Milbrandt4 1 Hydrometeorology and Arctic Lab, Environment Canada (EC) 2 Cloud Physics and Severe Weather Research Section, EC 3 Centre for Earth Observation Science, University of Manitoba 4 NWP Research Section, EC Project Overview NWC / NSSL Seminar Series NOAA Hazardous Weather Testbed Spring Experiment

  2. Outline • Rationale • Socioeconomic Issues • Forecast Challenges • Environment Canada Mandate • Project Goals and Deliverables • UNSTABLE Science Questions • Preliminary Experimental Design • Summary Spring Experiment 2007 – Seminar 9 May

  3. PASPC-WPG PASPC Areas of Responsibility PASPC-EDM Spring Experiment 2007 – Seminar 9 May

  4. Severe Wx on Canadian Prairies1984 – 2006 Averages Spring Experiment 2007 – Seminar 9 May

  5. What is UNSTABLE? • Field experiment in summer 2008 over the Alberta foothills designed to improve understanding of processes important for convective initiation (CI) and severe thunderstorm development better understanding  better watches/warnings • Focus on • ABL water vapour and convergence boundaries • Land surface processes (sensible / latent heat flux) • High-resolution NWP as a forecasting tool • 3-week IOP July 2008 • Both observational and modeling components • Led by Environment Canada in collaboration with Canadian Universities and the private sector • International participation welcome! Spring Experiment 2007 – Seminar 9 May

  6. Alberta Foothills experience more lightning days than anywhere else on the Canadian Prairies Rationale: Socio-economic Impacts Spring Experiment 2007 – Seminar 9 May

  7. Edmonton – Calgary corridor one of most densely populated regions in Canada and contains Canada’s 3rd (YYC) and 7th (YEG) busiest airports Rationale: Socio-economic Impacts Spring Experiment 2007 – Seminar 9 May

  8. Edmonton – Calgary corridor among fastest growing regions in Canada Rationale:Socio-economic Impacts Spring Experiment 2007 – Seminar 9 May

  9. Rationale:Socio-economic Impacts • Frequent (Severe) Thunderstorms + People + More People + Busy Airports = Potential Human and Economic Loss • Since 1980 > $2B and > 40 lives lost in AB due to severe thunderstorms • Improved understanding of processes leading to severe storms  better warnings  mitigate impacts of severe weather on Canadians Spring Experiment 2007 – Seminar 9 May

  10. Rationale: AB Severe Wx Forecast Challenges AB Forecasters face uncertainty with respect to: • ABL structure and evolution (especially vertical water vapour profiles in ABL) • Role and importance of mesoscale boundaries / circulations in foothills (dryline?) • Land surface – ABL interactions (sensible / latent heat fluxes) in foothills and upstream • Conceptual models for CI Compounded by: • Inadequate observation network to resolve the above • NWP performance with respect to above Spring Experiment 2007 – Seminar 9 May

  11. Rationale:Obs. Network Hourly SFC observations available to PASPC forecasters • Large void of real-time surface observations over the Alberta foothills • Foothills a known genesis region for severe thunderstorms Spring Experiment 2007 – Seminar 9 May

  12. Spring Experiment 2007 – Seminar 9 May

  13. Albert Thunderstorm Research • Rich history dating back to Albert Hail Studies (ALHAS) and Alberta Hail Project (AHP) • Later research largely focused on synoptic-scale and upper-air processes • Conceptual models for Alberta severe weather outbreaks established by Strong (1986) and Smith and Yau (1993) • Capping lid, underrunning ABL moisture and mountain-plain circulation • Little to no focus on ABL convergence boundaries Spring Experiment 2007 – Seminar 9 May

  14. Conceptual Model (Strong 1986) Spring Experiment 2007 – Seminar 9 May

  15. Conceptual Model (Smith and Yau 1993) Similar to model proposed by Strong (1986) but with more focus on MP Circulation Spring Experiment 2007 – Seminar 9 May

  16. SFC Analysis (Smith and Yau 1993)SFC Td and Wind Vectors 1600 1800 Shallow and capped ABL Shallow and capped ABL ABL Depth > 800m Spring Experiment 2007 – Seminar 9 May

  17. Rationale:Severe Wx Forecast Challenges • Dryline-like convergence boundary has been observed and measured in recent years • Appears to form mainly in response to subsidence and mixing in lee of Rocky Mountains • Bulges observed in response to mixing of momentum to the surface • Does this boundary conform to accepted conceptual model (e.g., Ziegler and Rasmussen 1998)? • Has been sampled with mobile observations in terms of humidity (mixing ratio) but not with wind measurements • Existing observational network far too coarse (~100km between SFC stations!) Spring Experiment 2007 – Seminar 9 May

  18. Rationale: The Dryline? Dryline observed with and without mobile observations (Hill 2006) Drylines and severe storm tracks from summer 2000 Dryline transect (Strong) Spring Experiment 2007 – Seminar 9 May Taylor (2004)

  19. Mixed / Coniferous Forest Low ET Transition Zone – Potential Gradient in Latent Heat Flux Prairie Crops / Grassland High ET Rationale:Ecoclimate Regions and ET Spring Experiment 2007 – Seminar 9 May

  20. Rationale: EC Results Management Framework • All of EC structured according to Outcome Project Plans (OPPs) – everything we do has an associated OPP • UNSTABLE addresses 10 OPPs related to: • Monitoring atmospheric conditions • Weather prediction • Understanding, detection, and prediction of severe and high-impact weather • Understanding the water cycle • Improved weather warnings, forecasts, and warning preparedness • Aviation weather services Spring Experiment 2007 – Seminar 9 May

  21. UNSTABLE Goals • To improve understanding of atmospheric processes (especially in ABL) prior to and during CI and severe thunderstorm development • To improve accuracy and lead time for severe thunderstorm watches and warnings • To assess utility of GEM-LAM-2.5 to resolve physical processes over AB Foothills and ability to provide useful guidance for CI and severe thunderstorm forecasts • To refine existing conceptual models describing CI and severe thunderstorm development over AB and the Western Prairies Spring Experiment 2007 – Seminar 9 May

  22. UNSTABLE Deliverables • Unique and high-resolution dataset of measurements from various platforms including surface, upper-air, and vertical profiles of atmospheric characteristics • Peer-reviewed articles, presentations / posters at conferences and workshops • Presentations / reference material targeting forecasters at SPCs with operational application • Through Research Support Desk (RSD) direct knowledge transfer to operational meteorologists in real time prior to and during high-impact weather events Spring Experiment 2007 – Seminar 9 May

  23. UNSTABLE Science Questions ABL Processes (Taylor/Sills – Environment Canada) 1. What are the contributions of ABL processes to the initiation of deep moist convection and the development of severe thunderstorms in the Alberta Foothills? Land Surface – ABL Interactions (Hanesiak – U of Manitoba) 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? Numerical Weather Prediction (Milbrandt – Environment Canada) 3. To what extent can high-resolution NWP models contribute to forecasting the initiation and development of severe thunderstorms originating in the Alberta Foothills? Spring Experiment 2007 – Seminar 9 May

  24. Science Question 1: ABL Processes • What is ABL evolution especially wrt water vapour prior to and during CI? • What is role and importance of mesoscale convergence boundaries and circulations associated with CI? • How are they influenced by terrain and synoptic-scale processes? • How do they affect storms (motion, intensity, morphology)? • What is 4D characterization of the ‘dryline’ and importance for CI? • Which storms become severe and why? How related to boundaries associated with CI? • Are conceptual models adequate? • How improve observational network to aid forecasters? Spring Experiment 2007 – Seminar 9 May

  25. Science Question 2: Land Surface – ABL Interactions • Influence of wet / dry areas on CI and storm evolution via agrometeorological model? • Can we resolve gradients in water vapour and mesoscale circulations (e.g., land breezes) across wet / dry areas? • If so how do they influence CI and storm evolution? • What are heat fluxes over the region wrt wet / dry areas and how influence temperature / humidity stratification? [tentative] • How does background flow modify gradients / circulations associated with wet / dry areas? • Can ET contributions to ABL column water vapour be quantified? [tentative] • How can observational network be improved to address the above? Spring Experiment 2007 – Seminar 9 May

  26. Science Question 3: Numerical Weather Prediction • What constitutes a “successful” high-resolution simulation? • How can we quantify the model’s ability to simulate observed convection? • Can the atmospheric state be classified a priorias “predictable” or “non-predictable” in terms of recommended use of the GEM-LAM-2.5 run to guide the forecast? • How realistic are simulated storm structures and microphysical fields? • How realistic is the evolution of the boundary layer and surfaceprocesses in the foothills regions? • Can deficiencies in physical parameterizations be identified? • What would be the effect of performing a subsequent nest to a higher-resolution (e.g. 1-km) grid driven from the 2.5-km run? • Can an ensemble of high-resolution runs improve the prediction of convective initiation? • Can a high-resolution analysisusing the additional observations improve the numerical prediction of CI and subsequent storm development? Spring Experiment 2007 – Seminar 9 May

  27. Experimental Design: Domain • Study area designed to include existing SFC and radar stations given climatological CI and thunderstorm activity • Primary domain defined by supplementary mesonet and FCA stations – main focus for mobile measurements • Secondary domain to include FCA and other stations – still deploy mobile measurements for interesting cases Red Deer Banff Calgary Spring Experiment 2007 – Seminar 9 May

  28. For Comparison… Spring Experiment 2007 – Seminar 9 May

  29. Aircraft Soundings Profilers Tethersonde Mobile SFC Fixed Mesonet Mobile SFC What is Needed to Resolve ABL and Other Processes Related to CI? N Spring Experiment 2007 – Seminar 9 May

  30. 19 Station Configuration 15 Station Configuration Supplemental Instrumentation Fixed • Mesonet stations (10-20) • 2 radiosondes • Tethersonde • 2 WV radiometers • Profiling radiometer (H2O profile) • GPS PW sensors • Eddy Correlation Flux Tower(s)? • Additional Profiling Radiometer (T, RH)? Mobile • AMMOS / Strong Mobile (T, P, RH) • MARS (PW, SFC wx, profile – wind, T, RH) • 3 radiosondes • Aircraft • Photography Locations of fixed radiometers, GPS sensors, tethersonde to be determined Spring Experiment 2007 – Seminar 9 May

  31. Wind DeltaT Additional: PM sensor? O3 sensor? Cell antenna Solar Radiation Pressure Solar Panel Precip T / RH + Fast T Logger DeltaT ATMOS SFC Mesonet Stations Automated Transportable Meteorological Observation System Spring Experiment 2007 – Seminar 9 May

  32. Wind GPS Compass Additional: Pressure Logger Photo / video T / RH + Fast T (ventilated) PM sensor? Rugged Laptop + Backup EC AMMOS Mobile Mesonet Unit Automated Mobile Meteorological Observation System Spring Experiment 2007 – Seminar 9 May

  33. How Will the AMMOS be Used? Collect data at 1 s intervals Measure gradients across boundaries (met and land use) Fill in holes in mesonet as needed Spring Experiment 2007 – Seminar 9 May

  34. portable rawinsonde weather station AERI sodar AMR University of Manitoba Instrumentation Spring Experiment 2007 – Seminar 9 May

  35. University of Manitoba Mobile Atmospheric Research System (MARS) Spring Experiment 2007 – Seminar 9 May

  36. Pursuing Funding for Aircraft National Research Council Canada Twin Otter (T, Td, SFC T, 3-axis wind & acceleration, vertical fluxes, radiation) Also investigating use of UAVs but limited expertise within Environment Canada WMI King Air w/ AIMMS-20 Instrument Package (T, P, RH, 3-axis wind & acceleration) Spring Experiment 2007 – Seminar 9 May

  37. Instrumentation Deployment* • Fixed mesonet (grid and line siting configuration) takes advantage of existing stations and climatologically favoured regions for CI and severe storms (includes high-resolution lines of mesonet stations) • Two fixed sounding locations near and upstream (at low-levels) of foothills – catch moist advection and pre-storm ABL • Fixed tethersonde, WV radiometers, GPS PW sensors, profiling radiometer(?) in primary study area near expected CI regions • Mobile surface platforms to be deployed on intensive observation days to obtain four-dimensional characteristics of ABL and upper troposphere • Deployment to target mesoscale boundaries and favoured CI regions within study area(s) • ‘Bookend’ AMMOS (and Strong’s) mobile mesonet with mobile radiosondes • Attempt to place MARS near to, and east of, observed boundaries (thermal, moisture, wind profiles) • Supplement ground-based observations with aircraft stepped traverses and circuits * Details of deployment will appear in UNSTABLE field plan Spring Experiment 2007 – Seminar 9 May

  38. Experimental Design: Duration and IOP UNSTABLE Study Period • 1 June to 31 August 2008 • Fixed mesonet stations to be deployed prior to June 1st 2008 • Mobile instrumentation / communications tests in 15 June to 31 June window Intensive Observation Period • Tentatively 9 July to 31 July (23 days) contingent on field participation, expendables,… • UNSTABLE Operations Plan to be developed this fall / winter Spring Experiment 2007 – Seminar 9 May

  39. Principal Investigators Neil Taylor, HAL, EC Science Question 1 Co-Lead, Project Manager Dave Sills, CPSWRS, EC Science Question 1 Co-Lead John Hanesiak, CEOS, U of Manitoba Science Question 2 Lead Jason Milbrandt, RPN, EC Science Question 3 Lead Pat McCarthy, PASPC, EC PASPC Severe Weather Program Supervisor Geoff Strong, Adjunct Professor, U of Alberta Craig Smith, Climate Research Division, EC Spring Experiment 2007 – Seminar 9 May

  40. Collaborators UNSTABLE is a collaborative project with National and Provincial Government, Canadian University, and Private Sector participation Spring Experiment 2007 – Seminar 9 May

  41. Summary • Potential for future human and economic loss in Alberta due summer severe storms is increasing • Accuracy and lead-time of convective watches and warnings needs to be maximized to mitigate impacts of summer severe weather • Severe weather forecast challenges wrt ABL water vapour, convergence boundaries, and land surface processes are compounded by • inadequate observations • need for updated conceptual models • sometimes questionable model performance Spring Experiment 2007 – Seminar 9 May

  42. Summary • Field experiment being designed to investigate ABL processes significant for CI and severe storm development over the Alberta foothills (summer 2008) • Efforts to transfer results to SPC operations with aim to improve watches / warnings • UNSTABLE to include both observational and modeling components • targeted, high-resolution fixed and mobile surface and upper-air observations • 2.5 km configuration of CMC GEM LAM • Science questions and plan drafted – in process of refining science questions and instrumentation / measurement strategies Spring Experiment 2007 – Seminar 9 May

  43. Thank You! Neil.Taylor@ec.gc.ca (780) 951-8636 Spring Experiment 2007 – Seminar 9 May

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