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UNSTABLE The UNderstanding Severe Thunderstorms and Alberta Boundary Layers Experiment

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Title: UNSTABLE The UNderstanding Severe Thunderstorms and Alberta Boundary Layers Experiment


1
UNSTABLEThe UNderstanding Severe Thunderstorms
and Alberta Boundary Layers Experiment
Project Overview NWC / NSSL Seminar Series NOAA
Hazardous Weather Testbed Spring 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

2
Outline
  • Rationale
  • Socioeconomic Issues
  • Forecast Challenges
  • Environment Canada Mandate
  • Project Goals and Deliverables
  • UNSTABLE Science Questions
  • Preliminary Experimental Design
  • Summary

3
PASPC Areas of Responsibility
PASPC-EDM
4
Severe Wx on Canadian Prairies1984 2006
Averages
Event Type Alberta Saskatchewan Manitoba Average for Prairies
Tornado 13 14 9 36
Hail 39 33 25 97
Wind 12 20 13 45
Rain 10 7 8 25
All Events 74 75 55 203
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!

6
Rationale Socio-economic Impacts
7
Rationale Socio-economic Impacts
8
RationaleSocio-economic Impacts
9
RationaleSocio-economic Impacts
  • Frequent (Severe) Thunderstorms People More
    People Busy Airports Potential Human and
    Economic Loss
  • Since 1980 gt 2B and gt 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

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

11
RationaleObs. 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

12
(No Transcript)
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

14
Conceptual Model (Strong 1986)
15
Conceptual Model (Strong 1986)
16
Conceptual Model (Smith and Yau 1993)
Similar to model proposed by Strong (1986) but
with more focus on MP Circulation
17
SFC Analysis (Smith and Yau 1993)SFC Td and Wind
Vectors
1600
1800
Shallow and capped ABL
Shallow and capped ABL
ABL Depth gt 800m
18
RationaleSevere 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!)

19
Rationale The Dryline?
Dryline observed with and without mobile
observations (Hill 2006)
Drylines and severe storm tracks from summer 2000
Dryline transect (Strong)
Taylor (2004)
20
RationaleEcoclimate Regions and ET
21
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

22
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

23
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

24
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?

25
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?

26
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?

27
Science Question 3 Numerical Weather Prediction
  • What constitutes a successful high-resolution
    simulation?
  • How can we quantify the models ability to
    simulate observed convection?
  • Can the atmospheric state be classified a priori
    as 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 surface processes 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 analysis using the
    additional observations improve the numerical
    prediction of CI and subsequent storm development?

28
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
29
For Comparison
30
What is Needed to Resolve ABL and Other Processes
Related to CI?
N
31
Supplemental Instrumentation
15 Station Configuration
  • 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
32
ATMOS SFC Mesonet Stations
Automated Transportable Meteorological
Observation System
33
EC AMMOS Mobile Mesonet Unit
Automated Mobile Meteorological Observation System
34
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
35
University of Manitoba Instrumentation
36
University of Manitoba Mobile Atmospheric
Research System (MARS)
37
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)
38
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 Strongs) 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
39
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

40
Timeline and Milestones
Date Event
Summer 2006 Test of ATMOS and AMMOS
27-29 September 2006 Preliminary Mesonet Site Selection
March 2007 UNSTABLE website and leads for science questions 2 and 3
6 April 2007 Draft Science Plan distributed and posted
18-19 April 2007 First UNSTABLE Science Workshop
Spring / Summer 2007 Finalize Science Plan
2-4 May 2007 Mesonet Site Selection
31 May 2007 Presentations at 41st CMOS Congress
18 June 13 July 2007 BAQS-Met field use of ATMOS, AMMOS, tethersonde
1 Sept 13 Nov 2007 Develop UNSTABLE Field Plan
27 Nov 2007 UNSTABLE Field Plan workshop
29 Feb 2008 UNSTABLE Field Plan finalized
31 Mar 2008 Finalize all land-use agreements
12-31 May 2008 Deploy fixed mesonet stations
1 June 31 Aug 2008 UNSTABLE Study Period
9-31 July 2008 UNSTABLE IOP
1-19 Sept 2008 Remove mesonet stations, etc.
22 Sept 2008 Begin data QC
Fall 2008 UNSTABLE article for CMOS / BAMS
Funding Requests
41
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

42
Collaborators
UNSTABLE is a collaborative project with National
and Provincial Government, Canadian University,
and Private Sector participation
43
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

44
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

45
Thank You!
  • Neil.Taylor_at_ec.gc.ca
  • (780) 951-8636
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