Lake breezes in the lower Great Lakes region during BAQS-Met 2007

David Sills1, Jeff Brook2, Ilan Levy2, Paul Makar2, Junhua Zhang2, Peter Taylor3, Katherine Hayden2, and Lesley Elliott1

1Cloud Physics and Severe Weather Research Section, Environment Canada, Toronto, Canada2Air Quality Research Division, Environment Canada, Toronto, Canada

3Department of Earth and Space Science and Engineering, York University, Toronto, Canada

2011 GLOM Workshop21–23 March, Ithaca, NY

Like déjà vu all over again

My lake breeze-related presentations at GLOMW:

• 1997 – ELBOW 97• 1999 – more ELBOW 97• 2000 – lake breezes and tornadoes• 2002 – ELBOW 2001• 2003 – more ELBOW 2001• 2005 – lake breezes at RSD• 2010 – comparing GEM / RUC lake breeze forecasts

Co-authored lake breeze-related presentations at GLOMW:

• 2001 – ELBOW 2001• 2004 – BAQS-Met preparations• 2008 – lake breezes / air quality case study

What more could this guy possibly sayabout #%&@ lake breezes?!?

Busy beavers

• Continuing analysis of the ELBOW 2001 data

• New data and analysis from the BAQS-Met 2007 lake breeze / air quality study

• Updated conceptual understanding of lake breezes and their impacts in the lower Great Lakes region

Why are lake breezes important?

• Affect the climate of the region around the lake

• Affect summer severe weather:– Lake air typically suppresses thunderstorms– The lake-breeze front provides a lifting mechanism for the

initiation of thunderstorms, most often over land

• Affect air quality:– 3-D transport of pollutants / precursors in lake-breeze

circulations– Increased insolation for photochemistry (ozone)– Decreased mixing height reduces pollutant dispersion

Past lake breeze research

• Great Lakes lake breeze studies– Biggs and Graves 1962, Estoque 1962, Moroz 1967,

Lyons 1972, Estoque et al. 1976, Estoque 1981, Ryznar and Touma 1981, Comer and McKendry 1993, Sills 1998, Laird et al. 2001, etc.

• Great Lakes lake breezes / svr wx studies– Shenfeld and Thompson 1962, Changnon 1966, Murphy

1991, Leduc et al. 1993, Clodman and Chisholm 1994, King 1996, King et al. 1996, King 1997, Sills 1998, King and Sills 1998, Sills and King 1998, King et al. 1999, Roebber and Eise 2001, King et al. 2003, etc.

• Great Lakes lake breezes / air quality studies– Lyons 1972, Lyons and Cole 1973, Lyons and Olsson

1973, Lyons and Cole 1976, Mukammal et al. 1982, Lyons et al. 1995, Reid et al. 1996, Sills 1998, Hastie et al. 1999, Harris and Kotamarthi 2005, etc.

BAQS-Met 2007

• Border Air Quality and Meteorology Study

• Focused on Detroit-Windsor and surrounding areas

• Environment Canada, York University, University of Toronto, University of Western Ontario

• June – August 2007, intensive 20 June – 10 July

• Investigate the impacts of mesoscale boundary-layer phenomena, particularly lake-breeze circulations, on local air quality and the regional transport of pollutants

Lake breeze (front) detection

Lake breeze (front) detection

Lake breeze (front) detection

Each has strengths and weaknesses, integrating data setsimproves lake-breeze front detection

Lake breeze (front) detection

Wind Speed

Temperature

Dew Point

1 min dataMerlin Station(~10 km N of Lake Erie)

Wind DirectionOzonePM2.5

Lake breeze stats

• Much higher than Great Lakes studies in literature (13 - 45%)…

• 100% of high ozone* days had active lake breezes

• 86% of days with thunderstorms had active lake breezes

• 100% of severe thunderstorm days had active lake breezes

For entire BAQS-Met 2007 period:

* 1-hr avg O3 >= 80 ppb at more than one station

Incredible lake breeze facts!

• Only one day in June / July without a lake breeze in study area

• Three periods with lake breezes on all lakes occurring over 11 consecutive days or more (8 June–18 June, 20 June–10 July, 21 July–4 August)

• Longest was 21 days (BAQS-Met IOP!)

• The Lake Huron shore had 24 consecutive lake breeze days between 20 June and 13 July

• That’s twice the highest number of consecutive lake breeze days previously reported (12 days on the Lake Michigan shore; Eichenlaub, 1979)

• Greatest observed lake-breeze front penetration distance was over 200 km

During BAQS-Met study period:

Moderate-deformation (MD)

High-deformation (HD)

‘Classic’Low Deformation

(LD)

Moderate Deformation (MD)

High-deformation (HD)

‘Classic’Low Deformation

(LD)

‘Classic’Low Deformation

(LD)

Moderate Deformation (MD)

High Deformation (HD)…

Lake breeze stats - intensive

• Lake breezes on each lake on each day of intensive

• 9 high ozone days, 3 thunderstorm days, 2 severe thunderstorm days – all with lake breeze influences

• Wide variety of synoptic regimes – wind speed light to moderate, direction S through NNE

• 3 LD, 13 MD, and 5 HD lake-breeze circulations

• 16 Twin Otter aircraft flights

Great data set!

Animations for each day at http://tinyurl.com/SillsBAQS-MetAnimations

During the 21-day intensive observation period:

GEM-LAM 2.5 Runs

• 58 hybrid-coordinate levels increasing monotonically with height from the Earth’s surface to 10 hPa

• Initial and boundary conditions for these high-resolution runs from 15 km GEM-REG with same vertical coordinates as the high-resolution simulation

• No convective parameterization scheme

• Used to drive air chemistry model (AURAMS)

sfc winds + 815 m vertical velocity

LD Case

MD Case

HD Case (Mildmaytornadoes)

Obs vs GEM penetration distancesat 1700 Local Time

Obs vs GEM penetration distancesat 1700 Local Time

Obs vs GEM penetration distancesat 1700 Local Time

Maximum penetration distances (km): 215 245 185 160 100 125

215 km LH Penetration

23 June 2007

190000

Very sharpgradients

Frontal widths~200 m!

Wind direction

TemperatureDew point

UTC

Lift at lake-breeze frontsUpdrafts at fronts up to 5 m s-1, but not quite how we thought…

ConvectiveMixedLayer

ResidualLayer /

Return Flow

F r e e A t m o s p h e r e

CAPPING INVERSION

CAPPING INVERSION ENTRAINMENT ZONE

1000

2000

He

igh

t (m

)

0

Inflow Layer

LCL

LCL

Lake Land

TIBL

Horizontal Distance

Lift at lake-breeze frontsUpdrafts at fronts up to 5 m s-1, but not quite how we thought…

ConvectiveMixedLayer

ResidualLayer /

Return Flow

F r e e A t m o s p h e r e

CAPPING INVERSION

CAPPING INVERSION ENTRAINMENT ZONE

1000

2000

He

igh

t (m

)

0

Inflow Layer

LCL

LCL

Lake Land

TIBL

Horizontal Distance

18 Jul 2007

Chatham area

(E of LSC)

No severe weather reported!?

MLCAPE ~ 900 K/kg0-6 km shear = 39 knots

BAQS-Met publications to date• Special issue of Atmospheric Chemistry and Physics

• Brook, J. R, P. A. Makar, D. M. L. Sills, K. L. Hayden, and R. McLaren, 2011: The 2007 Border Air Quality and Meteorology Study: exploring the nature of air quality over southern Ontario. Submitted to Atmos. Chem. Phys. Discuss.

• Hayden, K.L., D. M. L. Sills, J. R. Brook, S.-M. Li, P. Makar,M. Z. Markovic, P. Liu, K. G. Anlauf, J. M. O’Brien, Q. Lin, and R. McLaren, 2011: The impact of lake breezes on trace gases and particles during BAQS-Met 2007. Submitted to Atmos. Chem. Phys. Discuss.

• Sills, D. M. L., J. R. Brook, I. Levy, P. A. Makar, J. Zhang, and P. A. Taylor, 2011: Lake breezes in the southern Great Lakes region and their influence during BAQS-Met 2007. Atmos. Chem. Phys. Discuss., 11, 3579-3626.

• Levy, I., P. A. Makar, D. Sills, J. Zhang, K. L. Hayden, C. Mihele, J. Narayan, M. D. Moran, S. Sjostedt, and J. Brook: Unraveling the complex local-scale flows influencing ozone patterns in the southern Great Lakes of North America, Atmos. Chem. Phys., 10, 10895-10915.

• Makar, P. A., J. Zhang, W. Gong, C. Stroud, D. Sills, K. L. Hayden, J. Brook, I. Levy, C. Mihele, M. D. Moran, D. W. Tarasick, and H. He, 2010: Mass tracking for chemical analysis: the causes of ozone formation in southern Ontario during BAQS-Met 2007. Atmos. Chem. Phys., 10, 11151-11173.

• Many more related to various aspects of atmospheric chemistry

ELBOW 2001 Results

Convective Initiation

• Work by PhD candidate Lisa Alexander at YorkU

• Radar cells reaching 40 dBz were identified, and their distance to the nearest boundary measured

• Boundary and cell type/direction/speed, plus other parameters also recorded

Convective InitiationMAXR 40 dBZ Cell Distance to the Closest Boundary (Second Analysis)

0

10

20

30

40

50

60

70

80

90

0 to 4 5 to 9 10 to 14 15 to 19 20 to 24 25 to 29 30 to 34 35 to 39 40 to 44 45 to 49 50 to 54 55 to 59 60 to 64 65 to 69 70 andgreateror none

Distance to Boundary (km)

Nu

mb

er o

f 40

dB

Z C

ells

• Cell initiation clearly occurs more frequently closer to boundaries• Found that moving boundaries were by far the best initiators of storms (78%)• Also, lake-breeze fronts often generated the first storm cells, but subsequent gust fronts initiated the most storm cells (55%)

1351 LT 18 Jul 05Facing NE

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space in km

6 ms-1

18julymorning

ErieHuron

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Cloudbase (LCL)

No CuBuilding CuNo Cu

Acknowledgements

• Norbert Driedger, Emma Hung, Brian Greaves for their work on the mesoanalysis database and products

• Jake Urbanek, Bradley Drummond, Tomasz Stapf, Steven Brady, Tatiana Bukhman and Julie Narayan for contributions to data collection and quality control

• Katherine Hayden and Craig Stroud for assistance with data analysis

• Patrick King for many years of collaborative work on southern Ontario lake breezes

Future Work

• Lots of analysis left to do for both ELBOW 2001 and BAQS-Met 2007

• Focus on vertical velocity and parcel trajectories at lake-breeze fronts using aircraft data and GEM model output

• Also lake-breeze front interactions

• Will allow better understanding of factors affecting thunderstorm initiation and svr wx

• Look for yet another lake breeze talk soon!