1. Lake breezes in the lower Great Lakes region during BAQS-Met 2007 David Sills 1, Jeff Brook 2, Ilan Levy 2, Paul Makar 2, Junhua Zhang 2, Peter Taylor 3, Katherine Hayden 2, and Lesley Elliott 1 1 Cloud Physics and Severe Weather Research Section, Environment Canada, Toronto, Canada 2 Air Quality Research Division, Environment Canada, Toronto, Canada 3 Department of Earth and Space Science and Engineering, York University, Toronto, Canada 2011 GLOM Workshop 21–23 March, Ithaca, NY

2. 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 say about #%&@ lake breezes?!?

3. 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

4. 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

5. 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.

6. 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

8. Lake breeze (front) detection

10. Each has strengths and weaknesses, integrating data sets improves lake-breeze front detection

11. Lake breeze (front) detection Wind Speed Temperature Dew Point 1 min data Merlin Station (~10 km N of Lake Erie) Wind Direction Ozone PM2.5

12. 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

13. 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:

14. Moderate-deformation (MD) High-deformation (HD) ‘Classic’ Low Deformation (LD)

15. Moderate Deformation (MD) High-deformation (HD) ‘Classic’ Low Deformation (LD)

16. ‘Classic’ Low Deformation (LD) Moderate Deformation (MD) High Deformation (HD)…

17. 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:

18. 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

19. LD Case

21. MD Case

23. HD Case (Mildmay tornadoes)

25. Obs vs GEM penetration distances at 1700 Local Time

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

28. 215 km LH Penetration

29. 23 June 2007 190000 Very sharp gradients Frontal widths ~200 m! Wind direction Temperature Dew point UTC

30. Lift at lake-breeze fronts Updrafts at fronts up to 5 m s -1, but not quite how we thought… Convective Mixed Layer Residual Layer / Return Flow F r e e A t m o s p h e r e CAPPING INVERSION ENTRAINMENT ZONE 1000 2000 Height (m) 0 Inflow Layer LCL Lake Land TIBL Horizontal Distance

31. Lift at lake-breeze fronts Updrafts at fronts up to 5 m s -1, but not quite how we thought… Convective Mixed Layer Residual Layer / Return Flow F r e e A t m o s p h e r e CAPPING INVERSION ENTRAINMENT ZONE 1000 2000 Height (m) 0 Inflow Layer LCL Lake Land TIBL Horizontal Distance

32. 18 Jul 2007 Chatham area (E of LSC)

33. No severe weather reported!?

36. MLCAPE ~ 900 K/kg 0-6 km shear = 39 knots

37. 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

38. ELBOW 2001 Results

39. 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

40. Convective Initiation 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%)

42. 1351 LT 18 Jul 05Facing NE

43. Erie Huron

44. Erie Huron Cloud base (LCL) No Cu Building Cu No Cu

45. 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

46. 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!