Cloud Physics and Dynamics
Offices: Burnside Hall 944 | 818
Tel.: (514) 398-3719
Fax.: (514) 398-6115
peter [dot] yau [at] mcgill [dot] ca (E-mail)
Studies in hurricanes
Hurricanes represent one of the most violent weather phenomena. They form in the low latitudes but can also affect Canada when they move northward. Our work involves using high resolution numerical models to simulate these storms. Diagnostic studies are being conducted to understand the internal structure of the eye and eyewall, the waves propagating in the system, and the effect of wave mean flow interaction on the intensity change of hurricanes. We have applied novel analysis techniques, like empirical normal modes, to study wave activities in hurricanes. Recent case studies include hurricanes Andrew, Earl, Isabel, and Floyd.
We have developed simple and complex models to study the interactions of various physical processes in convective clouds. Our recent work includes simulation of the mechanism of mixing, and entrainment in cumulus clouds, the interactions involving radiation and cloud dynamics, and the effects of stochastic condensation and droplet collision in turbulence on the size spectra of cloud droplets.
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Severe weather over Alberta
Tornadic storms and hailstorms are extreme weather events over Alberta. We have carried out meso and synoptic scale analyses which showed that severe convection was triggered by a proper phasing of an advancing, synoptic scale trough and the mountain-plain circulation driven by strong surface radiation heating over the Alberta foothills. Concurrently, the northeasterly flow at the surface advects the moist plains air into the lower branch of the mountain plain circulation to effectuate a secondary destabilization leading to the outbreak of severe hail storms. We are carrying out high resolution experiments to validate these observations using the Canadian Mesoscale Compressible Community Model (MC2). Numerical modeling of tornadic storms is underway to understand the mechanism for tornadogenesis.
Simulation of high and low-latitude precipitation systems
We are studying processes in precipitation systems both in high latitudes and in the tropics through high-resolution modeling. Recent work includes simulation of blowing snow over the Mackenzie River Basin, and tropical clusters over TOGA COARE.
Improving quantitative precipitation forecasts
To improve 24-48 hr. precipitation forecasts using mesoscale models, we are performing research to: a) improve the initial conditions through assimilation of rainfall rates using variational techniques and key analysis error algorithms, and b) improve the representation of cloud processes in numerical models through the development of new multi-moment microphysics schemes and parameterization for autoconversion of cloud water to rain water in a turbulent cloud.
Some recent publications
Chosson, F., P. A. Vaillancourt, J.A. Milbrandt, and M.K. Yau, 2012: The treatment of sub-grid-scale clouds and precipitation for two-moment microphy- sics schemes in NWP models. J. Atmos. Sci. (submitted)
Lavaysse, C., M. Carrera, S. Belair, N. Gagnon, R. Frenette, M. Charron, and M.K. Yau, 2012: Impact of surface parameter uncertainties within the Canadian Regional Ensemble Prediction System. Mon. Wea. Rev. (in press).
Menelaou, K., M.K. Yau, and Y. Martinez, 2012b: Impact of asymmetric dynamical processes on the structure and intensity change of two-dimensional hurricane-like annular vortices J. Atmos. Sc. (in press).
Sun, J., P.A. Ariya, H.G. Leighton, and M.K. Yau, 2012: Modelling study of ice formation in warm-based precipitating shallow cumulus clouds. J. Atmos. Sci. (in press).
Yip, Z.K., and M.K. Yau, 2012: Application of artificial neural networks on North Atlantic tropical cyclogenesis potential in climate change. J. Atmos. Oceanic Technol., 29, 1202-1220.
Menelaou, K., M.K. Yau, and Y. Martinez, 2012a: On the dynamics of the secondary eyewall genesis in Hurricane Wilma (2005), Geophys. Res. Lett., 39, L04801, doi:10.1029/2011GL050699.
Yang, J., and M.K. Yau, 2011: Blowing snow cooling effects on a case of anticyclogenesis and cyclolysis. J. Geophys. Res., 116, D11113, doi:10.1029/2010JD014624 .
Martinez, Y., G. Brunet, M.K. Yau, and X. Wang, 2011: On the dynamics of concentric eyewall genesis: Space-time empirical normal modes diagnosis. J. Atmos. Sci., 77, 457-476.
Dawson, D.T., M. Xue, J. A. Milbrandt, and M. K. Yau, 2010: Comparison of evaporation and cold pool development between single-moment and multi-moment bulk microphysics schemes in idealized simulations of tornadic thunderstorms. Mon. Wea. Rev., 138, 1152-1171.
Yang, J., M. K. Yau, X. Fang, and J. W. Pomeroy, 2010: A triple-moment blowing snow-atmospheric model and its application in computing the seasonal wintertime snow mass budget. Hydrol. Earth Syst. Sci.,14, 1063-1079.
Sun, J., P.A. Ariya, H.G. Leighton, and M.K. Yau, 2010: The mystery of ice multiplication in warm-based precipitating shallow cumulus clouds. Geophys. Res. Lett., 37, L10802, doi:10.1029/2010GL042440.
Milbrandt, J.A., M.K. Yau, J. Mailhot, S. Belair, and R. McTaggart-Cowan, 2010 : Simulation of an orographic precipitation event during IMPROVE-2. Part II: Sensitivity to the number of moments in the bulk microphysics scheme. Mon. Wea. Rev., 138, 625-642.
Martinez, Y., G. Brunet, and M.K. Yau, 2010a: On the dynamics of two-dimensional hurricane-like concentric rings vortex formation. J. Atmos. Sci., 76, 3253-3268.
Martinez, Y., G. Brunet, and M.K. Yau, 2010b: On the dynamics of two-dimensional hurricane-like vortex symmetrization. J. Atmos. Sci., 76, 3559-3580.
Wang, X., M.K. Yau, B. Nagarajan, and L. Fillion, 2010: The impact of assimilating radar estimated precipitation rates on simulation of the 17-18 July 1996 Chicago Floods. Adv. Atmos. Sci., 27,doi 10.1007/ s00376-009-8212-6.
Chung, K.-S., I. Zawadzki, M.K. Yau, and L. Fillion, 2009: Short-term forecasting of a midlatitude convective storm by the assimilation of single–doppler radar observations. Mon. Wea. Rev.,137, 4115–4135.
Déry, S. J., and M.K. Yau, 2008: Recent studies on the climatology and modelling of blowing snow in the Mackenzie River Basin (MRB), pages 241-257. Textbook entitled ‘ Cold Region Atmospheric and Hydrologic Studies, The Mackenzie GEWEX Experience, Volume 1: Atmospheric Dynamics’ (Ming-ko Woo Editor; Springer-Verlag); ISBN 978-3-540-73935-7, 470 pp.
Ioannidou, L., and M.K. Yau, 2008: Climatological Analysis of the Mackenzie River Basin Anticyclones: Structure, Evolution and Interannual Variability , pages 51-60. Textbook entitled ‘Cold Region Atmospheric and Hydrologic Studies, The Mackenzie GEWEX Experience, Volume 1: Atmospheric Dynamics’ (Ming-ko Woo Editor; Springer-Verlag); ISBN 978-3-540-73935-7, 470 pp.
Szeto, K.K., R.E. Stewart, M.K. Yau, and J. Gyakum, 2008: The Mackenzie Climate System: A Synthesis of MAGS Atmospheric Research, pages 23-50. Textbook, entitled ‘Cold Region Atmospheric and Hydrologic Studies, The Mackenzie GEWEX Experience, Volume 1: Atmospheric Dynamics’ (Ming-ko Woo Editor; Springer-Verlag); ISBN 978-3-540-73935-7, 470 pp.
Milbrandt, J.A., M.K. Yau, J. Mailhot, S. Belair, 2008 : Simulation of an orographic precipitation event during IMPROVE-2. Part I: Evaluation of the triple-moment run. Mon. Wea. Rev. , 136, 3873-3893.
Ioannidou, L., and M.K. Yau, 2008: Climatology of Northern Hemisphere anticyclonic activity. J. Geophy. Res. 113, D08119, doi:10.1029/2007JD008409.
Yang, J., and M. K. Yau, 2008: A new triple-moment blowing snow model. Boundary Layer Meteor., 126, 137-155.
Szeto, K. K., R. E. Stewart, M. K. Yau, and J. R. Gyakum, 2007: Northern tales: a synthesis of MAGS atmospheric and hydrometeorological research. Bull. Amer. Meteor. Soc., 88,1411-1425.
Caron, J.-F., M. K. Yau, and S. Laroche, 2007: The characteristics of key analysis errors. Part III: A diagnosis of their evolution. Mon. Wea. Rev., 135, 2754-2777.
Franklin, C.N., P. A. Vaillancourt, and M.K. Yau, 2007: Statistics and parameterizations of the effect of turbulence on the geometric collision kernel of cloud droplets. J. Atmos. Sci., 64, 938-954.
Caron, J.-F., M. K. Yau, S. Laroche, and P. Zwack, 2007a : The characteristics of key analysis errors. Part I: Dynamical balance and comparison with observations. Mon. Wea. Rev., 135, 249-266.
Caron, J.-F., M. K. Yau, S. Laroche, and P. Zwack, 2007b : The characteristics of key analysis errors. Part II: The importance of the PV corrections and the balance. Mon. Wea. Rev., 135, 267-280.
Milbrandt, J., and M. K. Yau, 2006a: A multi-moment bulk microphysics parameterization. Part III: Simulation of a hailstorm. J. Atmos. Sci., 63, 3114–3136.
Milbrandt, J., and M. K. Yau, 2006b: A multi-moment bulk microphysics parameterization. Part IV: Sensitivity experiments. J. Atmos. Sci ., 63, 3137–3159.
Theriault, J. M., R. E. Stewart, J. A. Milbrandt, and M. K. Yau, 2006: On the simulation of winter precipitation types. J. Geophy. Res., 111, D18202, doi:10.1029/2005JD006665.
Desgagne, M., R. McTaggart-Cowan, W. Ohfuchi, G. Brunet, P. Yau, J. Gyakum, Y. Furukawa, and M. Valin, 2006: Large atmospheric computation on the Earth Simulator- the LACES project. Scientific Programming, 14, 13-25.
Spyksma, K., P. Bartello, and M. K. Yau, 2006: A Boussinesq moist turbulence model. J. Turbulence, 7 (32), 1-24. DOI: 10.1080/14685240600577865.
Nagarajan, B., M. K. Yau, and L. Fillion, 2006: A numerical study of the 1996 Saguenay flood cyclone: Effect of assimilation of precipitation data on quantitative precipitation forecast. Mon. Wea. Rev., 134, 1371-1388.
Milbrandt, J., and M. K. Yau, 2005a: A multi-moment bulk microphysics parameterization. Part I: Analysis of the role of the spectral shape parameter. J. Atmos. Sci., 62, 3051-3064.
Milbrandt, J., and M. K. Yau, 2005b: A multi-moment bulk microphysics parameterization. Part II: A proposed three-moment closure and scheme description. J. Atmos. Sci., 62, 3065-3081.
Franklin, C. N., P. A. Vaillancourt, M. K. Yau, and P. Bartello, 2005: Collision rates of cloud droplets in turbulent flow. J. Atmos. Sci. 62, 2451–2466.
McTaggart Cowan, R., J. R. Gyakum, and M. K. Yau, 2004a: The impact of tropical remnants on extratropical cyclogenesis: case study of hurricanes Danielle and Earl (1998). Mon. Wea. Rev., 132, 1933 1951.
McTaggart Cowan, R., J. R. Gyakum, and M. K. Yau, 2004b: Reply to Comments on "The Influence of the Downstream State on Extratropical Transition: Hurricane Earl (1998) Case Study" and "A Study of the Extratropical Reintensification of Former Hurricane Earl Using Canadian Meteorological Centre Regional Analyses and Ensemble Forecasts". Mon. Wea. Rev.,132, 2514 2519.
Yau, M. K., Y. Liu, D. L. Zhang, and Y. Chen, 2004: A multiscale numerical study of hurricane Andrew (1992). Part VI: Small scale inner core structures and wind streaks. Mon. Wea. Rev. 132, 1410 1433.
Nagarajan, B., M. K. Yau, and D. L. Zhang, 2004: Numerical study of the 15 December 1992 TOGA COARE Mesoscale Convective System: Part II. Organization. Mon. Wea. Rev., 132, 1000 1017.
Cao, Z., R. E. Stewart, and M. K. Yau, 2004: A new perspective of the physical processes associated with the clear sky greenhouse effect over high latitudes. Advances in Atmos. Sciences, 21, 171 180.
Nagarajan, B., M. K. Yau, and P. H. Schuepp, 2004: The effects of small water bodies on the atmospheric heat and water budgets over the MacKenzie River Basin. Hydrological Processes, 18, 913 938.
Rogers, R.R., and M.K. Yau, 1989: A Short Course in Cloud Physics, 3rd Edition, Butterworth-Heinemann, 293 pp.