Cloud Physics and Dynamics
Offices: Burnside Hall 944 | 818
Tel.: (514) 398-3719
Fax.: (514) 398-6115
peter.yau [at] mcgill.ca (E-mail)
1. Improving quantitative precipitation forecasts
NSERC and Hydro-Quebec has been supporting our Industrial Research Chair Program on “Improving short-term forecast of precipitation”. The efficient generation and distribution of hydro-electric power depends on accurate forecast of inflows in reservoirs and drainage basins, which in turn is affected significantly by the quality of the forecast of the type and amount of precipitation. During the first mandate of the Industrial Research Chair program (2009-2014), various tools have been developed to improve the forecast of when, where, how much, and what type of precipitation would occur over a lead time of one to two days. During the second mandate (2014-2019), this forecast lead time will be increased to one week which would be highly beneficial for capacity management of hydroelectric power.
Specific projects during the second mandate include study on condensation and collisional growth of cloud droplets in turbulence using direct numerical simulation (DNS) techniques, the development of a unified aerosol-microphysics multi-moment scheme across model resolutions, the improvement on the representation of upright and slantwise convection in the Canadian computer weather prediction models, and the evaluation of quantitative precipitation and hydrological forecasts as a result of the better representation of convective and cloud/precipitation processes.
2. Studies on hurricanes
Hurricanes are violent vortices in the atmosphere and can contribute significantly to precipitation. For hurricane prediction, two major problems remain. One is to forecast the rapid intensification (RI) of the storm and the other is to forecast when a storm will form.
Convection in the eyewall can affect RI in two ways. First, latent heating released in cloud processes is a main source of energy. Its spatial distribution affects RI especially when bursts of convection occur inside the radius of maximum wind. Second, latent heating in the eyewall produces a hollow tower of potential vorticity (PV) that supports propagating vortex Rossby waves (VRW) which may become unstable to mix eyewall PV into the eye to effect intensity change. Additionally, VRWs in a hurricane vortex can radiate gravity waves leading to another instability known as radiative pumping. The understanding of these instabilities is important to improve hurricane forecasting.
Our current research projects on hurricanes include:
- The role of microphysical processes on hurricane intensity change and the distribution of precipitation.
- Mechanism for oscillating wobbles in tropical cyclones with concentric eyewalls.
- Kelvin cat’s eye and the genesis of hurricanes.
- The formation of elliptic eyewalls from spontaneous emission of spiral inertial-gravity waves.
- Dynamics of inner eyewall dissipation in hurricane Wilma (2005).
Some recent publications
- Rousseau-Rizzi, R., D. J. Kirshbaum, and M.K. Yau, 2017: Initiation of deep convection over an idealized mesoscale convergence line. J. Atmos. Sci., 74, 835-853.
- Surcel, M., I. Zawadzki, M.K. Yau, M. Xue, and F. Y. Kong, 2017: More on the scale-dependence of the predictability of precipitation patterns. Extension to the 2009-2013 Spring Experiment ensemble forecasts. Mon. Wea. Rev., 145, 3625-3646.
- Paull, G., K. Menelaou, and M. K. Yau, 2017: Sensitivity of tropical cyclone intensification to axisymmetric heat sources: The role of inertial stability. J. Atmos. Sci., 74, 2325-2340.
- Asaadi, A., G. Brunet, and M. K. Yau, 2017: The importance of critical layer in differentiating developing from nondeveloping easterly waves. J. Atmos. Sci., 74, 409-417.
For a complete list of publication for prof. Yau, please visit Google Scholar.