 n
the interview below, Dr. M.K. (Peter) Yau talks about his
highly cited work on tropical storms. In our analysis of
tropical storms research over the past decade, Dr. Yau’s
work ranks at #3, with 14 papers cited a total of 255 times.
His most-cited paper, "Multiscale numerical study of
Hurricane Andrew (1992). 1. Explicit simulation and
verification," (Monthly Weather Review 125:
3073-93, 1997), ranks at #6, with 74 cites. Dr. Yau hails from
McGill University, where his work centers on cloud physics and
dynamics.
|
 What
first interested you in storm research?
I first got interested in storms when I worked in a weather
office (Hong Kong Royal Observatory) for two years before I started
my university education. At that time, the Observatory built its own
satellite picture receiving equipment and captured some of the early
spectacular typhoon pictures from the Tiros and Nimbus satellites. I
was intrigued by the spiral bands, the strong winds, and heavy
rainfall from these storms.
Tell
us about the extensive series of studies you and your colleagues did
on Hurricane Andrew—what did you learn about Andrew in particular,
and about hurricanes in general?
|
“ We showed using a high-resolution numerical model with explicit representation of cloud and precipitation processes, that the observed evolution and inner-core structures of Andrew can be well simulated from observed initial conditions.”
|
|
Our Hurricane Andrew studies started as a team effort when Yubao
Liu (now at the National Center for Atmospheric Research [NCAR]), Da-Lin
Zhang (now at the University of Maryland), and I were colleagues
at McGill University. We showed using a high-resolution numerical
model with explicit representation of cloud and precipitation
processes, that the observed evolution and inner-core structures of
Andrew can be well simulated from observed initial conditions. These
results demonstrate the feasibility of predicting reasonably well
the track, intensity, and inner-core structures of hurricanes from
tropical synoptic conditions if a model has high grid resolution and
realistic physics.
(Read an interview with the coauthor of this
paper: Zhang,
DL )
The numerical model output also furnished us with a consistent
dataset to understand how the storm operates. Extensive analysis of
this dataset led to a series of papers on Andrew’s detailed
inner-core structures, an explanation of the subsidence warming in the
eye, a study of the thermodynamics of the storm, and an investigation
of the strong winds in the eyewall and spiral bands. With Yongsheng
Chen (now at NCAR) and Gilbert Brunet (at Environment Canada), we
showed convincingly the presence of propagating waves, so called
vortex Rossby waves, in the simulated hurricane. These waves represent
a new way of understanding the dynamics of hurricanes and they may
affect significantly the change of hurricane intensity with time.
Please
talk a little bit about your 2004 Monthly Weather Review paper
examining Hurricanes Danielle and Earl.
Hurricanes Danielle and Earl were tropical storms that moved into
the mid-latitudes. Their characteristics then changed from a
tropical storm to an extratropical one. The so-called extratropical
transition is difficult to forecast. In our 2004 paper, we examined
how the moisture and circulation associated with the tropical
remnant of Danielle and Earl affected the transition process. We
found that for ex-Hurricane Danielle, the remnant tropical
circulation and moisture were important for rapid redevelopment as
it moved into the mid-latitudes. However, the rapid
reintensification of ex-Hurricane Earl was not sensitive to the
moisture and circulation of the tropical remnant.
For
the uninitiated, how does one go about modeling hurricanes? Is it
computer simulated or done in a lab? What elements go into planning
such a model?
Nowadays, it is much more common to simulate hurricanes in a
computer. To build such a numerical model, we first gather the
equations governing the wind, temperature, pressure, and various
hydrometeors like cloud droplets, rain drops, ice and snow, and
graupel. We then divide the storm into little boxes and write the
equations for each box in a form that can be solved by a computer
utilizing a particular numerical method. The calculated results like
winds, temperature, pressure, etc., for all the boxes at discrete
time intervals then tell us how the hurricane develops and moves.
What
are your current projects?
I am trying to understand how hurricanes change their intensity
especially when more than one eyewall forms in a hurricane. Other
projects include investigating how cloud and precipitation form in
storms and how to improve their representation in numerical models.
Dr. M.K. (Peter) Yau
McGill University
Montreal, Quebec, Canada
Read an interview with the coauthor of this
paper: Da-Lin
Zhang.
|
ESI Special
Topics: October 2006
Citing URL: http://esi-topics.com/tropical/interviews/PeterYau.html
|
|
