In the press
Book
reviews
Interaction
of sea waves with wind
By Peter
Janssen. Cambridge University Press (2004). viii + 300
pages. ISBN 0-521-46540-0 (h/b). Price: £70/US$ 120.
Surface
gravity waves are well-known, complicated phenomenona, which
have always been the subject of great interest. They are
easily observed but difficult to describe mathematically.
Many works have been devoted to wind wave investigation and
this monograph by Peter Janssen is an important
contribution.
About 20 years
ago, the author was a member of the International Wave Modelling Group (WAMDI). At present, the
resulting WAM model is being improved, tested and widely
used both at the global scale and in local water areas. The
operational WAM model variant assimilates satellite
information for updating the wave forecast. Nowadays it is
one of the most popular wind wave models used in many
countries.
Peter Janssen
pays attention to the problem of interaction of atmospheric
boundary layer and sea waves. Winds generate ocean waves
but, at the same time, airflow is modified due to the loss
of energy and momentum to the waves; thus, momentum from the
atmosphere to the ocean depends on the state of the waves.
Wind-wave numerical simulation is made on the basis of wave
action balance equation.
Peter
Janssen’s book describes ocean-wave evolution due to
advection and physical processes such as wind input,
dissipation and non-linear energy transfer in the wave
spectrum. An overview of non-linear transfer is given and,
as a by-product, the role of four-wave interactions in the
generation of extreme events, such as freak waves, is
discussed. Coupled ocean-atmosphere modelling gives improved
weather and wave forecasts.
The problem of
wind wave energy dissipation is not fully studied, however.
Nowadays, there are at least two different approaches to
dissipation description: that used in the WAM model, based
on the influence of spectrum evolution almost in all the
frequency domain and that proposed by V. Zakharov, according
to which dissipation is located in the high frequency range.
By fitting the
dissipation parameters, it is possible to achieve
satisfactory agreement between numerical results and field
data for wave evolution. But the effect of the
ocean-atmospheric boundary layer interaction is principally
different in these two cases as in the second case essential
energy fluxes from ocean to atmosphere can exist. It may contribute to the problem of weather forecast
and climate prediction.
The author
describes the algorithm of the energy balance equation
numerical output used in the WAM model. Nevertheless, not enough attention is paid to this problem.
It is known that error due to insufficient accuracy of the
numerical output can lead to the similar error produced by
not well studied wind wave physics and incorrectness of wind
speed used in numerical simulations.
The book is
useful for students, engineers and scientists who are
interested in the problem of ocean weather forecast and
climate formation.
Igor V.
Lavrenov
lavren@aari.nw.ru
New
books received for review in the WMO Bulletin
Monitoring
and Predicting Agricultural Drought
Vijendra K.
Broken, Arthur P. Cracknell, and Ronald L. Heatcote (Eds.).
ISBN 0-19-516234-X.xix
+ 472 pp. Price:
US$ 124.50
Agricultural
droughts affect whole societies, leading to increased food
costs, threatened economies, and even famine. In order to
mitigate such effects, researchers must first be able to
monitor agricultural droughts and then predict them;
however, no book currently focuses on accurate monitoring or
prediction of these devastating kinds of droughts. The editors of Monitoring and Predicting
Agricultural Drought have assembled a team of expert
contributors to make a global study,
describing biometeorological models and monitoring methods
for agricultural droughts. These models and methods note the
relationships between precipitation, soil moisture, and crop
yields, using data gathered from conventional and remote
sensing techniques. The coverage of the book includes
probabilistic models and techniques developed worldwide. It concludes with coverage of climate change
and resultant shifts in agricultural productivity, drought
early warning systems and famine mitigation.
Encyclopedia
of Weather and Climate
By Michael
Allaby. Facts on File, New York (2002). ISBN 0-8160-4071-0
(two volumes). Price: US$ 150.
This
two-volume encyclopedia summarizes present knowledge of
weather and climate in 4 000 cross-referenced entries
accompanied by nearly 300 maps, charts, diagrams, and
photographs, with several appendixes and a 34-page index.
By moving
from one entry to another, the encyclopedia can be used to learn how
different processes cause the weather we experience day by
day. It explains the causes of blizzards, ice storms,
tornadoes, hurricanes and ice ages, as well as ordinary rain
showers, dew and frost. It also recounts how meteorological
instruments came to be invented and how they work. There are
also brief accounts of the lives of some of the scientists
who have contributed to the disciplines of climatology and
meteorology.
Baroclinic
Tides—Theoretical Modeling and Observational Evidence
Vasiliy
Vlasenko, Nataliya Stashchuk and Koluman Hutter. Cambridge
University Press (2005). ISBN
0-521-84395-2. xix + 351 pp. Price:
£70/US$ 120.
This book demonstrates the analytical and numerical methods used
to study the generation and evolution of baroclinic tides
and, by comparison with experiments and observational data,
shows how to distinguish and interpret internal waves.
Strongly non-linear solitary internal waves, which are
generated by internal tidal waves at the final stage of
their evolution, are investigated in detail. This book is
intended for researchers and graduate students of physical
oceanography, geophysical fluid dynamics and
hydro-acoustics.
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