Environmental Engineering Reference
In-Depth Information
3
Scales of C limate in Designing with the Desert
Anthony J. Brazel
CONTENTS
3.1 Introduction .......................................................................................................................... 59
3.2 Global Scale ........................................................................................................................... 60
3.3 Regional Scale ....................................................................................................................... 62
3.4 Regional to Local Scale ....................................................................................................... 64
3.5 Human-Dominated Effects within the Region ............................................................... 67
3.6 Conclusions ........................................................................................................................... 70
References ....................................................................................................................................... 71
3.1 Introduction
Climate is considered an ensemble of weather processes and varies in its characteristics
depending on the time scale chosen and spatial area considered. 1 Table 3.1 provides an
example of the types of meteorological motion systems and space/time scales. If one were
to study wind gusts as extreme events that might affect buildings, observational methods
or calculations would have to address processes that happen over seconds to minutes and
resolve effects over areas less than a square mile (e.g., a microburst from a cloud). On
the other hand, forecasting midlatitude cyclones requires only a coarse time and space
domain to assure awareness of impending storms across a region (e.g., a spatial resolution
of hundreds of miles).
Climatology consists of concepts such as how frequent these variable processes occur;
their magnitudes and dimensions—including frequencies and magnitudes over time; the
mean state; and whether there are significant cycles, step jumps, or subtle long-term trends
that are evident in the climate system. The expression “climate system” is typically used to
indicate a series of complex physical and dynamic processes between earth's surface and
the atmosphere that interact to characterize a climate. The theoretical climatologists must
get at the fundamental causes for these frequencies/magnitudes and their changes over
time using physical and mathematical principles.
The applied climatologist and planner, who is asked to advise on issues of desert liv-
ing, is faced with what might be perceived as an equally daunting set of issues. He or she
asks what difference a climate makes to citizens, cities, towns, companies, agencies, and
governments, and what is it about the climate system that must be understood so that we
can provide meaningful strategies to mitigate or adapt to the negative consequences of
climate and take advantage of the positive consequences. Contemporary applied problems
(design-related or otherwise), more often than not, start out with an appreciation of the
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