environment is repeatedly encountered, new features are added to the “map,” and
the level of detail increases.
Scholars of behavioral geography are especially interested in mental maps,
because such maps form the core of spatial perception and reveal a great deal
about how people view the world around them, as well as the world at large. The
mental maps one carries may play a significant role in the formation ofcultural
identity,as well as how other regions are perceived. Studies have shown that
nation-statesemphasize the development of amore detailed domestic mental
map among students in their public school systems than mental maps they form
of adjacent countries, even in students who live adjacent to internationalbounda-
ries. Views ofregionsthat are not precisely defined provide interesting insight
into spatial perception. For example, the boundaries of the “Deep South’ in the
United States vary considerably, depending on where the question is asked. The
mental maps of the “South” that the average resident of Alabama holds will differ
markedly from that held by a resident of Nebraska. Interestingly, many people
form mental maps not only about places they have encountered, but also about
places theyhave notyet been to. These sorts of maps may be formed from media
reports or other sources of information that are not geographical, yet in many cases
people form a spatial concept from them. Some research has found, for example,
that a significant number of people link spatial extent to the frequency of hearing
information about a place, so that the greater the times a country is mentioned in
the media, for example, the larger it is perceived to be.
Middle Latitude Cyclones
A middle latitude cyclone (MLC) is a large disturbance that lasts for several days,
and is the most significant weather-maker of the middle latitudes. This storm is
also known as an extratropical cyclone or a wave cyclone. The term “cyclone”
denotes a central low pressure with closed isobars. Middle latitude cyclones,
hurricanes, tornadoes, and dust devils are cyclones of various causes, sizes, and
strengths. In particular, a middle latitude cyclone is the largest of all cyclones
and is a complicated admixture of the polar front jet stream,air masses,and
fronts. The MLC is a seminal concept in understanding the middle latitude
weather of our planet and was first proposed by Norwegian scientists shortly after
World War I.
The origin of an MLC, called cyclogenesis, is directly related to energy imbal-
ances between equator and poles. As such, the strongest MLCs are usually
reserved for the winter season when the imbalance is greatest. Near the polar front
Middle Latitude Cyclones 225