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distance NDBC-44001 from Sandy eye was about 600 km but Instability Indicator
reacts on the cyclone passing.
In the United States, Hurricane Sandy affected 24 states, including the entire
eastern seaboard from Florida to Maine and west across the Appalachian Mountains
to Michigan and Wisconsin, with particularly severe damage in New Jersey and
New York. Its storm surge hit New York City on October 29. The OAS Instability
Indicator showed that at this time Sandy diameter was changed from 700 to
900 km. All weather stations actually located on the southeastern coast given the
OAS Instability Indicator jump. Maximal value of the OAS Instability Indicator on
October 29 was at NOAA-ACYN4 and it was moved to the direction of NOAA-
CBL01 where its maximal level was achieved on October 30. Therefore, calcula-
tions of the OAS Instability Indicator for series of weather stations located on given
territory and aquatory gives the possibility to synthesize the cyclone track with
determination of its impact zones.
7.7 Searching the Indicator-Precursors of Tropical
Hurricane Beginning
The solution to the problem related to the search of indicator-precursor for the
tropical hurricane origin is connected with the assessment of the ocean-atmosphere
system (OAS) state and with the revealing situations when this system begins to
change its phase position. It is known that the origin of tropical hurricanes is one of
the displays of the cyclone moving. Basic phases of the OAS are (Mazur and
Ivanov 2004):
tempest
—
wind that has velocity 19
23 m/s and corresponds to the 8 balls by the
-
Beaufort scale;
storm
strong wind corresponding to more than 9 balls by the Beaufort scale
with wind speed 23
—
30 m/s; and
-
hurricane
—
12 balls and wind speed is more than 35 m/s.
So far, as all environmental changes connected with this process have stochastic
character, the solution to the problem of the detection of the time moment when
OAS transitions to the origin of storm transformation to the hurricane of
rst
category really needs the chaos modeling, that is the complex problem in his turn
(Mees et al. 1997; Abu-Zaid and Ahmadi 1989). So, it is necessary to take into
consideration the fact that numerous other natural catastrophes are characterized by
the same dynamics, but they differ only by series of environmental parameters that
in
uence their beginning. Therefore, the search of laws describing the tropical
hurricane origin needs to analyze other natural phenomena in the atmosphere, and
maybe in the more narrow space. For example, as it follows from study by Bondur
et al. (2008), the processes on the Sun signi
fl
uence the tropical cyclone
beginning, and in general it was determined that there exists a correlation between
cantly in
fl
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