Geoscience Reference
In-Depth Information
Thus, from 31 considered tropical depressions, 5 depressions were formed and
developed further up to storm and hurricanes at temperatures of an ocean
'
s surface
below 27
—
subduction zones and rift zones of ocean. As it has appeared, tropical storm Delta and
Unnamed were formed and at temperature of an ocean
°
C. 10 tropical depressions were formed in areas of high tectonic activity
C, and
near to zones of high tectonic activity. In the previous report, assumptions have been
formulated and mechanisms of possible active in
'
s surface below 27
°
uence of degassing processes of
the Earth (especially in tectonic active zones of oceans) on processes initiation and
origin of tropical depressions are described. The materials presented by the given
report have convincingly shown an opportunity of existence of such processes in the
nature on examples of origin of tropical cyclones and depressions in Atlantic Ocean
for a season of 2005.
The mechanisms of possible active in
fl
uence of degassing processes of the Earth
(especially in active tectonic zones of oceans) on processes initiation and origin of
tropical depressions have been described by Syvorotkin (2002). It was also shown
that warm and cold ocean currents and
fl
uence
on tropical cyclogenesis. This fact is observed when analyzing the variability of the
origin zones of tropical cyclones (TC) and in the study of seasonal and other
variations in ocean currents and winds.
We have already carried out a joint analysis of the impact of potential risk factors
for the tropical cyclogenesis, depending on the time period for the territory of the
Atlantic Ocean. In this study, an attempt was made to analyze a part of the globe for
distribution of these TC forming factors. The Western Hemisphere of the Earth was
chosen for the analysis. When working, it was decided to use the following method:
recalculation of the presence or absence of some TC forming factors on a grid with
cell size 1
fl
flows of air masses have powerful in
fl
.
Coordinate grid was formed containing 32,400 cells (180
°
by 1
°
). The num-
bering of cells is a line from the lower left corner. Cells lying entirely in the territory
of land were excluded from further consideration (about 7,000 cells). As an indi-
cator of tectonic activity the following data were collected: (1) data points of
recorded earthquakes (for period from 1973 to 2011); (2) the data on the location of
major volcanoes; map with boundaries of tectonic plates with different types of
faults (subduction zones, rift zones, transform faults, spreading, displacement). It is
important to note that the location points of volcanoes are given only to surface
volcanoes, the data for submarine volcanoes are absent, so we'll
°×
180
°
ll keep in mind that
most of the submarine volcanoes are associated with the tectonically active zones.
For earthquakes data it was decided to allocate three gradations of danger (points):
'
0
small risk (the number of earthquakes for the entire period of less than
or equal to 5), 2
—
no risk, 1
—
—
high. Points of volcanoes: 0
—
no volcanoes nearby, 1
—
small risk
—
(the number of volcanoes less than or equal to 2), high
2. To determine the prox-
imity of cells to tectonic faults were allocated three grades: 0
—
no tectonic fault
—
“
nearby, 1
close to a fault, the proximity was determined by constructing a
buffer
zones
the cell is directly at tectonic fault.
Data on the tectonic faults were calculated separately for the oceanic and continental
faults.
”
all along the faults width of 100 km, 2
—
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