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UFLICOEL-96/003
ANALYSIS OF HURRICANE CYCLES IN FLORIDA
by
Lihwa Lin
and
Robert G. Dean
May, 1996
UFL/COEL-96/003
Analysis Of Hurricane Cycles In Florida
by
Lihwa Lin
and
Robert G. Dean
May, 1996
----- ----- ----- ----- ----- ----- ----- ----- ----- ---- ----- -----
REPORT DOCUMENTATION PAGE
1. Report No. 2. 3. Recipient' 0 ccessioo o.
4. Title sod Subtitle 5. Report Date
ANALYSIS CF HJ RRCANE CYCLES IN FLORIDA May 151 1996
6.
7. Author(s) 8. performing Orgaization Report No.
Lihwa Lin, Pobert G. Dean UFL/COEL-96/003
9. Performing Organiatioo Name and Address 10. rroject/Task/Mork Unit Ho.
Coastal and Oceanographic Engineering Department
University of Florida 11. contract or crant No.
336 Weil Hall
ainegsviep F T. -326(11 13. Type of Report
12. Sponsoring Organization Ham and Address F final
14.
15. Supplementary Notes
16. Abstract
Hurricane cycles were studied for the hurricanes affecting Florida over the 110 years
from 1886 to 1995. A total of 111 hurricanes which affected Florida during this
period, as identified from the North Atlantic Tropical Cyclone Climatology Data
compiled by the National Hurricane Center), were used for the study. The data show
that the occurrences of Florida hurricanes were less frequent from 1970 to 1995 as
compared to that from 1886 to 1970. By using a spectral analysis, the occurrences
of Florida hurricanes were found to peak at the intervals of 11, 18, and 55 years.
The cyclical characteristics of Florida hurricanes were also investigated for the
hurricanes in different type paths affecting different regions in Florida. It is
found that the occurrences of hurricanes were more frequent and uniformly distributed
from 1886 to 1995 along the west/northwest coast than the east coast. On the
average, the return periods of Florida hurricanes are found to be equal to 1.71 years
on the west/northwest coast and 4.28 years on the east coast.
17. Originator's Key words 18. Availability Statment
Cycles
Hurricane
Return Period
19. U. S. Security CLassif. of the Report 20. U. S. Security Classf. of This Page 21. No. of ptges 22. Price
Unclassified Unclassified 46
Contents
1 Introduction ......................................................................................................... 1
2 Histogram of Florida Hurricane Occurrences from 1886 to 1995 ............................. 1
3 Spectral Analysis of Florida Hurricane Cycles from 1886 to 1995 ............................ 2
4 Analysis of Hurricane Cycles for Different Types of Hurricane Path ........................ 3
5 C conclusions ........................................................................................................ 5
R references ......................................................................................................... 6
List of Figures
1 Hurricanes affecting the Florida area and five different types of hurricane path .......... 7
2 Histogram of all 111 Florida hurricanes (1886-1995) ............................................. 8
3 Histogram of Category 2, 3, 4, and 5 hurricanes (1886-1995) ................................. 9
4 Histogram of Category 3, 4, and 5 hurricanes (1886-1995) ................................... 10
5 Histogram of Category 4 and 5 hurricanes (1886-1995) ........................................... 11
6 Histogram of Category 5 hurricanes (1886-1995) ............................................... 12
7 Spectrum of monthly data of hurricane category (1886-1995) .............................. 13
8 Spectrum of annual data of accumulation of hurricane categories (1886-1995) .......... 14
9 Spectrum of annual data of accumulated squares of hurricane categories
(1886-1995) .................................................................................................. 15
10 Spectral presentation of occurrences of Florida hurricanes (1886-1995) ................... 16
11 Tracks for Type (A) path hurricanes (1886-1995) ............................................... 17
12 Tracks for Type (B) path hurricanes (1886-1995) ............................................... 18
13 Tracks for Type (C) path hurricanes (1886-1995) ............................................... 19
14 Tracks for Type (D) path hurricanes (1886-1995) .............................................. 20
15 Tracks for Type (E) path hurricanes (1886-1995) .............................................. 21
16 Plot of hurricane category versus time for Type (A) path hurricanes .................... 22
17 Plot of hurricane category versus time for Type (B) path hurricanes ................... 23
18 Plot of hurricane category versus time for Type (C) path hurricanes ....................... 24
19 Plot of hurricane category versus time for Type (D) path hurricanes ................... 25
20 Plot of hurricane category versus time for Type (E) path hurricanes .................. 26
Sii
21 Plot of hurricane category versus time for Type (B)+(C) path hurricanes ................ 27
22 Plot of hurricane category versus time for Type (C)+(D) path hurricanes ................ 28
23 Plot of hurricane category versus time for Type (C)+(D)+(E) path hurricanes ......... 29
24 Histogram of Type (B)+(C) path hurricanes (1886-1995) .................................... 30
25 Histogram of Type (C)+(D) path hurricanes (1886-1995) ...................................... 31
26 Histogram of Type (C)+(D)+(E) path hurricanes (1886-1995) .............................. 32
27 Spectrum of monthly hurricane category of Type (C)+(D) ................................... 33
28 Spectrum of monthly hurricane category of Type (C)+(D)+(E) ................................. 34
29 Plot of coastal wind versus time for Type (A) path hurricanes ............................. 35
30 Plot of coastal wind versus time for Type (B) path hurricanes ............................. 36
31 Plot of coastal wind versus time for Type (C) path hurricanes ............................. 37
32 Plot of coastal wind versus time for Type (D) path hurricanes ............................. 38
33 Plot of coastal wind versus time for Type (E) path hurricanes ............................. 39
34 Plot of coastal wind versus time for Type (B)+(C) path hurricanes .......................... 40
35 Plot of coastal wind versus time for Type (C)+(D) path hurricanes ............................ 41
36 Plot of coastal wind versus time for Type (C)+(D)+(E) path hurricanes ................. 42
List of Tables
1 Saffir/Simpson hurricane scale ranges ............................................ ................ 2
2 Average return period of Florida hurricanes from 1886 to 1995 .............................. 4
Analysis Of Hurricane Cycles In Florida
1. Introduction
This report contains the results of a statistical study of hurricane cycles in Florida for
the period from 1886 to 1995. A total of 111 hurricanes which affected Florida during this
period were analyzed. Among them, 90 hurricanes made landfall on the Florida Peninsula and
47 hurricanes were classified as major hurricanes with maximum windspeeds exceeding 95
knots (110 mph) according to the Saffir/Simpson Scale. On the average, nearly one hurricane
per year affected Florida, while about four hurricanes struck Florida every five years. In
reality, however, the number of hurricane occurrences in Florida is seen to be unevenly
distributed on the yearly basis. The tendency of different intensity hurricanes to cluster in
certain years and in certain areas was also observed (Jordan, 1966; Sheets, 1992; Hebert, et
al., 1995). Therefore, it seems more appropriate to study a cyclical nature of hurricanes
regarding both hurricane strength and geographical area.
In this report, a histogram of occurrences of all Florida hurricanes occurring from
1886 to 1995 was presented first. These hurricane data were then examined based on the
spectral analysis. The cyclical nature of these hurricanes was also investigated by considering
hurricanes with different types of storm paths in different regions.
2. Histogram of Florida Hurricane Occurrences from 1886 to 1995
Histograms of occurrences of historical Florida hurricanes from 1886 to 1995 were
constructed for the study of hurricane cycles. The hurricane information used in the
histograms were from the North Atlantic Tropical Cyclone Climatology Data compiled at the
National Hurricane Center (Jarvinen'and Neumann, 1978; Hebert, et al., 1995). Hurricanes
affecting Florida are defined as those with storm track crossing through a pentagonal area as
delineated in Figure 1. Figures 2 to 6 show the histograms of occurrences of Florida
hurricanes from 1886 to 1995 with respect to various hurricane strength categories according
to the Saffir/Simpson scale, which ranks hurricanes based on the central pressure, maximum
wind speed, storm surge height, and the potential of damage level. Table 1 presents the
Saffir/Simpson hurricane scale ranges. In Figures 2 to 6, the width of each histogram cell is
5 years.
As an example, Figure 2 presents a histogram of the occurrences of all the historical
Florida hurricanes from 1886 to 1995, whereas Figures 3 to 6 present the histograms of those
Florida hurricanes with intensity above Categories 2, 3, 4, and 5, respectively. It is noticed
in Figure 2 that hurricanes are less frequent from 1970 to 1995 compared to the period from
1886 to 1970. However, some cyclical patterns of hurricane occurrences are clearly
noticeable from the histograms shown in Figures 2 to 6.
Table 1: Saffir/Simpson Hurricane Scale Ranges
Category Central Pressure Maximum Winds Storm Surge Damage
(millibars) (knots) (ft)
1 >980 65--82 4--5 Minimal
2 965--979 83-95 6--8 Moderate
3 945--964 96-113 9-12 Extensive
4 920--944 114--135 13--18 Extreme
5 <920 >135 >18 Catastrophic
3. Spectral Analysis of Florida Hurricane Cycles from 1886 to 1995
The characteristics of hurricane cycles can also be studied based on a spectral analysis.
The spectral method applied herein is the standard which finds the frequency components in
a noisy time domain signal through the use of Fourier transforms of the signal. The spectral
method is used for analyzing historical hurricane data in four cases: (1) monthly data of
hurricane category, (2) annual data of accumulation of hurricane categories in each year, (3)
annual data of accumulation of squares of hurricane categories in each year, and (4) the
numbers of hurricane occurrences in the 5-year basis from 1886 to 1995. The analyses of
Cases (1), (2), and (3) are intended to find the return period of stronger hurricanes while the
analysis of Case (4) is used to find the cyclical peak of occurrences of hurricanes.
Figures 7, 8, and 9 present the results of spectral analyses for Cases (1), (2), and (3).
In Case (1), the spectrum of monthly hurricane category data exhibits a very noisy pattern
such that it does not reveal sufficient information to distinguish the cyclical characteristics of
different category hurricanes. In Cases (2) and (3), the spectra analyzed based on annual data
of hurricane category exhibit much clear pictures about the repeating nature of stronger
hurricanes. In Figures 8 and 9, the spectra of annual hurricane category data show that major
hurricanes can return to Florida in the smallest intervals of 2.07 and 2.44 years, which
correspond to frequencies of 0.48 and 0.41 per year, respectively.
Figure 10 presents the results from spectral analysis for Case (4). It is seen that the
occurrences of hurricanes generally peaked at the intervals of 11, 18, and 55 years, which
correspond to frequencies of 0.09, 0.056, and 0.018 per year, respectively. It is especially
interesting that the occurrences of major hurricanes, which include all Category 3, 4, or 5
hurricanes, peaked more predominantly about every 18 years.
4. Analysis of Hurricane Cycles for Different Types of Hurricane Path
To study the cyclical nature of the historical Florida hurricanes, it seems necessary to
separate the hurricanes with different characteristics of storm paths. One particular reason
is that hurricanes formed in the Gulf of Mexico or Caribbean Sea, and in the tropical Atlantic
may have different causes (Jordan, 1966; Neumann and Dale, 1976). By examining storm
tracks of all the Florida hurricanes from 1886 to 1995, five different types of hurricane paths
can be distinguished. They are: (A) a storm path of a parabolic type curve originating over
the tropical Atlantic or Caribbean Sea, recurving into the North Atlantic off the east Florida
coast without landfalling, and continuously moving northwards to the northeast U.S. coast
or to a higher latitude area in the North Atlantic Ocean, (B) a storm path similar to (A) but
landfalling on the east coast of Florida, (C) a storm path commencing on a northwesterly or
westerly track from the tropical Atlantic, crossing the lower or central Florida, and continuing
a northwestly course into the Gulf of Mexico before landfalling on the northwest coast of
Florida, (D) a storm track starting from either the tropical Atlantic, Gulf of Mexico, or
Caribbean Sea, moving generally northwards in the Gulf, and making landfall on the
northwest coast of Florida, and (E) a storm path similar to (D) but landfalling on the central
or lower west coast of Florida. Of these five different types of hurricane paths, Types (B) and
(C) can be combined in the case of which hurricanes made landfall on the east coast of
Florida, Types (C) and (D) can be combined in the case of which hurricanes made landfall on
the northwest coast of Florida, whereas Types (C), (D) and (E) together can be used for the
study of hurricane cycles with landfalling on the west and northwest coast of Florida.
From all the Florida hurricanes occurring from 1886 to 1995, a total number of 98
hurricanes, which clearly fell into one of the five type paths with still hurricane wind intensity
affecting Florida, were selected for further studies of the cyclical pattern of hurricane
occurrences. Figures 11 to 15 show the storm tracks separated into the five type paths.
Figures 16 to 20 plot the category of these historical hurricanes versus time based on the
Saffir/Simpson Scale for different hurricane paths of Types (A), (B), (C), (D), and (E),
respectively. Figures 21 to 23 plot the category of the hurricanes versus time for Types
(B)+(C), (C)+(D), and (C)+(D)+(E), respectively. Table 2 presents the average return
period of hurricanes and the associated standard deviation for the five different path types and
three combinations of them. It is seen that for Types (A), (B), (C), (D), and (E) a clear
pattern of hurricane cycles does not exist regardless of whether the historical hurricanes are
of the same category or not. This is also evident from larger standard deviations of the return
period computed for the five different path types shown in Table 2. For Type (B)+(C), in
which hurricanes made landfall on the east coast of Florida, a cyclical pattern was not found.
However, for Type (B)+(C), it is interesting to see that hurricanes were most likely to make
landfall only in the lower half part of the east coast of Florida. In summary, 25 out of a total
of 26 hurricanes of Type (B)+(C) from 1886 to 1995 were seen to make landfall from the mid
east coast near Cape Canaveral to the lower east coast in the Florida Keys. As shown in
Figure 22, Type (C)+(D), in which hurricanes made landfall on the northwest coast of Florida,
a cyclical pattern was noticeable, regardless of hurricane category. For Type (C)+(D)+(E),
S: 3
in which hurricanes made landfall on the west and northwest coast of Florida, a clear cyclical
pattern was also seen, regardless of hurricane category, in Figure 23. These cyclical patterns
of the hurricanes of Types (C)+(D), and (C)+(D)+(E), which struck the northwest and
west/northwest coasts, respectively, can be noted as well from smaller standard deviations of
return periods shown in Table 2.
Table 2: Average Return Period of Florida Hurricanes from 1886 to 1995
Type of Path Number of Average Return Period Standard Deviation
Occurrences (year) (year)
(A) 21 5.06 5.30
(B) 12 8.00 10.11
14 8.23 8.93
(D) 30 3.77 4.98
(E) 21 5.12 5.28
(B)+(C) 26 4.28 5.48
(C)+(D) 44 2.54 1.95
(C)+(D)+(E) 65 1.71 1.54
Figures 24, 25, and 26, present the histograms of the Florida hurricanes of Types
(B)+(C), (C)+(D), and (C)+(D)+(E), respectively. It is seen in Figures 25 and 26 that Types
(C)+(D), and (C)+(D)+(E) hurricanes occurred more uniformly over the 110 years from 1886
to 1995, which implies the periodic nature of the occurrences of these hurricanes. On the
average, the return periods of hurricanes which impacted the east, northwest, and
west/northwest coasts are equal to 4.28, 2.54, and 1.71 years, respectively.
The averaged return period of hurricanes affecting a relatively small coastal area can
also be computed based on the averaged return period of hurricanes affecting the relatively
large area by assuming that hurricanes making landfall in the relatively large area are
uniformly distributed in space. For instance, the averaged return period of hurricanes that
make landfall on the coast of Walton County, which is located in the center of northwest
coast of Florida, can be computed based on the averaged return period of hurricanes affecting
the northwest coast of Florida. Since the lengths of coastline of Walton County and the
northwest Florida are about 26 and 225 miles, respectively, and the average return period of
hurricanes which impacted the northwest coast is 2.54 years, the averaged return period of
hurricanes making landfall on the coast of Walton County is (2.54 yr)x(225 miles)/(26 miles)
=22 years.
Figures 27 and 28 present the spectra of the monthly data of hurricane category for
Types (C)+(D) and (C)+(D)+(E), respectively. These spectra display a smallest dominant
return period of 1.47 years, which corresponds to the frequency of 0.68 per year. In terms
of the total number of hurricane occurrences from 1886 to 1995, 65 hurricanes made landfall
on the west/northwest coast versus 26 hurricanes on the east coast. These results indicate
that the occurrences of hurricane affecting Florida is more frequent and periodic on the west
coast than the east coast.
It should be noted that hurricanes with a higher category on the Saffir/Simpson Scale
do not necessarily imply stronger coastal wind condition since the hurricane category is based
on the maximum intensity attained during the life cycle of the hurricane. However, coastal
wind conditions can be more representative of a hurricane affecting Florida than the
corresponding hurricane category. Figures 29 to 36 plot the maximum coastal windspeeds
(within the hurricane affecting area as delineated in Figure 1) of hurricane versus time for
Types (A), (B), (C), (D), (E), (B)+(C), (C)+(D), and (C)+(D)+(E), respectively. Again,
special attention should be paid to the cases of Type (C)+(D), and (C)+(D)+(E), in which
more regular patterns of hurricane cycles were observed. In the cases of Types (C)+(D), and
(C)+(D)+(E), it is seen that extreme wind conditions with windspeeds greater than 120 knots
were generally rare. The regular cyclical patterns of hurricane occurrences of Types (C)+(D),
and (C)+(D)+(E), are more likely for the coastal wind conditions with the hurricane intensity
windspeeds ranging from 60 to 120 knots.
5. Conclusions
Temporal characteristics of occurrences of the hurricanes which affected Florida over
the 110 years from 1886 to 1995 were studied in this report. The hurricane information used
in this study were from the North Atlantic Tropical Cyclone Climatology Data compiled at
the National Hurricane Center. A total of 111 hurricanes which affected Florida were first
identified from the data. Among them, 90 hurricanes made landfalls on the Florida Peninsula
whereas 21 came only closer to the coast without landfalling in Florida. By expressing the
number of occurrences of these hurricanes in a histogram, it is seen that the occurrences of
Florida hurricanes were less frequent from 1970 to 1995 as compared to that from 1886 to
1970. Patterns of hurricane cycle are, however, observed from the histogram. The
occurrences of Florida hurricanes were noticed, according to a spectral analysis, to peak at
the intervals of 11, 18, and 55 years. The cyclical pattern is particularly interesting for the
occurrences of major hurricanes, which include all Category 3, 4, and 5 hurricanes based on
a Saffir/Simpson Scale, that these hurricanes tend to peak more predominantly about every
18 years.
The cyclical characteristics of the historical Florida hurricanes were further
investigated for the hurricanes in five different type paths. In the case of that hurricanes came
from the tropical Atlantic and also made landfall on the east coast of Florida, no clear cyclical
figure of hurricane occurrences was found. In the case of that hurricanes struck the west and
northwest coasts, the occurrences of hurricanes were more frequent and uniformly distributed
from 1886 to 1995. Over the 110 years from 1886 to 1995, there are 65 hurricanes made
landfall on the west/northwest coast and 26 hurricanes on the east coast of Florida. On the
average, the return periods of Florida hurricanes are found to be equal to 1.71 years on the
west/northwest coast and 4.28 years on the east coast.
References
1. Hebert, P.J., J.D. Jarrell, and M. Mayfield, 1995. "The Deadliest, Costliest, and Most
Intense United States Hurricanes of This Century," Proceedings of the 17th Annual National
Hurricane Conference. Atlantic City, New Jersey. April 11-14, 1995. pp. 12-50.
2. Jarvinen, B.R., and C.J. Neumann, 1978. "Atlantic Tropical Cyclone Tracks by 5, 10, 15,
and 30 day periods," NOAA Technical Memorandum, NWS/NHC/5, National Hurricane
Center, Miami, Florida.
3. Jordan, C.L., 1966. "Climatological Features of the Formation and Tracks of Hurricanes,"
Proceedings of Hurricane Symposium. Houston, Texas. American Society for Oceanography.
October 10-11, 1966. pp.82-101.
4. Neumann, C.J., 1976. "Computerized Tropical Cyclone Climatology," Mariners Weather
Log, Vol.20, No.5. National Weather Service, NOAA. Coral Gables, Florida. Sep. 1976.
5. Sheets, R.C., 1992. "The United States Hurricane Problem: An Assessment for the
1990's," Proceedings ofthel4th Annual National Hurricane Conference. Norfolk, Virginia.
April 8-10, 1992. pp. 1-46.
?D35- (A)
2 Long e (E)
25 -
20 -
15-
10-
00 90 80 70 60 50
Longitude (degree)
Figure 1: Hurricanes affecting the Florida area and five different types of hurricane path.
7
Histogram of Hurricane Occurrence in Florida
1900 1920 1940 1960 1980
Year
Figure 2: Histogram of all 111 Florida hurricanes (1886-1995).
Histogram of Hurricane Occurrence in Florida
1900 1920 1940
Year
1960 1980
Figure 3: Histogram of Category 2, 3, 4, and 5 hurricanes (1886-1995).
Histogram of Hurricane Occurrence in Florida
I I I
For category 3, 4, and 5 hurricanes
1920
1940
Year
nn
1960
Figure 4: Histogram of Category 3, 4, and 5 hurricanes (1886-1995).
10-
8-
0
0
o
0
E
1,=
Z
4
1900
nn
1980
A
I I II I I I I 11 1 II I ,. I. ..
Histogram of Hurricane Occurrence in Florida
I I
For category 4 and 5 hurricanes
10-
nn
.n
n n n
n lI I I I I -I I .. .-_. .
1900
1940
Year
1980
1920
1960
Figure 5: Histogram of Category 4 and 5 hurricanes (1886-1995).
0 8
O
0
-D
E
Z
Histogram of Hurricane Occurrence in Florida
For category 5 hurricanes
10-
A I I n 1n
1900
1920
1940
Year
1960
1980
Figure 6: Histogram of Category 5 hurricanes (1886-1995).
8
r-
06
0
E
Z
Z
0.4 0.6
Frequency(l/year)
Figure 7: Spectrum of monthly data of hurricane category (1886-1995).
13
0
0"
S20
15 -
0 I I I I
5-
I15-
0 l
0 0.1 0.2 0.3 0.4 0.5
Frequency(l/year)
Figure 8: Spectrum of annual data of accumulation of hurricane categories (1886-1995).
S150
Si)
a)
-100
50
0 0.1 0.2 0.3 0.4 0.5
Frequency(1/year)
Figure 9: Spectrum of annual data of accumulated squares of hurricane category
(1886-1995).
Spectrum of Occurrence of Florida Hurricanes
0 0.02 0.04 0.06 0.08 0.1
Frequency(1/year)
Figure 10: Spectral presentation of occurrences of Florida hurricanes (1886-1995).
2 3
O)
a)
S2.5
co 2
51 I I 1 -i- I_ _
100 90 80 70 60
Longitude (degree)
Figure 11: Tracks for Type (A) path hurricanes (1886-1995).
17,
90 80 70 60 50
Longitude (degree)
Figure 12: Tracks for Type (B) path hurricanes (1886-1995).
18
90 80 70 60 50
Longitude (degree)
Figure 13: Tracks for Type (C) path hurricanes (1886-1995).
a) 35
a)
0)
*0
30
S25
TYPE (D) PATH
50 9
45
40
0 35-
-o
30 -
30 25 s
20-
15-
10-
00 90 80 70 60 50
Longitude (degree)
Figure 14: Tracks for Type (D) path hurricanes (1886-1995).
TYPE (E) PATH
80 70 60
Longitude (degree)
Figure 15: Tracks for Type (E) path hurricanes (1886-1995).
TYPE (A) PATH
4.5 -
Ave Return Period= 5.065.30 (year)
1900
1920
Figure 16: Plot of hurricane category versus time for Type (A) path hurricanes.
X I X
2.5-
X X )K
XK X
1.5-
0.5 F
nL
1880
1940
Year
1960
1980
2000
TYPE (B) PATH
XI )K X
Ave Return Period= 8.00+ 10.11 (year)
' III I I
1880
1900
1920
1940
Year
1960
1980
2000
Figure 17: Plot of hurricane category versus time for Type (B) path hurricanes.
51 X)
4.5
3.5 F
o 3
0)
D 2.5
2,2
5 2
I
1.5 P
TYPE (C) PATH
X )KEX
Ave Return Period= 8.23 8.93 (year)
I I I
1940
Year
1960
1980
Figure 18: Plot of hurricane category versus time for Type (C) path hurricanes.
:; .A--A--------
4.5
2.5
1.5-
1880
1900
1920
2000
i- I I
A i I
TYPE (D) PATH
W K X X
MK WX
W W
Ave Return Period= 3.77 4.98 (year)
380 1900 1920 1940 1960 1980 2000
Year
Figure 19: Plot of hurricane category versus time for Type (D) path hurricanes.
4
3.5
S3
(D
0
a 2.5
rC
0
1 2
1.5
X XIIe
Ave Return Period= 5.12+ 5.28 (year)
II I I
1940
Year
1960
1980
2000
Figure 20: Plot of hurricane category versus time for Type (E) path hurricanes.
4.5-
3.5h
2.5F
TYPE (E) PATH
*II 1 *
1.5F
r1L
1880
1900
1920
F;
TYPE (B) + (C) PATH
xx *3K
Ave Return Period=
1940
Year
1960
4.28+ 5.48 (year)
1980
2000
Figure 21: Plot of hurricane category versus time for Type (B)+(C) path hurricanes.
3K 3K
4.5-
3.5F
2.5-
W W
1.51
0.5-
1880
1900
1920
ni I i .
At At A X
TYPE (C) + (D) PATH
W W W W
3.5-
)e R n P = 2K 1 r)
Ave Return Period= 2.54 1.95 (year)
1920
1940
Year
1960
1980
2000
Figure 22: Plot of hurricane category versus time for Type (C)+(D) path hurricanes.
2.5 F
1.5F
AL
1880
1900
I I I
W^^ WX XK w6
TYPE (C)+(D)+(E) PATH
4.5-
K X)m
)X K )1
Ave Return Period= 1.71+ 1.54 (year)
I I I
1900
1920
1940
Year
1960
Figure 23: Plot of hurricane category versus time for Type (C)+(D)+(E) path hurricanes.
3.5
03
0)
a 2.5
C
(0
2
"-
1.51
0.5 F
1880
X )K
1980
2000
R- X X X X-
IL
Histogram of Hurricane Occurrence
10 1 i i
TYPE (B)+(C) PATH
9
8
7
CD
0
C
S6-
0
E 4-
Z
3-
2-
1 -
1900 1920 1940 1960 1980
Year
Figure 24: Histogram of Type (B)+(C) path hurricanes (1886-1995).
Histogram of Hurricane Occurrence
101 -
5h-
TYPE (C)+(D) PATH
1900
1920
1940
Year
1960
Figure 25: Histogram of Type (C)+(D) path hurricanes (1886-1995).
1980
n 'il -- -1 -111I 1- 1 .. 1 -' .-
Histogram of Hurricane Occurrence
10 1 ,
TYPE (C)+(D)+(E) PATH
9
8
7
L 6
0 5
0
o
E4
z
3
3 -
2
1
0
1900 1920 1940 1960 1980
Year
Figure 26: Histogram of Type (C)+(D)+(E) path hurricanes (1886-1995).
0 0.2 0.4 0.6 0.8 1
Frequency(l/year)
Figure 27: Spectrum of monthly hurricane category of Type (C)+(D).
33
TYPE (C)+(D)+(E) PATH
0 0.2 0.4 0.6 0.8
Frequency(1/year)
Figure 28: Spectrum of monthly hurricane category of Type (C)+(D)+(E).
0.16
CM
S0.14
0.12
I 0.1
o
TYPE (A) PATH
Ave Return Period= 5.065.30 (year)
K*
)
I I
1900
1920
1940
Year
1960
1980
Figure 29: Plot of coastal wind versus time for Type (A) path hurricanes.
1i .-
160
140-
. 120
-c-
o
S100
80F
60
1880
2000
"1 t3
Ave Return Period= 8.00+ 10.11(year)
140-
100O
80
60F
1880
1900
1920
1940
Year
1960
1980
2000
Figure 30: Plot of coastal wind versus time for Type (B) path hurricanes.
1 I I
TYPE (B) PATH
TYPE (C) PATH
Ave Return Period= 8.23 8.93 (year)
W W
120F
80
W W
I I
1900
1920
1940
Year
1960
1980
Figure 31: Plot of coastal wind versus time for Type (C) path hurricanes
1801
160F
140-
1880
2000
.CO
tn
.5 120-
0100- 3K
80 )K X
80- 3X K) X
K X
60
I I I I I
1880 1900 1920 1940 1960 1980 2000
Year
Figure 32: Plot of coastal wind versus time for Type (D) path hurricanes.
TYPE (E) PATH
nK K
Ave Return Period= 5.12 5.28 (year)
W
M*S1 W
7r ?
Kn) X
1900
1920
1940
Year
1960
1980
2000
Figure 33: Plot of coastal wind versus time for Type (E) path hurricanes.
1801
160-
140F
.; 120
'F)
0
o
100
80
1880
TYPE (B) + (C) PATH
Ave Return Period= 4.28+ 5.48 (year)
mX
m)K
X K
1900
1920
1940
Year
1960
1980
2000
Figure 34: Plot of coastal wind versus time for Type (B)+(C) path hurricanes
1801
1601
1401
120
100O
60 F
1880
TYPE (C) + (D) PATH
Ave Return Period= 2.54 1.95 (year)
X
180
160
140
S 120
(a
o
0
0 -1 nn
L
)NE )Km
31
X X w w w
60F
I I
1880
1900
1920
1940
Year
1960
1980
Figure 35: Plot of coastal wind versus time for Type (C)+(D) path hurricanes.
X X
801
2000
I U ,I
)K X
Ave Return Period= 1.71+ 1.54(year)
140-
120F
Xm
100O
W XXW X
X AX X
80
X X
W x x
60
1880
1900
1920
1940
Year
1960
1980
Figure 36: Plot of coastal wind versus time for Type (C)+(D)+(E) path hurricanes.
2000
I _
TYPE (C)+(D)+(E) PATH
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