Citation
Analysis of hurricane cycles in Florida

Material Information

Title:
Analysis of hurricane cycles in Florida
Series Title:
UFLCOEL-96003
Creator:
Lin, Lihwa
Dean, Robert G ( Robert George ), 1930-
University of Florida -- Coastal and Oceanographic Engineering Dept
Place of Publication:
Gainesville Fla
Publisher:
Coastal & Oceanographic Engineering Dept., University of Florida
Publication Date:
Language:
English
Physical Description:
iii, 42 leaves : ill. ; 28 cm.

Subjects

Subjects / Keywords:
Hurricanes -- Statistics -- Florida ( lcsh )
Hurricanes -- History -- Florida ( lcsh )
Dissertations, Academic -- Coastal and Oceanographic Engineering -- UF ( lcsh )
Coastal and Oceanographic Engineering thesis, M.S ( lcsh )
Genre:
bibliography ( marcgt )
non-fiction ( marcgt )

Notes

Bibliography:
Includes bibliographical references (leaf 6).
General Note:
"May 1996."
Statement of Responsibility:
by Lihwa Lin and Robert G. Dean.

Record Information

Source Institution:
University of Florida
Holding Location:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
36800148 ( OCLC )

Full Text
UFL/COEL-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. Recipiets Accession No.
4. Title sad Subtitle 5. Report Date
ANALYSIS CF IVJRICANE CYCLES IN FLORIDA May 151 1996
6.
7. Author(s) 8. performing Orgenization Report No.
Lihwa Lin, Pobert G. Dean UFL/COEL-96/003
9. Per ol ing Organizatio ame and Address 10. ?roject/Task/Work Unit No.
Coastal and Oceanographic Engineering Department University of Florida 11. contract or Crant NO.
336 Weil Hall
Gainesvile. FT. 32 611 13. Type of Report
12. Sponsoring Organization Wan 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 1il 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 tey Words 18. Availability Statement
Cycles
Hurricane
Return Period
19. U. S. Security Classif. of the Report 20. U. S. Security Clas2lf. of Ths Page 1. No. of Pages 22. Price
Unclassified Unclassified i 46




Contents
I 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 Conclusions .............................................................................................................. 5
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 H1istogram of Category 2, 3, 4, and 5 hurricanes (1886-1995) ........................ 9
4 Histogram of Category 3, 4, and 5 hurricanes (1886-1995) ........................... 10
5 Hi-stogram of Category 4 and 5 hurricanes (1886-1995) ............................... 11
6 Hi-stogram 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 (1 886-1995) ............. 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

11




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 I111 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 Safflr/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
HI-stograms 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 a., 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 Safllr/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/Sinipson 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 96-1 113 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 p eaked at the intervals of 11, 18, and 5 5 years, which correspond to frequencies of 0.09, 0.056, and 0.0 18 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),

K 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 of thel4th Annual National Hurricane Conference. Norfolk, Virginia. April 8-10, 1992. pp. 1-46.




(35 (A)
CD
30
2 5 20
15 10
Too 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

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 I
1,.
0
0
E
z
4F

1900

R

1980

A

I I I 1 1 11 .. .. . .. .




Histogram of Hurricane Occurrence in Florida

I I

For category 4 and 5 hurricanes

10-

i

.n

Hn'nH

( II I I I I

1900

1940 Year

1980

1920

1960

Figure 5: Histogram of Category 4 and 5 hurricanes (1886-1995).

( 8
06
0
E
z




Histogram of Hurricane Occurrence in Florida 2I
For category 5 hurricanes

10-

A I I H1, F1 ,

1900

1920

1940 Year

1960

1980

Figure 6: Histogram of Category 5 hurricanes (1886-1995).

8
(D ,...
I-.
0 6 CU) ~0
E z3
Z




0.4 0.6
Frequency(l/year)

Figure 7: Spectrum of monthly data of hurricane category (1886-1995).
13




0
20 C15
5
~11
0
" 1
C
U)
W 10

.II a I I I
0
0 0.1 0.2 0.3 0.4 0.5
Frequency(1/year)
Figure 8: Spectrum of annual data of accumulation of hurricane categories (1886-1995).




C
0 CO
100
I.
:3
S150
0
CI)
C
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). a)
a
-~100a)
CL
50
00.1 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(l/year)
Figure 10: Spectral presentation of occurrences of Florida hurricanes (1886-1995).

3
a)
CL S2.5
0




100 90 80 .70 60
Longitude (degree)
Figure 11: Tracks for Type (A) path hurricanes (18 86-1995).

117,




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).

3,1
a)3 35
a)
0 "0
-30
0
_.12




55,,
TYPE (D) PATH
50-.
45400 3530 32- 3 0
2015
10
T0 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 F

Ave Return Period= 5.06+5.30 (year)

1900

1920

Figure 16: Plot of hurricane category versus time for Type (A) path hurricanes.

X IX

2.5 -

X X )K

X XI

1.5-

0.5 F

('L

1'880

1940 Year

1960

1980

2000




TYPE (B) PATH

XI )K XX

Ave Return Period= 8.00+ 10.11 (year)
' I II 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 F

3.5 F

o 3 0)
0 D 2.5
C
.
tI

1.5 P




TYPE (C) PATH

X)K*)X

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.

:; .AA

4.5 F

2.5 F

1.51-

1880

1900

1920

2000

fI I I

A i I




o 3 NOK )K W E X K X E
0)
c)
0
D 2.5
C
CO
0
S2 -)wWN XE
1.5
0.5
Ave Return Period= 3.77 4.98 (year)
C I I I i I
1880 1900 1920 1940 1960 1980 2000
Year
Figure 19: Plot of hurricane category versus time for Type (D) path hurricanes.




X XIeI(

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.

4.51-

3.5F

2.5 F

TYPE (E) PATH
XI X K
X X
**) X X

1.5F

01I

1'880

1900

1920




TYPE (B) + (C) PATH xxK 3

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

W W

3.5F

2.5F

1.51-

0.5F

1'880

1900

1920




At% At' A X

TYPE (C) + (D) PATH

W W WI W

3.5-

)*K XI )KI X
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

0l

1'880

1900

W WX XK




TYPE (C)+(D)+(E) PATH

4.5-

3)K )

)XE )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) 0)
a 2.5
C
CO
0
= 2

1.51-

0.5 F

1880

X )K

1980

2000

R. X X X X

0




Histogram of Hurricane Occurrence
10 1 1 ,
TYPE (B)+(C) PATH
9
8
7
0
C
- 6
0
O
O5
o ..
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 ,

51r-

TYPE (C)+(D) PATH

1900

1920

1940 Year

1960

Figure 25: Histogram of Type (C)+(D) path hurricanes (1886-1995).

1980

n il 11 11 11 1- 1- ....




Histogram of Hurricane Occurrence
10 1 1
TYPE (C)+(D)+(E) PATH
9
8
7

O
L.6
O S5
0
-o
E4
z
3
2
1
0 e
1900 1920 1940 1960 1980
Year
Figure 26: H-istogram of Type (C)+(D)+(E) path hurricanes (1886-1995).




j0 0.2 0.4 0.6 0.8 1
Frequency(1/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
o0 CM
~ 0.14
0.12
C
0
cc 0.12
0.1
o




TYPE (A) PATH

Ave Return Period= 5.06+ 5.30 (year)

)K
)K )

I I

1900

1920

1940 Year

1960

1980

Figure 29: Plot of coastal wind versus time for Type (A) path hurricanes.

18 0

160

140-

. 120
o
-100
C,)
0
o0100

80F

60F

1880

2000

"1 t3




Ave Return Period= 8.00+ 10.11(year)

140F

100E

80F

60F

1880

1900

1920

1940 Year

1960

1980

2000

Figure 30: Plot of coastal wind versus time for Type (B) path hurricanes.

TYPE (B) PATH




TYPE (C) PATH

Ave Return Period= 8.23 8.93 (year)

WK W

120F

80F

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




120
X
.CO
(n
)1( X X1 X1 X
0
o100 X )K
U)I
)W )K XK
80 X )K K X3
X )K A
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
)K )K

Ave Return Period= 5.12 5.28 (year)
*K

NENE XE

1900

1920

1940
Year

1960

1980

2000

Figure 33: Plot of coastal wind versus time for Type (E) path hurricanes.

1801

160F

140F

.; 120
o
100
0
o0100

80F

1880




TYPE (B) + (C) PATH

Ave Return Period= 4.28+ 5.48 (year)

X X

)K X

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-

140

120

100E

60 F

1880




TYPE (C) + (D) PATH

Ave Return Period= 2.54 1.95 (year)
X

180
160 140 .~ 120
0
S1 n

L.

)1E 11 X
X 31E

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 XI

80

2000

! tJ k,,I

)K X




Ave Return Period= 1.71+ 1.54(year)

140-

120F

Xm

100E

W X W X
X K A

80F

X XE

W x x w

60F

1880

1900

1920

1940 Year

1960

1980

Figure 36: Plot of coastal wind versus time for Type (C)+(D)+(E) path hurricanes.

2000

TYPE (C)+(D)+(E) PATH