DTIC ADA249726: Precipitation Distribution and Kinematic Structure of Hurricane Hugo Over the Carolinas

57 Pages·1.8 MB·English

by  Defense Technical Information Center

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2. RPORDATT 3. REPORT TYPE AND DATES COVERED
1991RTDAE THESIS/I KRXUM
4. TTLEAND UBTTLES. FUNDING NUMBERS
6. AUTHOR(S)
James E. Hammett, Jr., Capt
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AFIT Student Attending: North Carolina State University AFIT/CI/CIA- 91-113
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ERNEST A. HAYGOOD, Captain, USAF
Executive Officer
13. A13STRACT (MaXimr 200 words)
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47
6E.P R;CE- CODE
S17. SECURITY CLASSIFICATION 18. S-CURkTY CLASSI ICATION .sE. r L'CASSIC 20 I..I1! j TAT : 0 C ;.2S T F
OF REP'ORT OF THIS PAGE C'l AESTR.CT
ABSTRACT
HAMMET'T, JAMES E. JR. Precipitation Distribution and Kinematic Structure of
Hurricane Hugo over the Carolinas. (Under the direction of Steven Businger and
Gerald F. Watson.)
An investigation of the precipitation distribution and kinematic structure of
Hurricane Hugo over land was conducted for a 19-hour period beginning with landfall
of associated precipitation. Surface kinematics and thermodynamics, NWS radar
reflectivity observations, and hourly precipitation data (HPD) were compared to
investigate the nature of the precipitation systems associated with Hugo. Surface data
over Georgia, South Carolina, North Carolina, and Virginia from the NWS, AWS, and
FAA stations was supplemented by power plant data.
A stationary band complex (SBC), observed to the left of Hugo's track, was the
predominate feature of radar imagery. This feature resulted in a storm-total rainfall
maximum to the left of Hugo's track. Heavy amounts of hourly rainfall (> 20 mm)
occurred within the SBC from 0500 UTC until 1000 UTC, and an equivalent potential
temperature minima is associated with the SBC after landfall of Hugo.
A regression equation was constructed to investigate the hourly precipitation for
select land stations. The results indicate that over 37% of the variability in the HPD was
accounted for when precipitation was occurring during Hugo. The distance to the
eyewall contributed significantly to the variability of precipitation over land, in this case.
It was found that terrain slope, surface wind speed, surface wind direction, and surface
wind convergence were generally uncorrelated to hourly precipitation. However, when
the data set was separated into geographic regions, terrain slope increased in importance
from the coast to the mountains while wind speed decreased in importance.
92-11983
01 021
*2r5
PRECIPITATION DISTRIBUTION
AND KINEMATIC STRUCTURE
OF HURRICANE HUGO OVER THE CAROLINAS
by
JAMES EDWARD HAMMETT, JUNIOR
A thesis submitted to the Graduate Faculty of
North Carolina State University
in partial fulfillment of the
requirements for the Degree of
Master of Science
DEPARTMENT OF MARINE, EARTH, AND ATMOSPHERIC SCIENCE
Raleigh
1991
APPROVED BY:
STEVEN BUSINGER / (AD F. WATSON
Co-chairman Co-chairman
ACe4-4L,4& For
D7W.NYCHK NTIS U&1
Avhllabiltty Cods
""1A ap ' c /or ...
.......................................
ii
ACKNOWLEDGEMENTS
Thanks to all who made this thesis possible. I would like to extend a special
thanks to:
my fellow classmates whose help and encouragement were invaluable. In
particular I want to thank Steve ChisweU, Capt David Musick, Capt Lauraleen
O'Connor, Capt Dewey Harms, and Robert Rozumalski.
R. Nick Keener, Jr., George J. Oliver, and M.H. Knapp for their power plant
data.
Irv Watson for sending me photos of WSI composite radar images during
landfall of Hugo.
Joe Pellisier for his expertise in the field of hurricanes and his support.
Scott Ross for his programming support.
Ksenjisa for her draftsmanship.
TABLE OF CONTENTS
Page
LIST OF TABLES............................................................. iv
LIST OF FIGURES ............................................................ v
LIST OF SYMBOLS AND ABBREVIATIONS.................................. vi
1. INTRODUCTION........................................................... 1
2. DATA ANALYSIS ......................................................... 9
3. REGRESSION EQUATION ............................................... 29
4. SUMMARY AND CONCLUSIONS........................................ 36
5. APPENDIX Regression Equation values .................................. 38
-
6. LIST OF REFERENCES .................................................. 45
i
LIST OF TABLES
Page
I Reflectivity Intensity ........................................................ 9
2 Full Model ANDVA ........................................................ 32
3a Region 1 ANOVA ......................................................... 33
3b Region 2 ANOVA ......................................................... 34
3c Region 3 ANOVA ......................................................... 34
v
LIST OF FIGURES
PAGE
1. H ugo's track ............................................................................. 5
2. 500 mb analysis at 1200 UTC on 21 September 1989. Height contours
(solid lines) in decameters. Dashed lines are absolute vorticity (10-5 s-1) ........ 7
3. 500 mb analysis at 1200 UTC on 22 September 1989. Height contours
(solid lines) in decameters. Dashed lines are absolute vorticity (10-5 s-1) ...... 8
4. Hourly Precipitation Data (HPD) stations ......................................... 10
5. Hourly surface observations (SA) stations ......................................... 10
6. Surface analysis at 2100 UTC on 21 September 1989 ................................ II
7. Surface analysis at 0000 UTC on 22 September 1989 ............................ 14
8. Surface analysis at 0300 UTC on 22 September 1989 ............................ 16
9. Surface analysis at 0600 UTC on 22 September 1989 ............................ 19
10. Surface analysis at 0900 UTC on 22 September 1989 .......................... 21
11. Surface analysis at 1200 UTC on 22 September 1989 .......................... 24
vi
12. Storm-total precipitation for a 19-h period (mm) .................................. 27
13. Three geographic regions the data set was separated into ....................... 31
vii
LIST OF SYMBOLS AND ABBREVIATIONS
ANOVA Analysis of Variance
AWS Air Weather Service
b Regression coefficient estimate
i
Bi Model coefficient estimate
°C Degrees Centigrade
CON Convergence
cos Cosine
D Dimensional
Dep Mean The overall average of the variable
DEW Distance to the eyewall
Exp Exponent
F Value Model sum of squares divided by the model mean square
FAA Federal Aviation Administration
h Hour
HPD Hourly precipitation data
K Kelvin temperature
km Kilometers
log Natural logarithm
mb Millibars
mm Millimeters
rn sl Meters per second
NCDC National Climatic Data Center
NWS National Weather Service
viii
p-value Test for significance
Prob Probability
Q Mean of any meteorological variable
Qi Observed value of any meteorological variable at a grid point
r Radius
R2 Model sum of squares divided by the total sum of squares
Root MSE Square root of the mean square for error
SA Surface observations
SBC Stationary band complex
Sept September
S N Slope number
T for HO T-value for testing the null hypothesis that the parameter equals 0
t-value Test for Significance
tan Tangent
UTC Universal time code
VIP level Reflectivity intensity level
WD Wind direction
w i Observational weight given to a meteorological variable
WS Wind speed
y(obs) Observation point for the regression equation
Y(obs) Observation point for the model
oX smoothing parameter
> greater than
< less than
% percent