scientimate.hurricanewavecontourh16#

Hsgrid, Tpgrid, Hsmax, Tpmax = scientimate.hurricanewavecontourh16(xgrid, ygrid, Vgrid, xCenter, yCenter, VtAzmdir=0, G=0.88, fetchCalcMethod='constant', distCalcMethod='gc', dispout='no')

Description#

Calculate hurricane wave height and wave period field (contours) on given mesh using
method from Hwang (2016) and Hwang & Walsh (2016)
For method from Young (1988) use hurricanewavecontoury88
For method from U.S. Army Corps of Engineers use hurricanewavecontourhcem

Inputs#

xgrid
x (longitude) of points which outputs are calculated at
xgrid can be a single point or 1d or 2d array
ygrid
y (latitude) of points which outputs are calculated at
ygrid can be a single point or 1d or 2d array
Vgrid

Resultant hurricane 1-min averaged wind velocity at 10 m above surface (Vx^2+Vy^2)^0.5 on defined mesh in (m/s)

xCenter

x (longitude) of hurricane center (track)

yCenter

y (latitude) of hurricane center (track)

VtAzmdir=0
Hurricane center velocity azimuth (bearing) direction in (Degree)
azimuth (bearing) direction which is measured clockwise from the north:
0 (degree): toward North, 90 (degree): toward East, 180 (degree): toward South, 270 (degree): toward West
G=0.88
Wind gust factor to convert 1-min averaged wind to 10-min averaged wind
e.g. Young (2017); Liu et al. (2017)
G=U(600s)/U(60s), therefore U(600s)=G*U(60s)
G=1/1.1; based on Powell and Houston (1996)
G=1/1.08; based on Harper (2013)
G=0.88; based on World Meteorological Organization (2015)
G=1/1.08 to 1/1.16; based on Liu et al. (2017)
fetchCalcMethod=’constant’
Effective wind fetch calculation method
‘constant’: Use constant coefficients needed for effective wind fetch calculation
‘interp’: Use interpolateed coefficients needed for effective wind fetch calculation
Earth radius coonsidered as mean earth radius=6371000 m
distCalcMethod=’gc’
Distance calculation method
‘cart’: Distances are calculated on cartesian coordinate
‘gc’: Distances are calculated on Great Circle based on Vincenty formula, Vincenty (1975)
Earth radius coonsidered as mean earth radius=6371000 m
dispout=’no’
Define to display outputs or not
‘imagesc’: 2 dimensional plot using imagesc or imshow
‘pcolor’: 2 dimensional plot using pcolor
‘contour’: 2 dimensional contour plot, number of contour=ncolor
‘no’: not display
Use dispout=’no’ if calculation mesh is not 2d array

Outputs#

Hsgrid

Hurricane significant wave height on grid mesh in (m)

Tpgrid

Hurricane peak wave period on grid mesh in (s)

Hsmax

Hurricane maximum significant wave height in (m)

Tpmax
Hurricane maximum peak wave period in (s)
Note: Maximum values of wave height and wave period should be limited to fully developed values

Examples#

import scientimate as sm
import numpy as np
import matplotlib.pyplot as plt


#EXAMPLE 1

#Creating calculation mesh
xgrid,ygrid=np.meshgrid(np.linspace(-98,-68,100),np.linspace(16,44,100))

#Longitude of Hurricane Katrine center at max velocity
longCenter=-88.6

#Latitude of Hurricane Katrine center at max velocity
latCenter=26.3

#Hurricane Katrina centeral pressure (Pa) at max velocity
Pc=90200

#Hurricane Katrina translational velocity (m/s) at max velocity
Vt=5.18467

#Hurricane Katrina velocity azimuth (bearing) in (Degree) at max velocity
VtAzmdir=306.76219

#Hurricane Katrina 1-min sustained maximum velocity (m/s) at max velocity
Vmax=76.5
Vmax=Vmax-Vt #Removing hurricane translation velocity from Vmax
Vgmax=Vmax/0.8 #Converting surface velocity to gradient velocity

#34 kt (17.49 m/s) wind radii maximum extent in northeastern quadrant in (m) for Hurricane Katrina at max velocity
Rknown=370400
VRknown=17.49
VRknown=VRknown-Vt #Removing hurricane translation velocity from VRknown
VgRknown=VRknown/0.8 #Converting surface velocity to gradient velocity

Pn=101325 #Ambient surface pressure (external pressure) in (Pa)
Rhoa=1.204 #Air density in (kg/m3)

#Calculating distance (radius) from hurricane center to each point
Rgrid=(np.arccos(np.sin(np.deg2rad(latCenter))*np.sin(np.deg2rad(ygrid))+np.cos(np.deg2rad(latCenter))*np.cos(np.deg2rad(ygrid))*np.cos(np.deg2rad(xgrid)-np.deg2rad(longCenter))))*6371000

#Generting wind velocity for Hurricane Katrine at max velocity using SLOSH model
Vggrid=Vgmax*(2*32197*Rgrid)/(32197**2+Rgrid**2) #Gradient wind velocity
Vggrid[Rgrid>=423e3]=0
Vgrid=Vggrid*0.8 #Wind velocity at 10m height

Hsgrid,Tpgrid,Hsmax,Tpmax=sm.hurricanewavecontourh16(xgrid,ygrid,Vgrid,longCenter,latCenter,VtAzmdir,0.88,'constant','gc','contour')


#EXAMPLE 2

xgrid=np.linspace(0,10,100) #(Degree)
ygrid=np.ones(100)*20 #(Degree)
longCenter=0 #(Degree)
latCenter=20 #(Degree)
Pc=90200 #(Pa)
Vt=5.18467 #(m/s)
VtAzmdir=306.76219 #(Degree)
Vmax=76.5 #(m/s)
Vmax=Vmax-Vt
Vgmax=Vmax/0.8 #(m/s)
Rknown=370400 #(m)
VRknown=17.49 #(m/s)
VRknown=VRknown-Vt
VgRknown=VRknown/0.8 #(m/s)
Pn=101325 #Ambient surface pressure (external pressure) in (Pa)
Rhoa=1.204 #Air density in (kg/m3)
Rgrid=(np.arccos(np.sin(np.deg2rad(latCenter))*np.sin(np.deg2rad(ygrid))+np.cos(np.deg2rad(latCenter))*np.cos(np.deg2rad(ygrid))*np.cos(np.deg2rad(xgrid)-np.deg2rad(longCenter))))*6371000
Vggrid=Vgmax*(2*32197*Rgrid)/(32197**2+Rgrid**2) #Gradient wind velocity
Vggrid[Rgrid>=423e3]=0
Vgrid=Vggrid*0.8 #Wind velocity at 10m height

Hsgrid,Tpgrid,Hsmax,Tpmax=sm.hurricanewavecontourh16(xgrid,ygrid,Vgrid,longCenter,latCenter,VtAzmdir,0.88,'constant','gc','no')
plt.plot(Rgrid,Hsgrid)

References#

Data

  • www.nhc.noaa.gov/data/

  • www.nhc.noaa.gov/data/hurdat/hurdat2-format-nencpac.pdf

  • coast.noaa.gov/hurricanes

  • www.aoml.noaa.gov/hrd/data_sub/re_anal.html

Harper, B.A. (2013) Best practice in tropical cyclone wind hazard modelling: In search of data and emptying the skeleton cupboard. In Proceedings of the 16th Australasian Wind Engineering Society Workshop, Brisbane, Qld, Australia, 18–19 July 2013

Hwang, P. A. (2016). Fetch-and duration-limited nature of surface wave growth inside tropical cyclones: With applications to air–sea exchange and remote sensing. Journal of Physical Oceanography, 46(1), 41-56.

Hwang, P. A., & Walsh, E. J. (2016). Azimuthal and radial variation of wind-generated surface waves inside tropical cyclones. Journal of Physical Oceanography, 46(9), 2605-2621.

Liu, Q., Babanin, A., Fan, Y., Zieger, S., Guan, C., & Moon, I. J. (2017). Numerical simulations of ocean surface waves under hurricane conditions: Assessment of existing model performance. Ocean Modelling, 118, 73-93.

Powell, M. D., & Houston, S. H. (1996). Hurricane Andrew’s landfall in South Florida. Part II: Surface wind fields and potential real-time applications. Weather and Forecasting, 11(3), 329-349.

World Meteorological Organization. Tropical Cyclone Programme, & Holland, G. J. (2015). Global guide to tropical cyclone forecasting. Secretariat of the World Meteorological Organization.

Young, I.R. (2017) A Review of Parametric Descriptions of Tropical Cyclone Wind-Wave Generation. Atmosphere 2017, 8, 194.