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#
Inputs#
- xgrid
- x (longitude) of points which outputs are calculated atxgrid can be a single point or 1d or 2d array
- ygrid
- y (latitude) of points which outputs are calculated atygrid 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 winde.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 calculationEarth 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 displayUse 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.