will1: Model wind speed at a grid point for a storm track...
In stormwindmodel: Model Tropical Cyclone Wind Speeds

Description Usage Arguments Details Value References

View source: R/willoughby2006eqs.R

Models the gradient wind speed at a certain radius from a storm's center. To do this, it uses different equations and subfunctions depending on how large the radius is (see details). This function requires, as inputs, Willoughby wind model parameters calculated using the add_wind_radii function.

1	will1(cdist, Rmax, R1, R2, vmax_gl, n, A, X1, X2 = 25)

`cdist`	Distance (in km) from center of tropical cyclone to grid point.
`Rmax`	Numeric vector of the radius at which the maximum wind occurs, in kilometers
`R1`	A numeric vector of one of the parameters of the Willoughby model.
`R2`	A numeric vector of one of the parameters of the Willoughby model.
`vmax_gl`	Numeric vector of the tangential wind component of the maximum gradient wind speed, in meters per second
`n`	A numeric vector of one of the parameters of the Willoughby model.
`A`	A numeric vector of one of the parameters of the Willoughby model.
`X1`	A numeric vector of one of the parameters of the Willoughby model.
`X2`	A numeric vector of one of the parameters of the Willoughby model.

If r ≤ R1, this function is calculating the equation:

V(r) = Vi = vmax_gl (r / Rmax)^n

where:

V(r): Maximum sustained gradient wind speed at a radius of r from the storm's center
r: Radius from the storm center, in kilometers
vmax_gl: Maximum sustained gradient wind speed of the storm, in meters per second
R1: A parameter for the Willoughby wind model (radius to start of transition region)
Rmax: Radius (in kilometers) to highest winds
n: A parameter for the Willoughby wind model

If R2 ≤ r, this function is calculating the equation:

V(r) = Vo = vmax_gl[(1 - A) e^((Rmax - r) / X1) + A e^((Rmax - r) / X_2)]

where:

V(r): Maximum sustained gradient wind speed at a radius of r kilometers from the storm's center
r: Radius from the storm center, in kilometers
vmax_gl: Maximum sustained gradient wind speed of the storm, in meters per second
Rmax: Radius (in kilometers) to highest winds
A, X1, X2: Parameters for the Willoughby wind model

If R1 < r ≤ R2, this function uses the equations:

ξ = (r - R1) / (R2 - R1)

and, if 0 ≤ ξ < ≤ 1 (otherwise, w = 0):

w = 126 ξ^5 - 420 ξ^6 + 540 ξ^7- 315 ξ^8 + 70 ξ^9

and then:

V(r) = Vi (1 - w) + Vo w

where, for this series of equations:

V(r): Maximum sustained gradient wind speed at a radius of r kilometers from the storm's center
r: Radius from the storm center, in kilometers
w: Weighting variable
R1, R2: Parameters for the Willoughby wind model

Returns a numeric vector with gradient wind speed at a radius of r from the storm's center, in meters per second.

Willoughby HE, Darling RWR, and Rahn ME. 2006. Parametric representation of the primary hurricane vortex. Part II: A new family of sectionally continuous profiles. Monthly Weather Review 134(4):1102-1120.

stormwindmodel documentation built on July 27, 2020, 9:06 a.m.