TCHazaRds (version 1.1.4)

KepertVerticalWindField: Kepert Vertical Wind Field (u, v, Ks, w)

Description

As your KepertWindField but also computes vertical velocity w(r) = (1/r) * dQ/dr where Q(r) = r*C*Vg*(Vg + 2*vs) / ( f + Vg/r + dVg/dr ). Derivatives use 3-point stencils with radii r - dr, r, r + dr.

Usage

KepertVerticalWindField(
  rMax,
  vMax,
  vFm,
  thetaFm,
  f,
  Rlam,
  VZ,
  surface,
  dr_m = 10
)

Value

NumericMatrix with columns: 1) u (m/s), 2) v (m/s), 3) Ks (-), 4) w (m/s)

Arguments

rMax

radius of maximum winds in km

vMax

maximum wind velocity in m/s

vFm

forward speed of TC (m/s)

thetaFm

forward direction of TC (deg)

f

single coriolis parameter (1/s)

Rlam

two columns: [radius_km, azimuth_deg] from grid point to TC centre

VZ

two columns: [Vi (m/s), Zi (1/s)]

surface

equals 1 for surface winds (reduced from gradient level), otherwise gradient winds.

dr_m

finite-difference step in metres (default 10 m)