Struct EkmanProfile 

pub struct EkmanProfile {
    pub geostrophic_mps: f64,
    pub latitude_deg: f64,
    pub eddy_viscosity_m2s: f64,
    pub direction_from_deg: f64,
}

Ekman spiral: the classic solution for a neutrally stratified boundary layer with constant eddy viscosity K. At the ground the wind is zero; aloft it approaches the geostrophic speed G. See Holton, An Introduction to Dynamic Meteorology.

u = G(1 − e^(−γz)·cos(γz)), v = sign(f)·G·e^(−γz)·sin(γz) with γ = sqrt(|f| / 2K) and Coriolis f = 2Ω·sin(latitude). u runs along the geostrophic flow and v to its LEFT, so in the northern hemisphere the surface wind is backed about 45° from the geostrophic wind (turned toward low pressure) and veers with height; the southern hemisphere mirrors this. The result is rotated so the geostrophic direction matches direction_from_deg aloft.

z is height above the GROUND, the surface where the spiral is calm: the altitude argument of wind_at and position_m[1] in WindField::wind must both be height above ground. In a frame whose y is altitude above sea level, read it at y - ground elevation, in one place only (this crate has no offset wrapper; see Sounding::to_profile_field).

Fields

geostrophic_mps: f64

Geostrophic wind speed aloft, m/s.

latitude_deg: f64

Latitude, degrees (sign sets the turning sense).

eddy_viscosity_m2s: f64

Constant eddy viscosity K, m²/s.

direction_from_deg: f64

Meteorological direction the geostrophic wind comes FROM aloft, degrees.

Implementations

impl EkmanProfile

pub fn new( geostrophic_mps: f64, latitude_deg: f64, eddy_viscosity_m2s: f64, direction_from_deg: f64, ) -> Result<Self>

Validate the parameters.

pub fn wind_at(&self, altitude_m: f64) -> Wind

Wind at an altitude, rotated so the geostrophic direction aloft matches direction_from_deg.

Trait Implementations

impl Clone for EkmanProfile

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for EkmanProfile

impl Debug for EkmanProfile

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl WindField for EkmanProfile

fn wind(&self, _time_s: f64, position_m: [f64; 3]) -> Wind

World-frame air velocity at a time (seconds) and position ([x, y, z] metres, Y up).