gradient_to_surface: Calculate symmetrical surface wind from gradient wind

In geanders/stormwindmodel: Model Tropical Cyclone Wind Speeds

Calculate symmetrical surface wind from gradient wind

Description

Calculates the surface wind speed based on an estimated gradient wind speed at a point and the radius from the storm center to the grid point.

Usage

gradient_to_surface(wind_gl_aa, cdist, glandsea)

Arguments

wind_gl_aa	The gradient-level wind at the location at which the wind is being modeled (in m/s)
cdist	The distance from the center of the storm to the location at which the wind is being modeled (in kilometers)
glandsea	A logical value that specifies whether the location at which the wind is being modeled is over land (TRUE) or over water (FALSE)

Details

The reduction factor is based on Figure 3 of Knaff et al., 2003. Over water, it is estimated to be 0.9 up to a radius of 100 km, 0.75 for a radius of 700 km or more, and decrease linearly between a radius of 100 km and 700 km. Points over land use a reduction factor that is 20% lower.

Value

A numeric value giving the surface-level wind at that location (before incorporating the role of forward motion of the storm) (in m/s)

References

Knaff JA, DeMaria M, Molenar DA, Sampson CR, and Seybold MG. 2011. An automated, objective, multiple-satellite-platform tropical cyclone surface wind speed analysis. Journal of Applied Meteorology and Climatology 50(10):2149-2166

geanders/stormwindmodel documentation built on Feb. 10, 2025, 11:58 a.m.