sulfur: Sulfur Model Function
In gek: Gradient-Enhanced Kriging

View source: R/testfunctions.R

sulfur

R Documentation

Sulfur Model Function

Description

The sulfur function is defined by

f_{\rm sulfur}(x) = -\frac{1}{2} S_0^2 (1 - A_c) T^2 (1 - R_s)^2 \bar{\beta} \Psi_e f_{\Psi_e} \frac{3 Q Y L}{A}

with x = (Q, Y, L, \Psi_e, \bar{\beta}, f_{\Psi_e}, T, 1-A_c, 1-R_s).

Usage

sulfur(x, S_0 = 1366, A = 5.1e+14)
sulfurGrad(x, S_0 = 1366, A = 5.1e+14)

Arguments

`x`	a numeric `vector` of length `9` or a numeric `matrix` with `n` rows and `9` columns.
`S_0`	solar constant in `\rm W/m^2`. Default is `1366`.
`A`	surface area of the earth in `\rm m^2`. Default is `5.1e+14`.

Details

The sulfur model function calculates the direct radiative forcing by sulfate aerosols \rm [W/m^2].

Input	Central value	Uncertainty factor	Description
`Q`	`71`	`1.15`	source strength of anthropogenic sulfur in `\rm Tg/yr`
`Y`	`0.5`	`1.5`	fraction of `\rm SO_2` oxidized to `\rm SO_4^=`
`L`	`5.5`	`1.5`	average lifetime of atmospheric `\rm SO_4^=` in `\rm days`
`\Psi_e`	`5`	`1.4`	aerosol mass scattering efficiency in `\rm m^2/g`
`\bar{\beta}`	`0.3`	`1.3`	fraction of light scattering into upward hemisphere
`f_{\Psi_e}`	`1.7`	`1.2`	fractional increase in aerosol scattering efficiency due to hygroscopic growth
`T`	`0.76`	`1.2`	atmospheric transmittance above aerosol layer
`1-A_c`	`0.39`	`1.1`	fraction of earth not covered by cloud
`1-R_s`	`0.85`	`1.1`	surface coalbedo

The inputs are all log-normally distributed.

Value

sulfur returns the function value of sulfur function at x.

sulfurGrad returns the gradient of sulfur function at x.

Author(s)

Carmen van Meegen

References

Charlson, R. J., Schwartz, S. E., Hales, J. M., Cess, R. D., Coakley, Jr., J. A., Hansen, J. E., and Hoffman, D. J. (1992). Climate Forcing by Anthropogenic Aerosols. Science, 255:423–430. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1126/science.255.5043.423")}.

Penner, J. E., Charlson, R. J., Hales, J. M., Laulainen, N. S., Leifer, R., Novakov, T., Ogren, J., Radke, L. F., Schwartz, S. E., and Travis, L. (1994). Quantifying and Minimizing Uncertainty of Climate Forcing by Anthropogenic Aerosols. Bulletin of the American Meteorological Society, 75(3):375–400. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1175/1520-0477(1994)075<0375:QAMUOC>2.0.CO;2")}.

Tatang, M. A., Pan, W., Prinn, R. G., and McRae, G. J. (1997). An Efficient Method for Parametric Uncertainty Analysis of Numerical Geophysical Model. Journal of Geophysical Research Atmospheres, 102(18):21925–21932. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1029/97JD01654")}.

gek documentation built on April 4, 2025, 12:35 a.m.