sulfur {gek} | 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 |
S_0 |
solar constant in |
A |
surface area of the earth in |
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. 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. 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. doi:10.1029/97JD01654.