lifton2006sp.m

Syntax:

scalingfactor = lifton2006sp(h,Rc,S);

Calculates the geographic scaling factor for cosmogenic-nuclide production for particular cutoff rigidity and altitude according to the scheme in:

Lifton N.A., Bieber J.W., Clem J.M., Duldig M.L., Evenson P., Humble J.E., Pyle R., 2005. Addressing solar modulation and long-term uncertainties in scaling secondary cosmic rays for in situ cosmogenic nuclide applications. Earth and Planetary Science Letters, v. 239, pp. 140-161.

The input arguments are h, atmospheric pressure (hPa), Rc, cutoff rigidity (GV), and S, the solar modulation factor (nondimensional; see the source paper for details). Accepts vector arguments.

This function:

Converts atmospheric pressure $h$ (hPa) to atmospheric depth $x$ (g $\cdot$ cm$^{-2}$) by multiplying by 1.0197.

Assigns cutoff rigidities below 1.907 GV a value of 1.907.

Calculates the scaling factor $I$ (Lifton's nomenclature) using Equation (4) in the source paper:

$$\ln{(I)} = c_{1}\ln{\left( XS \right)} - S\exp{\left[ \frac{c_{2}... ...ft( R_{C} + 4S \right) X \right]^{c_{6}} +c_{7} \left(R_{C} + 4S\right)^{c_{8}}$$ (40)

where $R_{C}$ is the cutoff rigidity, $S$ is the solar modulation factor, and the constants $c_{i}$ are:

$c_{1}$	1.8399
$c_{2}$	$-1.1854 \times 10^{2}$
$c_{3}$	$-4.9420 \times 10^{-2}$
$c_{4}$	$8.0139 \times 10^{-1}$
$c_{5}$	$1.2708 \times 10^{-4}$
$c_{6}$	$9.4647 \times 10^{-1}$
$c_{7}$	$-3.2208 \times 10^{-2}$
$c_{8}$	1.2688

Accepts either scalars or vectors of equal sizes for all the input arguments. Returns either a scalar or a vector of the appropriate size.