Be exposure age calculator MATLAB function reference Version 2

2.7 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 · 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:
[
]
c 2 S
ln (I) = c 1 ln (XS) − S exp
(R C + 5S) 2S + c 3 X c4 + c 5 [(R C + 4S) X] c6 + c 7 (R C + 4S) c8 (41)
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 × 10 2
c 3 −4.9420 × 10 −2
c 4 8.0139 × 10 −1
c 5 1.2708 × 10 −4
c 6 9.4647 × 10 −1
c 7 −3.2208 × 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.
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