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dunai2001sp.m

Syntax:

scalingfactor = dunai2001sp(h,Rc)

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

Dunai T.J., 2001. Influence of secular variation of the geomagnetic field on production rates of in situ produced cosmogenic nuclides. Earth and Planetary Science Letters, v. 193, pp. 197-212.

The input arguments are h, atmospheric pressure (hPa) and Rc, cutoff rigidity (GV). Accepts vector arguments.

This function:

Converts atmospheric pressure $ h$ (hPa) to atmospheric depth between sea level and the site $ \delta z$ (g $ \cdot$ cm$ ^{-2}$) by:

$\displaystyle \delta z = 1.0197\left( 1013.25 - h\right)$ (33)

Calculates the sea level scaling factor $ S_{sl}$ according to Equation (3) of the source paper:

$\displaystyle S_{sl} = Y + \frac {A} {\left[ 1 + \exp{\left( - \frac{R_{C}-X}{B} \right)} \right]^{C}}$ (34)

where $ R_{C}$ is the cutoff rigidity (GV) and the other constants in the equation are:

$ A$ 0.5221
$ B$ -1.7211
$ C$ 0.3345
$ X$ 4.2822
$ Y$ 0.4952

Calculates the atmospheric attenuation length $ \Lambda_{atm}$ according to Equation (4) of the source paper:

$\displaystyle \Lambda_{atm} = y + \frac {a} {\left[ 1 + \exp{\left( - \frac{R_{C}-x}{b} \right)} \right]^{c}}$ (35)

where $ R_{C}$ is the cutoff rigidity (GV) and the other constants in the equation are:

$ a$ 17.183
$ b$ 2.060
$ c$ 5.9164
$ x$ 2.2964
$ y$ 130.11

Finally, calculates the scaling factor at the site $ S$ according to Equation (5) of the source paper:

$\displaystyle S = S_{sl}\exp{ \left( \frac{\delta z}{\Lambda_{atm}} \right) }$ (36)

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


next up previous contents
Next: ET_objective.m Up: Subsidiary calculation functions Previous: desilets2006sp.m   Contents
2007-11-13