ratio_to_delta: Convert isotope ratio to delta value

In jmerc13/LakeIsodrology: Lake isotope hydrology

Description

This function, ratio_to_delta takes the heavy isotope ratio of a known element, either hydrogen or oxygen, and converts it a delta value (per mille) for a given standard. Applicable standards include Vienna Standard Mean Ocean Water (VSMOW), Greenland Ice Sheet Precipitation (GISP), and Standard Light Antarctic Precipitation (SLAP).

Usage

ratio_to_delta(ratio, element, standard = "VSMOW", unit)

Arguments

ratio	Heavy isotope ratio of either hydrogen or oxygen, [-].
element	Character value indicating either "Hydrogen" or "Oxygen".
standard	Character value indicating the acronym of the standard to be used: "VMSOW", "GISP", or "SLAP".
unit	Character value explicitly stating if the output value should be in "decimal" or "permille" units.

Details

The relationship used to convert a given isotope ratio to delta notation:

δ^{A}X = \Bigg(\frac{{}^{A}R}{{}^{A}R_{Standard}} - 1\Bigg) 1000

Where A indicates the isotope of element X, R is the ratio of the sample, and R_{Standard} is the isotope ratio of the standard being used.

Below are the values of each standard and its isotope ratio used in this function.

Standard	2H/1H	18O/16O
VSMOW	0.00015576	0.00200520
GISP	0.00012624	0.00195555
SLAP	0.00008902	0.00189391

VSMOw and SLAP standard information can be found at: https://nucleus.iaea.org/rpst/documents/VSMOW_SLAP.pdf

GISP standard information: https://nucleus.iaea.org/rpst/Documents/rs_GISP.pdf

Value

A numeric delta value in either permille or decimal units.

jmerc13/LakeIsodrology documentation built on May 5, 2019, 5:52 p.m.