dex: Deuterium excess

In SPATIAL-Lab/isoWater: Discovery, Retrieval, and Analysis of Water Isotope Data

Deuterium excess

Description

Calculates deuterium excess or line-conditioned excess.

Usage

dex(HO, form = "dex", MWL = NULL)

Arguments

HO	data.frame. Hydrogen (column 1) and oxygen (column 2) isotope values for 1 or more water samples.
form	character. Calculate deuterium excess (“dex”), line-conditioned excess (“lcex”), or “both”.
MWL	numeric. Vector the first two elements of which contain the meteoric water line slope and intercept (e.g., as created by mwl). The default value (if MWL = NULL) reflects the Global Meteoric Water Line estimated from a global precipitation compilation in Bowen, et al. (2019). Ignored for form = "dex".

Value

Returns a copy of HO with an added field(s) “dex” and/or “lcex” containing the calculated values. Deuterium excess is calculated following Dansgaard (1964) as: dex = \delta2H - 8 * \delta18O, and lc-excess following Landwehr & Coplen (2006) as lcex = \delta2H - m * \delta18O - b, where m and b are the slope and intercept of MWL, respectively.

References

Bowen et al. (2019) Isotopes in the water cycle: Regional- to global-Scale patterns and applications. Annual Review of Earth and Planetary Sciences 47 453–479. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1146/annurev-earth-053018-060220")}.

Dansgaard (1964) Stable isotopes in precipitation. Tellus 16 436–468. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1111/j.2153-3490.1964.tb00181.x")}.

Landwehr & Coplen (2006) Line-conditioned excess: A new method for characterizing stable hydrogen and oxygen isotope ratios in hydrologic systems. In Isotopes in Environmental Studies, International Atomic Energy Agency, 132–135. http://www-pub.iaea.org/MTCD/publications/PDF/CSP_26_web.pdf.

Examples

O = runif(10, -15, -2)
H = O * 8 + 10 + rnorm(10, 0, 6)
d = dex(data.frame(H, O), form = "both")
print(d)

SPATIAL-Lab/isoWater documentation built on Dec. 9, 2024, 1:05 a.m.