Numerical experiments on firn isotope diffusion with the Community Firn Model
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Numerical experiments on firn isotope diffusion with the Community Firn Model. / Gkinis, Vasileios; Holme, Christian; Kahle, Emma C.; Stevens, Max C.; Steig, Eric J.; Vinther, Bo M.
In: Journal of Glaciology, Vol. 67, No. 263, 01.06.2021, p. 450-472.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Numerical experiments on firn isotope diffusion with the Community Firn Model
AU - Gkinis, Vasileios
AU - Holme, Christian
AU - Kahle, Emma C.
AU - Stevens, Max C.
AU - Steig, Eric J.
AU - Vinther, Bo M.
PY - 2021/6/1
Y1 - 2021/6/1
N2 - Advances in analytical methods have made it possible to obtain high-resolution water isotopic data from ice cores. Their spectral signature contains information on the diffusion process that attenuated the isotopic signal during the firn densification process. Here, we provide a tool for estimating firn-diffusion rates that builds on the Community Firn Model. Our model requires two main inputs, temperature and accumulation, and it calculates the diffusion lengths for delta O-17, delta O-18 and delta D. Prior information on the isotopic signal of the precipitation is not a requirement. In combination with deconvolution techniques, diffusion lengths can be used in order reconstruct the pre-diffusion isotopic signal. Furthermore, the temperature dependence of the isotope diffusion and firn densification makes the diffusion length an interesting candidate as a temperature proxy. We test the model under steady state and transient scenarios and compare four densification models. Comparisons with ice core data provide an evaluation of the four models and indicate that there are differences in their performance. Combining data-based diffusion length estimates with information on past accumulation rates and ice flow thinning, we reconstruct absolute temperatures from three Antarctic ice core sites.
AB - Advances in analytical methods have made it possible to obtain high-resolution water isotopic data from ice cores. Their spectral signature contains information on the diffusion process that attenuated the isotopic signal during the firn densification process. Here, we provide a tool for estimating firn-diffusion rates that builds on the Community Firn Model. Our model requires two main inputs, temperature and accumulation, and it calculates the diffusion lengths for delta O-17, delta O-18 and delta D. Prior information on the isotopic signal of the precipitation is not a requirement. In combination with deconvolution techniques, diffusion lengths can be used in order reconstruct the pre-diffusion isotopic signal. Furthermore, the temperature dependence of the isotope diffusion and firn densification makes the diffusion length an interesting candidate as a temperature proxy. We test the model under steady state and transient scenarios and compare four densification models. Comparisons with ice core data provide an evaluation of the four models and indicate that there are differences in their performance. Combining data-based diffusion length estimates with information on past accumulation rates and ice flow thinning, we reconstruct absolute temperatures from three Antarctic ice core sites.
KW - Glaciological model experiments
KW - ice and climate
KW - ice core
KW - ice temperature
KW - polar firn
KW - STABLE WATER ISOTOPES
KW - CONTINUOUS-FLOW ANALYSIS
KW - DRONNING MAUD LAND
KW - ICE-CORE
KW - POLAR FIRN
KW - DOME C
KW - TEMPERATURE
KW - FRACTIONATION
KW - RECORDS
KW - DENSIFICATION
U2 - 10.1017/jog.2021.1
DO - 10.1017/jog.2021.1
M3 - Journal article
VL - 67
SP - 450
EP - 472
JO - Journal of Glaciology
JF - Journal of Glaciology
SN - 0022-1430
IS - 263
ER -
ID: 269499506