Modeling the sensitivity of precipitation oxygen isotopes to the Last Glacial Maximum boundary conditions: A study using Community Atmosphere Model (CAM3.0)

To understand the validity of d18O proxy records as indicators of past temperature change, a series of experiments was conducted using an atmospheric general circulation model fitted with water isotope tracers (Community Atmosphere Model version 3.0, IsoCAM). A pre-industrial simulation was performed as the control experiment, as well as a simulation with all the boundary conditions set to Last Glacial Maximum (LGM) values. Results from the pre-industrial and LGM simulations were compared to experiments in which the influence of individual boundary conditions (greenhouse gases, ice sheet albedo and topography, sea surface temperature (SST), and orbital parameters) were changed each at a time to assess their individual impact. The experiments were designed in order to analyze the spatial variations of the oxygen isotopic composition of precipitation (d18Oprecip) in response to individual climate factors. The change in topography (due to the change in land ice cover) played a significant role in reducing the surface temperature and d18Oprecip over North America. Exposed shelf areas and the ice sheet albedo reduced the Northern Hemisphere surface temperature and d18Oprecip further. A global mean cooling of 4.1 °C was simulated with combined LGM boundary conditions compared to the control simulation, which was in agreement with previous experiments using the fully coupled Community Climate System Model (CCSM3). Large reductions in d18Oprecip over the LGM ice sheets were strongly linked to the temperature decrease over them. The SST and ice sheet topography changes were responsible for most of the changes in the climate and hence the d18Oprecip distribution among the simulations.

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Tharammal, Thejna, Paul, André, Merkel, Ute, Noone, David (2013). Dataset: Modeling the sensitivity of precipitation oxygen isotopes to the Last Glacial Maximum boundary conditions: A study using Community Atmosphere Model (CAM3.0). https://doi.org/10.1594/PANGAEA.834468

DOI retrieved: 2013

Additional Info

Field Value
Imported on November 30, 2024
Last update November 30, 2024
License CC-BY-3.0
Source https://doi.org/10.1594/PANGAEA.834468
Author Tharammal, Thejna
Given Name Thejna
Family Name Tharammal
More Authors
Paul, André
Merkel, Ute
Noone, David
Source Creation 2013
Publication Year 2013
Subject Areas
Name: Atmosphere

Name: Lithosphere

Related Identifiers
Title: Influence of Last Glacial Maximum boundary conditions on the global water isotope distribution in an atmospheric general circulation model
Identifier: https://doi.org/10.5194/cp-9-789-2013
Type: DOI
Relation: IsSupplementTo
Year: 2013
Source: Climate of the Past
Authors: Tharammal Thejna , Paul André , Merkel Ute , Noone David .