Representing icebergs in the i LOVECLIM model (version 1.0) – a sensitivity study

International audience Recent modelling studies have indicated that icebergs play an active role in the climate system as they interact with the ocean and the atmosphere. The icebergs' impact is due to their slowly released meltwater, which freshens and cools the ocean and consequently alters t...

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Bibliographic Details
Published in:Geoscientific Model Development
Main Authors: Bügelmayer, M., Roche, Didier M., Renssen, H.
Other Authors: Vrije Universiteit Amsterdam Amsterdam (VU), Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Modélisation du climat (CLIM), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2015
Subjects:
Online Access:https://hal.science/hal-01806128
https://hal.science/hal-01806128/document
https://hal.science/hal-01806128/file/gmd-8-2139-2015.pdf
https://doi.org/10.5194/gmd-8-2139-2015
Description
Summary:International audience Recent modelling studies have indicated that icebergs play an active role in the climate system as they interact with the ocean and the atmosphere. The icebergs' impact is due to their slowly released meltwater, which freshens and cools the ocean and consequently alters the ocean stratification and the sea-ice conditions. The spatial distribution of the icebergs and their meltwater depends on the atmospheric and oceanic forces acting on them as well as on the initial icebergs' size. The studies conducted so far have in common that the icebergs were moved by reconstructed or modelled forcing fields and that the initial size distribution of the icebergs was prescribed according to present-day observations. To study the sensitivity of the modelled iceberg distribution to initial and boundary conditions, we performed 15 sensitivity experiments using the iLOVECLIM climate model that includes actively coupled ice sheet and iceberg modules, to analyse (1) the impact of the atmospheric and oceanic forces on the iceberg transport, mass and melt flux distribution, and (2) the effect of the initial iceberg size on the resulting Northern Hemisphere climate including the Green-land ice sheet, due to feedback mechanisms such as altered atmospheric temperatures, under different climate conditions (pre-industrial, high/low radiative forcing). Our results show that, under equilibrated pre-industrial conditions, the oceanic currents cause the icebergs to stay close to the Greenland and North American coast, whereas the atmospheric forcing quickly distributes them further away from their calving site. Icebergs remaining close to Greenland last up to 2 years longer as they reside in generally cooler waters. Moreover , we find that local variations in the spatial distribution due to different iceberg sizes do not result in different climate states and Greenland ice sheet volume, independent of the prevailing climate conditions (pre-industrial, warming or cooling climate). Therefore, we conclude that local ...