A simulation of small to giant Antarctic iceberg evolution: Differential impact on climatology estimates.

Rackow, Thomas, Wesche, Christine, Timmermann, Ralph, Hellmer, Hartmut H., Juricke, Stephan and Jung, Thomas (2017) A simulation of small to giant Antarctic iceberg evolution: Differential impact on climatology estimates. Open Access Journal of Geophysical Research: Oceans, 122 (4). pp. 3170-3190. DOI 10.1002/2016JC012513.

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Abstract

We present a simulation of Antarctic iceberg drift and melting that includes small, medium‐sized, and giant tabular icebergs with a realistic size distribution. For the first time, an iceberg model is initialized with a set of nearly 7000 observed iceberg positions and sizes around Antarctica. The study highlights the necessity to account for larger and giant icebergs in order to obtain accurate melt climatologies. We simulate drift and lateral melt using iceberg‐draft averaged ocean currents, temperature, and salinity. A new basal melting scheme, originally applied in ice shelf melting studies, uses in situ temperature, salinity, and relative velocities at an iceberg's bottom. Climatology estimates of Antarctic iceberg melting based on simulations of small (≤2.2 km), “small‐to‐medium‐sized" (≤10 km), and small‐to‐giant icebergs (including icebergs >10 km) exhibit differential characteristics: successive inclusion of larger icebergs leads to a reduced seasonality of the iceberg meltwater flux and a shift of the mass input to the area north of 58°S, while less meltwater is released into the coastal areas. This suggests that estimates of meltwater input solely based on the simulation of small icebergs introduce a systematic meridional bias; they underestimate the northward mass transport and are, thus, closer to the rather crude treatment of iceberg melting as coastal runoff in models without an interactive iceberg model. Future ocean simulations will benefit from the improved meridional distribution of iceberg melt, especially in climate change scenarios where the impact of iceberg melt is likely to increase due to increased calving from the Antarctic ice sheet.

Document Type: Article
Keywords: iceberg drift: iceberg melting; giant icebergs; melt climatology; Southern Ocean; FESOM‐IB
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1002/2016JC012513
ISSN: 2169-9275
Projects: PalMod in-kind
Date Deposited: 14 Sep 2018 09:39
Last Modified: 01 Feb 2019 15:13
URI: http://oceanrep.geomar.de/id/eprint/44309

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