Simulated tracks and associated melting of 6912 small to giant Antarctic icebergs, September 1997 to December 2008

We present a dataset of Antarctic iceberg drift tracks and melting that includes small, medium-sized, and giant tabular icebergs with a realistic size distribution. An iceberg model is initialized with 6912 observed iceberg positions and sizes around Antarctica. The dataset is the result of a 2017 study "A simulation of small to giant Antarctic iceberg evolution: Differential impact on climatology estimates" published in JGR:Oceans (https://doi.org/10.1002/2016JC012513).

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.

本研究构建了一套南极冰山漂移轨迹与消融数据集，该数据集涵盖小型、中型及巨型平顶冰山（tabular icebergs），并采用符合真实观测的尺寸分布。本数据集基于南极周边6912条观测到的冰山位置与尺寸初始化冰山模型，其源自2017年发表于《地球物理研究杂志：海洋分册》（JGR:Oceans）的研究论文《南极小型至巨型冰山演化模拟：对气候学估算的差异化影响》，DOI链接为https://doi.org/10.1002/2016JC012513。

本研究利用基于冰山吃水深度平均得到的海流、海水温度与盐度，模拟冰山的漂移与侧向消融。本研究采用了一种最初用于冰架消融研究的新型底部消融方案，该方案利用冰山底部的原位温度、盐度与相对流速数据。基于三类模拟场景的南极冰山消融气候学估算结果呈现出差异化特征：三类场景分别针对小型冰山（≤2.2 km）、“中小型”冰山（≤10 km）以及全尺寸冰山（含＞10 km的巨型冰山）。随着模拟中纳入的冰山尺寸逐渐增大，冰山融水通量的季节性特征会被削弱，且融水质量输入的区域会向南纬58°以北偏移，同时向近岸区域释放的融水量会有所减少。

这表明，仅基于小型冰山模拟得到的融水输入估算会引入系统性的经向偏差：这类估算低估了向北的质量输送，其效果更接近于在未耦合交互式冰山模型的模式中，将冰山消融简单处理为沿岸径流的粗糙方案。未来的海洋模拟研究将得益于冰山消融经向分布的优化结果，尤其是在气候变化情景下——由于南极冰盖崩解事件增多，冰山消融的影响预计会进一步加剧。