Recent ice dynamics and mass balance of Jorge Montt Glacier, Southern Patagonia Icefield
Recent ice dynamics and mass balance of Jorge Montt Glacier, Southern Patagonia Icefield
复制标题
DOI：
10.1017/jog.2019.47
复制
发表时间：
2019-10-01
影响因子：
3.4
通讯作者：
Moffat, Carlos
中科院分区：
文献类型：
--
作者：
Bown, Francisca;Rivera, Andres;Moffat, Carlos
近几十年来，南巴塔哥尼亚冰原（SPI）退缩在邻近盆地之间表现出截然不同的行为。体积损失最大的盆地之一位于SPI的最北端。我们参考了Jorge Montt潮汐冰川（南纬48度30分/西经73度30分，2018年为445公里），该冰川在2011年至2018年期间退缩了2.7公里，并在此期间以高达21米的速度变薄（-1）。基于退缩记录、遥感影像、野外数据、质量平衡模型和产犊参数化，我们试图区分气候引起的变化（即地表质量平衡）和动态响应（即产犊通量）。2012 - 2017年地表物质平衡达到-4.15 km(3) w.e.a（-1）。当包括锋面消融时，净质量平衡为-17.79 km(3) w.e.a（-1）。这表明与2010年以前的正表面质量平衡的模拟估计相比，趋势发生了变化。这种变化归因于较高的消融率，因为已知在1980年至2015年期间积累有所增加。因此，现有证据表明，锋面消融是主要因素，Jorge Montt在2015年观测到的冰速高达3.81 km(3) w.e.a(-1)，冰速峰值为11 km a（-1）。
The Southern Patagonia Icefield (SPI) withdrawal in recent decades shows contrasting behaviours between adjacent basins. One of the basins with highest volumetric losses is located at northernmost SPI. We refer to Jorge Montt tidewater glacier (48 degrees 30 ' S/73 degrees 30 ' W, 445 km(2) in 2018), which retreated 2.7 km between 2011 and 2018 and thinned at rates of up to 21 m a(-1) over this period. Based on the retreat record, remote-sensing imagery, field data, a mass-balance model and a calving parameterisation, we attempted to differentiate climatic-induced changes (i.e. surface mass balance) and dynamic responses (i.e. calving fluxes). The surface mass balance reached -4.15 km(3) w.e. a(-1) between 2012 and 2017. When frontal ablation is included, the net mass balance is -17.79 km(3) w.e. a(-1). This represents a change of trend compared with modelling estimations of positive surface mass balance prior to 2010. This shift is attributed to higher ablation rates given that accumulation is known to have increased between 1980 and 2015. The available evidence, therefore, indicates that frontal ablation is the main factor, supported by observed rates at Jorge Montt as high as 3.81 km(3) w.e. a(-1) in 2015, with ice velocities peaking at 11 km a(-1).