Located in the eastern lap of the Karakoram Range, the Siachen Glacier is the second longest glacier in the non-polar areas of the world. High altitude, extreme climate and frequent military conflicts on this glacier create antagonistic surroundings for conventional field studies. Although recent advancements in geodetic technique have helped in the estimation of Siachen mass budget (MB), these geodetic estimates have been observed only for short time periods ranging 6 to 10 years. Hence, current study presents a comprehensive assessment of the Siachen long-term MB (32 years) based on temperature index (TI) model. Annual surface MB variability was modelled between 1986 and 2018 by forcing daily air temperature and precipitation from multiple ground stations distributed well across accumulation/ablation zone of the glacier. Mean annual temperature lapse rate (LR) was found midway between dry adiabatic and moist adiabatic LRs. Precipitation gradient (PG) was observed remarkably different below and above 4800 m.a.s.l. glacier altitude. Furthermore, snowmelt factor (SMF) was also estimated using snow thickness and positive degree days (PDDs) information over the glacier surface. Model results showed a nearly balanced condition (− 0.02 ± 0.05 m.w.e./year) during 1986–2006 followed by an accelerated rate of mass loss during 2007–2018 (− 0.11 ± 0.05 m.w.e./year), thus making the overall condition of Siachen MB negative during the period 1986–2018 (− 0.05 ± 0.05 m.w.e./year). Comparison of modelled MB was made with few geodetic studies conducted for the Siachen Glacier at different time scales (mainly after year 2000). Further, the sensitivity of the modelled glacier-wide MB was − 0.24 m.w.e./year for a temperature rise by 1 °C, while the sensitivity towards 10% increase in precipitation was estimated to be + 0.16 m.w.e./year. A relationship of the annual MB with accumulation area ratio (AAR) and equilibrium line altitude (ELA) was also established for Siachen glacier.

中文翻译：

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东喀喇昆仑州Siachen冰川的长期质量平衡模型（1986-2018）和气候敏感性。

Siachen冰川位于喀喇昆仑山脉东部圈，是世界非极性地区第二长的冰川。该冰川的高海拔，极端气候和频繁的军事冲突为常规的野外研究创造了不利的环境。尽管大地测量技术的最新进展有助于估算Siachen的总预算（MB），但仅在6至10年的短时间内观察到了这些大地测量估计。因此，本研究基于温度指数（TI）模型对Siachen长期MB（32年）进行了全面评估。1986年至2018年之间，通过强迫来自分布在冰川堆积/消融区的多个地面站的每日气温和降水来模拟年表面MB的变化性。在干绝热和湿绝热LR之间的中间发现年平均温度下降率（LR）。在4800 masl冰川海拔以下，观测到的降水梯度（PG）明显不同。此外，还使用冰川表面的积雪厚度和正度日（PDDs）信息估算了融雪因子（SMF）。模型结果表明，在1986–2006年期间几乎达到平衡状态（− 0.02±0.05兆瓦/年），然后在2007–2018年期间加速了质量损失率（− 0.11±0.05毫瓦/年），从而使Siachen MB的总体状况在1986年至2018年期间为负值（-0.05±0.05兆瓦/年）。比较了在不同时间尺度（主要是在2000年之后）对Siachen冰川进行的大地测量研究与模型MB的比较。进一步，当温度升高1°C时，模拟的冰川范围MB的灵敏度为-0.24 mwe /年，而对降水增加10％的灵敏度估计为+ 0.16 mwe /年。锡亚琴冰川还建立了年MB与堆积面积比（AAR）和平衡线高度（ELA）的关系。