Snow and ice were monitored by thermistor-string-based Snow and Ice Mass Balance Array (SIMBA) in Lake Orajärvi in northern Finland. An existing automatic SIMBA-algorithm was further developed to derive air/snow, snow/ice and ice/water interfaces based on the SIMBA environment temperature (ET) profiles. The identified interfaces agreed with in situ observations made in 2011/12 winter season. The method was capable to identify upward-moving snow/ice interface that was also visible from SIMBA heating temperature (HT) profiles, which responds to differences in the thermal diffusivities of air, snow, ice and water. The SIMBA data obtained in winters 2017/18 and 2018/19 were used to investigate snow and ice mass balance. An upward-moving snow/ice interface was detected as a result of meteoric ice (snow ice and superimposed ice) formation. Snow contributed to granular lake ice formation up to 40–55% of the total ice thickness on the seasonal mean. Heavy snowfalls and low air temperature in early winter are favourable for granular ice formation. The seasonal mean snow depth on nearby land was 2.7–2.9 times of that on the lake. The estimation of freeboard from snow and ice mass-balance measurement is sensitive to the snow density. Accurate ice freeboard calculation is still a challenge.

中文翻译：

---

从北极湖上的冰质量平衡浮标测量的高分辨率垂直温度剖面检测空气/雪、雪/冰和冰/水界面

芬兰北部 Orajärvi 湖的冰雪由基于热敏电阻串的冰雪质量平衡阵列 (SIMBA) 监测。进一步开发了现有的自动 SIMBA 算法，以根据 SIMBA 环境温度 (ET) 剖面推导出空气/雪、雪/冰和冰/水界面。确定的界面与 2011/12 冬季进行的现场观测一致。该方法能够识别从 SIMBA 加热温度 (HT) 剖面中也可见的向上移动的雪/冰界面，该界面响应空气、雪、冰和水的热扩散率的差异。2017/18 和 2018/19 冬季获得的 SIMBA 数据用于研究冰雪质量平衡。由于流星冰（雪冰和叠加冰）的形成，检测到向上移动的雪/冰界面。雪促成了粒状湖冰的形成，占季节性平均冰层总厚度的 40-55%。初冬的大雪和低温有利于颗粒冰的形成。附近陆地的季节平均积雪深度是湖面积雪深度的2.7～2.9倍。从冰雪质量平衡测量估计干舷对雪密度很敏感。准确的冰干舷计算仍然是一个挑战。