Snow depth, sea ice thickness and interface temperatures derived from measurements of SIMBA buoy 2014T14

The Snow and Ice Mass Balance Array (SIMBA) is a thermistor string type IMB (Jackson et al., 2013) which measures the environmental temperature SIMBA-ET and a temperature change around the thermistors after a weak heating is applied to each sensor (SIMBA-HT). SIMBA 2014T14 (a.k.a. Awi_55) is an autonomous instrument that was installed on drifting sea ice in the Arctic Ocean (Polarstern PS87 (ARK28/4, ALEX) in 2014) as part of the project Sea Ice Physics @ AWI (AWI_SeaIce). Its thermistor chain is 5 m long, and equipped with 240 thermistors (Maxim Integrated DS28EA00) at a spacing of 2 cm. Based on a manual classification method, the SIMBA-ET and SIMBA-HT were processed to obtain snow depth and ice thickness (smoothed with a 3-day running mean), as well as the thermistor number, the vertical position Z relative to the snow-ice interface and the measured SIMBA-ET at each detected interface (atmosphere-snow, snow-ice and ice-ocean) for the period between 2014-08-26T21:00:39 and 2015-06-24T09:00:39. To do this, we combined two derivatives of measured temperatures (the ET vertical gradient and HT rise ratio) to reduce the detection uncertainty of all interfaces considered. The snow or ice surface, consequentially the snow depth, is determined by the ET vertical gradient. Potential formation of snow ice is not explicitly considered in this data set, but may occur as depicted by vertical changes of the snow-ice interface position. The ice-ocean interface is usually determined using the HT rise ratio and serves as the lower limit for ice thickness. Overall, the accumulated error is 2 to 4 times the sensor spacing for both the snow depth and ice thickness. For interface temperatures, individual sensors in the chain measure with a temperature resolution of 0.0625°C, with the overall accuracy landing in the range of ± 2°C (Jackson et al., 2013). After the snow cover has melted, negative values for snow depth may indicate the onset of ice surface melt.

冰雪质量平衡阵列（SIMBA）是一种热敏电阻（thermistor）串型IMB（Jackson等人，2013），可测量环境温度（SIMBA-ET）以及对每个传感器施加弱加热后热敏电阻周围的温度变化（SIMBA-HT）。SIMBA 2014T14（又名Awi_55）是一款自主仪器（autonomous instrument），于2014年安装在北冰洋的漂流海冰上（极地stern PS87航次，ARK28/4，ALEX），作为阿尔弗雷德·韦格纳研究所（AWI）海冰物理项目（AWI_SeaIce）的一部分。其热敏电阻链长5米，配备240个热敏电阻（Maxim Integrated DS28EA00），间距为2厘米。基于手动分类方法，SIMBA-ET和SIMBA-HT数据经过处理，得到雪深和冰厚（经3日滑动平均（running mean）平滑处理），以及2014年8月26日21:00:39至2015年6月24日09:00:39期间的热敏电阻编号、相对于雪冰界面的垂直位置Z，以及在每个检测到的界面（大气-雪、雪-冰、冰-海洋）处测得的SIMBA-ET值。为此，我们结合了测量温度的两个衍生量——ET垂直梯度（vertical gradient）和HT上升比（rise ratio），以降低所有目标界面的检测不确定性。本数据集未明确考虑雪冰的潜在形成，但雪冰形成可能通过雪冰界面位置的垂直变化得以体现。冰-海洋界面通常通过HT上升比确定，并作为冰厚的下限。总体而言，雪深和冰厚的累积误差为传感器间距的2至4倍。对于界面温度，链中的单个传感器测量温度分辨率为0.0625°C，整体精度在±2°C范围内（Jackson等人，2013）。当积雪融化后，雪深的负值可能表明冰面融化的开始。