Diurnal snow pit measurements observed during the SIPEX II voyage of the Aurora Australis, 2012

Motivation:

One of the characteristics of this voyage is that we have long ice stations which last for a few days. Taking this opportunity, we decided to examine the diurnal change of snow properties at the fixed snow pit site. Since this measurement was not included in the original plan, Time interval was a bit variable from 3 hours to 5 hours depending on the progress of the other work.

Observation items:

Snow thickness, Temperature profile (every 3 cm), Grain size, Grain shape, Snow density, Hardness, Salinity

Instruments:

Folding scales, Spatula, Thermometer, Snow sampler, Magnifying glass, Salinometer

Information pertaining to the dataset:

Time - recorded in local time

Hs - snow depth in cm

Cloud measurements - oktas

Water level - distance between snow surface and surface seawater in cm

Depth - depth of the individual layer referenced to snow/ice interface (upper column) or snow surface (lower column) in cm

Ta - air temperature in degrees celsius

DH, FC, PP, DF, RG stand for Depth hoar, Faceted crystals, Precipitation particles, Decomposing and fragemented precipitation particles, Rounded grains - according to "The International Classification for Seasonal Snow on the Ground" (Colbeck et al., 1990).

Weight - g

Mid-depth - cm

研究背景：
本次航次的显著特征之一是设置了多处长时冰站，单次作业时长可达数日。借此契机，我们计划在固定雪坑点位开展雪层特性日变化的观测研究。由于该项测量未纳入原始观测方案，观测时间间隔需根据其他作业的推进情况灵活调整，介于3至5小时之间。

观测项目：
雪层厚度、温度廓线（每3cm采集一次）、雪粒粒径、雪粒形态、雪密度、雪层硬度、盐度

观测仪器：
折叠标尺、刮刀、温度计、雪层取样器、放大镜、盐度计

数据集相关说明：
时间：采用当地时间记录
Hs：雪深，单位为厘米（cm）
云量观测：采用八分云量（oktas）作为计量单位
水位：雪面与表层海水之间的垂直距离，单位为厘米（cm）
层厚：单雪层的厚度，以上覆雪/冰界面（上表列）或雪面（下表列）为参考基准，单位为厘米（cm）
Ta：气温，单位为摄氏度（℃）
DH、FC、PP、DF、RG分别对应深霜（Depth hoar）、棱角晶（Faceted crystals）、降水粒子（Precipitation particles）、分解碎裂型降水粒子（Decomposing and fragmented precipitation particles）、圆粒雪（Rounded grains），分类标准引自《地面季节性雪国际分类》（Colbeck等，1990）
重量：单位为克（g）
中层深度：单位为厘米（cm）