snow pit density - manual measurement

Manual measurements of snow density in snow pits, obtained during annual surveys at the end of the snow season. Missing information is indicated by -9999 for numerical and '-' for text columns.本数据集为积雪季末期年度调查中获取的雪坑雪密度手动测量数据。数值列的缺失信息以-9999标记，文本列的缺失信息以'-'标记。