TVC Array

Matlab Array of TVC Snowpit Data from "Impact of measured and simulated tundra snowpack properties on heat transfer", Dutch et al. (2021). [DOI Pending]. Version 2.0.Code and other data at: https://github.com/V-Dutch/TVCSnowCLMAbstract Snowpack microstructure controls the transfer of heat to, and the temperature of, the underlying soils. In situ measurements of snow and soil properties from four field campaigns during two different winters (March and November 2018, January and March 2019) were compared to an ensemble of CLM5.0 (Community Land Model) simulations, at Trail Valley Creek, Northwest Territories, Canada. Snow MicroPenetrometer profiles allowed snowpack density and thermal conductivity to be derived at higher vertical resolution (1.25 mm) and a larger sample size (n = 1050) compared to traditional snowpit observations (3 cm vertical resolution; n = 115). Comparing measurements with simulations shows CLM overestimated snow thermal conductivity by a factor of 3, leading to a cold bias in wintertime soil temperatures (RMSE = 5.8 ℃). Bias-correction of the simulated thermal conductivity (relative to field measurements) improved simulated soil temperatures (RMSE = 2.1 ℃). Multiple linear regression shows the required correction factor is strongly related to snow depth (R2 = 0.77, RMSE = 0.066) particularly early in the winter. The use of an alternative parameterisation of snow thermal conductivity also improved simulations of wintertime soil temperatures (RMSE = 2.5 ℃). Furthermore, CLM simulations did not adequately represent the observed high proportions of depth hoar. Addressing uncertainty in simulated snow properties and the corresponding heat flux is important, as wintertime soil temperatures act as a control on subnivean soil respiration, and hence impact Arctic winter carbon fluxes and budgets.

本数据集为荷兰等人（2021）发表于《实测与模拟苔原雪层特性对热传输的影响》研究中的特雷瓦尔谷溪（TVC）雪坑数据Matlab数组，DOI待提交，版本2.0。相关代码与其他数据集详见：https://github.com/V-Dutch/TVCSnowCLM

【研究摘要】雪层微观结构决定了向下伏土壤传递的热量及下伏土壤温度。本研究于加拿大西北地区特雷瓦尔谷溪区域，针对两个冬季开展的四次野外考察（2018年3月、11月，2019年1月、3月）获取的雪层与土壤原位特性数据，与多组陆面模式CLM5.0（Community Land Model）模拟结果开展对比分析。相较于传统雪坑观测（垂直分辨率3 cm，样本量n=115），雪微穿透仪（Snow MicroPenetrometer）剖面数据可实现更高的垂直分辨率（1.25 mm）与更大的样本量（n=1050），由此反演得到雪层密度与热导率。实测数据与模拟结果的对比显示，CLM对雪层热导率的模拟值偏高3倍，进而导致冬季土壤温度呈现冷偏差（均方根误差Root Mean Square Error, RMSE=5.8 ℃）。基于野外实测数据对模拟热导率进行偏差校正后，土壤温度的模拟精度得到显著提升（RMSE=2.1 ℃）。多元线性回归分析表明，所需校正因子与雪深存在显著相关性（决定系数R²=0.77，RMSE=0.066），尤其在冬季初期表现突出。采用雪层热导率的替代参数化方案后，冬季土壤温度的模拟结果同样得到改善（RMSE=2.5 ℃）。此外，CLM模拟未能准确复现观测到的高占比深霜（depth hoar）。鉴于冬季土壤温度是雪下土壤呼吸（subnivean soil respiration）的核心调控因子，进而直接影响北极冬季碳通量与碳预算，因此修正模拟雪层特性及对应热通量的不确定性至关重要。