Instituto Federal do Rio de Janeiro, Campus Pinheiral, Rua José Breves, 550, 27197-000 Pinheiral, RJ, Brazil.
Departamento de Ciências Ambientais, Instituto de Florestas, Universidade Federal Rural do Rio de Janeiro, Rodovia BR 465, Km 07, 23851-970 Seropédica, RJ, Brazil.
An Acad Bras Cienc. 2022 Feb 28;94(suppl 1):e20200458. doi: 10.1590/0001-3765202220200458. eCollection 2022.
Heat transfer process in the soil active layer is important for the knowledge of its thermal properties linked with climate issues. The objective of this work was to analyze the energy flux in different soil profiles by estimating the apparent soil thermal diffusivity ($ATD$). The study was carried out in Keller Peninsula, located at King George Island in four different sites differing by soil characteristics, as well as vegetation coverage and landscape setting. The $ATD$ was estimated in function of the long-term hourly temperature records at different soil depths. In addition, we estimated the seasonal mean of the $ATD$ and the freezing $N$-factor. Results showed that $ATD$ values were smaller at shallow depths and increased with depth. The diffusivity values presented lower variability in colder conditions, especially at deeper soil layers. Water content was the main factor affecting soil thermal diffusivity at sites $1$ and $3$ (more than $70$ and $63%$ of probability). At sites $3$ and $4$ lower $N$-factors were observed, suggesting higher snow pack and permafrost closer to the soil surface. Hence, positive $ATD$ appears in the summer due to thawing increases soil moisture, while negative $ATD$ appears during the freeze of the snow pack and precipitation.
土壤活跃层中的热量传递过程对于了解其与气候问题相关的热特性非常重要。本工作的目的是通过估计表观土壤热扩散率（$ATD$）来分析不同土壤剖面中的能量通量。该研究在位于乔治王岛的凯勒半岛的四个不同地点进行，这些地点的土壤特性、植被覆盖和景观设置存在差异。$ATD$是根据不同土壤深度的长期每小时温度记录来估计的。此外，我们还估计了$ATD$的季节性平均值和冻结$N$因子。结果表明，$ATD$值在浅层较小，并随深度增加而增加。在较冷的条件下，扩散率值的变化较小，尤其是在较深的土壤层中。水分含量是影响站点$1$和$3$土壤热扩散率的主要因素（超过$70%$和$63%$的概率）。在站点$3$和$4$，观察到较低的$N$因子，这表明靠近土壤表面的积雪和多年冻土更多。因此，由于融化增加了土壤水分，夏季出现正的$ATD$，而在积雪冻结和降水期间出现负的$ATD$。
