Department of Geography, Masaryk University, Brno, Czech Republic.
Department of Geography, Masaryk University, Brno, Czech Republic.
Sci Total Environ. 2023 Apr 15;869:161690. doi: 10.1016/j.scitotenv.2023.161690. Epub 2023 Jan 16.
Climate change and its impacts on sensitive polar ecosystems are relatively little studied in Antarctic regions. Permafrost and active layer changes over time in periglacial regions of the world are important indicators of climate variability. These changes (e. g. permafrost degradation, increasing of the active layer thickness) can have a significant impact on Antarctic terrestrial ecosystems. The study site (AWS-JGM) is located on the Ulu Peninsula in the north of James Ross Island. Ground temperatures at depths of 5, 50, and 75 cm have been measured at the site since 2011, while air temperature began to be measured in 2004. The main objective is to evaluate the year-to-year variability of the reconstructed temperature of the top of the permafrost table and the active layer thickness (ALT) since 2004 based on air temperature data using TTOP and Stefan models, respectively. The models were verified against direct observations from a reference period 2011/12-2020/21 showing a strong correlation of 0.95 (RMSE = 0.52) and 0.84 (RMSE = 3.54) for TTOP and Stefan models, respectively. The reconstructed average temperature of the permafrost table for the period 2004/05-2020/21 was -5.8 °C with a trend of -0.1 °C/decade, while the average air temperature reached -6.6 °C with a trend of 0.6 °C/decade. Air temperatures did not have an increasing trend throughout the period, but in the first part of the period (2004/05-2010/11) showed a decreasing tendency (-1.3 °C/decade). In the period 2011/12-2020/21, it was a warming of 1.9 °C/decade. The average modelled ALT for the period 2004/05-2020/21 reached a value of 60cm with a trend of -1.6 cm/decade. Both models were found to provide reliable results, and thus they significantly expand the information about the permafrost and ALT, which is necessary for a better understanding of their spatiotemporal variability and the impact of climate change on the cryosphere.
气候变化及其对南极敏感极地生态系统的影响在世界上的极地区域相对研究较少。多年冻土和活动层随时间在世界上的多年冻土区的变化是气候变率的重要指标。这些变化（例如，多年冻土退化，活动层厚度增加）可能对南极陆地生态系统产生重大影响。研究地点（AWS-JGM）位于詹姆斯·罗斯岛北部的乌鲁半岛。自 2011 年以来，该地点一直在测量 5、50 和 75 厘米深处的地面温度，而自 2004 年开始测量空气温度。主要目标是使用 TTOP 和 Stefan 模型分别基于空气温度数据评估自 2004 年以来重建的多年冻土顶温和活动层厚度（ALT）的年际变化。模型通过参考期 2011/12-2020/21 的直接观测进行了验证，分别显示出 0.95（RMSE = 0.52）和 0.84（RMSE = 3.54）的强相关性。2004/05-2020/21 期间重建的多年冻土顶平均温度为-5.8°C，呈-0.1°C/decade 的趋势，而平均空气温度达到-6.6°C，呈 0.6°C/decade 的趋势。空气温度在整个期间没有呈现出上升趋势，而是在该期间的前半部分（2004/05-2010/11）呈现出下降趋势（-1.3°C/decade）。在 2011/12-2020/21 期间，升温趋势为 1.9°C/decade。2004/05-2020/21 期间重建的平均 ALT 值达到 60cm，呈-1.6cm/decade 的趋势。这两个模型都被发现提供了可靠的结果，因此它们大大扩展了多年冻土和 ALT 的信息，这对于更好地了解它们的时空变异性以及气候变化对冰冻圈的影响是必要的。
