We analyze ground temperatures measured daily at depths of 0–10 m in the Nadym region, north‐west Siberia (65°18′N, 72°6′E). Nadym is located within the discontinuous permafrost zone and the forest–tundra transition subzone, thus representing an area threatened by permafrost thawing. Soil comprises a 0.4–1.0‐m‐thick topmost layer of peat with high porosity (~0.9), underlain by layers of mineral soil (sand, clay, loam) with lower porosities of 0.3–0.4. With a numerical heat transfer model, we provide predictions of general permafrost development for the next 300 years. Furthermore, we apply the model with the same time frame, to predict permafrost evolution in two monitoring boreholes (BH) in the Nadym area, BH 1‐09 and 3‐09 with present (2012–2016) temperatures at the top of the permafrost (TTOP) of −2.0 and 0.0 °C, respectively. Applying a mild warming trend (0.02 °C/yr in mean annual air temperature [MAAT], corresponding to the IPCC representative concentration pathway trend RCP 2.6) does not lead to thawing of permafrost during the applied 300 years of simulation time in BH 1‐09, whereas in BH 3‐09 thawing has already begun. Applying a strong warming trend of 0.05 °C/yr in MAAT (corresponding to RCP 8.5) leads to gradual thawing of permafrost in both boreholes.

中文翻译：

---

西伯利亚西北部 Nadym 不连续多年冻土带地温演化的观测和模拟

我们分析了西伯利亚西北部 Nadym 地区（65°18'N，72°6'E）每天在 0-10 m 深度测量的地面温度。Nadym 位于不连续的永久冻土带和森林-苔原过渡亚带内，因此代表了一个受永久冻土融化威胁的区域。土壤包括 0.4-1.0 米厚的最顶层泥炭，具有高孔隙率 (~0.9)，下面是矿质土壤层（沙子、粘土、壤土），孔隙率较低，为 0.3-0.4。通过数值传热模型，我们提供了对未来 300 年一般永久冻土发展的预测。此外，我们应用具有相同时间范围的模型来预测 Nadym 地区的两个监测钻孔 (BH) 中的永久冻土演化，BH 1-09 和 3-09 以及永久冻土顶部的当前 (2012-2016) 温度(TTOP) 分别为 -2.0 和 0.0 °C。应用温和的变暖趋势（年平均气温 [MAAT] 为 0.02 °C/yr，对应于 IPCC 代表性浓度路径趋势 RCP 2.6）在 BH 1- 应用的 300 年模拟时间内不会导致永久冻土融化09，而在 BH 3-09 中解冻已经开始。在 MAAT（对应于 RCP 8.5）中应用 0.05 °C/yr 的强烈变暖趋势会导致两个钻孔中的永久冻土逐渐融化。