ABSTRACT

Tropical mountain permafrost has a unique thermal regime due to ground surface exposure to strong solar radiation. The intensity of the surface offset resulting from snow cover also strongly affects the absence or presence of permafrost. Latent heat transfer and reflected solar radiation (higher albedo) that occur during the snow-covered season contribute to a positive feedback that cools the ground. Eleven ground temperature monitoring sites were established on the mountain at 2,780 to 5,820 m.a.s.l. The geothermal heat flow is locally high in the caldera of this volcano, as shown by borehole temperature data. Permafrost is located near the only glacier entirely within the caldera (Furtwängler). These three-year continuous records of ground temperature data encompass years of high and low snow cover. Our results show that the current lower boundary of permafrost is slightly above summit altitude and relict permafrost is present due to the influence of saturated sand on latent heat transfer. Permafrost tends to be lost more rapidly during drought years. The remaining permafrost seems likely to disappear in the future. The presence of permafrost and its thermal resistance depends on the ice content of caldera sand and the duration of snow cover.

摘要

由于地面暴露在强烈的太阳辐射下，热带山区的多年冻土具有独特的热态。积雪造成的表面偏移强度也会强烈影响永久冻土的存在与否。在积雪的季节发生的潜热传递和反射的太阳辐射（较高的反照率）有助于为地面降温的正反馈。在山上建立了11个地面温度监测点，海拔2780至5820马斯拉。如钻孔温度数据所示，该火山的火山口中的地热流局部较高。永久冻土位于火山口（Furtwängler）内唯一的冰川附近。这些连续三年的地面温度数据记录涵盖了多年的高低积雪。我们的结果表明，目前的多年冻土的下边界略高于最高峰高度，并且由于饱和砂对潜热传递的影响而存在遗留的多年冻土。在干旱年份，多年冻土流失的趋势往往更快。剩余的多年冻土似乎将来会消失。多年冻土的存在及其热阻取决于破火山口沙的含冰量和积雪的持续时间。