中文摘要：

利用藏东南色齐拉（也称色季拉）山高寒区林线地带连续的气象观测资料,分析了高山林线冷杉原始林土壤热通量的日、季节以及逐日变化特征及其与净辐射的关系,初步研究高寒区原始林土壤-大气热量交换特征。结果表明：随着土壤深度的增加,土壤热通量日变化振幅减小,至60cm处没有明显的日变化。除春季表层土壤5cm处热通量没有明显的日变化特征外,其余季节日变化呈明显“S”型曲线。不同深度的土壤热通量存在明显的季节及年内逐日变化特征,但变化的幅度表层土壤明显高于深层。不同年间土壤热通量逐日变化趋势非常一致。不同深度土壤年总热通量均为正值,表明高山林线地带土壤总体上为热汇。土壤热通量的变化与净辐射直接相关,但二者的同步性较差,土壤热通量对净辐射的反馈延时约6h,明显高于农田、草地及温带、亚热带森林,因此在利用净辐射估算土壤热通量时,要充分考虑植被类型及环境的影响。

英文摘要：

Based on the meteorological data collected at alpine virgin Abies george timberline area of the Serkyimla Mts,southeastern Tibetan Plateau,diurnal,seasonal and day-to-day variations of soil heat flux and its relationships with net radiation were analyzed to study soil-air thermal exchange characteristics at the alpine virgin forest area.The results suggested that the diurnal changes of soil heat fluxes decreased with the depth of soil layers,and no obvious variation was found at the depth of 60 cm.The diurnal change of soil heat fluxes at the 5 cm depth showed an ＂S＂ shape other than spring,in which no obvious diurnal change existed.Significant seasonal and day-to-day changes of soil heat fluxes were found in different depth soil,although it was less pronounced in deeper layer soil.The change trend of day-to-day soil heat fluxes was very consistent in two years.The total soil heat fluxes for different depth layers were all more than 0,suggesting that the soil at the alpine timberline area is totally heat sink,i.e.the heat flux transferring from air to soil.The change of soil heat flux was directly related to net radiation,however,the feedback of soil heat flux lagged 6 hours behind the net radiation,i.e.the changes of soil heat flux and net radiation was not synchronous.The lagged time was not only higher than in farmland or grassland,but also higher than in forest at temperate or subtropical zone,indicating that vegetation type and environment condition should be considered when soil heat flux was assessed by using net radiation.