采用微型蒸渗仪对青藏高原风火山流域不同退化高寒草甸凝结水进行了实地观测实验,根据观测数据分析了风火山流域凝结水的形成规律。研究结果表明,青藏高原风火山流域凝结水主要来源于两个方面,空气中的水汽,包气带向上迁移的水汽。其中来源于包气带的凝结水显著大于来源于空气的凝结水。凝结水基本发生在夜间20:00至次日8:00的时段内,并且在次日6:00-8:00之间凝结量最大,其形成深度主要集中在0-5cm土壤剖面范围内。该区凝结水量随着高寒草甸的退化表现为减小趋势,凝结水对于青藏高原高寒草甸生态系统平衡的维持具有十分重要的意义。

Using micro-lysimeter, we observed the condensed water in the soils of variously degraded alpine meadows in Fenghuoshan basin of the QinghaiTibet Plateau.The formation mechanism of condensed soil water was further analyzed according to the observation data.The results showed that condensed soil water came mainly from two sources:water vapor in the air and in the vadose zone migrated upward under the action of the geothermal gradient.The water vapor from the vadose zone was significantly greater than that from the air.The condensation mainly occurred during night from 20:00pm to 8:00am in the next day, and the largest amount of water was condensed in early morning between 6:00am and 8:00am.Meanwhile, the condensation mainly occurred within the upper 5cm of the soil profile.The amount of condensed water decreased with the degradation of alpine meadows, and the occurrence of condensation was of great significance in maintaining the balance of alpine meadow ecological system.