极干旱地区土壤与大气水分的相互影响

基于建立在莫高窟窟顶的密闭拱棚,通过监测棚内凝结水量和空气温湿度,对极干旱地区典型极干旱气候条件下土壤与大气水分的相互影响进行综合分析。棚内凝结水量和空气温湿度的监测结果表明,在热动力作用下存在地下水分向大气输送的过程,其原因主要是在温度作用下土壤结合水分的分解蒸发与土壤盐分的吸湿吸附的交替作用。这也是形成所谓“土壤凝结水分”与“土壤水分呼吸”的根源。当温度升高时,土壤结合水分分解蒸发“呼出”水分,当温度降低时土壤盐分吸湿吸附,“吸入”大气水分,形成土壤与大气不对称水分交流。称质量实验表明：土壤水分的变化与空气温度的变化完全对应;有深层水分支持的土壤吸收大气水分的能力相对较差。极干旱地区土壤与大气水分的相互影响研究结果能为莫高窟珍贵文物的保护提供参考。

Moisture Interaction Between Soil and Atmosphere in Extreme Dry Area

Based on airproof plastic greenhouse which built on the top of Mogao Grottoes and was used to monitor condensation water and air temperature and humidity,the moisture interaction between soil and atmosphere under the condition of classic extreme dry climate in extreme dry area was discussed.The measuring result of condensation water and air temperature and humidity in greenhouse showed that the groundwater was transferred to atmosphere under the influence of thermal power,and the main reason was the alternation of decomposition of bound water and adsorption of soil salinity under the action of temperature.It also caused ＂soil condensing water＂ and ＂soil moisture respiration＂.Bound water would ＂breath out＂ moisture when temperature rose,soil salinity would Absorb and ＂inbreathe＂ moisture from atmosphere when temperature dropped,and it became unsymmetrical moisture interaction between soil and atmosphere.The weighing experiments indicated that changes of atmosphere temperature and bound water were unanimous;the soil supported by deep phreatic water Absorbed atmosphere water slowly.The study on moisture interaction between soil and atmosphere in extreme dry area could provide some references for the protection of rare cultural relics in Mogao Grottoes.