Experiment Research Regarding Formation Mechanisms Of Condensing Water In The Wind Beach Area Of Ordos

Since may ,2005,we have begun to use self-made cage-lysimeter to do the experiment about condensing water in testing ground in Erdos Basin which is for water and salt transportation in Vadose zone. By analysing condensing water datas observed at typical time intervals in the two years, with the combination of synchronization meteorological element data, we have summarized formation and transformation rules of soil condensing water in wind-sand beach area in Erdos as follows:(1)There are two aspects about water vapor origin of soil condensing water, sometimes it comes from atmosphere, sometimes it comes from both Vadose zone.(2)During the time that is about from 7:00am to 6:00pm, above sand surface, moisture is evaporated to water vapor and diffuses to atmosphere; Below sand surface ,water vapor migrates to deeper Vadose zone and finally condenses at somewhere, the process provides vegetation in arid desert area the basic ecological needed water. After 6:00pm every day, atmospheric condensing water forms to the surface, until dawn both soil condensing water and atmospheric condensing water forms to the surface. The volume of condensing water increases. To about 7:00 next morning, few of the condensing water on the surface seeps into ground, other starts to evaporate into the atmosphere.(3)In the wind-sand beach area in Erdos, the biggest volume of soil condensing water is obtained no more than the depth of 10cm, condensing water also can be produced below the depth of 10cm, however, the quantity gradually decreases, below the depth of 20cm, there are not condensing water almostly.(4)The near ground temperature and ground temperature lowers to the dewpoint or below, condensing core exists, both of them are the precondition of the formation of condensing water; The difference of ground temperature as well as the relative humidity of the near ground are important factors for formation of soil condensing water; The sunny weather and breeze are advanced condition for the formation and transformation of soil condensing water.