Seasonal Change of Water Absorption Capability and Moisture Content of the Top Salt-crust in Lop Nur Dry Lake
Two observing sites within the Lop Nur dry salt lake were selected as field experiment areas to monitor the moisture content change on the surface of salt-crust, groundwater level and meteorological data, and a systematic observation lasted for more than one year. One observing site has typical bright stripes exhibiting white color and is named WOS, and the other has typical gray stripes assuming black color and is called BOS. Based on the experiment, it could be concluded that the seasonal moisture values of salt-crust in the two observing sites are different: the adsorbed water content on the surface of salt-crust is higher than the crystal water content, with the difference of adsorbed water content in the two observing sites being about 1%; the content of crystal water in BOS is over 3 times that in WOS. The field observation data indicate that the groundwater level is relatively stable, and it makes little contribution to the adsorbed water content of the surface in salt-crust in BOS. The absorption capability of salt-crust in BOS is remarkably stronger than that in WOS both under the conditions of high humidity and different temperatures in field test or laboratory simulation test, and the difference of water absorption capability is even more than 10 times, probably caused by the difference of the mineral compositions, such as the content of magnesium sulfate in the two observing sites during the salt-curst formation and development.