Study of Condensate Absorption Capacity in Exposed Soil when Water Recedes at the Bottom of Hoh Xil Lake, Qinghai

Abstract

In order to investigate the characteristics of the condensate absorption capacity in an exposed sandy bottom when water recedes, the characteristics of condensate variation, condensate formation time, condensate volume, and its absorption capacity were investigated in July 2021, using a micro-osmometer. The research area was the artificial water-retention layer and bare ground of the exposed sandy bottom, formed under the influence of the warming-wetting trend that occurs when water recedes in the salt-lake area of the Qinghai-Tibet Plateau, as well as two conditions: underpass and under sealed. According to the results, the time of condensation generation during the observation period in the salt-lake area of Hoh Xil begins at about 0:00 and ends at about 10:00 The artificial water-retention layer had little influence on the condensation generation time, and the trend of the condensation rate is the same. The unidirectional condensation of water in near-surface air is significantly better under artificial water-retention layer conditions than under bare ground conditions, with condensation occurring three times more frequently than under bare ground conditions. The amount of water condensation in the lower part of the soil under artificial aquifer conditions is 2.588 times greater than that in the near-ground air, while the amount of water condensation in the lower part of the soil under bare ground conditions is 1.783 times greater than that in the near-ground air. The total amount of bi-directional condensation under artificial water-retention layer conditions is slightly less than that in bare ground conditions, while the total amount of unidirectional condensation under artificial water-retention layer conditions is significantly higher, indicating that the artificial water-retention layer contributes to the absorption of water from near-surface air. Due to the presence of permafrost in the Qinghai-Tibet Plateau region, the zero-flux surface transport of evanescent heat in the salt-lake area of Hoh Xil lies approximately within 30 cm from the surface to the ground. The analogous humidity coefficient characterizes the condensate absorption capacity coefficient as the storage capacity of condensate in the surface layer of the soil in a certain area, providing strong evidence that the condensate absorption capacity is higher under the artificial water-retention layer conditions than in bare ground, regardless of whether the condensation is bi-directional or unidirectional. The results of this study can provide a theoretical basis for condensate absorption capacity and vegetation restoration in the bare ecologically degraded areas of the lake bottom.