干旱区高盐度潜水蒸发试验研究

Experiment on evaporation of high-TDS phreatic water in arid area

干旱区高盐度潜水蒸发试验研究国内外少有涉及。为分析干旱区高盐度潜水蒸发规律,开展了不同矿化度(3、30、100、250 g/L)潜水蒸发试验,着重分析不同处理潜水累积蒸发动态、日间蒸发动态及昼夜变化规律。结果表明:潜水累积蒸发量与时长、土壤剖面积盐量与矿化度均显著线性正相关;潜水蒸发相对于EФ20水面蒸发变化存在明显滞后;水面与潜水蒸发动态均表现为夜间变化强烈,不同矿化度潜水平均夜间蒸发量占日蒸发较大份额,除3 g/L处理外,均达60%左右。高盐度潜水蒸发过程对土质的影响呈非线性且非单一方向;夜间潜水蒸发的驱动因素为白天大气蒸发能力的延迟驱动及夜间水汽凝结产生的负压驱动。

Experiments on evaporation of High-TDS phreatic water in arid area are rarely inrestigated in home and abrood.Experiments on evaporation of different TDS（3,30,100,250 g/L） preatic water were carried out to research evaporation rule of High-TDS phreatic water in arid area.Results show that there is significant linear positive correlation between cumulative evaporation and time duration under the research condition,also the same relationship between TDS of phreatic water and cumulative salinity in soil profile.The variation of phreatic water evaporation is lag behind the change of surface measured by EФ20 equipment,but both of them are more drastic at nighttime than the daytime.Except the treatment of 3g/L TDS,the nighttime evaporation contribution to the whole day evaporation of phreatic water in other treatments achieved sixty percent.The research shows that the daytime evaporation capacity has significant effect on nighttime evaporation,and the soil water,vapor condense at profile also is an important driving factor for the nighttime evaporation.