Study on the Relationship between Evaporation from Bare-Soil Surfaces and Salinization in Arid and Semi-Arid Areas

干旱半干旱地区裸土蒸发与盐碱化关系研究

• 批准号: 09650575
• 负责人: SHIMOJIMA Eiichi
• 金额: $ 1.86万
• 依托单位: Daido Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650575/
• 关键词: evaporation from bare-soil; salinization; arid and semi-arid areas; experiment; numerical simulation

This research aims at clarifying the relation between evaporation from bare-soil surfaces and salinization in arid and semi-arid areas through an experiment and a numerical simulation. The following results were obtained.(1) In the experiment, dune sand in Western China was used for setting up a sand column and a controlled atmospheric condition (temperature, humidity and radiation) was applied on the upper surface of the column with initially uniform water content profile (field capacity). 1) Liquid water, water vapor and solute dissolved from soil particle behaved in a manner of similarity, and evaporation rate varied inversely as square root of time. 2) Application of radiation suppressed evaporation through a downward transport of vapor. 3) High salinization occurred in a dried zone ahead of the drying front lead descent of its vapor density but increase in resistance to the vapor transport owing to the crystallization was not seen. 4) Under the periodic atmospheric condition simulating night-time (non-radiation and moist air) and daytime (radiation and dry air), periodic occurrence of evaporation-condensation near the sand surface played an important role in the evaporation process.(2) A numerical simulation using a newly formed calculation-scheme for water and solute movement predicted characteristics of evaporation-salinization seen in the experiment, and its solutions became very useful information for understanding the evaporation-salinization process.

这项研究旨在通过实验和数值模拟来阐明裸土表面蒸发与干旱和半干旱地区的盐水之间的关系。 （1）在实验中，中国西部的沙丘砂用于建立砂柱，并在柱的上表面上应用了具有统一的水含量剖面（现场容量）的控制大气条件（温度，湿度和辐射）。 1）液态水，水蒸气和溶质从土壤颗粒中以相似性的方式溶解，而蒸发速率则以时间的平方根成反比。 2）通过蒸气的向下运输施加辐射抑制蒸发。 3）高盐分发生在干燥前铅下降的干燥区域的蒸气密度下降，但由于没有结晶而对蒸气转运的抗性增加。 4) Under the periodic atmospheric condition simulating night-time (non-radiation and moist air) and daytime (radiation and dry air), periodic occurrence of evaporation-condensation near the sand surface played an important role in the evaporation process.(2) A numerical simulation using a newly formed calculation-scheme for water and solute movement predicted characteristics of evaporation-salinization seen in the experiment, and its solutions became very useful information for understanding the蒸发 - 盐化过程。