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2000 Fiscal Year Final Research Report Summary

Relationships between vapor condensation, evaporation and salinization near ground surfaces in arid and semi-arid areas.

Research Project

Project/Area Number 11650536
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 水工水理学
Research InstitutionDaido Institute of Technology

Principal Investigator

SHIMOJIMA Eiichi  Daido Inst.of Technol., Fac.of Eng., Professor, 工学部, 教授 (80027276)

Co-Investigator(Kenkyū-buntansha) TAMAGAWA Ichiro  Gifu University, Fac.of Eng., Associate Professor, 工学部, 助教授 (40273198)
Project Period (FY) 1999 – 2000
Keywordsarid-and seim-arid areas / evaporation / vapor condensation / salinization / experiment / numerical simulation
Research Abstract

By paying attention to the condensation of atmospheric vapor, the relation between soil-surface evaporation and salinization in arid/semi-arid areas was explored through an evaporation experiment from a sand column and a numerical simulation to meteorological data observed in a desert area in West China (HEIFE).
Using air-dried dune sand for HEIFE (Case A) and a fine silica sand (Case B), sand columns were set up on the balance, where only in the latter case, a shallow water table of NaCl solution with a high concentration was set. The columns were exposed to ambient air controlled at 65% humidity (corresponding to nighttime) and at 20% (daytime) alternately, where the air temperature is kept constant (25℃) and 550 W/m^2 of heat radiation was applied on the sand surface only at the dry air stage. Locations and movements of the evaporation and condensation zone for both cases were analyzed using information on vapor in the sand columns measured by humid-cups. For Case B the condensation amount at the wet stage was almost equal to the evaporation one at the dry stage, while for Case A, the evaporation was about ten times larger than the condensation and source of its surplus evaporation was the underlying aquifer. Soil water ahead of the evaporation front for Case B was chemically saturated and its concentration behind the front decayed exponentially with depth, while salinization for Case A was much lower.
A numerical simulation using a model of heat-moisture-solute movement in the atmosphere-land system was successfully undertaken. And it was known that source of evaporation in that desert was almost rainfall and a spike of solute concentration profiles observed at 〜10 cm deep from the ground surface appeared through the interaction between rain-infiltration and soil-water evaporation.

  • Research Products

    (4 results)

All Other

All Publications (4 results)

  • [Publications] 玉川一郎: "国際プロジェクトにおける地上観測-HEIFEを例に"水文・水資源学会誌. 13. 69-75 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 下島栄一: "蒸発過程における砂層中での水分・溶質移動に関する相似性"水文・水資源学会誌. 14(印刷中). (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Ichiro Tamagawa: "Meteorological observation in international projects-HEIFE"J.Japan Soc.Hydrol.And Water Resour.. Vol.13, No.1. 69-75 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Eiichi Shimojima: "Similarity on water and solute movement in a sand column induced by evaporation"J.Japan Sco.Hydrol.And Water Resour.. Vol.14, No.2 (in press). (2001)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2002-03-26  

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