img

官方微信

高级检索

中国沙漠 ›› 2002, Vol. 22 ›› Issue (6): 534-540.

• 研究论文 • 上一篇    下一篇

沙坡头人工植被固沙区天然降水的入渗和分配研究

王新平, 李新荣, 张景光   

  1. 中国科学院 寒区旱区环境与工程研究所沙坡头沙漠试验研究站, 甘肃 兰州 730000
  • 收稿日期:2002-04-12 修回日期:2002-09-08 出版日期:2002-12-20 发布日期:2002-12-20
  • 作者简介:王新平(1969-),男(汉族),甘肃通渭人,副研,博士生,主要从事干旱区水文水资源研究工作。E-mail:w_xinping@yahoo.com
  • 基金资助:
    中国科学院寒区旱区环境工程研究所知识创新工程项目(CACX210031;210094);中国科学院沙坡头沙漠试验研究站开放基金(20025)资助

Infiltration Processes of Precipitation in a Revegetated Sand Dune with Caragana korshinskii Shrub

WANG Xin-ping, LI Xin-rong, ZHANG Jing-guang   

  1. Shapotou Desert Research and Experiment Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China
  • Received:2002-04-12 Revised:2002-09-08 Online:2002-12-20 Published:2002-12-20

摘要: 土壤、植被冠层与大气界面间(SVAT)物质传输过程日益成为水文学研究最感兴趣的领域,降水量的迁移与转换是非灌溉区SVAT主要的物质传输过程。干旱半干旱区稀疏灌丛蒸散量占降水量的90%以上,因此对降水入渗与水分在土壤内植物根际区再分配的研究显得十分重要。试验于2001年8月17日至9月30日在中国科学院沙坡头试验站进行,主要观测人工植被荒漠灌木柠条(Caraganakorshinskii)灌丛固定沙丘降水入渗与再分配过程。结果表明:在7次不连续降水过程中,土壤入渗深度与降水强度呈简单线性相关关系,土壤入渗速率约为降水强度的10倍。当次降水过程中降水强度小于0.46mm·h-1时,土壤入渗速率约为0cm·h-1,此时的降水对沙区土壤基本上没有水分补给作用。受荒漠灌木柠条根系吸水作用的影响,其根系密集剖面深度40~140cm内降水水分入渗积累不明显。降水入渗速率及入渗深度受土壤剖面初始含水率多寡而变化,干燥土壤剖面有助于提高瞬时入渗速率。降水以后随着时间的推移,人工固沙区微环境内空气温度、湿度等气象条件适宜,柠条生长进入相对旺盛阶段,其根系密集层140cm深度处土壤含水率在总体上下降的过程中,表现出昼消夜长的趋势,试验期间翌日8:00时土壤含水率值略高于前一日20:00时水分值0.1%~0.3%。

关键词: 固定沙丘, 人工植被, 柠条灌丛, 沙坡头

Abstract: The experiment on precipitation infiltration and redistribution was conducted in an artificial shrub sand dune at Shapotou Desert Experimental Research Station, Chinese Academy of Sciences, from August 17 to September 30, 2001. The study site is located at southeast of the Tengger Desert at an elevation of 1330 m (MSL) with latitude of 37°27'N and longitude of 104°57'E. The climate of Shapotou region is semi-arid. A mean monthly maximum temperature of 24.3 ℃ was recorded during July and the lowest value of -6.9 ℃ during January. The average monthly relative humidity was the lowest (32.7%) during April, while the highest value of 54.1% during August. The sunshine hours during January and October range from 6.9 to 6.7 hour per day, and 7.0 to 8.2 hour per day in the remaining months. Average annual rainfall is 191.1 mm, of which 83% is received during May through September. During the experimental period, there were seven individual rainfall events, the precipitation varying from 1.5 mm to 40.7 mm. The maximum infiltration rate for precipitation of 40.7 mm was up to 0.42 mm·min-1, under a maximum rainfall intensity of 3.4 mm h-1 (14:00~15:00, Sep.18), with an average initial volumetric soil moisture of 5.4%. For the precipitation of 38.9 mm, the individual rainfall event started at around 16:00, August 17, 2001, lasting for about 26 hours to 18:00, August 18, 2001, it has an average rainfall intensity of 1.50 mm·h-1. The highest rainfall intensity of 5.3 mm·h-1 was recorded between 9:00~10:00, Aug 18, the overall precipitation amounts for 38.9 mm. The result indicated that the infiltration rate differed significantly under each individual rainfall with different initial soil moisture status and rainfall intensity. A drier soil profile favors the infiltration process, and obviously, there is a simple linear relationship between the infiltration rate and the rainfall intensity, whilst that the infiltration rate has a 10 times magnitude of the rainfall intensity. It has no contribution to the soil water supplement if the intensity of an individual rainfall event is less than 0.46 mm·h-1. Due to the soil-water uptake by vegetation root activities, the overall cumulative infiltration depth was less than 60 cm under an individual precipitation of around 40 mm with a intensity of 1.50 mm·h-1. At a certain soil depth of 140 cm, where featured by the concentration of rooting system, the soil moisture was depleted gradually, though it still varied in a fluctuation way of 12 h periodically between daytime and night, mainly due to the vegetation water consumption at daytime and the soil moisture flow concentration at night, the difference from dawn to the end of daytime was around 0.1%~0.3%.

Key words: stabilized sand dune, artificial vegetation, Caragana korshinskii shrub

中图分类号: