黄土高原半干旱草地降水前后土壤的温、湿度及热力特征  

Characteristics of Soil Temperature,Moisture and Heat Pro-and Postprecipitation in Semiarid Grassland over Longzhong Loess Plateau

作　　者：岳平[1,2] 张强[1] 王胜[1] 王润元[1] 李宏宇[1] 王若安[1] 

机构地区：[1]中国气象局兰州干旱气象研究所甘肃省干旱气候变化与减灾重点实验室/中国气象局干旱气候变化与减灾重点开放实验室,甘肃兰州730020 [2]张掖国家气候观象台,甘肃张掖734000

出　　处：《中国沙漠》2013年第6期1766-1774,共9页Journal of Desert Research

基　　金：国家自然科学基金项目(40830597;41075008;41075009);国家重点基础研究发展计划项目(2013CB430206;2012CB955304);中国博士后基金项目(20110490854);中国博士后特别资助基金项目(2013T60901);中国气象局干旱气象科研基金项目(KYS2011BSKY01)资助

摘　　要：本文利用兰州大学半干旱气候与环境观测站(简称SACOL站)陆面过程综合观测资料,分析了强降水前后榆中黄土高原半干旱草地土壤温、湿特征的差异,讨论了水分状况对土壤热力参数及地表能量分配的影响。结果表明:水分胁迫条件下,黄土高原半干旱草地土壤在10cm深度存在一个湿层;强降水过程可使土壤湿度受影响范围接近40cm深度。水分胁迫条件下,感热通量是黄土高原半干旱草地生态系统能量分配过程中净辐射的最大消耗项;无水分胁迫条件下,潜热通量是能量平衡系统中净辐射分量的最大消耗项。降水改变了土壤湿度并使得土壤热传导率发生变化,土壤热传导系数和土壤热容量随土壤湿度增加而增大。By using the radiation, turbulence flux, soil recorded at the Semi-Arid Climate and Environment temperature and soil moisture, and soil heat flux data Observatory of Lanzhou University （SOCAL）in June 2008, the influence of water stress on soil moisture, temperature and soil thermal parameters for semi-arid grassland on the Loess Plateau were studied. The influence of water stress on energy fluxes and partitioning in semi-arid grassland were also discussed. The results suggest that a wetting layer exists at a depth of 10 cm under the surface of the semi-arid Loess Plateau grassland soil. Under the condition of water stress, heavy precipitation allows soil moisture to be affected as deep as 40 cm below the surface. When this occurs, the sensible heat flux of net radiation energy is mostly consumed during energy distribution of the Loess Plateau semi-arid grassland ecosystem. However, in the absence of water stress, the latent heat flux con- sumes most of the net radiation components of the energy balance system.

关 键 词：半干旱草地 水分胁迫 能量分配 土壤热力参数 

分 类 号：S152.8[农业科学—土壤学]