摘要
土壤冻融过程中水分和盐分的耦合迁移一直是土壤水科学研究的难点和热点。为了解最大冻深期日最低气温与土壤水盐的尺度变化关系,该文利用墨西哥帽小波变换分析方法对内蒙古河套灌区1994-2006年最大冻深期(2月)日最低气温、0～40cm土层平均水分和盐分的时间-频率的尺度变化特征进行了分析。结果表明:在所研究的时间域内,该地区最大冻深期日最低气温、土壤水盐变化具有周期性特征;最大冻深期日最低气温以3a周期振动最强,土壤水盐均以2a周期振动最强;日最低气温、0～40cm土层水分和盐分有比较好的对应关系,即气温偏高期对应水分偏低期和盐分偏高期;日最低气温、0～40cm土层水分和盐分的周期性突变点位于1997年和2000年左右;盐分表现出不同时间尺度的振动变化,较日最低气温和水分变化更为复杂。该研究可为进一步研究干旱寒冷地区节水改造和盐渍化的防治提供参考。
Water and salt coupling transfer in freezing and thawing soils is the difficult point and hotspot research of soil water science. In order to understand the variation characteristics of air temperature and water salt, in this study, variation characteristics of daily minimum air temperature, average moisture and salt within 0-40 cm soil depth were analyzed using the Mexican hat function during freezing period in Feb. for 12 years （1994-2006） in Hetao Irrigation District, Inner Mongolia. The results showed that daily minimum air temperature and soil water salt change had a periodic characteristic during study period. The strongest wave period was 3 year, 2 year, 2 year for daily minimum air temperature, average moisture and salt within 0-40 cm soil depth, respectively. The changes of daily minimum air temperature show correlation with that of soil water and salt. High temperature period corresponded to that of the low water and high salinity, respectively. There are two abrupt change points around 1997 and 2000. Scale change of soil salt presented much more complicated compared with that of air temperature and soil water, respectively. These results are useful to soil salinization prevention and water-saving reconstruction in arid-cold area in future research.
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2012年第6期82-87,共6页
Transactions of the Chinese Society of Agricultural Engineering
基金
内蒙古自然科学基金项目(200508010303
2011BS0301)
国家农业科技成果转化资金项目(2010A40060873)
内蒙古农业大学科技创新团队基金(NDTD2010-7)
国家科技支撑计划项目(2011BAD29B03)
关键词
小波变换
温度
土壤水分
盐分
冻融期
wavelet transforms, temperature, soil moisture, salt, freezing-thawing period
