【作者】 刘艳伟；

【导师】 朱仲元；

【作者基本信息】 内蒙古农业大学 ， 农业水土工程， 2011， 博士

【摘要】 论文以国家自然科学基金地区项目“浑善达克沙地天然植被蒸散发计算与耗水机理研究(50769005)”以及国家自然科学基金重点研究项目“京蒙沙源区植被建设中水资源优化配置研究(50139040)”为支持,进行了精细周密的野外试验及室内实验,选取典型频率年—2004年(降水频率为43%)、2005年(降水频率为84%)及2006年(降水频率为14%)的气象数据、作物生物生理指标及土壤特性等数据进行计算和分析。用实测的表层土壤物化性质及土壤质地数据对资料缺测地区土壤水力特性参数进行确定。采用4种方法计算研究区参考作物腾发速率ET_o,以FAO56 Penman- Monteith为基准对其他三种常用ET_o计算式进行气象因子的的校正;用双作物系数法和Isareg模型计算植被腾发速率,对典型频率年腾发速率特征及其影响因素进行分析;比较典型频率年水汽热在表层、根系层、变饱和带迁移规律;进一步研究了土壤剖面昼夜、晴阴天水汽热运移规律;辐射平衡、能量平衡和光合作用特征及其影响因素的分析。得出以下主要结论:1.资料缺测地区土壤水力特性参数的确定。用实测的表层土壤物化性质及土壤质地数据,分别采用RETC软件中的PTFs函数及通过SPSS软件建立的当地PTFs函数对资料缺测地区土壤水力相关参数进行确定,通过了拟合相关图和均方差的检验,认为得出的饱和导水率、饱和含水率与土壤物化特性及土壤质地不是简单的线性关系,建立的当地PTFs函数在该地区可用。通过SPSS软件建立资料缺测地区的PTFs函数,把非线性问题转化为线性问题为本文的创新点之一。2.采用4种方法计算研究区ET_o,对典型频率年腾发速率特征及其影响因素进行分析。(1)对遗传算法率定ET_o相关参数(a_s和b_s)的可行性进行分析,取得了更加适合当地的较精确结果;(2)以普适性强、精度高的FAO56 Penman-Monteith为基准对其他三种常用ET_o计算式进行气象因子的的校正,本文在此处实现创新,为寻找计算参照作物腾发速率的简易模型提供了新途径,在其他地区的实用性及普适性有待于进一步考证;(3)对腾发速率与环境因子的关系进行了探讨,认为丰枯年影响因子大体相同,只是枯水年湿度的影响大于气温的影响,丰水年正好相反。3.对天然植被土壤水汽热通量的时间、空间信息进行同步分析的还鲜见报道。用枯水年资料建模,丰水年资料进行模型参数的检验。对丰枯年土壤剖面水通量的异同点进行了分析,揭示了丰枯年土壤剖面水汽通量特征和土壤剖面水汽热昼夜运移规律。4.以天然植被为例,进行了丰枯能量平衡对比。枯水年冠层潜热通量与其有效能量的关系为λE_c=0.965Ln(A_c)+3.803,R~2=0.59;丰水年二者的关系为λE_c=1.158A_c + 1.479,R~2=0.79。通过生育期λE_s/(λE_c+λE_s)的变化过程可以判断丰水年冠层达到全覆盖时对应的叶面积指数LAI=2.17,而枯水年难以判断。更多还原

【Abstract】 This study was supported by the Chinese National Science Foundation Program“Study for Evapotranspiration and Water Consumption Mechanism of Natural Vegeta- tion in the Otindag Sandy Land Region, China”(50769005) and the Chinese National Science Foundation Key Program“The scientific allocation of water resources in the ecological construction area between Inner Mongolia and Beijing, China”(50139040). We carried out open test and interior experiment carefully, use different hydrological years meteorological observation, crop index, and soil texture data during the there hydrological years to calculate and analysis.Measured surface soil physicochemical property and soil texture data were used to determined soil hydraulic properties. Four methods were used to calculate reference crop evapotranspiration and adjust by meteorological data. Evapotranspiration was calculated and evaluated using FAO-56 dual crop coefficient approach and Isareg model, analyze the characteristics and the key influences factors on actual evapotranspiration during the different hydrological years. Analyz and compare the variation and fluxes of the water- vapor-heat in surface, root-zone and variably-saturated media. Compare the water-vapor flux between sunny and rainy. Energy balance and photosynthetic properties were analyzed and influences of environmental factors were considered. The main conclusions are as follows:1. RETC-PTFs (pedo-transfer functions) and local-PTFs function structureded by SPSS were used to simulate soil hydraulic properties with measured surface soil physico- chemical property and soil texture data. The simulation results were assessed by the approach of fitting curve and by RMSE. Saturated hydraulic conductivity, saturated water contents and physicochemical property, soil texture are not linear relation and local-PTFs is effective. It is an innovation that linearity is turned into non-linear by SPSS.2.Four methods were used to calculate reference crop evapotranspiration and adjust by meteorological data. Analysis the characteristics and the key influences factors on evapotranspiration during the different hydrological years.(1) Relevant parameters estimation of reference crop evapotranspiration was determined by Genetic Algorithm. The results show that in those areas which lack net solar radiation, as and bs determined by Genetic Algorithm can be used in the estimation of reference crop evapotranspiration with preferable accuracy.(2) Other three common formulas were adjusted by meteorological data basing on universality strongly, high precision FAO56 Penman-Monteith. Provide a new simple way for reference crop evapotranspiration calculated, and the practical and universal needs to be research.(3) Inquire into the relationship between actual crop evapotranspiration and meteor- ological factors. Different hydrological year’s actual crop evapotranspiration has the same impact factor. The moisture influence is greater than the influence of the tempe- rature in low flow year, and the opposite in high flow year.3.Natural vegetation soil water-vapor-heat flux of synchronize time and space, analyze the day and night water-vapor-heat flux and characteristics; the paper studies the soil profile migration regularity of water-vapor-heat day and night. To model with experimental data in low flow year, test parameters with data in high flow year. Analyz and compare the variation and fluxes of the water-vapor-heat in surface, root-zone and variably-saturated media. Summarize the differences and similarities during different hydrological years. The soil profile has same vapor flux trends and characteristics. Compare the water-vapor flux between sunny and rainy.4.Analyze and compare the energy balance. The relationship between canopy of latent heat flux and the energy efficient in low flow year isλE_c=0.965 Ln(A_c)+3.803, R~2= 0.59; in high flow year it isλE_c=1.158A_c+1.479, R~2=0.79. The canopy full coverage in high flow year can be judged by the change processes ofλE_s/(λE_c+λE_s), the correspond- ing LAI =2.17 and the same results can not be judged in low flow year.更多还原