Knowledge Resource Center for Ecological Environment in Arid Area
| 地表土壤热通量遥感估算方法研究 | |
| 其他题名 | Research on land surface soil heat flux remote sensing estimation |
| 朱伟伟 | |
| 出版年 | 2014 |
| 学位类型 | 博士 |
| 导师 | 吴炳方 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 地表土壤热通量是地表能量平衡的重要组成部分，它是指在地表层土壤与下层土壤之间因多种因素作用而产生的一种热量交换，它对于研究干旱区与半干旱区的陆表蒸散具有重要意义。在陆表蒸散遥感估算模型中，它主要影响着感热通量与蒸发比的估算；而陆表蒸散是区域水量平衡分析的重要变量，在区域水文生态研究过程中陆表蒸散量起着关键性的作用。因此，精确的估算地表土壤热通量对于地表能量平衡、陆表蒸散遥感估算以及区域水文生态方面研究具有重要意义。 本文利用MODIS数据与FY静止气象卫星数据，分别从经验方法与一维土壤热传导理论出发，研究晴天卫星过境瞬时地表土壤热通量以及日地表土壤热通量的遥感估算模型。主要结论如下： （1）影响地表土壤热通量的主导因子是地表净辐射、比值植被指数、太阳高度角、短波红外反射率以及地表温度，基于这些主导因子建立了基于MODIS的黑河流域晴天白天卫星过境瞬时地表土壤热通量的经验估算方法；地面观测数据验证表明，在盈科站、阿柔站、花寨子站、马莲滩站、冰沟站估算值与地面观测值之间的决定系数R2分别为0.841、0.893、0.801、0.877、0.803，均在0.8以上，可以满足实际应用需求。 （2）改进了传统地表土壤热通量估算的半阶法，建立了地表土壤热通量日值遥感估算模型，能够基于地表温度的遥感数据估算出裸土区及植被覆盖区的地表土壤热通量的日变化过程，进而估算出地表土壤热通量日值；基于MODIS四次卫星过境瞬时信息模拟出来的晴天地表温度日变化数据，分别在黑河流域盈科绿洲站与阿柔高寒草地站进行估算地表土壤热通量，地面观测数据验证结果表明，日地表土壤热通量估算值与地面观测值之间的决定系数R2分别为0.916与0.887。 （3）无论是在干旱区的黑河流域与半干旱区的海河流域，地表土壤热通量的季节性日内变化过程在晴天状况是随着净辐射的变化而有规律的变化，一般来说，地表土壤热通量的最大值出现在中午时间段，且出现最大值的时间早于地表净辐射出现最大值的时间，总体变化曲线如柏松函数变化；在阴雨天以及灌溉条件下，地表土壤热通量的日内变化过程呈不规则。 （4）日地表土壤热通量在数值上明显的不为零，在冬季均表现为负值，在春季表现为由负值转变为正值，在夏季均表现为正值，在秋季，地表土壤热通量由正值转变为负值；一般来说，每年6月份日地表土壤热通量会出现最大值，每年12月份会出现最小值。 |
| 英文摘要 | Surface soil heat flux (G0), the exchange of heat energy between the soil surface and subsoil generated by the combined action of multiple factors, is a key component of the Earth’s surface energy balance, especially over relative dry land surfaces. At the daily temporal scale it affects the surface soil temperature regime and surface evapotranspiration, which are used as input for various surface eco-hydrological models; it especially affects the accuracy of evapotranspiration estimation algorithms. Therefore accurate estimation of surface soil heat flux is important for researchers working on meteorology, hydrology and agriculture. This study focused on the instantaneous surface soil heat flux at the satellite transit time and daily soil surface heat flux estimation based on the MODIS data and FY data with empirical method and one-dimensional theory of soil heat conduction on sunny day. The main conlusions are as follows: 1) The dominant factors of affecting surface soil heat flux were the ratio vegetation index, solar elevation angle, shortwave infrared reflectivity and surface temperature at the Heihe River Basin. An empirical ratio method was developed to estimate surface soil heat flux at the satellite transit time based on MODIS and those dominant factors on sunny day. The R2 in Yingke station, Arou station, Huazhaizi station, Maliantan station, and Binggou station is respectively 0.841、0.893、0.801、0.877、0.803, respectively. The R2 is more than 0.8 in every station. The result can meet the needs of practical applications. 2) An improved diurnal surface soil heat flux estimation method was proposed from traditional half-order method, which can only use surface temperature from remote sensing data to estimate the diurnal surface soil heat flux at the bare soil and vegetation cover area, and then estimate the daily surface soil heat flux. The daily surface soil heat flux on sunny day was estimated based the proposed method with the diurnal surface temperature simulated from four times MODIS transit data and surface temperature from FY-2F product data at the Heihe River Basin and Hai Basin. Estimation results show that the accuracy was better at the Heihe River Basin from the improved half-order method based on four times MODIS transit data. The R2 in Yingke station and Arou station is respectively 0.916 and 0.887. 3) Seasonal diurnal surface soil heat flux has a regular variation with net radiation on the sunny day both in arid areas of the Heihe River Basin and semi-arid areas of the Haihe River Basin. In generally, the maximum surface soil heat flux was occur at noon time and the time of the maximum surface soil heat flux was earlier than the time of maximum net radiation. The curve of diurnal surface soil heat flux was Poisson function distribution. Diurnal surface soil heat flux has an irregular variation on the rainy day and irrigation conditions. 4) Daily surface soil heat flux significantly is not zero, which was less than zero in winter, changes from negative to positive in the spring, positive in the summer, changes from positive to negative in the fall, and the maximum of daily surface soil heat flux was in June, the minimum in December. |
| 中文关键词 | 地表土壤热通量 ; 地表温度 ; FY-2F ; MODIS ; 蒸散发 ; 黑河流域 ; 海河流域 |
| 英文关键词 | Surface soil heat flux Surface temperature FY-2F satellite MODIS Evapotranspiration Heihe River Basin |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 地图学与地理信息系统 |
| 来源机构 | 中国科学院遥感与数字地球研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287455 |
| 推荐引用方式 GB/T 7714 | 朱伟伟. 地表土壤热通量遥感估算方法研究[D]. 中国科学院大学,2014. |
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