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| 基于优化的理论干线的二层遥感蒸散模型研究 | |
| 其他题名 | A Research Based on Optimized Theoretical Dry Line of Two Source Remote Sensing Evapotranspiration Model |
| 米素娟 | |
| 出版年 | 2016 |
| 学位类型 | 博士 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 蒸散发，包括土壤蒸发和植被蒸腾，是水圈、大气圈和生物圈水分和能量交换的主要过程，也是水循环的最重要的分量之一。随着对地表能量交换和物质迁移研究的深入以及水资源合理利用与管理定量化的迫切要求，蒸散发越来越受到人们的重视。基于遥感数据的大尺度蒸散发反演已经成为流域水资源配置和管理的热门课题。本论文以地表温度-植被覆盖度特征空间中理论干线位置的确定为研究方向，基于卫星遥感数据、地表观测的微气象数据等，提出一种利用简化热惯量估算特征空间理论干线的方法，从而进行遥感蒸散发的估算。本论文主要开展了如下工作：(1)提出利用简化热惯量估算理论干线的方法。由于二层遥感蒸散模型估算理论干线的方法在潮湿地区和湿润情况下的不适用性，本文首先提出利用净辐射通量代替土壤热通量估算理论干边的方法(DDTI)，即利用简化热惯量估算理论干线。利用华北平原2011年的遥感和微气象数据估算简化热惯量的标准值，得到裸土和全植被的标准的简化热惯量值。与实验室观测的简化热惯量数据相比，两者的简化热惯量值的偏差均小于20.因此，遥感模拟的简化热惯量值是合理的。(2)将标准简化热惯量值应用在半湿润的华北平原地区和干旱半干旱的黑河中游地区，进行遥感蒸散发的估算，并用地表观测的涡度相关数据进行评估和验证。结果表明，基于简化热惯量估算理论干线的二层遥感蒸散发模型，估算蒸散发达到较高的效果，能够满足地表水分及能量平衡分析的需要。(3)根据“土壤热量平衡与温度廓线实验”观测的净辐射通量、土壤热通量、地表温度等数据，提出一种利用净辐射通量和地表温度数据，估算2cm深白天的土壤热通量的方法。然后，根据观测的表层的土壤温度和1cm深的温湿度数据，提出一种基于净辐射通量和地表温度数据估算白天的地表土壤热通量的方法。最后，将该方法在“热量平衡与温度廓线实验”的其它时期进行验证。研究结果表明，模拟的土壤热通量基本反映了土壤热通量的白天尺度的变化过程。“热量平衡与廓线实验”模拟的土壤热通量与观测的土壤热通量的偏差介于7.99 W/M2~10W/M2。利用黑河中游沙漠站和戈壁站的观测数据，得到沙漠和戈壁两种类型的土壤热通量的估算公式，验证表明：沙漠站21天模拟的土壤热通量与观测的土壤热通量的偏差为8.84W/M2，RMSE为28.9W/M2；戈壁站20天模拟的土壤热通量与观测的土壤热通量的偏差为6.69W/M2，RMSE为25.3W/M2。 (4)利用简化热惯量的概念，估算白天FY-2D各个过境时刻所对应的理论干线，并根据普通劈窗算法反演FY-2D的地表温度，进而获取FY-2D数据各个时刻的波文比，进而利用二层遥感蒸散发模型估算白天时间过程的蒸散发及白天的总量。本文将该方法应用在华北平原地区，并从理论干线和蒸发比的白天变化过程、蒸散发结果与禹城站观测结果比较，以及蒸散发的空间分布三个方面进行验证。验证结果表明，本文提出的估算白天蒸散发的方法，从理论上和蒸散发量上看，优于恒定蒸发比法。最后，分析地表温度、起始温度对蒸散发结果的影响。潜热通量对初始温度的敏感性不强。初始温度1℃的误差，可以引起潜热通量1~3W/M2的误差。潜热通量对地表温度的敏感性较强，潜热通量随着地表温度的增高而降低。地表温度1℃的误差，将引起潜热通量20W/M2的误差。随着地表温度的升高，净辐射通量逐渐降低。地表温度1K的偏差，引起净辐射通量6W/M2的偏差。 |
| 英文摘要 | Evapotranspiration, which includes evaporation and transpiration, is a main process in the water-exchanging and energy exchanging of hydrosphere, atmosphere, biosphere and it is also the most important part in the water cycle. With the further research on the surface energy exchange and the matter migration on the earth surface, as well as urgent demand on the water resource management, people has increased attention on evapotranspiration these years. Evapotranspiration based on remote sensing is now a hot topic in the water resource distribution and management. This research is based on how to obtain therotical dry line in the LST-VFC feature space. With the help of remote sensing data and meteorogical data from many air stations, we proposed a method named simplified thermal inertia (STI) to obtain therotical dry line, then the two source remote sensing evapotranspiration model was used to estimate ET in the paper. Firstly, a method to estimate theoretical dry line was proposed in this paper by using simplified thermal inertia. For the reason that the two source remote sensing evapotranspiration model has some defects when used in wet situations. So a new concept named Simplified Thermal Inertia (STI) was proposed, which used net radiance to estimate dry line rather than soil heat flux. Its standard values in bare land and full vegetation covered area of the North China, were estimated by using remote sensing data and meteorogy data. At last, standard values were validated by an experiment in the laborotary and biases of two land cover types are less than 20.Therefore, two standard values of STI are reasonable.Secondly, the method to obtain dry line was validated in the NorthChina and the middle reaches of the Heihe River. The result showed that this method had a good relationship with data from Eddy Correlation and this method can be used to estimate ET in these two regions.Thirdly, a model to obtain soil heat flux in daytime was proposed and the data used to build this model were from an experiment named “heat energy balance in the soil surface and soil temperature profile experiment”. The net radiance and surface temperatures of different times are the only two parameters which included in this model. This model was validated by data from “heat energy balance in the soil surface and soil temperature profile experiment” and the “HiWATER” experiment. The result showed that soil heat flux estimated by new model reflected the trend of daytime soil heat flux. Soil heat flux estimated by the new method had biases with observed between 0.9 W/M2 and 16 W/M2; the biases in the desert and the Gobi were 8.844 W/M2 and 6.69 W/M2, respectively; and the RMSE were 28.9 W/M2 and 25.3 W/M2, respectively. .Endly, a method to estimate daytime ET was proposed by using STI to estimate therotical dry line in the daytime. Land surface temperatures were retieved by General Split Window Method, whose original data were from FY-2D data. After that, several instantaneous regional ET were obtained by two source remote sensing evapotraspiration model and daytime ET was estimated at last. This method was used in the NorthChina and three ways were used to validate the new method, which were changing trends of therotical dry line and EF in the daytime, comparing ET results with Yucheng Station, distribution of ET in regional area. Results showed that, the new method was better than method which used EF from an instantaneous time to estimate the whole day. LE has low sensitivity to the initial temperature, but has high sensitivity to the retrived LST. 1K difference with the truth value will bring error about 20W/M2 in the LE result. The net radiance will decrease with the increase of LST. 1K difference with the truth value will bring error about 6 W/M2 in the net radiance. |
| 中文关键词 | 蒸散发 ; 简化热惯量 ; 理论干线 ; 土壤热通量 ; 日时间尺度扩展 |
| 英文关键词 | Evapotranspiratoin Simplified Thermal Inertia Therotical Dry Line Soil Heat Flux Daily Scale Expand |
| 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 | 中国科学院地理科学与资源研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287653 |
| 推荐引用方式 GB/T 7714 | 米素娟. 基于优化的理论干线的二层遥感蒸散模型研究[D]. 中国科学院大学,2016. |
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