Knowledge Resource Center for Ecological Environment in Arid Area
| 考虑干旱水分胁迫的黑河中游蒸散发遥感估算研究 | |
| 其他题名 | Estimation of evapotranspiration under drought water stress conditions based on remotely sensed data over middle streams of Heihe River Basin |
| 李艳 | |
| 出版年 | 2014 |
| 学位类型 | 硕士 |
| 导师 | 卢玲 ; 黄春林 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 陆面蒸散发包括土壤蒸发和植被蒸腾两部分，是能量循环和水分循环的重要环节，准确估算陆面蒸散发对水文和气候等研究具有重要的现实意义。黑河中游地区是典型的干旱半干旱地区，以灌溉农业为主，水资源开发利用程度很高。在该地区开展蒸散发研究，可以进一步了解能量和水分的时空分布特征，促进水资源的合理利用。 为了获得精度相对较高的干旱半干旱地区陆面蒸散发时空分布情况。本研究以黑河中游荒漠绿洲区为研究区，在考虑了水分胁迫信息的情况下，基于地表能量平衡系统（SEBS）模型，利用卫星资料结合地面气象、通量观测数据，估算了研究区的蒸散发量。研究中使用的遥感数据均采用的中分辨率成像光谱辐射仪（MODIS）数据，地面观测数据（气象数据、通量数据）来自黑河综合遥感联合试验和黑河流域生态—水文过程综合遥感观测联合试验（HiWATER）。论文的主要研究内容包括以下三个方面： 1.应用高效、稳健的EFAST方法，以黑河流域盈科绿洲站为例，从三个方面对SEBS模型的参数敏感性进行了分析：（1）分别以感热通量、潜热通量、蒸发比作为SEBS模型的输出参数，分析其对12个输入参数的敏感性；（2）利用气象数据驱动模型，分析感热通量、潜热通量、蒸发比对6个地表特征参数的敏感性；（3）分析了参数取值范围对敏感性分析结果的影响。研究结果表明：感热通量、潜热通量、蒸发比都对参考高度处的气温和风速、地表温度以及植被特征参数的敏感性较高。参数间相互作用对感热通量、潜热通量的间接影响很小，而对蒸发比的影响较大。当气象输入参数确定时，6个地表参数中地表温度对模型输出的直接贡献最大，其主敏感度指数接近0.6。参数采样范围不同时，模型输入参数的敏感性表现不同。 2.有研究指出在干旱半干旱地区，SEBS模型存在低估感热通量，高估潜热通量的现象。本研究为了提高干旱水分胁迫条件下SEBS模型地表通量估算精度，首先分析了土壤供水情况与蒸散发的关系。在此基础上，选择归一化植被水分指数（NDWI）作为干旱水分胁迫信息，以线性、指数、S曲线三种不同形式结合到SEBS模型的kB-1系数中，建立了修正模型SEBS-E、SEBS-L、SEBS-S。 以黑河中游绿洲荒漠区为研究区域，选取2008-2011年盈科绿洲站的气象、通量数据对模型进行标定，选取2012年的HiWATER中游试验站的气象、通量数据对模型进行验证。 研究结果表明：土壤可利用水分不足，植被受到干旱水分胁迫时，土壤含水量对蒸散发的影响显著。存在干旱水分胁迫时，与原始SEBS模型相比，考虑了干旱水分胁迫信息的SEBS-E、SEBS-L、SEBS-S模型能够更为准确的估算地表通量。这三种修正方案对SEBS模型的改进程度基本一致，NDWI ≤ 0.24时，改进显著，最少能使感热通量的RMSE减小29 W/m2，Bias减小62 W/m2，潜热通量的RMSE减小77 W/m2，Bias减小91 W/m2。 3. 利用SEBS、SEBS-E、SEBS-L、SEBS-S估算了2012年6月24日、7月10日、8月2日、9月3日研究区瞬时地表通量，然后利用蒸发比不变法进行时间尺度扩展，估算了这四天研究区的日蒸发量。结果表明：研究区的地表通量、日蒸散发量空间分布差异明显，绿洲区和周围戈壁、沙漠和荒漠区的估算值差别显著。对于存在干旱水分胁迫的区域，原始SEBS模型估算的感热通量偏低，潜热通量和日蒸散发量偏高。相比之下，SEBS-E、SEBS-L、SEBS-S模型能够更加准确的估算研究区的蒸散发量。6至9月之间研究区的感热通量差异不大，但是潜热通量和日蒸发比季候变化特征明显。 |
| 英文摘要 | Evapotranspiration, the sum of evaporation from soil and transpiration from vegetation, is an important part of the energy cycle and the hydrologic cycle. Accurate evapotranspiration has important practical significance on research of hydrology and climate. The middle streams of the Heihe River Basin has a typical arid to semi-arid climate. The development and utilization of water resources is high in the study area. To understand the temporal and spatial distribution of the energy and water content and to promote the rational use of water resource, we estimated evapotranspiration over the study area. In order to obtain a relatively accurate temporal and spatial distribution of the land surface evapotranspiration over arid and semi-arid regions, we estimated evapotranspiration over middle streams of the Heihe River Basin under drought water stress condition based on the surface energy balance system (SEBS) by using satellite data combined with ground meteorological and fluxes observation data. The Moderate Resolution Imaging Spectroradiometer (MODIS) productions and ground observation data from the Water Allied Telemetry Experimental Research (WATER) and Heihe Watershed Allied Telemetry Experimental Research （HiWATER）were used to estimate fluxes and evapotranspiration. The main contents of this paper are as follows: 1. The Extend Fourier Amplitude Sensitivity Test (EFAST) was used to analyze the global sensitivity of SEBS model parameters in the Yingke oasis station located in the Heihe river basin from three points below: (1) the sensitivity of input parameters was analyzed, when the output parameter of the SEBS model such as sensible heat flux, latent heat flux and evaporation fraction, was fixed respectively. (2) The sensitivity of surface parameters was analyzed, when the meteorology data was fixed. (3) Impact of parameters ranges on sensitivity index was analyzed by tuning input parameter ranges. Results showed that the model is sensitive to air temperature, wind speed, surface temperature and vegetation parameters. The impact of parameter interactions is slight for sensible heat flux and latent heat flux but great for evaporation fraction. When the meteorological data is fixed, the output variables are highly sensitive to surface temperature with a high main sensitivity index (about 0.6).The sensitivities of input parameters are different from different parameter ranges. 2. In the arid and semi-arid regions, SEBS model has underestimated sensible heat flux and overestimated latent heat flux. To improve the accuracy of land surface fluxes estimated by SEBS under drought water stress conditions, we analyzed the relationship between soil water content and evapotranspiration. The normalized difference water index（NDWI） as a drought water stress information was integrated into SEBS to modify the value of parameter (kB-1) based on linear, exponential, and S-curve equations, respectively. Therefore three modified models were named as SEBS-E, SEBS-L and SEBS-S. The proposed scheme was calibrated by meteorological and fluxes observations in 2008-2011 from the Yingke oasis station and validated by meteorological and fluxes observations in 2012 from HiWATER. Results showed that the soil water content had significant effects on the evapotranspiration under water stress conditions. SEBS-E, SEBS-L and SEBS-S could significantly improve the land surface flux estimation in arid and semi-arid regions under drought water stress conditions. The issues of the underestimation of sensible heat fluxes and the overestimation of latent hear fluxes from SEBS could be improved by using the proposed scheme. When NDWI is less than 0.24, RMSE in estimated sensible and latent heat fluxes are reduced by 29 W/m2 and 77 W/m2. Biases in estimated sensible and latent heat fluxes are reduced by 62 W/m2 and 91 W/m2. 3. The instantaneous surface fluxes were estimated in June 24th, July 10th, August 2nd and September 3rd, respectively, using SEBS,SEBS-E, SEBS- |
| 中文关键词 | 黑河中游 ; 遥感 ; 干旱水分胁迫 ; 地表能量平衡模型 ; 蒸散发 |
| 英文关键词 | middle streams of Heihe River Remote Sensing drought water stress SEBS evapotranspiration. |
| 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 | 中国科学院西北生态环境资源研究院 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287383 |
| 推荐引用方式 GB/T 7714 | 李艳. 考虑干旱水分胁迫的黑河中游蒸散发遥感估算研究[D]. 中国科学院大学,2014. |
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