Knowledge Resource Center for Ecological Environment in Arid Area
| 黑河流域蒸散发的遥感估算 | |
| 其他题名 | Remote Sensing Estimation of Evapotranspiration in the Heihe River Basin |
| 郭晓寅 | |
| 出版年 | 2002 |
| 学位类型 | 博士 |
| 导师 | 程国栋 |
| 学位授予单位 | 中国科学院寒区旱区环境与工程研究所 |
| 中文摘要 | 蒸散发既包括从地表和植物表面的水分蒸发，也包括通过植物表面和植物体内的水分蒸腾。蒸散发既是水文循环的重要组成部分，同时由于水分变为气态的过程需要吸收热量，因此蒸散发也是热量平衡的主要项。地表热量、水分收支状况在很大程度上决定着地理环境的组成和演变，清楚地认识蒸散发，对了解大范围内能量平衡和水分循环具有重要意义，使我们能更深入认识陆面过程。可以正确评估气候和人类活动对自然和农田生态系统的影响。干旱区蒸散发的定量研究，有助于了解不同植被类型的蒸发特点，从宏观上确定其耗水量，进而对调整农业产业结构。确定农林牧三者的比例和分布，提供科学的依据。利用遥感资料并结合地面观测资料，计算黑河流域的蒸散，可以深入了解流域内的水分和能量的空间分配，进一步完善己取得的水资源和气象研究成果，使水资源的合理利用和分配定量化，同时也为黑河流域相关研究提供基础资料，为相近研究提供一种借鉴方法。本文选取NOAA AVHRR资料，对其进行辐射定标、几何纠正和大气纠正，并进行地图投影，与黑河流域其它资料匹配。选取了Priestley-Tavlor公式作为计算蒸散发的模型，并提出了用植被指数、地表温度和气温确定其中参数。的方法。同时，对多种地表生物物理参数的反演方法进行了讨论和分析，选取了简便易行的方法对黑河流域地表生物物理参数进行了估算。用分裂窗方法反演地表温度，用NDVI阈值发估算地表发射率，用NDVI确定窄波段反射率到宽波段反照率法中的转换系数。在对气温的估算中，本文通过对黑河实验数据的分析，提出了用植被指数和地表温度来反演气温的方法。在太阳辐射的计算上，充分考虑了坡度和坡向等地形因素，使山区太阳辐射的估算达到比较准确的程度。在对大气长波辐射的估算上，选取了用气温和海拔高度计算大气长波辐射的方法。 |
| 英文摘要 | Evapotranspiration includes the water evaporation from land surface and vegetation surface as well as the water transpiration from vegetation surface and vegetation body. It is not only an important component in hydrological cycle but also a main part of energy balance because when liquid water transfers to vapor it absorbs lager amount of heat. Therefore, to estimate the evapotranspiration correctly is very important for understanding the lager-scale energy and water balance. It is also a key for modeling land surface processes and evaluating the impacts of climate system and human activities on natural and farmland eco-systems. For the arid regions, the quantitative study of evapotranspiration is helpful to understand the evaporative characteristics of different kinds of vegetation and to calculate the water consumed by different ecosystems. These studies will lay a scientific foundation for adjusting the industrial structure among the agriculture, forestry and animal husbandry. The objective of the study presented in the paper is to clarify the spatial distribution of water and energy budget in the Heihe river basin by estimating the evapotranspiration with remote sensing, combined with ground observations. This study, closed related with the water resource and meteorological researches, could provide quantitative database for these relative studies. In our research the NOAA AVHRR data were selected and processed by calibration, geometric correction and atmospheric correction, then projected to match other data of Heihe river basin. We choose the Priestley-Taylor equation as the model for estimating evapotranspiration, and proposed to determine a by using vegetation indices, land surface temperature and atmospheric temperature, After analyzing many methods of retrieving land surface biophysical parameters, simple and convenient methods were selected. The split-window technique was selected to retrieve land surface temperature. Land surface emissivity was estimated using NDVI thresholds methods. Conversion coefficients of narrowband reflect to broadband albedo were determined by NDVI. On modeling solar radiation, topographic factors, such as slope and aspect, were considered, which make it possible for the precise estimate of solar radiation in mountainous area, we choose the atmospheric temperature and altitude for the estimate of the atmospheric longwave radiation. In our research we carried out remote sensing method for the estimation of the evapotranspiration in the Heihe river basin and proposed some ways to resolve the parameters in the evapotransiration model. Based on the upper methods the following conclusions were made: The validation of the surface parameters by using relative data of HEIFE Experiment was made, which shows that the results of the remote sensing estimation and the retrieval of evapotranspiration and some surface biophysical parameters reflects the characteristic of surface energy balance and distribution of these parameters. It is indicateed that the method used to estimate evapotranspiration in this article is operational. Spatial distribution of vegetation indices and evapotranspiration agree well, high vegetation indices corresponding to the high evapotranspiration. The area covered with density vegetation, such as grassland, marshes, forest, and oasis at the middle and lower reaches, have high vegetation indice and evapotranspiration, while area covered with sparse vegetation, such as cold desert, desert and gobi, the vegetaion indices and evapotranspiration are very low. The distribution of surface temperatures and net radiation agree well with the distribution of evapotranspiration and vegetation indices at the middle and lowest reaches. The distribution of surface temperature and net radiation at upper reaches are very complex, it is not only impacted by vegetation condition, but also relates to the topographical factor, such as aspect and slope. The Evapotranspiration is very low in the cold desert, desert and gobi. In the Ruoshui delta and Gurinai lake basin covered by well vegetation, evapotranspiration differs from their around areas. Evapotranspiration of oasis in middle reaches changes with the crop growth stage. The evapotranspiration of the natural oasis nearby the rivers differs from that of the around desert and gobi because of the different water resource conditions. The evapotranspiration in high degree overlay grassland and marshes is the highest in Heihe river basin, and it decreased at that area in middle degree overlay grassland and forest. Based on our research it shows that the remote sensing method for the estimation of evapotranspiration could reflect the evapotrranspiration and some surface parameters at the different time and areas in Heihe basin, at the same time we also should realize that many evapotranspiration models founded empirically, lacked physical basis, which will be restricted for the further development of the evapotranspiration studies. It is the hot point to develop the physical-based and practical methods for future studies on evapotranspiration estimation. |
| 中文关键词 | 黑河流域 ; 蒸散发 ; 遥感 ; 地表温度 ; 地表长波辐射 ; 净辐射 ; 植被指数 |
| 英文关键词 | Heihe river basin evapotranspiration remote sensmg surface temperature surface long-wave radiation net radiation vegetation indices |
| 语种 | 中文 |
| 国家 | 中国 |
| 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/2XILL650/286302 |
| 推荐引用方式 GB/T 7714 | 郭晓寅. 黑河流域蒸散发的遥感估算[D]. 中国科学院寒区旱区环境与工程研究所,2002. |
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