【作者】 杨永民；

【导师】 冯兆东；

【作者基本信息】 兰州大学 ， 地图学与地理信息系统， 2010， 硕士

【摘要】 地表能量通量是全球水循环和能量平衡的重要环节,是全球气候变化的重要研究内容之一,在陆地表层和大气之间的相互作用研究,水资源规划管理等各个方面具有重要价值。水是万物之源,是人类生存生活、社会经济发展、环境可持续发展的根本保证。随着人口的不断增长和经济的快速发展,水资源短缺已经成为很多地区社会经济发展的重要制约因素。水资源问题成为21世纪的热点问题。蒸散发作为水循环中的重要环节,深入的了解区域的蒸散发状况,对于水资源规划管理极为重要。在水资源短缺、水环境质量恶化的形势下,实现流域的真实节水,需要区域范围内的蒸散发量作为依据,进行流域水资源的有效管理。传统的站点观测资料,其时空代表性局限很大。近年来,随着遥感技术和定量反演方法的迅猛发展,基于卫星遥感的蒸散发检测逐渐成为研究的热点。采用遥感方法计算区域尺度的蒸散发状况可以有效的避免传统点尺度观测的缺陷,对于区域尺度的水资源规划管理具有重要价值。黑河流域作为我国西北干旱地区第二大内陆河流域,流域水资源可持续利用涉及生态、环境、社会、经济等重要领域,迫切需要对流域水分收支状况,在其空间分布和时间变化两方面,有科学、定量的了解。因而黑河流域蒸散发的机制,蒸散发的时空分布变化研究极为迫切,迫切需要对黑河流域的蒸散过程有清楚的认识,以提供流域管理的参考。本文收集整理了黑河流域范围内的MODIS数据,结合地面观测资料,基于定量遥感的理论和技术方法,获取了研究区的植被指数、叶面积指数、地表比辐射率等重要地表特征参数；使用时间序列分析方法提取分析了研究区内和植被生长相关的重要物候信息,如生长季开始时间,生长季结束时间,生长季长度,生长季NDVI幅度；基于SEBS模型,使用反演得到的地表参数作为输入,估算了黑河流域典型日的蒸散发状况,分析了蒸散发的时空变化特征；分析整理了遥感估算蒸散发的时间尺度扩展方法,使用METRIC方法对黑河流域蒸散发进行月尺度扩展研究,分析探讨了流域蒸散发的重要时空变化特征。本文得出的结论如下：(1)物候信息是植被生长状况的良好指示剂。使用MODIS16天最大合成NDVI数据,采用Savitzky-Golay滤波方法重建了NDVI时间序列图像,提取了流域范围内植被生长的重要物候参数。分析了流域内植被生长季开始时期,生长季结束时期,生长季长度,生长季NDVI幅度的空间特征,结果表明,黑河流域植被物候信息具有明显的空间特征,上游山区草地生长季较短,中下游区域受人类活动影响剧烈,物候信息的提取结果较为吻合黑河流域主要农作物小麦、玉米的生长状况信息。(2)黑河流域蒸散发机制、时空分布变化的深入研究是流域水资源可持续利用、流域管理的重要参考。本文基于SEBS模型,估算了2008年典型日蒸散发时空状况,并使用盈科站的通量观测数据进行了验证。结果表明,除121天和151天的结果有较大偏差外,其他天数的验证结果较好。(3)农田灌溉、水资源管理、水资源核算等研究中,月尺度、年尺度的蒸散发空间分布状况更具有实际价值。本文在总结蒸散发时空扩展方法的基础上,采用Allen提出的METRIC方法对黑河流域蒸散发进行了月尺度的扩展研究,计算得到黑河流域2008各个月份的蒸散量。更多还原

【Abstract】 Land surface energy flux is an important part in global water cycle and energy balance. The research on land surface energy flux is very important in global climate change, land surface atmosphere interaction, as well as in water resources management. Moreover, water is the source of life. More over, water is the fudamental guarantee of human survival, socio-economic development and sustainable development. With the increasing population and rapid development of economy, water shortage has become a restrictive factor to the development of many areas around the world. The water resource has become a hot issue in the 21st century. Evapotranspiration is an important part in water cycle. Thoroughly understanding of regional evapotranspiration condition is extremely important for water resources plan and water resources management. Under the situation of water shortage and deteriorating water quality, in order to utilize the water resources efficient, it is very important to realize regional evapotranspiration.The traditional site observation is only valid in small spatial size. In recent years, with the rapid development of remote sensing technology as well as quantitative inversion method, regional evapotranspiration detection based on remote sensing has become a hot research field. This method can effectively avoid the defect exists in traditional methods. It has great value for water resources planning and management in regional scale.Heihe River Basin is the second largest inland river basin in northwest of China arid region. Sustainable use of water resources related to ecological, environmental, econo-mic and other important areas. Therefore, there is an urgent need for acknowledge basin water balance in its spatial distribution and temporal changes with scientific and quantitative understanding.Thus, the research to the evapotranspiration mechanism, the spatial distribution and temporal changes of evapotranspiration in the Heihe River Basin, is extremely urgent. In order to afford some reference to watershed management, we need a clear understanding of the evapotranspiration process in the Heihe River Basin. In this paper, MODIS data and field observation data were collected. Based on the theory of quantitative remote sensing, vegetation index, leaf area index, surface emissivity, and other important surface parameters were retrived. Using time series analysis method, some important vegetation phenological information, such as the beginning of season, end of season, length of season, NDVI amplitude of season, were extracted. Based on SEBS model, using the surface parameters as input, evapotranspiration of typical days in the Heihe River Basin were calculated. The time scale expansion methods were systematic summarized. Using the METRIC method proposed by Allen as the time scale exapansion method, evapotranspiration in each month of 2008 were calculated.The main research results are as follows: 1.Phenological information is a good indicator of vegetation status. With the sixteen-day maximum value composite (MVC) MODIS dataset, the phonological information was extracted using the Savitzky-Golay filter. The spatial characteristics of the beginning of season, the end of season, the length of season, NDVI amplitude of season were analyzed. The result showed that phonological information in the Heihe River Basin have obvious spatial pattern. The upstream mountainous grass have a short grow season, the middlestream areas were affected by intense human activities, phonological information is consistent with crops of wheat, maize growth state.2.Deeply understanding of evapotranspiration mechanism, temporal and spatial distribution of evapotranspiration in Heihe River Basin is extremely important for durative use of water resources and watershed management. Based on SEBS model, evapotranspiration of typical days in the Heihe River Basin were calculated. Moreover, the results were verified with flux data of Yinke station. The results are nice except the result in the day of 121 st and 151 st.3.The spatial distribution of monthly evapotranspiration, annual evapotranspira-tion have more practical value in irrigation, water resources management. With the review of time scale expansion methods, the METRIC method which proposed by Allen was selected. Then, evapotranspiration in each month of 2008 were calculated.更多还原