基于蒸腾蒸发量指标的水资源合理配置方法

本文基于真实节水理念,提出了基于流域或区域蒸腾蒸发量(Evapotranspiration, ET)指标、以可消耗ET量分配为核心的水资源合理配置技术框架.该框架以分布式水文模型、多目标分析模型、水资源配置模拟模型等组成的模型体系为支撑,包括可消耗ET计算、可消耗ET分配和ET分配方案验证等技术流程,从流域或区域总来水量、蒸腾蒸发量和供水量、用水量、耗水量与排水量两层面,围绕ET指标进行水平衡分析与分配计算.以南水北调中线工程实施后北京市水资源合理配置问题为实例,进行了应用研究的尝试.     

滇池流域近30年参考蒸腾蒸发量计算方法探讨

收集了滇池流域昆明气象站近30年(1988—2017)的地面气候资料日值数据,根据联合国粮食及农业组织推荐的彭曼-蒙蒂斯公式(Penman-Monteith)和修正的彭曼公式对气象数据进行了分析计算,对各气象要素与参考蒸腾蒸发量的相关性分别进行分析,比较两种方法在滇池流域应用的区别,为本区域的农业节水和水资源配置起到一定的指导作用。比较两种方法所计算的参考蒸腾蒸发量(Reference Evapotranspiration,ET0),辐射项(ETrad)及其空气动力学项(ETaero)的不同之处,结果表明,两种方法计算得出的参考蒸腾蒸发量具有很好的相关关系,并且计算结果接近。彭曼-蒙蒂斯公式计算得出的ET0明显低于修正的彭曼公式所求得的值;彭曼-蒙蒂斯公式计算得出的ETrad明显低于修正的彭曼公式所求得的值;彭曼-蒙蒂斯公式计算得出的ETaero明显高于修正的彭曼公式所求得的值。彭曼-蒙蒂斯公式计算时对其影响最大的气象因素是日最高气温,修正的彭曼公式计算时对其影响最大的气象因素是平均气温。     

卫星遥感监测蒸腾蒸发量（ET）精度校验——以北京市GEF海河项目为例

概述了GEF海河项目利用卫星遥感技术监测流域蒸腾蒸发量(ET)进行流域水管理的思路,介绍传统人工监测和卫星遥感监测ET的原理和方法.对2种监测结果进行分析比较,得出的结论是:北京市CEF海河项目中大部分区(县)卫星遥感监测系统精度为±5%以内,各年有1个区(县)精度不达标,待用其它方法继续校验.     

基于蒸腾蒸发量的区域真实节水研究

本文提出以区域允许蒸腾蒸发量的控制来实现区域真实节水的技术框架,将节水由原来的只注重取水量的节约扩展到真正耗水量的节约上。该框架以蒸腾蒸发量为控制指标,在不突破流域总可消耗量(蒸腾蒸发量)的基础上,以准天然状态为参考,经由水文模型模拟分别得到流域内各区域允许蒸腾蒸发量、可控和不可控蒸腾蒸发量,并通过作物种植结构调整、减少灌溉水量、保墒等措施对区域可控蒸腾蒸发量调控,实现区域实际蒸腾蒸发量与区域允许蒸腾蒸发量的平衡。最后以河北省馆陶县真实节水为实例,进行了应用研究的尝试。     

基于ET技术的水权分配

通过研究减少蒸腾蒸发（ET），来达到“真实”节水。该文以馆陶县为例，通过计算馆陶县ET值，利用ET技术进行水权分配。为以后馆陶县水资源开发利用和保护提供了理论数据，对水资源的可持续发展具有重要的现实意义。     

基于ET技术的水权分配

通过研究减少蒸腾蒸发（ET）来达到“真实”节水，以馆陶县为倒，通过计算馆陶县ET值，利用ET技术进行水权分配。为以后馆陶县水资源开发利用和保护提供理论数据，对水资源的可持续发展具有重要的现实意义。     

基于作物耗水定额控制的灌溉管理模型

海河流域水资源供需矛盾突出,其中农业灌溉所占用水量和耗水量比例最大,而其水分利用效率相对偏低,因此节水潜力较大,为合理调控区域灌溉用水,本文将田间试验观测为基础的灌溉节水理论和方法与遥感数据反演区域耗水(ET)的点面优势相结合,提出了基于作物耗水定额管理的农业灌溉管理模型,通过控制区域上的作物耗水量分布,促进区域灌溉水资源的合理调配和利用,实现资源性节水。模型主要功能包括遥感反演数据统计分析、区域耗水目标分解、作物ET定额分配、种植结构调整、节水潜力分析以及净灌溉需水量估算。可实现从区域综合耗水控制目标向主要作物ET定额的分解,并转化为灌溉用水管理中可控制的灌溉定额,通过逐年设置主要作物的ET控制定额和种植结构情景方案,分析区域的节水潜力,消除奢侈耗水,实现不同水文年和耗水控制阶段目标下的灌溉定额管理,为区域灌溉水管理提供技术支持。     

基于遥感的小麦水分生产率计算与节水潜力分析

水分生产率是评价农业用水效率、分析节水潜力的一项重要指标.笔者利用遥感数据计算了大兴区"十一五"期间小麦产量、小麦种植区的蒸散量(ET),进而计算了小麦的水分生产率,在此基础上分析小麦水分生产率及小麦种植的节水潜力.     

浅析ET与农作物产品虚拟水之间的关系

首先引入ET和虚拟水及水分生产率的概念,详细介绍目前ET和虚拟水及水分生产率的计算方法,并对ET与农产品虚拟水的相互联系进行重点探讨,同时就目前国际上较为先进的ET技术和虚拟水战略理论的概要进行解释,提出了农业结构战略性的调整和区域水资源管理的有效措施和建议。     

基于遥感监测ET的馆陶县主要农作物耗水规律研究

农业节水管理的目标之一是减少灌溉区无效水分蒸发,提高水分利用效率,增加农作物产量。基于遥感监测ET技术,可实现灌区大范围、高精度、连续性的水分消耗监测。根据遥感监测ET及有效降水数据,对河北省馆陶县冬小麦、夏玉米和棉花3种主要农作物进行耗水分析,获得作物的耗水规律,为农业节水管理提供依据。     

黄河三角洲湿地蒸发蒸腾及其对土地利用/覆被变化的响应特征研究

以黄河三角洲为研究区,基于1986年6月5日和2009年6月4日的Landsat TM影像进行土地利用/覆被分类及变化特征研究,同时,基于SEBAL模型估算区域蒸发蒸腾量,进而分析湿地蒸发蒸腾的数量特征、空间格局特征及其对土地利用/覆被变化的响应特征。结果表明:23年间,58.74%的区域土地利用/覆盖类型发生了变化,未利用地大幅减少,水体和建设用地大幅增加,显著的土地垦殖与耕地荒废则同时存在;蒸发蒸腾强度大小按土地利用/覆被类型排序依次为水体>滩涂>苇地>林草地>耕地>建设用地>未利用地,研究区未利用土地变为水体和耕地是导致区域蒸发蒸腾整体提高的主导原因,而耕地流失则是导致区域蒸发蒸腾整体下降的主要原因,但23年间实际变化以前一种情形占优势,因而区域蒸发蒸腾总体呈现为增加趋势。研究结果对区域土地利用规划和水资源管理有重要的理论和实践指导意义。     

基于SEBAL 模型的锡林浩特蒸散量反演研究

陆面蒸散作为反映土地利用/覆盖变化所引起地表水热变化的敏感因子是当今全球气候变化研究的焦点之一.本文以内蒙古锡林郭勒盟锡林浩特市为研究区域,基于SEBAL（Surface Energy Balance Algorithm for Land）模型,采用研究区2005年8月17日的Landsat TM遥感影像对其地表蒸散量进行反演研究,分析蒸散量的空间变化格局.结果表明：锡林浩特日蒸散量平均值为4.3mm,最大值达到了7.5mm;日蒸散量呈现出西北低、东部高的空间分布格局;日蒸散量较少的区域主要分布于锡林浩特市的西部、北部以及最南部的部分区域,中部较少部分地区的蒸散量较低（接近于0）.     

Assessment of Water Availability and Consumption in the Karkheh River Basin,Iran—Using Remote Sensing and Geo-statistics

This study was conducted to assess water availability and consumption in the Karkheh River Basin in Iran using secondary data and freely available satellite data. Precipitation was estimated using geo-statistical techniques while a Surface Energy Balance approach was selected for evapotranspiration estimation. The spatial distribution of actual evapotranspiration (ET_a) for the Karkheh Basin has been estimated by use of 19 cloud free Moderate Resolution Imaging Spectroradiometer (MODIS) images, which cover a complete cropping year from November 2002 to October 2003. ET_a estimates were compared to potential crop evapotranspiration (ET_p) estimates for two predominantly irrigated wheat areas in Upper and Lower Karkheh. Differences were found to be 12.5% and 11.7% respectively. Results of the ETa and precipitation estimates reveal that for the study period, the Karkheh Basin received 18,507 × 10⁶m³ as precipitation while ET_a is estimated at 16,680 × 10⁶m³. Estimated outflow from the basin for the study period only is 7.8% of the precipitation and indicates that water is a very scarce resource in the Karkheh basin. The basin has been divided in sub-basins to allow for more detailed analysis and results indicate that water balance closure at sub-basin scale ranges from 7.2% to 0.6% of the precipitation. This suggests that the water balance is sufficiently understood for policy and decision making.     

Evaluation of Water Balance in a Mountainous Upland Catchment Using SEBAL Approach

Scarcity of water is now the biggest threat in many parts of the world, specially in arid and semi arid regions. Establishing balance between water resources and the demands in a catchment scale basis could be one of the most important strategies to overcome this problem. In this regard, determination and analysis of water balance components (inputs and outputs) would be necessary. This study has focused on estimation of water balance components in arid-mountainous catchment of Manshad in Yazd province of Iran, during the year 2006–2007 using remote sensing and GIS techniques. To estimate actual evapotranspiration (ET_a) of the catchment, time series of MODIS images were obtained and used via Surface Energy Balance Algorithm for Land (SEBAL) approach. Measured precipitation (P) and runoff (R) data of the catchment were also used to calculate water balance equation components. Results indicated that a large volume of catchment water (about 70%) is wasted through evapotranspiration, while the rainfall is not enough to compensate this volume of water during the year. It seems that the negative (descending) trend has become dominant to the water budget of the area and gradually moves to harsh conditions of water shortage in future decades. Therefore, some actions would be necessary to overcome the problem. Water conservation strategies‚ improvement of water use efficiency, and control on agricultural field expansions are some solutions that could be advised for the studied catchment.     

Application of the Sebs Water Balance Model in Estimating Daily Evapotranspiration and Evaporative Fraction from Remote Sensing Data Over the Nile Delta

Estimation of evapotranspiration is always a major component in water resources management. The reliable estimation of daily evapotranspiration supports decision makers to review the current land use practices in terms of water management, while enabling them to propose proper land use changes. Traditional techniques of calculating daily evapotranspiration based on field measurements are valid only for local scales. Earth observation satellite sensors are used in conjunction with Surface Energy Balance (SEB) models to overcome difficulties in obtaining daily evapotranspiration measurements on a regional scale. In this study the SEB System (SEBS) is used to estimate daily evapotranspiration and evaporative fraction over the Nile Delta along with data acquired by the Advance Along Track Scanning Radiometer (AATSR) and the Medium Spectral Resolution Imaging Spectrometer (MERIS), and six in situ meteorological stations. The simulated daily evapotranspiration values are compared against actual ground-truth data taken from 92 points uniformly distributed all over the study area. The derived maps and the following correlation analysis show strong agreement, demonstrating SEBS’ applicability and accuracy in the estimation of daily evapotranspiration over agricultural areas.     

Forecasting of Remotely Sensed Daily Evapotranspiration Data Over Nile Delta Region, Egypt

Daily evapotranspiration is a major component in crops water consumption management plans. Consequently, forecasting of daily evapotranspiration is the keystone of any effective water resources management plans in fragile environment similar to the Nile Delta region. The estimation of daily evapotranspiration was carried out using Surface Energy Balance System (SEBS), while the forecasting of the daily evapotranspiration was carried out using Auto Regressive Integrated Moving Average (ARIMA) and its derivative Seasonal ARIMA. Remote sensing data were downloaded from European Space Agency (ESA) and used to estimate daily evapotranspiration values. Remote sensing data collected from August 2005 till December 2009 on a monthly basis for daily evapotranspiration estimation. The application of the most adequate ARIMA (2,1,2) to the evapotranspiration data set failed to sustain the forecasting accuracy over a long period of time. Although, time series analysis of daily evapotranspiration data set showed a seasonality behavior and thus, using seasonal ARIMA [(2,1,2) (1,1,2)6] was the optimum to forecast the daily evapotranspiration over the study area and sustain the forecasting accuracy. A linear regression model was established to test the correlation between the forecasted daily evapotranspiration values using S-ARIMA model and the actual values. The forecasting model indicates an increase of the daily evapotranspiration values with about 1.3 mm per day.     

A Modified SEBAL Modeling Approach for Estimating Crop Evapotranspiration in Semi-arid Conditions

Remote sensing methods are becoming attractive to estimate crop evapotranspiration, as they cover large areas and can provide accurate and reliable estimations; intensive field monitoring is also not required, although some ground-truth measurements can be helpful in interpreting satellite images. For the purposes of this paper, modeling and remote sensing techniques were integrated for estimating actual evapotranspiration of groundnuts (Arachishypogaea, L.) that is cultivated near Mandria Village in Paphos District of Cyprus. The Surface Energy Balance Algorithm for Land (SEBAL) was adopted for the first time in Cyprus, employing the essential adaptations for local soil and meteorological conditions. Landsat-5 TM and 7 ETM+ images were used to retrieve the needed spectral data. The SEBAL model is enhanced with empirical equations determined as part of the present study, regarding crop canopy factors, in order to increase its accuracy. Maps of ET_a were created using the SEBAL modified model (CYSEBAL) for the area of interest. The results have been compared to the measurements from an evaporation pan (which was used as a reference) and those of the original SEBAL model. The statistical comparison has shown that the modified SEBAL yields results that are comparable to those of the evaporation pan. T-test application has revealed that the statistical difference between SEBAL and CYSEBAL is significant and quite crucial, especially in a place with limited surface and underground water resources.     

三江平原主要生态类型耗水分析和水分盈亏状况研究

利用SEBAL模型并集成MODIS卫星数据,计算了三江平原2006年生长季5—10月的地表蒸散量,结合降水量数据,借助GIS技术对主要生态类型的耗水和水分盈亏状况进行分析。计算结果表明:森林、湿地、旱田和水田生态系统在2006年生长季的耗水量分别为697.14、562.21、486.17和523.52mm,森林生态系统的蒸散量大于其他生态系统;从2006年生长季总体来看,三江平原北部和中部区域耗水量要小于降水量,东部、南部和西部则相反。森林、湿地、水田和旱田生态系统在2006年生长季水分盈亏量平均值分别为-193.46、-23.38、-1.86和37.59mm;从湿地、水田和旱田的水分盈亏情况对比来看,湿地开垦为水田比湿地开垦为旱田更适于当地的自然条件;对于农作物来说,从整个生长季来看三江平原降雨量可以基本满足地表蒸散的需求,但是时空不匹配,在特定的月份上,会出现干旱。     

基于SEBS模型的老哈河流域蒸散发研究

基于表面能量平衡系统(SEBS)模型,结合NOAA/AVHRR数据,估算半干旱的老哈河流域实际日蒸散发量,并将估算结果与结合FAO-Penman模型和作物系数法计算的参考作物蒸发量进行比较,最后综合分析了老哈河流域蒸散发与土地利用、归一化植被指数(NDVI)以及地表温度(LST)的关系.结果表明:SEBS模型在老哈河流域有较好的适用性;老哈河流域实际日蒸散发时空差异较大,其中7、8月份流域蒸散发量较大,9、10月份蒸散发量逐渐减小,流域西部山区的蒸散发量较大,中部和流域出口所在的平原区相对较小;流域不同土地利用类型蒸散发量不尽相同,其中林地的日平均蒸散发量最高,其次为耕地、灌丛和草地;流域实际蒸散发量与NDVI呈线性正相关,与LST呈线性负相关.     

基于蒸散遥感反演的全国地表缺水分区

本文采用日本GMS静止气象卫星数据进行遥感反演,提取地表实际蒸散量(E)和潜在蒸散量(Ep),据此计算出表征地表缺水程度的指标——SWDI。在GIS的支持下,通过数理统计和空间统计分析“自下而上”的对全国地表缺水状况进行分区。通过分析,全国可划分为5大缺水层次的分区,对比发现全国普遍缺水,不缺水区主要集中在南部沿海,且所占比重较小。全国缺水层次区域的划分,可为区域经济发展,环境保护以及各种国家或区域方针政策的制定提供科学依据。