【作者】 王瑶；

【导师】 赵传燕；

【作者基本信息】 兰州大学 ， 农业生态学， 2012， 硕士

【摘要】 作物需水量是农田水循环的一个关键的方面,它也决定了在生态环境系统中的水份和热量的输入输出,定量对作物需水量进行估算是评价陆地生态系统生产力、区域用水量、作物的产量的基础,同时也是区域内研究气候变化的重要组成部分。本文利用定量遥感方法估算了黑河中游2009年的作物需水量。由于本研究区涉及黑河中游整个陆面范围,空间尺度较大,且研究区内地形复杂多变,土地利用类型也比较丰富,这给本研究带来了一定的难度。为了能够更好地达到本研究的目的,本研究在利用遥感蒸散发模拟模型(SEBS)对黑河中游作物需水量进行模拟和分析的同时,也使用了其他方法进行了作物需水量的估算,并探讨了遥感蒸散发模拟模型(SEBS)中相关的输入部分参数的敏感性,用来深入了解时空尺度上作物需水量的反演的理论基础和物理机制。依据最初的研究目的,我们收集和整理了2009年相关的遥感数据、气象数据和植被等数据,还有地面气象站点的验证资料,在对SEBS遥感模型的基础上,应用这一模型进行黑河中游作物需水量进行模拟。并在这基础上对作物需水量的时空分布格局和影响作物需水量的因子的敏感性进行了分析。本文主要在以下几个方面进行了比较深入的工作：(1)不同月份的蒸散发2009年4月至9月研究区月均蒸散发量分别为56.55mm,72.37mm,89.10mm,73.54mm,72.81mm,38.38mm,蒸散发量最大值出现在6月,最小值出现在9月,呈现先增加后减小的趋势。4月至9月的蒸散发量变化范围在86.06-641.64mm之间,东北部的酒泉地区及研究区中部的高台、临泽、张掖、山丹及河道周边的蒸散发量很高,东北部及西北部的荒漠地区蒸散发量明显小于农田,且从分布图上可看出耕地边界明显,与该地区的土地利用数据相吻合。(2)作物需水量时空分布2009年作物生长季四个生长阶段作物需水量差异很大,全区各阶段需水量平均值分别为53.61mm,226.38mm,72.32mm,80.77mm,生长初期作物需水量最小,占全生长期的11.56%,生长发育期作物需水量最大,生长发育期作物需水量占全生长期的48.83%,生长中期与生长末期作物需水量分别占全生长期的15.60%,17.42%。各生长阶段的作物需水量从大到小排列为：生长发育期>生长末期>生长中期>生长初期。生长初期、发育期、中期和末期各生长阶段的作物需水量日平均值分别为1.29mm、2.89mm、2.83mm和1.92mm。各生长阶段的日作物需水量从大到小排列为生长发育期>生长中期>生长末期>生长初期。黑河中游作物需水量的空间差异很大。在全生长期内,作物需水量整体分布具有从南向北递增的趋势。研究区内全生长期作物需水量在88.34-632.17mm之间,平均值为463.63mm,临泽、张掖、酒泉三地的作物需水量较高且很接近(560mm左右),高台地区的作物需水量为529.58mm,山丹、民乐的作物需水量较小,分别为510.33mm、491.24mm。(3)不同方法计算作物需水量结果PM-Kc法计算得出的各阶段作物需水量基本上大于SEBS模拟得出的结果。其中生长初期、生长发育期、生长中期和生长末期各阶段两种方法的日平均差值分别为：0.03mm、0.43mm、1.24mm,0.62mm。(4)SEBS模型输入参数敏感性分析通过分析发现日蒸散发对模型输入参数敏感性各不相同。分析黑河中游日蒸散发的平均效应可知：黑河中游日蒸散发对日均气温、日照时数和空气湿度的敏感性十分小,平均日蒸散发相对变化量不超过1%；黑河中游日蒸散发对风速、归一化植被指数、地表比辐射率、地表反照率的敏感性较小都不超过5%；黑河中游日蒸散发对覆盖度、地面气压、参考高度处气压和地表温度的敏感性大于20%。各参数敏感性从大到小依次为：地表温度>参考高度处气压>地面气压>覆盖度>风速>地表比辐射率>地表反照率>归一化植被指数>日照时数>空气湿度>日均气温。更多还原

【Abstract】 Crop water requirement is very important for water cycle, and is a determinant for the estimation of water and heat transfer in the Soil-Plant-Atmosphere Continuum (SPAC). Quantitative estimation of crop water requirement is the base of appraising terrestrial NPP, regional water consumption, soil water transport, crop production, and land use/land planning. Especially, quantitative estimation of crop water requirement is important for the study on global or regional climate change.This study aims to simulate crop water requrement of the year2009by means of quantitative remote-sensing methods, the study ares covers the middle reach of Heihe River basin in northwest China. Due to the, for there are very comples terrains, various climate zones and diversiform land use, it is difficult to estimating crop water requrement at such spatial extent. In order to achieving this research purpose, the first step is simulation and analysis of crop water requierment, and secondly, sensitivity analyses of each parameters. This study lays particular emphasis analyzing on temporal and spatial analysis of crop water requirement of the middle Heihe river and the uncertainty of relevant key parameters of remote-sesing models for simulation crop water requirement, trying to arasp and understand physics mechanism of remote-sensing estimation of large space-time scale crop water requirement. According to this purpose, we firstly collected and processed relevant meteorological data, remote-sensing images, soil and vegetation data and ground validation information of the year2009, and secondly, on the basis of the remote sensing model of SEBS, we used this method to estimate crop water requirement of several days about the year2009. And quantitatively analyzedspatial-temporal patterns of crop water requirement. we also conducted the sensitivity analysis of the influence factors of SEBS. The main progresses includes:(1) Evapotranspiration in different monthsThe average monthly evapotranspiration was56.55,72.37,89.10,73.54,72.81and38.38mm respecively in April to September of2009. The maximum evapotranspiration was obtained in June and the minimum in September, the pattern of evapotranspiration showing a increase-then-decrease trend. Evapotranspiration from April to September varied from86.06to641.64mm, the evapotranspiration at Jiuquan region (in northeast part of study area),at Gaotai, Linze, Zhangye, Shandan (in middle part) and at those areas near Heihe river are relatively higher, the evapotranspiration in northeast and north-western desert region significantly less than farmland. The arable land boundary is reflected in the distribution map of evapotranspiration.(2) Spatial and temporal distribution of crop water requirementThe crop water requirement of growing season in four growth stages in2009varied significantly. The crop water requirement in study area of each stage were53.61,226.38,72.32and80.77mm, respecively. Within initial stage, the water requirement is minimum and account for11.56%of the entire growing season, whereas within development stage, the water requirement reaches maximum and account for48.83%of entire growing season. The crop water requirement in mid-season stage and late-season stage account for15.60%and17.42%. The crop water requirement in different stage over the entire growing stage follows a decreasing order:development stage> late-season stage> mid-season stage> initial stage.The daily crop water requirement in different growing stage was1.29mm,2.89mm,2.83mm and1.92mm, respectively. The different daily crop water requirement in dicreasing order as follows:development stage> mid-season stage> late-season stage> initial stage.The results show that the trend of crop water requirement gradually increased from south to north part, and crop water requirement varied from88.34to632.17mm over the entire growing season, with a mean of463.63mm. The spatial pattern of Crop evapotranspiration varied significantly. The crop water requirement for Linze, Zhangye and Jiuquan was relatively higher and very closed to560mm, and for Gaotai, Shandan and Minle, the water requirement was529.58,510.33and491.24mm, respectively.(3) Comparison of different methods for calculation of crop water requirementThe crop water requirement was calculated from PM-Kc method was greater than the the SEBS model simulated results in different growing stages. The daily average difference of crop water requirement for initial stage, the development stage, mid-season stage and late-season stage was0.03mm,0.43mm,1.24mm,0.62mm.(4) Input parameter sensitivity analysis of SEBS modelThe sensitivity analysis shows that daily evapotranspiration changed less than1%with the10%variation of average daily temperature, sunshine hours and air humidity. For the variation of wind speed, normalized difference vegetation index, surface emissivity and surface albedo, the daily evapotranspiration varied less than5%. The daily evapotranspiration varied larger than20%for the variation of ground coverage, the surface pressure, the reference height of the pressure and land surface temperature. The sensitivity analysis shows that the daily evapotranspiration varied acoording to the variation of each parameters as (from most sensitive to least sensitive):land surface temperature> reference height of the pressure> surface pressure> the percent of ground coverage> wind speed> surface emissivity surface albedo> normalized difference vegetation index> sunshine hours> air humidity> average daily temperatures.更多还原