基于改进的SEBS模型的作物需水量研究--测试文章

为了探讨以蒸散发为基础的作物需水量情况，便于为农业生产提供数据支持，利用风云三号、风云二号气象卫星数据，结合自动站气象数据，基于改进的SEBS模型对山西省进行作物需水量研究。结果表明：通过与实测数据对比验证发现模型结果精度较高。山西省2012年3—9月全省日均作物需水量最大值出现在春季的5月份，为1.27 mm，其中，以单季作物为代表的晋东北和中西部日均作物需水量最大值均出现在5月，分别为1.05 mm和1.38 mm；以双季作物为代表的晋东南日均作物需水量最大值出现在5月和7月，分别为1.28 mm和1.23 mm。可见山西省作物需水量普遍以春季最大，其中尤以中西部突出，晋东北则相对最低。     

Application of MIKE SHE modelling system to set up a detailed water balance computation

Estimation of total water balance is a substantial issue for watershed modelling in order to simulate the major components of the hydrological cycle to determine the stress of different anthropogenic activities on the available water resources within a catchment. In this context, the fully distributed physically based MIKE SHE modelling system was used to simulate the individual hydrological components of the total water balance for the Paya Indah Wetlands (PIW) watershed in the west of Peninsular Malaysia. Results reveal that the overall water balance is predominantly controlled by climate variables. Application of the model to the PIW watershed provides detailed estimation of the total water balance for a first‐order catchment in which actual evapotranspiration (ET) represents approximately 65 and 58%, while overland flow (OL) to the PIW lake system represents 12.38 and 12.3% of the total rainfall during the calibration and validation periods, respectively. The difference of the inflow and outflow was taken as storage in depth. Overall, the model gives a reasonable output of total error of less than 1% of the total rainfall, which in turn indicates that the interaction among components is satisfactorily sustained.     

基于SEBS方法的蒸散量计算及可靠度分析——以鄂尔多斯高原海流兔河为例

区域蒸散发量的分析计算,在水资源评价及分析研究中是至关重要的,其计算成果精度的高低对水资源的计算影响很大.但目前蒸散发还难以在大范围内进行直接测定,蒸散发量计算多采用间接估算的方法.表面能量平衡系统(SEBS)是近年来应用较为广泛的估算蒸散量的方法之一.该文将大范围的卫星遥感资料与地面和高空观测的气压、气温、相对湿度、...     

Remote sensing techniques for predicting evapotranspiration from mixed vegetated surfaces

Evapotranspiration (ET) is a key component of the hydrological cycle however it is also the most difficult factor to quantify. In recent decades, estimating ET has been improved by advances in remote sensing, particularly in agricultural studies. However, quantifying ET from mixed vegetation environs, particularly urban parklands, is still challenging due to the heterogeneity of plant species, canopy covers, microclimates, and because of costly methodological requirements. Several studies have recently been conducted in agriculture and forestry which may be useful for mixed landscape vegetation studies with some modifications. This review describes general remote sensing-based approaches to estimate ET and describes their advantages and disadvantages. Most of these approaches need extensive time investment, medium to high skill levels and are quite expensive. However, in addition to the reviewed methods, the authors recommend combining remotely sensed vegetation indices and ground-based techniques for ET estimation of mixed landscape vegetation such as urban parklands.     

区域蒸发计算方法的研究

以朱小堰蒸发试验小区的实验数据为基础,以太阳辐射总量和水面蒸发为主要参变量,建立了计算区域蒸发的半经验公式,并以安徽省24个小区域站对其应用的普遍性进行了检验.根据公式的数学特征,讨论其对应的物理意义和区域蒸发的空间变化规律.通过在安徽省13个面积为2349km2～2727km2分区的水资源评价中的应用,进一步验证了该方法的合理性.     

中国南方农田蒸散量实测及其影响因素分析

利用基于闭路QCLAS-EC激光分析仪的涡度相关法对湖南省岳阳市郊区的一片蔬菜地的实际蒸散发、水汽通量以及潜热通量进行了连续两年的野外观测,并对原始观测数据进行处理,计算蒸散量,以分析研究区域实际蒸散量的年际尺度周期变化趋势和季节变化规律。结果表明,实验区域全年蒸散量在730~803 mm之间;季节变化大,8月达到全年最高水平3.5 mm/d,而1月只有0.4 mm/d。整个研究区域实测蒸散量变化规律是:春夏季较高,秋冬季较低;种植季较高,非种植季较低;每天的正午以及下午较高,夜晚较低。此外,利用高分辨率的实测工具观察不同的农业活动对实际蒸散的影响,发现种植引起蒸散发上升,收割引起蒸散发下降,并且收割使蒸散发下降的幅度要明显高于种植使蒸散发上升的幅度;灌溉对蒸散发有促进作用但是作用较小,施肥对蒸散发的影响目前尚不明确。     

1980-2019年海河流域气象干旱和农业干旱变化及传播特征

研究干旱演变和传播特征可为流域防灾抗灾提供帮助和建议。以海河流域为例,采用标准化降水蒸散发指数(SPEI)和标准化土壤湿度指数(SSMI)分别表征气象干旱和农业干旱,并结合趋势分析和频率分析等方法,对1980-2019年该流域气象干旱和农业干旱时空演变规律以及传播特征进行研究。结果表明：在干旱发生频率上,气象干旱和农业干旱的高发区分别集中在流域东北部和中部,不同季节空间分布存在显著性差异,春季和夏季为气象干旱频发季,冬季和春季为农业干旱频发季;从变化趋势上看,SPEI值呈减小趋势的区域主要集中在流域的中东部,其中春季减小趋势最为显著,而SSMI值呈“北增南减”的分布格局,其中秋季减小趋势最为显著;农业干旱对气象干旱的响应具有延时性,不同季节差异显著,夏季传播时间仅为5个月,秋季、冬季和春季的传播时间分别为6、9和11个月;在空间分布上,春季和夏季的相关系数较低,低值区主要分布在流域北部地区,秋季和冬季的相关系数较高,高值区集中分布在流域中部地区。     

Variability of complementary relationship and its mechanism on different time scales

In the complementary relationship (CR) between actual and potential evapotranspiration, wet envi- ronment evapotranspiration (Ew) is usually calculated using the Priestley-Taylor (P-T) equation. Based on the data obtained from 38 catchments of the Haihe River basin and the Weishan experiment site in Shandong Province of China, this study has found variations in the Priestley-Taylor parameter α (e.g. increase in values with increase in the amount of precipitation on annual scale, seasonal fluctuation noted t...     

Necessity and feasibility for an ET-based modern water resources management strategy: A case study of soil water resources in the Yellow River Basin

The necessity and feasibility of an ET-based modern water resources management was analyzed to improve assessment of critical water resources scarcity in the region/basin. This analysis was based on the whole water cycle process and its analysis object is evapotranspiration (ET), a main consumption component in the water resources dynamic transformation process. A case study was undertaken by selecting soil water resources in the Yellow River Basin and employing the WEP-L distributed hydrological model with...     

多沙粗沙区林草植被建设对径流影响初析

依据以往的研究成果,针对多沙粗沙区北部、中部和西南部的实际情况,采用综合分析和统计的方法,在确定林草植被蒸散耗水量基础上,应用与坡地蒸散耗水量相对比的方法,分析了林草植被建设对径流量的影响。结果表明:①对于灌木草地来说,整个多沙粗沙区都能够满足其对水分的需求,而乔木林地在北部区基本上不能满足其需要。②林草植被蒸散耗水量的区域分布,与最大可能蒸发量的分布大体相似,而与降水量分布呈相反趋势,呈现出由西北向东南部递减以及自西向东减少的趋势;北部较中部乔灌草植被分别约偏多8%、10%和17%,而西南部较中部乔灌林地和人工草地分别偏多3%左右和约6%。③从水资源的适应性来说,多沙粗沙区适应乔木生长的区域还是有一定的限制。