基于SWAT模型的西江流域径流模拟研究

采用SWAT(Soil and Water Assessment Tool)模型,在整个珠江流域构建分布式水文模型,对西江流域1951~2008年的月径流过程进行模拟。选取西江流域的迁江、柳州、武宣3个水文站的径流数据,利用SWAT模型自带的敏感性分析模块和自动率定模块,采用LH-OAT敏感性分析方法和SCE-UA算法分别对选取的各参数进行敏感性分析和参数率定,并对率定模型进行验证。敏感性分析结果表明,不同的参数对流域月径流过程表现出不同程度的敏感度,其中CN2、ESCO、SOL_AWC、CH_K2和ALPHA_BF的敏感度较高,是较敏感因子。从率定和验证结果来看,3个水文站的径流模拟效果均较好,Nash-Suttcliffe效率系数ENS均在0.75以上,其中柳州站和武宣站率定期和验证期的ENS在0.8以上。SWAT分布式水文模型在西江流域月径流模拟中的应用效果良好。     

基于Morris和EFAST的CERES-Wheat模型敏感性分析

依据在陕西杨凌获得的冬小麦试验资料,用Morris法和EFAST(extended Fourier amplitude sensitivity test)法分析了CERES-Wheat模型输出变量中小麦开花期、成熟期、产量、地上生物量对品种和生长参数的敏感性,并分析比较了两种方法的一致性。结果表明,光周期影响因子(P1D)、出苗-穗分化期积温(P1)、穗分化-挑旗期积温(P2)和春化影响因子(VEFF)均对开花期和成熟期较敏感,灌浆期积温(P5)对成熟期有较大影响;挑旗前、后的光能利用率(PARUE,PARU2)、P1D、P1和P2均对产量和生物量有较大影响;最适条件下标准籽粒质量(G2)和开花期单位地上生物量的籽粒数(G1)对冬小麦产量有较大影响,第一标准叶的比叶面积(SLAS)对地上生物量有较大影响。Morris法和EFAST法得到的参数敏感性结果具有较高的相关性,表明计算工作量较小的Morris法较适于筛选模型敏感参数。     

基于SCE-UA算法的新安江模型与垂向混合产流模型参数优化应用研究

为解决流域水文模型人工试错率定参数呈现的经验性与不确定性问题,探寻模型参数率定的全局最优解,本文对三水源新安江模型与垂向混合产流模型采用复合形交叉进化算法(SCE-UA)优选率定模型参数。优化过程中拟定了两种模型参数优选边界,选定包含复合形个数p在内的SCE-UA算法参数,建立了基于洪峰、洪量、流量过程三要素的目标函数。经案例分析得出SCE-UA算法适用于上述两种水文模型调参应用,且垂向混合产流模型模拟结果优于三水源新安江模型。     

基于PEST的RZWQM2模型参数优化与验证

根据糯玉米-冬小麦田间喷灌试验不同处理结果,利用独立的自动参数估计软件PEST对RZWQM2模型进行参数优化,并分析了24个模型参数的综合敏感度。通过控制不同观测变量(土壤含水率、土壤氮素含量、作物叶面积指数、产量)模拟差异函数值在目标函数中的比重,优化目标方程,确定模型参数,并用田间试验数据对模型进行验证。结果表明,在不同观测变量的模拟差异函数值最接近条件下,冬小麦出叶间隔特性参数、冬小麦春化作用敏感特性参数及糯玉米出叶间隔特性参数等3个参数对模型整体模拟效果影响最大。相比试错法而言,基于PEST优化的RZWQM2模型能够更准确地模拟糯玉米-冬小麦轮作系统中水分、氮素及作物生长情况。     

基于贝叶斯模型平均的水文模型不确定性及集合模拟

单一模型在水文过程模拟和预报中存在诸多不确定性,集合模拟是减少不确定性影响的有效方法。在水文模型参数估计的两类方法基础上(分别选用SCE-UA算法和SCEM-UA算法为代表),选用3个基于子流域的半分布式水文模型(新安江模型、混合产流模型和HYMOD模型),综合考虑模型参数和模型输入的不确定性,并采用贝叶斯模型平均(BMA)将3个模型的模拟结果集合进行概率预报。结果表明:SCE-UA算法和SCEM-UA算法优化的参数都能使模型取得较好的模拟效果,但SCEM-UA算法能得到模型参数的后验概率分布,并获取模型的概率预报区间,具有更大的优势;考虑模型输入不确定性,模拟径流的精度没有较大提高,但概率预报区间精度有一定的改善;采用BMA方法集合多模型模拟结果,综合考虑模型参数、模型输入和模型结构的不确定性,其模拟结果要优于单一模型,说明水文集合模拟的优越性;BMA集合后,SCEM-UA算法的模拟结果较SCE-UA算法的模拟结果具有更准确的概率预报区间。     

基于二层规划理论的水文模型参数识别研究

流域水文模型有效应用的关键之一是参数识别,但由于水文模型存在高度敏感性参数以及参数之间的高度相关性增加了模型参数识别难度。本文以新安江模型为例,在分析参数敏感性和相关性的基础上,建立了基于二层规划理论的参数识别模型,研究了二层规划问题的求解算法,并进行了天福庙水库径流模拟的实例研究。通过与SCE-UA、PSO、PMSE-PSO和SMSE-PSO优化单目标函数的结果比较,可以看出,基于二层规划理论的新安江模型参数优选方法具有较高的预报精度,是一种有效可行的水文模型参数优选方法。     

非充分灌溉制度对Jensen模型的敏感性分析

分析了非充分灌溉中作物各生育阶段最优耗水量及产量对Jensen模型的敏感性。基于灌溉制度优化模型,构建了非充分灌溉制度对Jensen模型的敏感度计算公式,并以北京永乐店试验站1998～1999年度冬小麦的水分生产函数为例,进行了非充分灌溉制度对Jensen模型的敏感性分析。结果表明:1Jensen模型参数λi的波动对最优灌溉制度以及产量的计算结果影响较小;2与返青—拔节、灌浆—成熟阶段相比,拔节—孕穗、孕穗—灌浆阶段的最优耗水量计算结果受参数λi波动的影响比较小;3与返青—拔节、灌浆—成熟阶段相比,拔节—孕穗、孕穗—灌浆阶段的Jensen模型参数λi波动对各阶段最优耗水量及产量的计算结果影响较小。     

基于DEM栅格的分布式BTOPMC模型在水文模拟中的应用

应用一个基于DEM栅格的分布式水文模型BTOPMC(Block-wise use of TOPMODEL)模型进行水文模拟研究.该模型结合IGBP全球陆面土壤覆盖与FAO全球数字土壤组成信息,以栅格为计算单元,进行产流计算;汇流采用Muskingum-Cunge法.为了探讨模型的应用范围,将BTOPMC模型与新安江模型应用于湿润流域与半干旱半湿润流域的水文日径流过程模拟,并采用SCE-UA算法进行模型参数优化.结果表明2个模型均能很好地模拟湿润流域日径流过程,在半干旱半湿润流域BTOPMC模型的模拟效果较差,模型的产流机制需要进一步的完善,以扩大模型的应用范围.     

基于MOSCEM-UA的水文模型多目标参数优化研究

水文模型校准经验表明,单一目标函数不足以准确预报观测数据的所有特征。为解决这一问题定义多个目标函数用于度量系统模拟的不同方面,并根据多标准优化确定pareto非支配最优解。提出高效的MOSCEM-UA算法能够解决水文模型的多目标优化问题,MOSCEM是对SCE-UA全局优化算法的一种改进,它使用pareto非劣解概念而不是直接对单目标函数评估,pareto解集将最初的点群发展为一组解决源方案的稳定分布。通过对流域场次洪水的模拟,进行单目标与多目标模拟方案对比,从而选出较优的多目标优化的模型参数。结果表明,采用多目标最优非劣解准则选取最优解使筛选结果更具准确性和可靠性,为水文模型参数优化率定提供了较为综合的方法。     

分布式水文模型EasyDHM在增江流域的应用研究

为精细描述增江流域水文循环过程,基于分布式水文模型EasyDHM,实现对增江流域产汇流过程的模拟。首先对EasyDHM模型中的众多产汇流参数进行了敏感性分析,然后对其中敏感度较高的参数进行了优化。经参数优化后,三个断面的水文模拟精度在率定期和检验期均较高,说明EasyDHM模型在增江流域应用良好,可为流域水资源的管理、水资源合理利用以及流域洪水预报,起到科学支撑作用。     

Overland water and salt flows in a set of rice paddies

Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m⁻¹) and an infiltration rate of 5.8 mm day⁻¹. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day⁻¹), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day⁻¹ was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration.     

瓦房店市水果生产标准化发展研究

瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。     

金谷子耐旱TG118引种试种及推广应用

对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。     

对《种子法》存在问题的探讨

《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。     

Review of the Egyptian experience in implementing land drainage projects

About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered.     

和谐社会理论建设的几点哲学思考

在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。     

A European irrigation map for spatially distributed agricultural modelling

We present a pan-European irrigation map based on regional European statistics, a European land use map and a global irrigation map. The map provides spatial information on the distribution of irrigated areas per crop type which allows determining irrigated areas at the level of spatial modelling units. The map is a requirement for a European scale assessment of the impacts of irrigated agriculture on water resources based on spatially distributed modelling of crop growth and water balance. The irrigation map was compiled in a two step procedure. First, irrigated areas were distributed to potentially irrigated crops at a regional level (European statistical regions NUTS3), combining Farm Structure Survey (FSS) data on irrigated area, crop-specific irrigated area for crops whenever available, and total crop area. Second, crop-specific irrigated area was distributed within each statistical region based on the crop distribution given in our land use map. A global map of irrigated areas with a 5′ resolution was used to further constrain the distribution within each NUTS3 based on the density of irrigated areas. The constrained distribution of irrigated areas as taken from statistics to a high resolution dataset enables us to estimate irrigated areas for various spatial entities, including administrative, natural and artificial units, providing a reasonable input scenario for large-scale distributed modelling applications. The dataset bridges a gap between global datasets and detailed regional data on the distribution of irrigated areas and provides information for various assessments and modelling applications.     

粉质仪和拉伸仪在面粉生产中的应用

在介绍粉质仪和拉伸仪结构和原理的基础上,探讨了粉质曲线中吸水率、形成时间、稳定时间、弱化度和评价值等指标与面粉品质的关系,以及如何根据拉伸曲线中面团最大拉伸阻力、延伸度和拉伸曲线面积等指标来评价面团品质,并结合生产实际,概述了粉质仪和拉伸仪在面粉生产中的作用。     

农村信息化服务的现状及建设措施

分析当前我国农村信息化服务的现状,提出加强农村信息化服务的新举措。     

车辆ABS控制算法的研究及探讨

对现代汽车的ABS控制算法作了一些简单的介绍,同时指出了它们的一些缺陷,相应地提出了几种对ABS的其它控制方法并加以探讨,其中着重论述了ABS门限值控制算法中参考车速的确定方法和基于附着系数的控制算法。