中国黄土高原地区4～10月雨量时空变化特征分析   总被引：17，自引：6，他引：11  

王毅荣  王锡稳 《高原气象》2006,25(4):737-743

利用黄土高原区域40年的实测降水资料,研究了该区作物生长期(4~10月)降水量的时空变化特征,并对干年和湿年的降水进行了分析和比较。结果表明:黄土高原作物生长期降水在1985年左右发生突变,由历史上的多雨转为少雨;降水异常变化存在3~5年、8年左右和11~16年左右的振荡周期,3~5年的振荡周期更明显;干湿年降水存在明显差异,湿年比干年多40%以上;存在降水异常响应的敏感区,干旱在高原的东北部响应变幅大于其它地方,湿涝响应在高原的北部最为明显。  相似文献   

模糊分类技术在作物类型识别中的应用   总被引：8，自引：0，他引：8  

尤淑撑  张玮  严泰来 《国土资源遥感》2000,11(1):39-43

介绍了模糊分类技术,并将其应用于多时相ScanSAR的作物识别中。模糊分类技术比传统的最大似然法具有较高的识别精度。结合雷达图像的自身特点,将模糊分类技术与上下文处理相结合,是雷达图像处理的一种有效途径  相似文献   

Modelling of nitrate leaching from arable land into unsaturated soil and chalk 2. Model confirmation and application to agricultural and sewage sludge management     

R. J. Andrews  J. W. Lloyd  D. N. Lerner 《Journal of Hydrology》1997,200(1-4):198-221

A layered deterministic N-leaching model, IMPACT, has been calibrated using data from two study sites on the unconfined Chalk aquilfer of East Anglia, UK. The model predicts nitrogen species movement resulting from the application of sewage sludges and fertilizers to arable land for different vegetation-soil-hydrogeological conditions. One site received sludge in the form of digested sewage cake (DSC) for the first time during the study period, whilst the other site had over 15 years history of liquid undigested sludge (LUS) applications at 3 year intervals. Site data included: 3-monthly concentration profiles at 0.3 m intervals to depths of up to 6 m for N-species and chloride; unsaturated potential measurements; water level and saturated groundwater solute concentrations, fertilizer and sludge input; daily recharge, and soil/chalk type and moisture content. The observed average movement rate for nitrate peaks in the Lower Chalk, measured at one site, was 0.2 m year⁻². Leachate peaks were not observed annually but approximately every third year, being associated with large sludge applications and ploughing of grass crops. Significant correlation between observed and modelled nitrate profiles in soil and chalk were obtained which demonstrated applications. The relationship between crop demand, application times of fertilizers and sludge, nitrate availability and recharge was shown strongly to control the shape of nitrate profiles in the soil and chalk and the quantity of nitrate leached tochalk. The change in hydrogeological conditions at the soil-chalk contact and associated potential for denitrification was also shown to exert a significant control on the shape of the nitrate profile. Following calibration, different arable crop and sludge application regimes were examined for a 6 year period and ranked according to their nitrate leaching risk. Of the modelled cereal farming scenarios, the crop/sludge regime giving the least nitrate leaching was a late autumn surface spread application of DSC followed by winter cereals, while highest nitrate leaching was generated by an autumn injection of LUS followed by spring cereals. Field and modelled results may be used in the development of sludge disposal policies to arable land particularly with regard to sludge types, application times, and following crop types and fertilizer requirements. Overall, observed and model data demonstrate the importance of examining nitrate leaching as a continuum from the soil through the chalk to the water table.  相似文献   

气候变化对我国小麦地理分布的潜在影响   总被引：3，自引：0，他引：3       下载免费PDF全文

戴晓苏 《应用气象学报》1997,8(1):19-25

根据GCM模拟结果，分析了CO2增加对我国小麦生产地理分布的潜在影响。结果表明:在加倍CO2气候下，我国小麦生产区将进一步向北和向西扩展，小麦栽培特点和品种类型也有较大变化。气候增暖可能对东北地区产生有利影响，但在中部和南部则可能产生高温应力。小麦生长期间平均温度的升高，特别是收获前的高温可能会增加对更早熟、更耐热品种的需求。  相似文献   

Crop yield estimation model for Iowa using remote sensing and surface parameters     

Anup K. Prasad  Lim Chai  Ramesh P. Singh  Menas Kafatos 《International Journal of Applied Earth Observation and Geoinformation》2006

Numerous efforts have been made to develop various indices using remote sensing data such as normalized difference vegetation index (NDVI), vegetation condition index (VCI) and temperature condition index (TCI) for mapping and monitoring of drought and assessment of vegetation health and productivity. NDVI, soil moisture, surface temperature and rainfall are valuable sources of information for the estimation and prediction of crop conditions. In the present paper, we have considered NDVI, soil moisture, surface temperature and rainfall data of Iowa state, US, for 19 years for crop yield assessment and prediction using piecewise linear regression method with breakpoint. Crop production environment consists of inherent sources of heterogeneity and their non-linear behavior. A non-linear Quasi-Newton multi-variate optimization method is utilized, which reasonably minimizes inconsistency and errors in yield prediction.  相似文献   

近九十年吉林省松辽平原作物生长季气温变化的小波分析   总被引：11，自引：1，他引：10  

安刚  廉毅  王琪 《气象学报》1998,56(4):458-466

利用功率谱、小波分析及突变分析方法分析了以长春站为代表的吉林省松辽平原作物生长季（５～９月）平均气温近９０ａ的变化,结果表明其存在３ａ左右的甚低频振荡,１５ａ和６０ａ左右两个主要长周期振荡,从本世纪２０年代初期到５０年代初期处于暖阶段,从５０年代初期到７０年代末期为冷阶段,从７０年代末期至９０年代中期又处于暖阶段内。预计现在所处的暖阶段将持续到２０１０年左右。由突变分析结果表明,吉林省松辽平原作物生长季平均气温具有明显的阶段性变化,其各冷暖阶段同小波分析的结果具有很好的一致性,在作物生长季内月平均气温的变化有突变发生。在近期气温变化呈上升趋势。  相似文献   

Influence of Olive Oil Mill Waste Amendment on Fate of Oxyfluorfen in Southern Spain Soils          下载免费PDF全文

María Jesús Calderón  Miguel Real  Alegría Cabrera  William C. Koskinen  Juan Cornejo  Mari Carmen Hermosín 《洁净——土壤、空气、水》2015,43(7):1107-1113

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Modelling the water balance of a mesoscale catchment basin using remotely sensed land cover data     

Carsten Montzka  Morton Canty  Ralf Kunkel  Gunter Menz  Harry Vereecken  Frank Wendland 《Journal of Hydrology》2008,353(3-4):322-334

Hydrological modelling of mesoscale catchments is often adversely affected by a lack of adequate information about specific site conditions. In particular, digital land cover data are available from data sets which were acquired on a European or a national scale. These data sets do not only exhibit a restricted spatial resolution but also a differentiation of crops and impervious areas which is not appropriate to the needs of mesoscale hydrological models. In this paper, the impact of remote sensing data on the reliability of a water balance model is investigated and compared to model results determined on the basis of CORINE (Coordination of Information on the Environment) Land Cover as a reference. The aim is to quantify the improved model performance achieved by an enhanced land cover representation and corresponding model modifications. Making use of medium resolution satellite imagery from SPOT, LANDSAT ETM+ and ASTER, detailed information on land cover, especially agricultural crops and impervious surfaces, was extracted over a 5-year period (2000–2004). Crop-specific evapotranspiration coefficients were derived by using remote sensing data to replace grass reference evapotranspiration necessitated by the use of CORINE land cover for rural areas. For regions classified as settlement or industrial areas, degrees of imperviousness were derived. The data were incorporated into the hydrological model GROWA (large-scale water balance model), which uses an empirical approach combining distributed meteorological data with distributed site parameters to calculate the annual runoff components. Using satellite imagery in combination with runoff data from gauging stations for the years 2000–2004, the actual evapotranspiration calculation in GROWA was methodologically extended by including empirical crop coefficients for actual evapotranspiration calculations. While GROWA originally treated agricultural areas as homogeneous, now a consideration and differentiation of the main crops is possible. The accuracy was determined by runoff measurements from gauging stations. Differences in water balances resulting from the use of remote sensing data as opposed to CORINE were analysed in this study using a representative subcatchment. Resulting Nash–Sutcliff model efficiencies improved from 0.372 to 0.775 and indicate that the enhanced model can produce thematically more accurate and spatially more detailed local water balances. However, the proposed model enhancements by satellite imagery have not exhausted the full potential of water balance modelling, for which a higher temporal resolution is required.  相似文献   

活化灌溉水对土壤理化性质和作物生长影响途径剖析   总被引：4，自引：0，他引：4  

王全九  孙燕  宁松瑞  张继红  周蓓蓓  苏李君  单鱼洋 《地球科学进展》2019,(6):660-670

随着水资源短缺问题日益突出,提高我国农业水资源生产效率成为现代灌溉农业的重要研究内容。活化灌溉水技术为挖掘灌溉水的生理生产潜力、提高灌溉水在农业生态系统中的综合功效,提供了新的途径。在综合分析国内外有关活化水理化性质变化特征、活化灌溉水对土壤物质传输与转化、活化灌溉水促进作物生长等方面研究进展的基础上,根据土壤物理、作物生理和物质传输动力学基本理论,剖析了活化灌溉水对土壤物质传输、土壤物质转化、根系吸水吸养、作物产量形成的可能影响途径,并提出了未来重点研究的基础科学和应用技术问题,为科学合理利用活化灌溉水技术提供参考。  相似文献   

湖北省粮食生产中主要农业气象灾害变化分析     

冯明  胡幼林  马晓群  陈璇 《湖北气象》2007,26(3):266-270

使用1960年12月至2005年2月湖北省71个县(市)气象站常规气象资料,根据农业气象学原理和农业气象指标,统计、整合出对该省双季早稻、双季晚稻、一季中稻、小麦这四种主要粮食作物生产有影响的主要农业气象灾害。通过计算气候倾向率,对9类13种农业气象灾害进行了分析研究。结果表明:有6种农业气象灾害呈增加趋势,有7种呈减少趋势;冬季冻害、小麦赤霉病和盛夏冷害等三种农业气象灾害变化较为明显;任何一种农业气象灾害的气候倾向率呈减少趋势,并不意味着这种趋势变化对粮食生产就绝对有利,反之亦然。  相似文献