共查询到18条相似文献，搜索用时 812 毫秒
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大豆晴天群体光合作用农业气象数值模拟 总被引：10，自引：1，他引：10
运用农业气象、气象学等知识建立了一个晴天大豆群体光合农业气象数值模式.模式考虑了大豆叶片空间结构特征及本身生物学特征, 积分达到了瞬时时间尺度, 可以较准确地模拟出群体光合日变化过程, 平均模拟误差在8.7%左右, 并较好地反应了大豆群体光合午休过程.利用该模式进行数值分析, 给出了CO2、辐射及温度对群体光合午休影响的一些规律, 从而为作物超高产攻关提供了一定的理论指导. 相似文献
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本文将农田微气象模式与冬小麦冠层光合模式进行耦合，建立了一个具有较强机理的冬小麦冠层CO2分布廓线模式，冠层光合模式中考虑了气孔对叶片光合的调节作用，具有明确的生物学意义，实测资料验证表明，模式可以较准确地模拟拔节期冬小麦冠层CO2分布状况，平均相对误差为6．47％，数值分析表明：当冬小麦冠层风速为1m/s时，CO2廓线弯曲最为明显，随着风速加大，CO2廓线弯曲程度变小，CO2浓度升高后风速对廓线影响的基本规律没有发生改变，但是冠层中CO2浓度差将进一步加大。 相似文献
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森林下垫面陆面物理过程及局地气候效应的数值模拟试验 总被引：5，自引：0，他引：5
文中基于大气边界层和植被冠层微气象学基本原理 ,建立了一个森林植被效应的陆面物理过程和二维大气边界层数值模式。并应用该模式进行了植被和土壤含水量等生物和生理过程在陆面过程和局地气候效应方面的数值模拟试验。所得数值模拟试验结果与实际情况相吻合。结果表明 ,应用该模式可获得植被温度、植被冠层内空气温度、地表温度日变化特征 ;森林下垫面大气边界层风速、位温、比湿、湍流交换系数的时空分布和日变化特征。该模式还可应用于不同下垫面 ,模拟陆面物理过程与大气边界层相互作用机制及其局地气候效应的研究 ,这将为气候模式与生物圈的耦合研究奠定一个良好的基础。 相似文献
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在冬小麦抽穗—灌浆期进行了水分胁迫实验,利用美国Licor公司生产的Licor-188B辐射量子照度仪及Licor-6400便携式光合作用测定仪,对水分胁迫引起的冬小麦光合生理生态变化进行了系统观测,系统地给出了冬小麦多种农业气象指标对水分胁迫的响应状况。在大量实测数据基础上,给出了包含辐射强度、温度及土壤水分因子的冬小麦叶片光合作用模式。该模式具有严格的理论推导过程和大量实验数据的支持,改进了传统水分胁迫对叶片光合速率影响的简单阶乘方法,从而为进一步准确推算水分胁迫对大田冬小麦光合作用的可能影响,以及水分胁迫对区域农业干旱的可能影响奠定了前提条件。该研究是冬小麦干旱预测模型的叶片子模型,为冬小麦农业干旱预测模型提供了丰富的基本参数,同时也为建立冬小麦干旱预测模型奠定了基本条件。 相似文献
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作者认为目前农业气象学正处于一个转折点,即从经验统计方法转向以在水文气象条件和农业生态系统生产力之间的因果关系的模拟为基础的方法。论述了农业气象学的理论基础结构及其相应的数学模式。指出新的技术方法在解决下列任务时是非常有前途的;即农业气象条件诊断、生产过程的控制、与气候变化相联系的农业气候资源评价。本文的结论认为,实用农业气象学发展的重要方向是,建立为农业生产提供信息服务的各种尺度(地区、州、行政区、生产单位)的农业气象模拟系统。 相似文献
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金塔绿洲地表特征参数遥感反演研究 总被引：16，自引：9，他引：7
TM影像是陆地资源卫星（Landsat）携带的专题绘图仪（Thematic Mapper,TM）扫描计获取的遥感图像,近年来,该数据得到了广泛的应用。本文使用Landsat-5TM数据推算了金塔地区的地表参数,包括标准化差值植被指数NDVI、修正的土壤调整植被指数MSAVI、植被覆盖度、地表反射率及地表温度。并将地表反射率、地表温度的反演值与观测值进行对比,结果表明：地表温度反演结果的相对误差在9％以内,地表反射率反演结果的相对误差在8％以内。 相似文献
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全球气候变暖已经成为一个不争的事实,开展气候变化对冬小麦产量影响的数值模拟对制定农业政策以适应气候变化具有重要意义。本文使用荷兰瓦赫宁根大学开发的WOFOST模型,利用太谷2000年和2001年的数据对WOFOST模型进行验证,确定该模型在山西太谷地区的适用性。文章分析了太谷地区气温变化趋势,假定以1985年-2007年的变暖趋势增温,假设其它条件不变,从而构建了100年内每10a的时间间隔的气象情形。以这些气象情形驱动验证好的模型模拟100年内每10a的时间间隔气候变暖对冬小麦产量的影响。模拟结果表明,气温变化对冬小麦产量的影响不是单一的,未来冬小麦的产量是波动变化的。 相似文献
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GMS5卫星遥感气溶胶光学厚度的试验研究 总被引：20，自引：3，他引：20
通过模拟 GMS5卫星可见光通道的表观反射率 R对不同大气气溶胶模型、不同下垫面反射率以及不同气溶胶光学厚度的敏感性 ,对利用 GMS5卫星资料反演湖面上空气溶胶的可行性进行了分析 ,并结合地面多波段太阳光度计观测数据 ,反演了巢湖上空大气气溶胶光学厚度。结果表明 ,反演所得 0 .5336μm气溶胶光学厚度强烈依赖于湖面反射率的选取 ,通过选取合适的湖面反射率 ,卫星反演的气溶胶光学厚度和地面光度计遥感的月均值相对误差不超过 30 %。 相似文献
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本文采用了费希尔(Fisher.R.A)提出的积分回归模式,同时运用一些常用的统计学手段,对宿县冬小麦产量和全生育期间的气象条件进行了相关计算和回归分析,定量地探讨了冬小麦产量与当地的光、热、水等农业气象条件的基本关系,研究了在农业生产水平不断提高的条件下引起冬小麦产量波动的气象原因以及气象因子的波动对冬小麦生产影响的程度,试图从农业气象的角度为合理评价宿县冬小麦的农业气候资源,采取高产稳产栽培措施以及进行产量预测等提供依据。 相似文献
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冬小麦生长发育统一阶段模式的研究 总被引：3，自引：0，他引：3
本文以生物学为基础，发展了一个包含非线性积温模式并考虑了日长影响的冬小麦生长发育阶段（DVS）模式，该模式不同于一般以往的冬小麦分段发育模型，它是一个统一的发育模式，利用中国小麦生态实验资料研究表明：黄淮海地区秋播冬小麦发育速度模式可以拟合为V=2．34×10－3＋1．21×10－3×e0．30（DL-DL0）＋1．62×10－7×（T－Tmin）（1．93）（Tmax－T）（1．14），其中T为日平均温度，DL为日长，DL0为临界日长，Tmin、Tmax为小麦生育的最高、最低温度；V的逐日累加即为该日的DVS值。利用中国小麦生态资料确定的DVS值分别为：出苗0．03，三叶0．07，拨节0．70，抽穗0．88，开花0．89，成熟1．0。平均拟合误差3．6天。利用该模型可对大田冬小麦生长进行监测研究。 相似文献
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Intercomparison and validation of snow albedo parameterization schemes in climate models 总被引：1，自引：0，他引：1
Snow albedo is known to be crucial for heat exchange at high latitudes and high altitudes, and is also an important parameter
in General Circulation Models (GCMs) because of its strong positive feedback properties. In this study, seven GCM snow albedo
schemes and a multiple linear regression model were intercompared and validated against 59 years of in situ data from Svalbard,
the French Alps and six stations in the former Soviet Union. For each site, the significant meteorological parameters for
modeling the snow albedo were identified by constructing the 95% confidence intervals. The significant parameters were found
to be: temperature, snow depth, positive degree day and a dummy of snow depth, and the multiple linear regression model was
constructed to include these. Overall, the intercomparison showed that the modeled snow albedo varied more than the observed
albedo for all models, and that the albedo was often underestimated. In addition, for several of the models, the snow albedo
decreased at a faster rate or by a greater magnitude during the winter snow metamorphosis than the observed albedo. Both the
temperature dependent schemes and the prognostic schemes showed shortcomings. 相似文献
13.
钟强 《Acta Meteorologica Sinica》1998,(2)
The combination of field experiments and satellite observations is the fundamental way tounderstand the characteristics of spatial-temporal variation in surface albedo over the Tibetan(Qinghai-Xizang) Plateau. Under the condition without snow cover, the relatively regular annualvariation cycle of the surface albedo can be expressed by an empirical formula. The effect of snowcover on the surface albedo in winter can be expressed by introducing two variables of snow forcingand sensitivity parameter. The existing satellite retrieved results of surface albedo may provide thedigital grid data for describing the geographical distribution. However, some satellite retrievedsurface albedos available over the Tibetan Plateau are obviously too low in winter. Taking thesatellite derived results in summer as the background field representative of geographicaldistribution and combining the empirical formula of annual cycle based on the surface observations,a dynamic model of surface albedo is developed for the need of modeling the climatic influence ofthe underlying surface forcing of the Tibetan Plateau. 相似文献
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Zhong Qiang 《Acta Meteorologica Sinica》1998,12(2):177-189
The combination of field experiments and satellite observations is the fundamental way to understand the characteristics of spatial-temporal variation in surface albedo over the Tibetan(Qinghai-Xizang) Plateau. Under the condition without snow cover, the relatively regular annual variation cycle of the surface albedo can be expressed by an empirical formula. The effect of snow cover on the surface albedo in winter can be expressed by introducing two variables of snow forcing and sensitivity parameter. The existing satellite retrieved results of surface albedo may provide the digital grid data for describing the geographical distribution. However, some satellite retrieved surface albedos available over the Tibetan Plateau are obviously too low in winter. Taking the satellite derived results in summer as the background field representative of geographical distribution and combining the empirical formula of annual cycle based on the surface observations,a dynamic model of surface albedo is developed for the need of modeling the climatic influence of the underlying surface forcing of the Tibetan Plateau. 相似文献
15.
A new canopy radiation transfer and surface albedo scheme is developed as part of the land surface model EALCO (Ecological
Assimilation of Land and Climate Observations). The model uses a gap probability-based successive orders of scattering approach
that explicitly includes the heterogeneities of stands and crown elements and the radiation multiple scattering. The model
uses the optical parameters of ecosystem elements and physically represents ecosystem processes in surface albedo dynamics.
Model tests using measurements from a boreal deciduous forest ecosystem show that the model well reproduced the observed diurnal
and seasonal albedo dynamics under different weather and ecosystem conditions. The annual mean absolute errors between modeled
and measured daily albedo and reflected radiation are 0.01 and 1.33 W m−2, respectively. The model results provide a quantitative assessment of the impacts of plant shading and sky conditions on
surface albedo observed in high-latitude ecosystems. The contribution of ground snow to surface albedo in winter was found
to be less than 0.1 even though the canopy is leafless during this time. The interception of snow by the leafless canopy can
increase the surface albedo by 0.1–0.15. The model results show that the spectral properties of albedo have large seasonal
variations. In summer, the near infrared component is substantially larger than visible, and surface albedo is less sensitive
to sky conditions. In winter, the visible band component is markedly increased and can exceed the near infrared proportion
under cloudy conditions or when snow exists on the canopy. The spectral properties of albedo are also found to have large
diurnal variations under the clear-sky conditions in winter. 相似文献
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采用EFAST方法和SCE-UA算法优化WheatSM模型参数,采用区域模拟和单站插值的方法对2013—2017年鹤壁市冬小麦各发育期日数和产量进行模拟修订,为WheatSM作物模型在豫北地区的业务应用提供参考。研究发现:区域模拟方法对鹤壁地区冬小麦生育期开始日期的模拟效果除出苗期、越冬期的外,其他均好于单点插值方法的。单点插值方法对越冬期的模拟效果明显好于区域模拟方法的。冬小麦产量的模拟效果区域模拟方法也比单点插值方法好,但两种结果的相对误差均较大。通过对WheatSM模型得到的冬小麦气象产量模拟结果进行修订,可以明显提高模型产量模拟结果。2013—2017年鹤壁地区模拟产量的误差为-17. 92%～-2. 98%,RMSE为1114. 9 kg/hm~2,NMSE为12. 59,模拟效果较好。利用区域模拟方法可以对区域内单个站点的冬小麦生长发育和产量进行模拟,但对越冬期开始时间的模拟需要参考单点插值方法的相应结果。 相似文献
17.
Vesselin A. Alexandrov 《Climatic change》1997,36(1-2):135-149
In recent years the problem of climate and its variations under the influence of natural processes and factors of anthropogenetic origin has come to the forefront of scientific and practical problems on a world-wide scale. Climate change vulnerability assessments of agronomic systems in Bulgaria have been initiated. In this paper preliminary results of this study are presented. Different climate change scenarios were defined. Global circulation model (GCM) scenarios and incremental scenarios for Bulgaria were created and applied. The influence of climate change on potential crop growing season above a base of 5° and 10 °C in Bulgaria was investigated. Increases in temperature can be expected to lengthen the potential growing season, resulting in a shift of thermal limits of agriculture in Bulgaria. The Decision Support System for Agrotechnology Transfer (DSSAT) Version 2.1 was used to assess the influence of climate change on grain yield of maize and winter wheat. Maize and winter wheat yields decreased with increasing temperatures and decreasing precipitation. 相似文献
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