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1.
淮河流域农田光合有效辐射(PAR)的基本特征   总被引:5,自引:2,他引:3  
为了解淮河流域农田下垫面光合有效辐射的基本特征,分析淮河流域农作物生长的光、热条件,本文利用寿县国家气候观象台(32°30.83′ N,116°46.47′ E)2008年全年太阳辐射观测资料,采用30 min平均,按照线性关系y=cx做最小二乘拟合,得到PAR、RS以及PAR/Rs的日、月和季节均值,分析了该地区光合有效辐射(PAR)的日、季、年变化特征及所占太阳短波辐射(Rs)比例的一些基本特征,得出了该地区的光合有效辐射(PAR)的年总量为1970.8 MJ/m2,春、夏、秋、冬季的平均日总量分别为:6.83 MJ/m2、6.58 MJ/m2、4.28 MJ/m2、3.80 MJ/m2;得出了月平均PAR/Rs的值在0.37~0.43之间,最大值出现在夏季为0.43,最小值出现在冬季为0.37,年平均值为0.40;分析了晴天和阴天日PAR的变化有明显的区别,阴天日PAR/Rs的值比晴天日明天偏大,全年典型阴天日PAR/Rs的值为0.42,典型晴天日PAR/Rs的值的为0.39。对于PAR/Rs,云、水汽、太阳阳辐射强度以及大气浑浊度对其都有影响。  相似文献   

2.
张海宏 《中国农学通报》2015,31(21):162-166
为了研究长江源区光合有效辐射的变化特征,笔者利用玉树隆宝地区总辐射、光合有效辐射和空气湿度的观测资料,分析了该地区光合有效辐射和光合有效辐射系数的变化特征。结果表明:玉树隆宝地区光合有效辐射年总量13281mol/m2,平均日总量38.2mol/m2,年振幅26.7mol/m2。光合有效辐射4月份最高,12月份最低,全年变化趋势和总辐射全年变化趋势一致。光合有效辐射系数的值为1.82~2.01mol/MJ,在夏季略高,冬季略低,光合有效辐射系数与空气湿度呈正相关关系。利用观测资料得到光合有效辐射的估算方程,相对误差为4.35%。  相似文献   

3.
盘锦冬季日光温室光合有效辐射预报模型研究   总被引:1,自引:1,他引:0  
为了探索盘锦地区冬季日光温室光合有效辐射变化规律,更好地为本地区设施农业服务,利用2012 年冬季日光温室内小气候和附近气象站观测资料,采用相关统计和逐步回归分析方法分析了冬季不同天气类型日光温室中光合有效辐射特征及光合有效辐射占太阳总辐射的比值,建立了冬季不同天气类型日光温室光合有效辐射的预报模型,并对其进行拟合检验。结果表明:(1)晴天和多云天日光温室内PAR具有明显的日变化。阴天时日光温室内接受到的PAR 最大值一般在1~38 W/m2。(2)冬季典型多云天ηPAR最高,阴天次之,晴天最低。(3)采用逐步回归分析方法分别建立日光温室内日最高光合有效辐射、日光合有效辐射总量、日最大总辐射、日总辐射总量与外界气象要素的相关模型均通过了0.01 的显著性水平检验,并进行了拟合检验,晴天和多云天4个要素的拟合效果较好,阴天4个要素的拟合效果较差。  相似文献   

4.
The software (Integrated Resources for Evaluating Numerical Estimates) is a data analysis tool designed to provide easy access to statistical techniques for use in model evaluation. Mostly, non-replicated model estimates (Ei) are compared against non-replicated measurements (Mi). The software also allows comparing individual estimates against replicated measurements (or vice versa) and replicated estimates against replicated measurements. The evaluation of model performance is essentially based on the difference EiMi, or on the correlation–regression of Ei vs. Mi (or vice versa). In addition, model evaluation by probability distributions, pattern analysis, or fuzzy-based aggregation statistics is allowed. Graphics are included in most analytical tasks. The results are displayed in separate spreadsheets and can be exported into MS Excel workbooks.  相似文献   

5.
 通过光量子传感器,获取了2个棉花品种不同种植密度冠层6个关键生育时期的光合有效辐射(PAR),分析了吸收光合有效辐射(APAR)和光合有效辐射截获量(FAPAR)与棉花冠层生长特征的关系。结果表明;棉花开花期和花铃期,为APAR与FAPAR高值期,盛铃期和盛铃末期下降,吐絮期为低值期;利用多元统计分析技术,分别建立了棉花APAR、FAPAR与棉花冠层叶面积指数、覆盖度、地上鲜生物量和地上净初级生产力的相关关系模型。采用APAR与覆盖度,FAPAR与叶面积指数相关性最高的模型方程,分别估算棉花覆盖度和叶面积指数,实测值与估测值之间呈极显著的线性相关关系,估算精度分别为99.1%和99.5%。  相似文献   

6.
基于Richards扩展方程提取水稻灌浆结实光温特性参数   总被引:4,自引:1,他引:3  
以籼型两系杂交稻陵两优268和两优培九为材料,进行了为期两年(2012-2013)的大田分期播种试验,每年分7期播种,旨在研究水稻灌浆期光温要素对籽粒灌浆结实的影响,并提取与此有关的光温特性参数。因此,以Richards方程拟合观测数据得到的平均灌浆速率为纽带,通过引入光温订正方程,建立Richards扩展方程。结合全局优化算法SCE-UA (Shuffled Complex Evolution Algorithm),优化方程参数,估算2个品种灌浆结实的光温特征参数和响应曲线。结果显示,光照主要通过影响籽粒最终重量而间接作用于平均灌浆速率,温度则通过影响灌浆进程的快慢作用于平均灌浆速率。陵两优268灌浆结实期的光照阈值(R0)、最低(Tmin)、最高(Tmax)和最适温度(Top)分别为18.94 MJ m-2 d-1、6.81℃、30.28℃和33.29℃; 两优培九上述参数分别为21.71 MJ m-2 d-1、6.10℃、24.16℃和33.74℃。形成的光照和温度响应曲线,能够较好地反映两品种平均灌浆速率对光温条件的响应差异,其中陵两优268平均灌浆速率表现为“温度敏感型”,而两优培九表现为“光照敏感型”。本文运用数学模型方法定量分析和比较了光温要素对有效灌浆期内平均灌浆速率的影响,其方法和结论为建立相应的农业气象指标,评估气候资源对水稻产量的影响提供了重要参考依据。  相似文献   

7.
Rice is the staple food in many countries and is grown in varied climates from per‐humid to semiarid areas. Crop–weather models were used to predict rice yield in India. However, in spite of a significant influence of solar radiation on rice yield, none of these models used solar radiation as one of the predictors. In this paper, an attempt was made to predict the first season (June–September) rice yield at Coimbatore, Tamil Nadu, India by including solar radiation as one of the predictors. Ten years (1987/88–1996/97) data were used for the study. Seven predictors viz., percentage of rice area during first season (X1), number of days with minimum temperature below 22 °C in August and September (X2), average daily maximum temperature for three months (July, August and September; X3), average daily minimum temperature for three months (July, August and September; X4), total of average sunshine hours in August and September (X5), and total rainfall of July, August and September (X6) total average solar radiation of August and September (X7) were selected based on earlier report. Full model and stepwise regression analysis were performed using MSTAT computer package. The full model regression without solar radiation as predictor (Model I) recorded comparatively less R2 (0.6292). Inclusion of solar radiation (Model II) enhanced the R2 value considerably (R2=0.9464). Seven variables were further subjected to stepwise regression analysis and only four predictors were retained in the final model (Model III) with an R2 value of 0.9234. The model III with minimum parameters Y=22119.5758 + 19.6898, X1 ? 150.9261, X2 ? 1126.7501, X4 + 0.7179 X7 can be used to predict the first season rice yield (Y) at Coimbatore, India.  相似文献   

8.
采用随州周边4个辐射观测站 (武汉、郑州、西安1961-2017年,南阳1990-2017年)日照百分率和实测日太阳总辐射值,结合一元线性回归法拟合出适用于计算随州太阳总辐射的公式参数,再将随州本站及周边17个市县气象站2011-2016年日照百分率代入公式,推算出随州市境内月太阳总辐射值,再利用气候学计算方法和空间插值法对全年和各个季节太阳总辐射空间分布和时间变化展开剖析。其结果显示:随州市太阳总辐射的区域分布受其撮箕样地形影响,全年和各季节均表现出南多北少的特性,太阳总辐射在冬季为低值季,夏季为高值季,春秋适宜;年际和各季节的太阳总辐射值均呈减小趋势,且夏季减小速率最大;春夏秋三季的太阳总辐射偏大偏小期与全年变化步调相似,但冬季变化不显著。  相似文献   

9.
The software (Integrated Resources for Evaluating Numerical Estimates) is a data analysis tool designed to provide easy access to statistical techniques for use in model evaluation. Mostly, non-replicated model estimates (Ei) are compared against non-replicated measurements (Mi). The software also allows comparing individual estimates against replicated measurements (or vice versa) and replicated estimates against replicated measurements. The evaluation of model performance is essentially based on the difference EiMi, or on the correlation–regression of Ei vs. Mi (or vice versa). In addition, model evaluation by probability distributions, pattern analysis, or fuzzy-based aggregation statistics is allowed. Graphics are included in most analytical tasks. The results are displayed in separate spreadsheets and can be exported into MS Excel workbooks.  相似文献   

10.
针对麦棉套种的辐射竞争矛盾,结合气象学理论,初步建立了以棉行接受太阳直达辐射累积时间为主体的麦棉套种微气候学计算机模型。模拟结果表明,对棉花而言,东西行套种棉行受光较多,而南北行向则较少,小麦株高太高和预留棉行太窄,均会增加棉行的遮荫时间。理论分析认为,采用东西行种植,选择矮杆小麦品种或适时对小麦进行化学调控,起高垄种棉,用棉花育苗移栽方法缩短麦棉共生期等措施,皆有利于培育壮苗,为获得高产打下良好基础。  相似文献   

11.
The estimation of whole canopy carbon assimilation rate using the relationship between daily net CO2 assimilation rate (An) and daily incident photosynthetically active radiation (PAR) for individual leaves within the canopy has been considered an alternative to whole canopy gas exchange measurements. This relationship has been reported as being linear, but it has been explored only between the end of active shoot growth and harvest and in few species. Apple (Malus domestica) trees were used to study the seasonal changes in the relationship between daily An and incident PAR in individual leaves during the growing season of 2007 and this was done for pear (Pyrus communis) trees in 2008. Fifty leaves exposed to different light environments within the canopy of a given tree were selected. For each leaf seven times a day incident PAR and An was measured. Daily incident PAR and An was estimated by integrating instantaneous values. The relationship between daily An and daily incident PAR within the canopy had different patterns depending on the time of the season. It was always curvilinear early and late in the season, but tended to be more linear between the end of active shoot and harvest (mid-season). The initial slope and curvature of the relationship changed during the season and both were significantly related to daily PAR above the canopy. Whole canopy net carbon exchange rate was estimated considering canopy intercepted PAR and the relationship between daily An and incident PAR in individual leaves. The values were similar to those reported in the literature during mid-season. Estimated whole canopy net carbon exchange rate varied substantially after harvest, depending on whether a linear or curvilinear response of daily An to PAR for individual leaves within the canopy was considered. We showed that apple and pear whole canopy net carbon exchange rate can be estimated during mid-season, which is the most relevant phase for tree fruit production, using the following parameters: photosynthetic rate of well exposed leaves, daily pattern of incident photosynthetically active radiation (PAR), daily integral of PAR intercepted by the canopy and leaf area  相似文献   

12.
为了探明2020年5月上旬高温、强光照天气对红心猕猴桃幼果生长发育的影响,选取贵州西部3个国家气象观测站及其红心猕猴桃主要种植区的发耳、杨梅、猴场等19个基地2020年5月上旬高温、强光照天气过程中的逐日平均温度、最高温度、日照时数、太阳辐射等实时气象资料,分析高温、强光照天气对贵州西部红心猕猴桃幼果生长发育的影响。结果表明,5月3—9日,持续高温、强光照天气,导致红心猕猴桃果实日灼病严重,以都格基地红心猕猴桃果实被高温、强光照灼伤率33.3%为最高,其次是龙河、新窑两基地,其果实灼伤率在27%以上,再次是发耳、阿戛、米箩、鸡场和岩脚基地,其果实灼伤率在22%以上。在红心猕猴桃果实生长发育期,当连续4天及以上日最高温度超过35℃、太阳总辐射超过41 MJ/m2或日照时数超过10 h时,红心猕猴桃果实易发生日灼病;在红心猕猴桃果实生长发育期,当连续3天及以上日最高温度超过38℃、太阳总辐射超过41 MJ/m2或日照时数超过11 h时,红心猕猴桃果实一定发生日灼病。  相似文献   

13.
The method of small parameter and setting up model of dumbbells are used to calculate the gravitational radiation of Double Satellite,and the expression of quadrupole radiation power is obtained.The calculated results is coincident with the astronomical observed results.At the same time,the method of calculation is simpler and easier than the others.The high-order gravotational radiation(higher than the octapole radiation) can be discussed with the method of small parameter,so a new method and a way is supplied for the theory calculation of the high-order gravetational radiation.  相似文献   

14.
Dynamic simulations models may enable for farmers the evaluation of crop and soil management strategies, or may trigger crop and soil management strategies if they are used as warning systems, e.g. for drought risks and for nutrients shortage. Predictions by simulation models may differ from field observations for a variety of reasons, and such deviations can be revealed instantly by traditional or by new field monitoring techniques. The objective of this study was to improve simulation results by integrating remote sensing observations during the growing season in the simulation (i.e. run-time calibration). The Rotask 1.0 simulation model was used as it simulates daily interactions between climate (radiation temperature, vapour pressure, wind speed, precipitation), soils (water holding capacities, soil organic matter dynamics, evaporation) and crops (light interception, dry matter production, nitrogen uptake, transpiration). Various run-time calibration scenarios for replacing simulated values by remotely observed values were tested. For a number of times in the growing season, simulated values of leaf area index (LAI) and canopy nitrogen contents were replaced with values estimated from remote sensing. Field experiments were carried out in the Netherlands in 1997 (validation) and 1998 (calibration) with potato variety Bintje. Destructive field samplings were performed to follow LAI and canopy nitrogen development in the growing season. Remote sensing observations at canopy level were taken by CropScan™ equipment, covering the electromagnetic spectrum between 460–810 nm in eight spectral bands. LAI and canopy nitrogen were monitored at various moments throughout the growing season by relating them with vegetation indices (VI) that were calculated from the combination of specific remote sensing bands. The results of this study show that run-time calibration of mechanistic simulation models may enhance simulation accuracy, depending on the method how additional information is integrated. It is advised to synchronize dry matter balances and internal nitrogen balances in accordance with adjustments to observed calibration variables (in this case LAI and canopy nitrogen content). It is shown an integrated approach follows the actual crop–soil system more closely, which is helpful for specific crop management and precision agriculture in general. Run-time calibration with variables that can be estimated from remote sensing observations gives more accurate simulation results of variables that can not be observed directly, e.g. the evolution of soil inorganic nitrogen contents. High frequencies of remote sensing observations and interpolation in between them, allow reconstructing the evolution of LAI and canopy nitrogen contents to be integrated in the simulation, thereby increasing simulation accuracy of other model variables.  相似文献   

15.
External shading system of windows can reduce the indoor solar heating gain. Previous studies did not take the change of diffuse radiation into account. However, in fact, the change of diffuse radiation should not be neglected because of the existing of shading devices. Especially to those blinds, most direct radiation can be shaded while most diffuse radiation can reach the indoor space. Thus, a detail calculation model was established for diffuse radiation. With the analysis of the thermal characteristics of direct solar incidence on the blinds, a mathematic model was developed to calculate the transmittance and reflectance of the solar diffuse radiation. Based on this model, the relevant algorithm was developed.  相似文献   

16.
Summary Heritabilities of the pungency and single center traits were estimated in onion breeding populations using selection response and half-sib family analyses. Pungency was determined indirectly by measuring enzymatically produced pyruvic acid in individual bulbs. After one generation of selection, pungency was lowered by 8.1% and 8.9% in the populations 90-61-1 and 89-69-8, respectively, and realized heritabilities of 0.21 and 0.51 were estimated.Selection had no effect in lowering the pungency of population 90–62. Heritability estimates calculated through half-sib progeny analysis were 0.53, 0.48, and 0.25 for pungency in the populations 90-61-1, 90–62 and 89-69-8, respectively. The number of single centered onions was increased by 19% and 22% in populations 90–62 and 89-69-8, respectively, after one generation of selection, and the realized heritability estimates were 0.37 and 0.34, respectively.  相似文献   

17.
Summary Phenotypic and genetic correlations of flowering time (FT) with cut-flower yield (Y) were estimated from six generations of the Davis Population of gerbera (Gerbera hybrida, Compositae). The phenotypic correlation was –0.34; the genetic correlation was –0.47 when estimated from ANOVA of a NCII design and –0.72 when estimated from parent-offspring analysis. An indirect selection model was constructed to assess the efficiency of indirect selection for Y using FT as a marker. This model includes population size and generation time as variables because they differ for FT and Y. The results indicate that indirect selection will be more efficient than direct selection.Correlations of FT with flower quality traits, including scape length (SL), flower diameter (FD), scape dry weight (SDW) and flower dry weight (FDW), were also estimated. FT was phenotypically independent of these traits. However, statistically significant estimates of genetic correlation indicate that FT may be correlated with flower quality traits. Thus, indirect selection on FT to increase Y may result in undesirable correlated responses for flower quality.  相似文献   

18.
The field models for smoke flow in atrium, takings into account strong buoyancy, turbulence, radiation exchange and wall heat losses are developed according to the characteristics of the atrium fire. Realistic combustion processes in the burning fuel have not been included. A six-flux radiation model is included in a general mathematical model for fires, which are taking as a volumetric heat source, It is applied to the predictions of fire smoke development in a small-scale atrium. In order to avoid complicated radiation exchange models, radiation heat loss effects are combined to the wall heat loss. A General-purpose compute program PHOENICS has been developed to meet this need. Results of numerical calculations based on the field model are compared with test data for a fire in the small-scale atrium test facility. The resullts indicate that radiation transfer has the minor effects, due to the relatively low temperatures encountered. The method that the effect of radiation is included in the calculation of wall heat transfer losses by using maximum heat transfer coefficient is feasible. The field model used in the present study is not good enough, which a turbulent combustion sub-model must be included.  相似文献   

19.
There is much data on the impact of weather variables on the growth of sugar beet from studies conducted under controlled conditions or single field experiments, but these data are of only limited validity for other sites or larger areas. The aim of the present study was to quantify the influence of weather conditions on the growth of sugar beet for the further development of simulation models, based on data representative of sugar beet cultivation in Germany. For this purpose, 27 field trials were conducted in 2000–2001 in commercial fields with variable climatic and soil conditions. From the end of May until the end of the season, beets were harvested manually every 4 weeks, the dry matter yield of leaves and taproot was determined and their growth rates were calculated. Temperature, solar radiation, rainfall and humidity were recorded daily for each site and the potential evapotranspiration and climatic water balance were estimated. The soil water content to a depth of 0.9 m was determined at every harvest date.Several functions were developed to describe the growth of sugar beet as affected by the given meteorological variables. From sowing to the end of June, the dry matter accumulation of both leaves and taproot was strongly enhanced by increasing temperature and during this period leaf dry matter increased linearly with thermal time. After reaching 700 °C d, the taproot dry matter accumulated exponentially with thermal time. The optimum mean daily air temperature for taproot growth was approximately 18 °C. Higher temperature occurring in July and August decreased final taproot yield, but by the end of the season, growth was independent of temperature. High solar radiation advanced growth during the first 65 days after sowing and again in October.Neither the water input by rainfall and irrigation nor the climatic water balance adequately described the growth of the leaves or taproot, but it was shown that the increase in taproot dry matter during July and August depended on the amount of available water in the soil. The maximum sugar yield that can theoretically be achieved in Germany and comparable agroclimatic regions was calculated as 24 t ha−1. The present data reliable for a large agroclimatic region in Europe are of significant value as input for simulation models.  相似文献   

20.
贺俊杰 《中国农学通报》2014,30(20):244-248
为了合理利用太阳能和调整农牧业产业结构提供依据,利用2010年平均光合有效辐射(PAR)和太阳总辐射(Rs)资料,采用线性关系进行最小二乘拟合,分析该区的光合有效辐射特征。结果表明:典型晴天日和阴天日的PAR和Rs曲线变化趋势基本一致,且前者的值明显大于后者;PAR的月平均总量为8.15 MJ/m2,年总量为2983.1 MJ/m2,春、夏、秋、冬四季的平均日总量季节变化较明显,夏季最大,冬季最小;PAR/Rs晴天日的值明显小于阴天日,全年平均值为0.497,月平均值在0.422~0.544之间,最大值出现在夏末的8月,为0.544,最小值出现在冬季的1月,为0.42。PAR/Rs的变化幅度和当地的天气气候有关,受天空云、大气气溶胶、大气中水汽含量等因素的影响。  相似文献   

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