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通过对冬小麦穗粒结构与产量形成之间的内在关系进行分析，利用线性规划方法，构造产量最大目标函数，得出最优的产量穗粒结构。 相似文献
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通过对冬小麦穗粒结构与产量形成之间的内在关系进行分析,利用线性规划方法,构造产量最大目标函数,得出最优的产量穗粒结构. 相似文献
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本文运用统计学原理和分析计算方法，较全面地分析了春小麦发育阶段气象因子对穗粒数的影响规律。小麦拔节一抽穗期间降水偏少，日较差小，是影响穗粒数的不利因素；抽穗后降水偏多或偏少，气温偏高，对穗粒数的增加都有影响。 相似文献
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水稻的产量结构是由每亩穗数、每穗实粒数和千粒重所组成。这些产量结构因素的优劣,是根据作物自身的生育规律,在不同发育阶段遇到不同的外界环境条件而先后形成的。在三熟制栽培条件下水稻的丰产性状,穗数是决定的首要因素,在这个多穗的基础上,培养大穗多粒和提高粒重,是高产更高产的关键。 在论述水稻丰产性状诸因素与气象条件的关系之 相似文献
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华北及莎车膜下条播冬小麦的试验研究结果表明：冬前及冬季膜内温度提高，土壤墒情较好，冬季麦苗不停止生长，各发育期提前，越冬成活率高，穗分化和灌浆期延长，亩穗数、穗粒数多，千粒重大，亩增产百千克左右。 相似文献
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温光生态因子及时间对春小麦幼穗分化影响的研究杨淞，杨文彬（巴盟农业气象研究所）每穗小麦的小穗数、小花数和小花的发育程度，取决于本身形成的早晚、发育时间的长短等。一般认为，穗部某些器官形成越早，分化发育时间越长，越有利于形成多粒大穗。而器官形成的早晚和... 相似文献
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土壤水分对小麦开花及结实的影响 总被引：2，自引：0，他引：2
研究了不同生育期土壤水分与小麦的小花发育、开发、结实率及产量的关系，并进行了土壤水分对穗粒数影响的定量分析研究，提出了保持小花正常发育和提高小麦结实率的适宜土壤水分范围。 相似文献
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刘新春 《沙漠与绿洲气象(新疆气象)》2012,6(2):44-48
利用环境扫描电镜(SEM/EDS)分别对2009年四季在雷达站、卫星站、年轮实验室和白杨沟站采集的TSP样品进行微观形貌和能谱分析,结果表明:乌鲁木齐市TSP形貌具有明显的时空分布特征。春季TSP颗粒较大,形状不规则,可能来源沙尘;夏季TSP中颗粒少且小,可能含有土壤扬尘和植物花粉;秋季TSP颗粒多为蓬松链状,可能是烟尘聚集体;冬季TSP颗粒较大,形状规则的颗粒增多且多为圆形,是典型的燃煤飞灰形态。北郊、市区TSP中颗粒物数量高于南郊山区的白杨沟站,秋冬季燃煤对北郊和市区TSP形貌影响较大。TSP主要含Si、S、Ca、Al、Fe、Mg、Cl、Na,说明TSP来源广泛,并且由多种颗粒混合而成。春夏季乌市TSP中Si、Ca Al、Na、Mg含量较高,秋冬季Si、S、Ca、Al、Fe、Cl含量很高。市区TSP中S、Fe、Al较白杨沟同期所占比重大,白杨沟TSP中元素种类较少,S、Fe含量不高,表明燃煤、工业排放影响不大。 相似文献
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采用CloudSat卫星资料2B-CLDCLASS及2B-CWC-RVOD数据集和Aqua卫星资料的CERES Aqua MODIS Edition 3A数据集,针对2010年12月2-4日北疆地区一次暴雪过程分析了云的类型分布、冰粒子等效半径、低层云等效高度等宏微观物理属性的垂直分布及空间分布情况。结果表明,此次暴雪过程中,云层分布在12km以下,云中冰粒子等效半径和冰水含量均随云层高度增加而减少,冰粒子数浓度在垂直高度上呈单峰分布,高值分布在云层中部5.5km处。北疆地区暴雪前和暴雪后基本为低层云云量小于40%的低值区,暴雪时则为大于60%的高值区,云等效高度暴雪前和暴雪后大多为小于6km值域区,暴雪时为大于6km的高值区。 相似文献
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盘锦芦苇湿地土壤微生物初步研究 总被引：7，自引：0，他引：7
基于盘锦湿地生态系统野外观测站芦苇群落生长季的定位观测资料,分析了芦苇湿地土壤微生物不同层次上的比率变化。结果表明:在0—10,10—20 cm和20—30 cm的3个层次上及微生物总数中土壤的细菌所占比率最大,而且在3个层次上的比率自上至下逐渐增大;其次是放线菌,且在3个层次上的比率逐渐减少;最少的是真菌,在3个层次上相差不大接近为零,在整个微生物中所占比率为最少的。这是由于盘锦芦苇湿地的土壤偏盐碱性,有利于细菌和放线菌繁殖,抑制了真菌的繁殖;而且季节性积水导致通气状况不良也抑制了真菌的生存。在盘锦芦苇湿地土壤微生物垂直梯度的比率中,细菌垂直梯度变化比较明显,基本上是下面2个层次所占比率比表层大一些;放线菌垂直梯度变化明显,一般表层比率最大,下面2层比率较小;真菌垂直梯度上所占的比率没有明显变化,接近为零。 相似文献
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利用四川144个气象站1971~2014年的逐月日照时数数据和四川6个辐射站的逐月太阳总辐射数据,以气候学模拟的方法,计算了四川144个气象站的逐月太阳总辐射值。基于44年四川太阳辐射的平均分布和EOF分析的第一模态,将四川分成3个区域,并研究了四川太阳辐射的时空变化。结果表明:(1)四川年太阳总辐射从东南往西北随海拔升高呈阶梯式增加,结合年太阳总辐射EOF第一模态可把四川分为3个区域,分别是川西高原、攀西地区和四川盆地;(2)川西高原年总辐射随时间呈先下降后趋于平稳的变化,攀西地区年总辐射随时间的变化是先下降后上升,四川盆地总辐射变化不大,有缓慢下降趋势;(3)20世纪70年代四川大部分地区太阳总辐射是正距平,80年代除川西高原和雅安地区外基本是负距平,90年代是负距平,2001~2014年除攀西地区外基本是负距平。 相似文献
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2017年春季（3—5月）大气环流特征为：北半球极涡呈单极型分布,主体位于北冰洋上空,中高纬西风带呈5波型分布。3月,地面冷高压偏强,冷空气活动频繁。4月,环流由纬向型向经向型逐渐调整,冷空气势力减弱。5月,东北气旋明显加强,冷暖势力相当,入海气旋增多。春季,我国近海海域主要有16次8级以上大风过程,其中冷空气大风过程有7次,冷空气和温带气旋共同影响的大风过程有1次,入海温带气旋过程有4次,东北冷涡影响大风过程有3次,强对流导致雷暴大风过程1次;且有8次明显的浪高在2 m以上的大浪过程。春季共有6次比较明显的海雾过程,分别为3月1次、4月2次、5月3次。西北太平洋和南海共生成1个台风“梅花”和1个热带低压,其他各大洋共有热带气旋15个,分别为大西洋1个、东太平洋1个、南太平洋5个、南印度洋6个、北印度洋2个。 相似文献
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WANG Xinfeng WANG Tao Ravi Kant PATHAK Mattias HALLQUIST GAO Xiaomei NIE Wei XUE Likun GAO Jian GAO Rui ZHANG Qingzhu WANG Wenxing WANG Shulan CHAI Fahe CHEN Yizhen 《大气科学进展》2013,30(2):341-353
For the 2008 Olympic Games, drastic control measures were implemented on
industrial and urban emissions of sulfur dioxide (SO2), nitrogen oxides
(NOx) and other pollutants to address the issues of poor air quality in
Beijing. To investigate the effects of SO2 and NOx reductions on
the particulate sulfate and nitrate concentrations as well as their size
distributions, size-segregated aerosol samples were collected using
micro-orifice uniform deposit impactors (MOUDIs) at urban and downwind rural
sites in Beijing before and after full-scale controls. During the sampling
period, the mass concentrations of fine particles (PM1.8) at the urban
and rural sites were 94.0 and 85.9 μg m-3, respectively. More than
90% of the sulfates and ～60% of nitrates formed as fine
particles. Benefiting from the advantageous meteorological conditions and
the source controls, sulfates were observed in rather low concentrations and
primarily in condensation mode during the Olympics. The effects of the
control measures were separately analyzed for the northerly and the
southerly air-mass-dominated days to account for any bias. After the control
measures were implemented, PM, sulfates, and nitrates were significantly
reduced when the northerly air masses prevailed, with a higher percentage of
reduction in larger particles. The droplet mode particles, which dominated
the sulfates and nitrates before the controls were implemented, were
remarkably reduced in mass concentration after the control measures were
implemented. Nevertheless, when the polluted southerly air masses prevailed,
the local source control measures in Beijing did not effectively reduce the
ambient sulfate concentration due to the enormous regional contribution from
the North China Plain. 相似文献
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Juan Huang Yanli Feng Jian Li Bin Xiong Jialiang Feng Sheng Wen Guoying Sheng Jiamo Fu Minghong Wu 《Journal of Atmospheric Chemistry》2008,61(1):1-20
The levels of carbonyl compounds in Shanghai ambient air were measured in five periods from January 2007 to October 2007 (covering
winter, high-air-pollution days, spring, summer and autumn). A total of 114 samples were collected and eighteen carbonyls
were identified. Formaldehyde, acetaldehyde and acetone were the most abundant carbonyls and their mean concentrations of
19.40 ± 12.00, 15.92 ± 12.07 and 11.86 ± 7.04 μg m−3 respectively, in the daytime for five sampling periods. Formaldehyde and acetaldehyde showed similar diurnal profiles with
peak mixing ratios in the morning and early afternoon during the daytime. Their mean concentrations were highest in summer
and lowest in winter. Acetone showed reversed seasonal variation. The high molecular weight (HMW, ≥C5) carbonyls also showed
obvious diurnal variations with higher concentrations in the daytime in summer and autumn, while they were all not detected
in winter. Formaldehyde and acetaldehyde played an important role in removing OH radicals in the atmosphere, but the contribution
of acetone was below 1%. The carbonyls levels in high-air-pollution days were reported. More carbonyl species with higher
concentrations were found in high-air-pollution days than in spring. These carbonyls were transported with other pollutants
from north and northwest in March 27 to April 2, 2007 and then mixed with local sources. Comparing with Beijing and Guangzhou,
the concentrations of formaldehyde and acetaldehyde in Shanghai were the highest, which indicated that the air pollution in
Shanghai was even worse than expected. 相似文献
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B. D. Amiro 《Boundary-Layer Meteorology》1990,51(1-2):99-121
Three-dimensional sonic anemometers were used to measure velocities and temperatures within three natural boreal forest canopies. Vertical profiles of atmospheric turbulence statistics for a black spruce forest, a jack pine forest, and a trembling aspen forest, all located in southeastern Manitoba, were plotted and compared. The canopy structures were quite different, with total leaf-area indices of 2, 4 and 10, for the pine, aspen, and spruce forests, respectively.The profiles of the first and second moments differed among the canopies, where velocities decreased more rapidly in the top portions of the denser canopies. The velocity distributions were skewed and kurtotic within all canopies, and showed some differences among the canopies. Eulerian time scale profiles were generally similar among the canopies, and the vertical and streamwise time scale profiles were almost mirror images of each other. Eulerian length scale profiles showed some differences among canopies caused by differences in the velocity profiles. Ratios of vertical-to-horizontal time and length scales had a maximum in mid-canopy.Shear stress profiles were similar in the top parts of all canopies, and upward momentum fluxes were occasionally observed within the canopy trunk space. Countergradient heat fluxes were also observed sometimes. The countergradient fluxes and the skewed, kurtotic velocity distributions indicate the contribution of intermittent, large-scale eddies that are important for energy and mass transfer within canopies. 相似文献