共查询到20条相似文献，搜索用时 93 毫秒
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利用NCEP 0.5°×0.5°全球再分析资料和中尺度自动站雨量观测,雷达资料等,综合分析2010年10月海南岛秋季一次特大暴雨过程,并对相关物理量场进行诊断分析。结果表明：此次暴雨是高空低槽、低层东风急流和低压环流共同影响所造成的,持久的东风急流为暴雨区提供了充沛的水汽和能量,水汽通量散度等物理量所揭示出的强水汽辐合中心与强降水中心具有很好的对应关系,辐合越强,暴雨的量级越大。回波的“列车效应”使降水增幅,持续时间长。 相似文献
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海南岛秋季暴雨天气的环流特征和形成机制初探 总被引：1，自引：0，他引：1
对海南岛2000年和2008年两次秋季暴雨的特性和影响系统的分析发现：暴雨的发生、维持和消失主要与大陆冷高、南海低值系统、热带云团活动密切相关，暴雨一般与华南沿海的低空偏东风急流相伴。对流层中层正差动涡度平流和副高南侧的暖平流破坏了海南岛及邻近区域的准地转平衡，动力强迫和热力强迫共同作用激发了次级环流，导致暴雨区上空的垂直运动的发展，促使暴雨增强。对流层中层干冷空气的侵入，正的差动假相当位温平流加剧了大气层结的不稳定，强的风垂直切变更促使对流上升运动的发展，这对暴雨局地的再增强起到了重要作用。可以综合提出 相似文献
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《福建热作科技》2019,(4)
通过自动站资料、NCEP再分析资料、高空探空资料、雷达资料等对2019年5月26-27日漳浦县暴雨过程进行技术总结分析。分析结果表明,此次暴雨过程是在500 hPa西风槽槽后西北气流与副高北侧西南风水汽输送带气流交汇,低空急流辐合共同影响的形势背景下产生的;东南风与漳浦沿海线交角最大,气流堆积辐合最明显,导致沿海乡镇降水比内陆强;高层辐散、低层辐合的动力抬升条件,低层充沛的水汽辐合,大气层结不稳定等物理量配置有利于本次暴雨的触发;此次降水属于暖云降水,具有热带海洋性质,降水效率高,容易产生短时强降水;及时准确的天气预报预警服务,对农业生产有着积极的促进作用。 相似文献
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《福建热作科技》2021,(1)
利用常规高空地面资料、区域自动站资料、欧洲细网格数值预报产品、雷达资料等对2020年5月19日漳浦县暴雨进行成因分析,并反思暴雨对农业生产的影响,提出应对措施。结果表明:此次暴雨是在东北冷涡东移过程中引导地面冷空气南下与西南暖湿气流冷暖交汇、低层切变维持在华南沿海的环流背景下产生的;强烈的高层辐散、低层辐合的动力抬升条件,低层充沛的水汽辐合和大气层结不稳定等物理量场配置有利于触发暴雨的产生;梁山山脉地形作用影响,为此次强降水提供更有利的动力条件,导致沿山脉地区暴雨落区的出现;强回波及大的VIL值,容易产生极端的小时雨强;开展因地制宜、趋利避害的为农服务,对农业生产有积极的促进作用。 相似文献
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针对2016年1月22-26日影响漳州的寒潮天气过程进行分析,通过形势场、物理量诊断等方面进行了综合分析。通过分析可知,此次寒潮天气过程在中高纬为两槽一脊的大形势下,东亚地区为温度低至-44℃的强大低涡中心控制,低压槽位置偏北,槽后不断有冷空气从中路扩散南下影响我市,导致我市出现了强烈降温;从孟加拉湾输送的强盛西南急流为此次降水提供了水汽输送条件,700 h Pa辐合配合500 h Pa高空辐散的维持并加强,为降水出现提供了重要的动力条件。低层冷空气不断南下扩散,不仅抬升了对流层中上层的暖湿气流,造成了持久稳定的逆温层,也使850 h Pa及以上的气温降到0℃以下,致使我市西部和北部等高海拔地区的降水形态快速发生变化,出现了罕见的雪和雨夹雪天气。 相似文献
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2008年海南罕见长“低温阴雨”天气过程成因分析 总被引：4，自引：0，他引：4
为了对今后"低温阴雨"灾害天气过程的预报和服务起到积极的推动作用,利用NCEP再分析资料和单站要素资料对2008年1月下旬至2月中旬海南省出现的长"低温阴雨"灾害性天气过程进行了分析.得出:高空环流形势异常、以乌拉尔山阻塞高压为主体的两槽一脊环流形势长时间稳定是导致此次长"低温阴雨"天气过程出现的直接原因.另外,200 hPa散度分布、850 hPa水汽通量、气象要素在单站剖面图上的演变情况等,对分析和预报此次长"低温阴雨"天气过程也起到一定的作用. 相似文献
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利用漳州市10个气象观测站1981-2018年的暴雨统计资料,分析了漳州市冬季暴雨的时空分布特征、气候背景相关性以及影响天气系统。结果表明,漳州南部地区是冬季暴雨的多发区,有利地形是重要因子之一,月际分布上主要在2月份;对厄尔尼诺事件有一定的响应,若出现厄尔尼诺现象时,有利于漳州当年冬季发生暴雨;冬季暴雨的地面影响系统主要为冷空气和地面倒槽,高空影响系统主要为500hpa西风槽、低空西南急流和低层切变线;漳州冬季暴雨经常伴随冷空气南下,对农业生产经常带来寒、冻害和滞、涝等灾害。 相似文献
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利用地面观测与高空探测资料对2017年7月29日至8月2日发生在漳州市一次台风暴雨过程进行分析,得出暴雨成因并发现此次过程具有累积雨量大、影响范围广、滞留时间长、降雨强度强、风浪危害重和防御难度大的特点。气象部门针对此次台风暴雨过程进行预报与服务,收集了民众和相关部门的反馈意见,评估此次过程预报及服务农牧业的效果,得出在未来气象服务中,一方面要强化气象服务的敏锐性和主动性,提出行之有效的合理化建议,为气象防灾减灾提供科学依据;另一方面要进一步拓宽漳州市农业气象服务手段。 相似文献
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为提高海南热带农产品流通的现代化水平,确保海南热带农产品的质量安全,在分析海南省热带农产品供应链现有模式及存在问题的基础上,结合封闭供应链的概念及研究现状,设计4种类型核心企业主导的基于质量可跟踪和追溯的海南省热带农产品封闭供应链模式。为海南省热带农产品封闭供应链模式设计、工程应用和系统开发提供参考,对于确保海南省热带农产品质量安全具有重要意义。 相似文献
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《Plant Production Science》2013,16(2):189-198
AbstractGrain number per spike of wheat is lower in early sowing than in the conventional standard cultivation in Yamaguchi, Prefecture, Japan. Components of the grain number per spike in five cultivars were analyzed with respect to temperature during the spike development period throughout three growing seasons 2001/2002, 2002/2003 and 2003/2004 to find the cause of the problem of early sowing cultivation. The plants sown in early-October and late-November were called the early sown group and the standard group, respectively, in the following. Three of the five cultivars, Hokushin, Akitakko and Nanbukomugi, showed a strong winter habit, which requires very cold temperatures for spike differentiation. The other two cultivars, Iwainodaichi and Airakomugi, had a moderate winter habit. Grain number per spike and grain yield were decreased by early-sowing (compare with the standard group) in almost all cultivars throughout the three growing seasons. The three cultivars which had a strong winter habit had fewer spikelets per spike in the early-sown group than in the standard group. The other two cultivars which had a moderate winter habit had fewer grains per spikelet in the early-sown group. The higher the temperature during the spikelet formation phase, which is from flag leaf initiation to terminal spikelet initiation, the higher the number of spikelets per spike in the standard group. The spikelet number per spike in the early-sown group increased with the increase in productive tillers under fertile conditions. Such conditions also increased the grain number per spike. 相似文献
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《Journal of Crop Improvement》2013,27(2):415-432
Summary This paper reviews the effects of allelopathic interactions in agroecosystems in Spain on plant physiological activity and their ecological advantages. The phenological stage of growth of donor plants and the effective allelochemicals in the soil solution while studying the role of phenolic compounds were highlighting. Finally possible future prospects and conclusions regarding weed control by allelochemi-cals under integrated crop management strategies are discussed. 相似文献
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以翔实的资料对2009年中国稻米生产、消费、进出口、供求平衡、库存、价格走势、购销政策和国际稻米供求等情况进行了全面地分析,对影响2010年稻米市场价格走势的各种因素进行了深入研究,并在此基础上对2010年我国稻米市场价格走势进行了预测,结论是我国稻米价格仍呈上行趋势。 相似文献
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Corné Kempenaar Thomas Been Johan Booij Frits van Evert Jean-Marie Michielsen Corné Kocks 《Potato Research》2017,60(3-4):295-305
Precision agriculture is a farming management concept based on observing, measuring and responding to inter- and intra-field variability in crops. In this paper, we focus on responding to intra-field variability in potato crops and analyse variable rate applications (VRAs). We made an overview of potential VRAs in potato crop management in The Netherlands. We identified 13 potential VRAs in potato, ranging from soil tillage to planting to crop care to selective harvest. We ranked them on availability of ‘proof of concept’ and on-farm test results. For five VRAs, we found test results allowing to make a cost-benefit assessment. These five VRAs were as follows: planting, soil herbicide weed control, N side dress, late blight control and haulm killing. They use one of two types of spatial data: soil maps or biomass index maps. Data on costs and savings of the VRAs showed that the investments in VRAs will pay off under practical conditions in The Netherlands. Savings on pesticide use and N-fertilizer use with the VRAs were on average about 25%, which benefits the environment too. We foresee a slow but gradual adoption of VRAs in potato production. More VRAs will become available given ongoing R&D. The perspectives of VRAs in potatoes are discussed. 相似文献
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Summary Diurnal changes in net photosynthetic rate were measured in a furrow-irrigated potato crop and in a riverbed crop where the
water table was always maintained at 20–28 cm from the soil surface. In the irrigated crop, the photosynthetic rate during
mid-afternoon was about half the peak rate observed at noon. This reduction was accompanied by a near tripling of stomatal
resistance, a 45% reduction in transpiration, and a 5-fold increase in the difference between leaf and air temperatures. No
such changes were observed in the riverbed crop where the photosynthetic rate remained nearly constant at about 0.9 mg m−2 s−1 between 9 a.m. and 4 p.m. Tuber yield in the riverbed crop was about 30% higher than in the irrigated crop. 相似文献
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体细胞无性系变异是一种重要的细胞工程育种技术,其应用于棉花育种的前提是建立高效的组织培养诱导再生植株体系.本文简要综述了棉花离体诱导植株再生研究的现状,重点讨论了棉花体细胞无性系变异的表现、利用方法及机理,提出了当前研究存在的问题并对今后的研究进行了展望. 相似文献