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1.
本研究自1979年3月至1996年11月,历时18年。1995年1月列为中国气象局科技课题,主持单位为喀左县气象局,参加单位有喀左县科委、喀左县植保站、辽宁省气象学校及有关乡镇农业站、气象哨技术人员,先后有15名同志参加课题试验和田间调查及技术推广。本项研究包括收集整理资料、调研分析、田间试验、模式设计计算、应用效果等几个阶段,涉及高粱蚜虫发生和天气、气候及生态环境关系,发生程度的定量分析和数学方法预测及防治实用技术推广。 相似文献
2.
河南省农业气候区划指标分析方法 总被引:5,自引:0,他引:5
利用农业气象调查中所获得的农作物物候、农业气象灾害情况等资料,与相应时期的气象资料进行对比分析,或利用田间试验所获得的农作物方面的资料及相应的气象资料进行对比分析,确定农业气候区划指标。 相似文献
3.
利用江苏南京、安徽宣城两地的水稻田间试验数据和气象资料,对ORYZA2000模型基本作物参数进行调整,包括不同发育阶段的发育速率、干物质分配系数、比叶面积等。两试验点的作物营养生长参数(DVRJ)和生殖生长参数(DVRR)差异很大,反应了模型的区域差异性。模拟效果均能准确反应叶面积指数、生物量的动态变化过程,在地上部生物量的模拟准确度最高。两试验点的叶面积指数、地上部生物量、绿叶生物量、茎生物量和穗生物量的归一化均方根NSMSE值分别为9%、19%、18%、13%、25%和16%、25%、17%、19%、24%,因而南京试验点的模拟效果比宣城好,参数更具区域适应性。 相似文献
4.
Rapid and significant advances in issues relevant to weather modification have been made in the
last decade in China due to high water resource stresses and severe weather hazards induced by climate
change. This paper reported some progress in aspects of theoretical modeling, field experiment and
cloud-seeding tools, as well as research projects regarding weather modification during the ten years
from 1997 to 2007.
More advanced theoretical models such as cloud models with bin-microphysics and
glaciogenic and hygroscopic seeding processes, and mesoscale cloud-resolving models with AgI-seeding
processes have been developed to study seeding-induced changes of cloud structure and precipitation
as well as to understand critical issues in association with weather modification. More advanced
cloud-seeding tools such as mobile ground-based launching system of AgI-rockets and aircraft-based
AgI-flares have been developed and used in operation. Several important projects aimed at exploring
weather modification techniques and their applications have been conducted during this period. 相似文献
5.
Field experiments were conducted on bed load transport in the Diaoga River, a mountain stream in southwest China, to study the variation of bed load transport with varying sediment supply. The rate of bed load transport is greatly affected by incoming sediment (load and size). Under the same flow conditions, bed load transport rates may differ by three orders of magnitude depending on whether measurements were taken before or after the first flood of the year. The relation of the "bed load transport rate versus flow intensity" appears to have similar characteristics as a clockwise looped-rating curve. Experiments also were conducted during the non-flood season to study bed load transport processes with different incoming load from an upstream section. Bed load with different sizes can be grouped into two types: traveling bed load and structural bed load. Traveling bed load is composed of sediment finer than a critical size, De, and its transport rate depends mainly on the incoming sediment rate. The incoming sediment rate can alter the rate of bed load transport by three orders of magnitude. Structural bed load is composed of coarser sediment and its transport rate closely relies on the flow intensity. 相似文献
6.
The automatic all-sky imager developed by the Institute of Atmospheric Physics, Chinese Academy of Sciences, provides all-sky visible images in the red, green, and blue channels. This paper presents three major calibration experiments of the all-sky imager, geometric angular calibration, optical calibration, and radiometric calibration, and then infers an algorithm to retrieve relative radiance from the all-sky images. Field experiments show that the related coefficient between retrieved radiance and measured radiance is about 0.91. It is feasible to use the algorithm to retrieve radiance from images. The paper sets up a relationship between radiance and the image, which is useful for using the all-sky image in numerical-simulations that predict more meteorological parameters. 相似文献
7.
冬小麦,夏玉米叶水势,蒸腾和液态水流阻力的田间试验研究 总被引:12,自引:0,他引:12
根据对冬小麦,夏玉米生长期间的叶水势,蒸散,棵间蒸发,土壤含水量等要素日变化过程的测定,计算了土壤-植物-大气系统水从土至叶片的液态水传输阻力和其日变化过程,结果表明,随着蒸腾强度的增加,液态水流阻力呈非线性的递减状太民。 相似文献
8.
Field experiment of subgrade vibration induced by passing train in a seasonally frozen region of Daqing 总被引:1,自引:1,他引:0
Ling Xianzhang Zhang Feng Zhu Zhanyuan Ding Lin Hu Qingli . School of Civil Engineering Harbin Institute of Technology Harbin China . Institute of Subgrade Prevention Engineering China . Information & Engineering Technology College Sichuan Agricultural University Ya’an China . School of Architectural Engineering Heilongjiang University Harbin China Professor PhD Associate Professor 《地震工程与工程振动(英文版)》2009,8(1):149-157
The vibration characteristics and attenuation of the subgrade caused by passing trains in a seasonally frozen region of Daqing, China are investigated. Three field experiments were conducted during different times through the year, in normal, freezing and thawing periods, respectively, and the influence of the season, train speed and train type, is described in this paper. The results show that: (l) the vertical component is the greatest among the three components of the measured vibration near the rail track, and as the distance to the railway track increases, the dominant vibration depends on the season. (2) Compared with the vibration in the normal period, the vertical and longitudinal vibrations increase while the lateral vibration decreases in the freezing period. However, in the thawing period, the vertical and longitudinal vibrations decrease, and the lateral vibration increases. (3) As train speeds increase, the subgrade vibration increases. (4) The vibration induced by a freight train is greater than by a passenger train. These observations provide a better understanding of the vibration and dynamic stability of the subgrade and may be useful in developing criteria for railway and building construction in cold regions. 相似文献
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10.
HE Jin-Hai 《大气和海洋科学快报》2009,2(2):91-96
Research on the Asian-Pacific monsoon has a long history. This paper starts by summarizing field experiments investigating the Asian-Pacific monsoon. Since the 1960s, a number of international and regional monsoon projects and field experiments have been carried out, and substantial progress regarding research on the Asian-Pacific monsoon has been made. Second, the onset and the seasonal march of the Asian summer monsoon and the annual cycle of active and break periods of the monsoon, which are characterized by precipitation maxima and minima, are studied. Since the inter-tropical convergence zone (ITCZ or TCZ) is the dominating weather system and is the major birthplace of typhoons and tropical convective systems, the monsoonal rainfall and ITCZ are analyzed after the onset of the Asian monsoon. Finally, because the ITCZ has a close relationship with tropical convective systems and rainfall events in monsoon regions, analyses of the developments of deep convection and rainfall events are briefly introduced. 相似文献