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1.
梨小食心虫成虫发生规律的气象因子分析   总被引:1,自引:0,他引:1  
为掌握梨小食心虫发生规律,2010~2014年在辽宁省大连市金州区东、西部2个试验点,利用屋式诱捕器对梨小食心虫成虫发生进行动态监测。在此基础上,结合同期气象资料,分别研究春、夏不同季节梨小食心虫成虫发生期、发生量与气象因子的关系。结果表明:春季平均气温与梨小食心虫越冬代成虫发生期相关性显著。每年自3月中旬开始,当旬平均气温的累积值≥30℃的下一旬将是越冬代成虫的发生期。夏季,气温、日照条件正常,降水量多的年份,梨小食心虫发生量多。大连金州区梨小食心虫的代数为3~4代,各代高峰期的间隔约20 d,其后6 d为卵期,此时是最佳防治期。掌握越冬代成虫发生的高峰,用间距法预测其它各代高峰期,以期达到早预测早防治的目的。  相似文献   

2.
气象因素对大豆食心虫的影响及预报   总被引:1,自引:0,他引:1  
本文采用灰色系统分析中的GM(1,1)模型,分析了大豆食心虫虫食率的变化规律,并建立趋势预报模型,又选用9种非线性模型,用并联度选优的方法定量地分析气象因素对大豆食心虫数量的影响。并建立了综合响应方程。  相似文献   

3.
中国夏季雨日降水量的概率分布   总被引:5,自引:1,他引:5  
利用全国174站夏季逐日降水资料估计了雨日降水量的无条件和有条件概率密度函数,并递推得各站1至20d内最大日降水量的概率分布及10d、20d内最大日降水量≥10mm、≥25mm、≥50mm的概率。主要结果是:在无条件和前一天有雨或无雨条件下雨日降水量r分布的形状参数α都小于1,且差别不大,而绝大部分站无条件下的尺度参数口大于前一天无雨条件下的卢。而小于前一天有雨条件下的β;无条件和分条件下,雨日降水量的均值和方差的地理分布都是东南沿海地区大于西北内陆地区,且绝大部分站无条件下的纵盯。分别大于前一天无雨条件下的μ0、α^20,而小于前一天有雨条件下的μ1、α^20;Γ分布能较准确地逼近前一天无雨和前一天有雨两种条件下雨日降水量的样本频率分布;10d、20d内最大日降水量≥10mm、≥25mm、≥50mm概率的地理分布,都是东南沿海地区大于西北内陆地区,与同样等级的样本频率的地理分布非常接近。广西西部、云南东部一带为高值区,安徽南部、江西北部一带为次高值区。  相似文献   

4.
桃小食心虫发生规律及防治方法研究   总被引:1,自引:0,他引:1  
张波 《吉林气象》2004,(1):30-31
桃小食心虫是果树的主要害虫之一。在国内分布比较广泛,特别是东北地区是桃小食心虫的主要分布区域。其危害的果树种类较多,但危害较重的有苹果、梨、桃、李、杏、山楂等。本文对九台市桃小食心虫的发生活动规律,桃小食心虫与气象因子的关系,其发生的气象指数等进行了认真的总结和分析,并结合实践提出了切实可行的防治措施。  相似文献   

5.
分析四川省2014—2018年滑坡灾害与前期降水量之间的关系,构建滑坡灾害气象预报模型,并验证模型在延伸期-月尺度中的应用效果,为四川省延伸期滑坡灾害预报工作提供理论参考。利用历史实测降水数据对四川省滑坡灾害发生的前45 d、35 d、25 d、15 d、10 d和6 d降水量进行统计分析,结果显示,滑坡灾害的发生与其相关性是逐步递减的;在此基础上,结合逻辑回归法分析滑坡灾害发生前2 d降水量的权重关系,得到降水诱发滑坡灾害概率值;再确定滑坡灾害预报模型的易发性背景值与降水诱发滑坡灾害概率值的权重系数;最后,分别计算川东、川西和川西南三个区域临界雨量,优化滑坡灾害预报模型。结果表明:四川省滑坡灾害发生当日、前1 d和前2 d降水量对灾害的影响权重分别为0.048、0.031和0.029;滑坡灾害模型的易发性概率值和降水诱发滑坡灾害概率值的权重参数川东为0.249和0.751,川西为0.655和0.345,川西南为0.501和0.499;分区域临界雨量计算结果有明显差异,川东地区临界雨量值最大,川西南地区次之,川西地区最小。利用CFSv2降水预报产品对滑坡灾害预报模型在延伸期-月尺度中的应用效果进行验证,证实模型对延伸期滑坡灾害整体有较好的预报效果。  相似文献   

6.
利用1961—2013年国家气象信息中心提供的全国753站逐日降水资料、NCEP/NCAR逐日再分析风场和比湿资料,以及NOAA的HYSPLIT模式同期驱动资料,分析了华南前汛期9个典型涝年的低频降水特征及其与低频水汽输送的关系,探讨了低频水汽输送通道及源地。结果表明,华南前汛期9个典型涝年降水存在显著的10~20 d低频振荡周期,闽赣地区30~60 d低频周期也显著。华南前汛期850 hPa纬向、经向水汽通量都存在10~20 d的显著低频周期。影响华南前汛期典型涝年10~20 d低频降水的四个低频水汽输送通道及源地为:以马达加斯加岛北部印度洋、赤道中印度洋为参考源地的西南水汽通道;以日本群岛东南洋面和赤道中太平洋为源地的东南水汽通道;以里海北部和贝加尔湖东南侧为参考源地的西北冷空气通道;以白令海为参考源地的东北冷湿水汽通道。对广东佛冈站和江西广昌站的典型涝年进行水汽后向轨迹模拟验证了上述四个水汽通道,模拟源地均位于水汽通道关键区域。水汽信号参考源地和模拟源地,可作为华南前汛期提前2~6 d延伸期预报时重点考察地区。   相似文献   

7.
国庆节长假期间,我去了乡下的外婆家做客。 一跨进院门,惊奇地发现,院子里的一株红心李树,竟然盛开着一树的花,远远看去,特别招眼。红心李树开花的时间应该是5月.果子成熟的季节在8月。按常理,这时应该既没有李花,也没有李子的。  相似文献   

8.
温、湿度对桃小食心虫发生数量的影响   总被引:1,自引:0,他引:1  
魏同 《气象》1979,5(6):38-39
桃小食心虫(Carposina niponensis walsingham)是我国苹果产区的主要害虫之一。近几年来,由于管理粗放,为害严重。在正常情况下,桃小食心虫的发生数量受气象因子的影响很大。从1956年起,有关方面就组织各方面力量进行了协作研究,并证明  相似文献   

9.
气象条件对浙江省泡桐物候期的影响研究   总被引:3,自引:1,他引:2  
利用气候资料及泡桐物候期数据,分析了浙江省泡桐关键生育期与相关气象要素的关系,研究了泡桐开花展叶前相关气候特征,探讨了冷空气对泡桐秋季物候期的可能影响。从统计值的关系来看,其物候期主要取决于气温及≥10℃有效积温的高低,降水量的影响其次,日照时数的影响最小。泡桐物候期对当季的气温条件非常敏感,降水对其开花、展叶的影响有滞后作用。泡桐开花和展叶始期前3个月的≥10℃有效积温一般分别要达到200℃·d和300℃·d以上;由落叶末期至下一年开花和展叶始期的≥10℃有效积温也分别要基本达到200℃·d和300℃·d以上;开花展叶前3个月的降水量和日照时数一般在230 mm和在210 h以上。泡桐秋季物候期前7 d内的冷空气,特别是中等强度以上的冷空气对其影响很大,落叶前的冷空气促使泡桐开始落叶,落叶开始后,冷空气将加速落叶。开花末期前2周的冷空气,在一定程度上促进了泡桐花期的结束。  相似文献   

10.
利用NCEP/NCAR再分析和全国740站逐日降水资料,运用一点滞后相关等方法,对2007年夏季江淮流域强降水期间低频振荡的波动活动特征及其与降水低频变化的联系进行了分析。结果表明,在2007年夏季降水中,降水低频分量起着重要作用。降水的低频振荡主周期为10~30d,降水距平时间序列与10~30d低频分量具有较好的对应关系。低频扰动在对流层上层和低层都呈现波列状分布,且在降水活跃位相时,低频环流在高、低层具有斜压结构。在对流层上层,低频扰动有缓慢的东移倾向,相速度为每天2~3个经度。西风带中存在多次移动性波列向下游的传播,且在120°E以西以每天14经度的群速度向下游频散能量,表明10~30d低频波动具有明显的下游发展特征。在强降水开始5d前,低频波动与能量可起源于高纬的乌拉尔山附近,沿着西北-东南向的路径向下游传播。下游发展的低频波动为江淮流域带来了能量,为强降水的发生提供了条件。这些结果加深了人们对低频波动在江淮流域强降水过程中所起作用的认识,可为寻找江淮流域强降水过程预报线索提供科学依据。  相似文献   

11.
叶茵  余清 《贵州气象》2004,28(4):37-38
我局从1999~2003年,测报工作连续4年未出现错情,在此期间共有1个250个班,9个百班无错通过上级业务部门验收.在仪器保管、使用、维护上符合要求,对外报送的各种表、簿都能做好出门合格.  相似文献   

12.
13.
Summary ?Some features of the climate system that can be considered predictors of the onset and end of the convective season over the Amazon were identified using one-month lag correlations and field composites. The fields analyzed were sea surface temperature (SST), outgoing long-wave radiation (OLR), vertical velocity and upper tropospheric winds. Warm (cold) anomalies in the SST in the tropical North Atlantic and the Caribbean Sea tend to be associated with delayed (early) onsets. Likewise, there is a tendency towards a delayed (early) end of the convective season with cold (warm) anomalies in these ocean regions. In addition, the SST in the cold tongue region of the equatorial Pacific is negatively, though weakly correlated with the onset date. The signal of this SST is more evident in the case of the end date, which is earlier with respect to its mean date in most of El Ni?o cases. The convective activity intensity itself conditions the onset and the end of the convective season, as it is evidenced by the behavior of the OLR and the vertical velocity fields. The more (less) intense the convective activity over South America during the preceding month, the earlier the onset and the later the end of the convective season on the Amazon region. The prediction of the onset and end dates of the convective season in the Amazon region was explored using a simple multiple regression technique based on the variables that have shown precursor signals with respect to these dates. The correlation coefficient between the predicted and the observed onset date is 0.81, and in the case of the end date, it is 0.76. The skill to predict early, delayed and normal categories was high, since in more than two thirds of the cases the category was successfully predicted, and there were no predictions of categories opposed to those observed. Received July 23, 2001; revised February 22, 2002; accepted April 26, 2002  相似文献   

14.
2005 is the bicentenary of the Beaufort Scale and its wind-speed codes: the marine version in 1805 and the land version later. In the 1920s when anemometers had come into general use, the Beaufort Scale was quantified by a formula based on experiment. In the early 1970s two tornado wind-speed scales were proposed: (1) an International T-Scale based on the Beaufort Scale; and (2) Fujita's damage scale developed for North America. The International Beaufort Scale and the T-Scale share a common root in having an integral theoretical relationship with an established scientific basis, whereas Fujita's Scale introduces criteria that make its intensities non-integral with Beaufort. Forces on the T-Scale, where T stands for Tornado force, span the range 0 to 10 which is highly useful world wide. The shorter range of Fujita's Scale (0 to 5) is acceptable for American use but less convenient elsewhere. To illustrate the simplicity of the decimal T-Scale, mean hurricane wind speed of Beaufort 12 is T2 on the T-Scale but F1.121 on the F-Scale; while a tornado wind speed of T9 (= B26) becomes F4.761. However, the three wind scales can be uni-fied by either making F-Scale numbers exactly half the magnitude of T-Scale numbers [i.e. F′half = T / 2 = (B / 4) − 4] or by doubling the numbers of this revised version to give integral equivalence with the T-Scale. The result is a decimal formula F′double = T = (B / 2) − 4 named the TF-Scale where TF stands for Tornado Force. This harmonious 10-digit scale has all the criteria needed for world-wide practical effectiveness.  相似文献   

15.
准两年振荡对大气中微量气体分布的影响   总被引:11,自引:5,他引:6  
张弘  陈月娟  吴北婴 《大气科学》2000,24(1):103-110
NCAR的包含化学、辐射、动力相互作用的两维模式(SOCRATES)移植回国后进行了初步的模拟试验,用以研究某些对环境问题重要的微量气体的化学、辐射、动力传输过程。在不考虑极地平流层云和气溶胶表面非均相化学等情况下,模式积分多年,计算结果稳定,模拟的风场、温度场显示出正常的季节变化,模拟的微量气体分布与卫星实测资料对照,结果也比较一致。为了探讨热带平流层风场的准两年周期振荡(QBO)对平流层微量气体分布的影响,我们做了QBO强迫的数值试验,即在模式中加入QBO强迫,并与不考虑QBO强迫的模拟结果对比。结果表明,QBO与其相关的次级环流所引起动力输送的变化,使平流层微量气体分布发生变化。  相似文献   

16.
Here, we analyze the characteristics and the formation mechanisms of low-level jets(LLJs) in the middle reaches of the Yangtze River during the 2010 mei-yu season using Wuhan station radiosonde data and the fifth generation of the European Centre for Medium-Range Weather Forecasts(ERA5) reanalysis dataset. Our results show that the vertical structure of LLJs is characterized by a predominance of boundary layer jets(BLJs) concentrated at heights of 900–1200 m.The BLJs occur most frequently at 230...  相似文献   

17.
The impact of high resolution modern vegetation cover on the West African climate is examined using the International Centre for Theoretical Physics Regional Climate Model implementing the NCAR Community Land Model. Two high resolution 25 km long-term simulations driven by the output from a coarser 50-km resolution simulation are performed for the period 1998–2010. One high resolution simulation uses an earlier and coarser-resolution version of plant functional type distribution and leaf area index, while the other uses a more recent, higher-quality, and finer-resolution version of the data. The results indicate that the new land cover distribution substantially alters the distribution of temperature with warming in Central Nigeria, northern Gulf of Guinea and part of the Sahel due to the replacement of C4 grass with corn; and cooling along the coastlines of the Gulf of Guinea and in Central Africa due to the replacement of C4 grass with tropical broadleaf evergreen trees. Changes in latent heat flux appear to be largely responsible for these temperature changes with a net decrease (increase) in regions of warming (cooling). The improved land cover distribution also results in a wetter monsoon season. The presence of corn tends to favor larger precipitation amounts via more intense events, while the presence of tropical broadleaf evergreen trees tends to favor the occurrence of both more intense and more frequent events. The wetter conditions appear to be sustained via (1) an enhanced soil moisture feedback; and (2) elevated moisture transport due to increased low-level convergence in regions south of 10N where the most substantial land cover differences are present. Overall the changes induced by the improved vegetation cover improve, to some extent, the performance of the high resolution regional climate model in simulating the main West African summer monsoon features.  相似文献   

18.
19.
流场配置及地形对西南低涡形成的动力作用   总被引:10,自引:8,他引:10  
高守亭 《大气科学》1987,11(3):263-271
本文采用定常二层模式讨论较小地形及高、低层流场配置对西南低涡形成的动力作用。指出了西南低涡的形成是与盆地、河谷以及其上气流分层有关的一种定常态.在上、下为西风分层时期,低层的浅薄暖湿西风有利于西南低涡的形成.在上、下为东、西风分层时期,上层浅薄东风亦有利于西南低涡的形成.小型的凸起山脉对西南低涡的形成没有作用.  相似文献   

20.
由中国历史气候记录对季风导致唐朝灭亡说的质疑   总被引:1,自引:0,他引:1  
2007年1月4日杂志发表了Yancheva等10人的题为"Influence of the intertropical convergence zone on the East-Asian monsoon"(热带辐合带对东亚季风的影响)的论文[1],这是德国波兹坦地学研究中心气候动力与沉积学科的主管豪格(G.H.Haug)率领的科研小组的一项成果,认为是季风的变化引起的长期干旱导致了唐朝的灭亡.  相似文献   

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