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1.
依据安康气象局安康站1953—2015年逐日降水量和太阳黑子逐年相对数,利用Mann-Kendall突变检验、Morlet小波分析等方法,对安康地区近63 a降水变化特征及其与太阳黑子相对数关系进行了分析。结果显示:近63 a安康地区年降水量以及夏季降水整体呈增加趋势,增加量分别为0.99 mm·a~(-1)、1.65 mm·a~(-1),春季、秋季和冬季降水整体呈下降趋势,减少量分别为0.26 mm·a~(-1)、0.35 mm·a~(-1)、0.06 mm·a~(-1),降水集中分布在夏季和秋季。年降水距平极值与太阳黑子相对数峰谷值主要存在0~3 a滞后;近63 a安康地区年降水有显著3 a和28 a的变化周期,与太阳黑子相对数的9 a变化周期存在一定差异。  相似文献   

2.
太阳黑子活动可能对气候的变化起到了诱导和调制作用,文中以陕西省降水量为分析对象研究太阳黑子活动对区域性降水的影响。利用集合经验模态分解方法(EEMD)对1960-2010年陕西省降水量和太阳黑子相对数进行了周期分析。研究结果表明:陕西省降水量存在16.7a、9.8a、4.9a和3.3a的平均周期,主要的平均周期9.8a与同时期的太阳黑子相对数10.3a的平均周期基本一致,在该时间尺度上两者成负相关关系,但降水量有滞后现象。结论说明太阳黑子活动是影响陕西省降水量的重要因子,但陕西省降水量还存在其他周期,说明陕西省降水量除受太阳活动的影响外,还受其他因素的影响。  相似文献   

3.
西安夏、秋季降水与太阳黑子的关系   总被引:1,自引:0,他引:1  
基于西安市1960-2007年的降水数据和太阳黑子相对数,采用一元线性回归、Mann Kendall检验等方法,对西安降雨量进行分析,然后采用小波分析方法研究了西安夏、秋两季降水量与太阳黑子之间的关系。结果表明:夏、秋两季降水量约占西安全年降水量的80%;西安夏季降水量呈上升趋势,秋季降水量则呈下降趋势;降水量的变化与太阳黑子数多少密切相关,在太阳黑子出现极值年及2 a左右,降水量也出现极值;西安夏季降水量有10 a左右的周期,秋季降水量有9 a左右周期;太阳黑子在9 a时间尺度上与降水量有很强的相关性,且夏季降水量与太阳黑子相差1~2 a的正相关,秋季降水量则与太阳黑子提前2 a左右的负相关关系。  相似文献   

4.
基于清代(1644-1911年)华中地区干旱灾害历史资料的搜集与整理,利用启发式分割算法和互补集合经验模态函数等方法,分析华中地区干旱灾害的时间分布特征。结果表明:1)清代华中地区旱灾发生频繁,共208年次,占总年数的77.6%,其变化总体上呈下降趋势。2)华中地区旱灾于1694年发生突变,突变后旱灾频率明显减少。3)华中地区旱灾存在显著的周期性,存在2.6a、9.7a、21.6a、29.4a和102.1a的周期,其中9.7a和21.6a的周期与太阳黑子周期相一致。4)交叉小波分析表明太阳黑子数与华中地区旱灾变化在不同时间段内具有不同程度的相关关系。  相似文献   

5.
影响柴达木盆地降水量变化的主要天气动力因素   总被引:3,自引:0,他引:3  
为了解柴达木盆地内近57 a来降水量变化与太阳黑子、北极涛动(AO)和厄尔尼诺-南方涛动(ENSO)等因素间的关系,运用线性趋势法、Mann-Kendall检验法和小波分析法等对盆地内8个气象站的降水量进行了分析。发现近57 a来盆地内降水量年平均增加0.628 mm,夏季增加0.423 mm,夏季降水占全年总增加量的67%,年降水量存在2~3 a和1 a的显著周期。降水量与太阳黑子相对数存在近似正相关的8~12 a的主共振周期,降水量滞后1.2~1.8 a。年降水量与AO主要存在近似正相关的2~3 a和1~2 a的共振周期。年降水量与ENSO存在近似负相关的3 a和近似正相关的5~6 a的共振周期。表明盆地内降水与其天气动力因素在不同的周期尺度上存在不同的相关性。  相似文献   

6.
内蒙古西部地区气候变化特征及影响因子分析   总被引:3,自引:0,他引:3  
利用内蒙古西部地区8个台站的逐月气温、降水资料,采用线性趋势和Mann-Kendall突变检验等方法,结合大气环流指数、涛动和季风等影响因子,研究了内蒙古西部地区1961-2009年温度和降水的变化特征,探讨了区域气候变化与影响因子的关系。研究表明:1961年以来,内蒙古西部地区气温呈显著增加趋势,增加趋势为0.42℃/10a,冬季对气候变暖的贡献最大;21世纪以来增加最显著,在1990年发生突变。降水量也呈现出明显的增加趋势,冬季的增加趋势最显著,但没有表现出明显的突变特征。内蒙古西部地区气温变化与青藏高原指数、北极涛动指数和西风环流指数有明显的正相关关系,而东亚夏季风的进退以及所携带的水汽是影响该区域降水量变化的主要因素之一。  相似文献   

7.
近50年来吉林西部半干旱区气候变化特征   总被引:7,自引:0,他引:7  
根据吉林省西部地区6个具有代表性的气象站1961-2010年间的逐日气温、降水数据,运用趋势分析、小波分析和Mann-Kendall检验等统计方法,对吉林省西部半干旱区气候变化特征进行了分析。研究表明:近50年来,吉林西部半干旱区气温存在明显的增温趋势,以冬季气温升幅最大;降水则呈现减少趋势,夏季表现尤为明显。在不同的时间尺度上,气温、降水的变化趋势存在差异,年平均气温主要有5a左右,12a左右和30a以上的震荡周期,并在1989年发生突变;年平均降水主要有5a左右,30a左右的震荡周期,年际交替频繁。通过分析干燥度指数,吉林西部半干旱区干燥度指数主要存在6a左右、10a左右和35a左右震荡周期,并在1997-2002年之间发生突变,干燥程度总体呈现上升趋势,但上升趋势不明显,上升幅度自西向东逐渐减小。  相似文献   

8.
近50年中国气温变化的区域差异及其与全球气候变化的联系   总被引:50,自引:2,他引:50  
采用1961-1990年逐年年平均气温资料,运用旋转经验正交函数(REOF),将中国大陆划分为8个气温变化区。之后依据1951-2000年逐月气温和年平均气温资料,采用线性回归和滑动平均等方法分析各个区域的气温变化趋势和特征。最后分析了六个遥相关指数与每个区域年平均气温、冬季气温、夏季气温标准化序列的相关关系,指出中国气温变化与全球气候变化的相关性。研究发现:1951—2000中,我国大陆35oN以北地区年平均气温变暖显著于35oN以南。23-35oN、90-112.5oE即青海南部、西藏东部、四川和云南的西部变冷。所有区域90年代为最暖期,且都存在显著变暖趋势。35oN以北地区冬季的变暖速率显著大于夏季和年平均气温的升温速率。我国的气温变化与全球气候变化有一定程度的相关关系,而且不同季节,响应全球大气变化的区域也不同。  相似文献   

9.
1965-2012年新疆北部地区气候变化及其对北极涛动的响应   总被引:1,自引:1,他引:0  
近年来,增温增湿趋势影响着新疆北部(以下称北疆)的生态系统与农牧业发展,有必要对北疆气候变化及其归因进行深入剖析.根据北疆地区23个台站月平均气温、降水资料和北极涛动指数(AOI)标准化序列资料,采用线性倾向估计、累积距平、滑动t检验、相关分析、小波变换等统计方法,分析了1965-2012年北疆地区气温与降水的变化特征及其对北极涛动(AO)的响应.结果表明:①北疆年平均气温与年降水量变化呈上升趋势,线性倾向率分别为0.41 ℃·(10a)-1及11.26 mm·(10a)-1;二者发生突变时间分别在1988年和1986年前后;突变后,北疆春、秋、冬季增温显著,夏季气温增幅不明显;北疆降水量各季都有所增加,且以冬季增幅最大.②北疆气温、降水与AOI的变化周期具有一定程度的相似性:冬、夏季气温及降水与AOI在准3 a尺度周期上有很好的频域对应关系.③北疆冬季气温序列与AOI相关性较高;北疆冬季气温、降水与AO变化在多个周期尺度上呈显著相关且滞后0.5 ~1 a,说明AO变化对北疆气温和降水具有实际预报价值.  相似文献   

10.
中国干旱区气温变化对全球变暖的区域响应   总被引:13,自引:5,他引:13  
选取中国干旱区77个气象站点1961-2007年的均一化气温资料,采用线性倾向估计、Mann-Kendall检验和Morlet小波分析等方法,研究了干旱区气温变化对全球变暖的区域响应。分析表明:①我国干旱区气温变化对全球变暖响应显著且具有鲜明的区域特色。1961-2007年,我国干旱区年平均气温呈明显上升趋势,约上升了1.8℃,平均气温升温速率为0.39℃/10a,增暖幅度与波动幅度高于同期全球以及中国区域平均。②我国干旱区气温变化季节与区域差异显著。各季平均气温均呈上升趋势,其中秋、冬两季增温明显,冬季气温线性变化率最大,为夏季增温的两倍有余。年均温与各季升温幅度区域差异较大,其中北疆、阿拉善高原升温幅度最大,南疆与河西走廊升温相对较慢。③年均温与各季气温的年距平序列突变主要发生在20世纪80年代中期以后。研究区各站点普遍存在着16~17年的年代际变化和6~7年的年际变化。综合我国干旱区年均温距平序列及其突变时间和振荡周期,可推断出干旱区气温将会持续以较高的变暖速率上升,至少最近10年这种趋势不会改变。④我国干旱区水热相互反馈作用错综复杂,气候变暖如何影响干旱区水热相互反馈作用机制,这将是进一步研究的重点。  相似文献   

11.
Fifteen species of dermestid beetles were recorded at ‘Evolution Canyon’ (EC), Lower Nahal Oren, Mt. Carmel, Israel. They represent ~35% of known Israeli dermestid species. The following three species were recorded for the first time in Israel:Trogoderma svriaca Dalla Torre, 1911;Ctesias svriaca Ganglbauer, 1904; andAnthrenus (s.str.) jordaniens Pic, 1934. Adults of 13 species were collected on the more solar radiated, warmer and climatically more fluctuating south-facing slope (SFS); ten species were collected on the opposite, north-facing slope (NFS), which was cooler and climatically more stable. The abundance of adult dermestid beetles was 1.9 times higher on the SFS than on the NFS (86 and 47, respectively). Species richness and abundance distribution at EC (three collecting stations on each slope and one at the valley bottom) were significantly negatively correlated with the plant cover that consisted of trees and bushes (Spearmanr s ,P=0.007 and 0.039, respectively) and perennials (Spearmanr s ,P=0.039 and 0.077, respectively), indicating that non-woody plants were preferred by adult dermestid beetles.  相似文献   

12.
Recent data on the epidemiology of the common mycotoxigenic species of Fusarium, Alternaria, Aspergillus and Penicillium in infected or colonized plants, and in stored or processed plant products from the Mediterranean area are reviewed. Emphasis is placed on the toxigenicity of the causal fungal species and the natural occurrence of well known mycotoxins (aflatoxins, ochratoxins, fumonisins, trichothecenes, zearalenone, patulin, Alternaria-toxins and moniliformin), as well as some more recently described compounds (fusaproliferin, beauvericin) whose toxigenic potential is not yet well understood. Several Fusarium species reported from throughout the Mediterranean area are responsible of the formation of mycotoxins in infected plants and in plant products, including: Fusarium graminearum, F. culmorum, F. cerealis, F. avenaceum, F. sporotrichioides and F. poae, which produce deoxynivalenol, nivalenol, fusarenone, zearalenone, moniliformin, and T-2 toxin derivatives in wheat and other small grains affected by head blight or scab, and in maize affected by red ear rot. Moreover, strains of F. verticillioides, F. proliferatum, and F. subglutinans, that form fumonisins, beauvericin, fusaproliferin, and moniliformin, are commonly associated with maize affected by ear rot. Fumonisins, were also associated with Fusarium crown and root rot of asparagus and Fusarium endosepsis of figs, caused primarily by F. proliferatum. Toxigenic A. alternata strains and associated tenuazonic acid and alternariols were commonly found in black mould of tomato, black rot of olive and citrus, black point of small cereals, and black mould of several vegetables. Toxigenic strains of A. carbonarius and ochratoxin A were often found associated with black rot of grapes, whereas toxigenic strains of A. flavus and/or P. verrucosum, forming aflatoxins and ochratoxin A, respectively, were found in moulded plant products from small cereals, peanuts, figs, pea, oilseed rape, sunflower seeds, sesame seeds, pistachios, and almonds. Finally, toxigenic strains of P. expansum and patulin were frequently found in apple, pear and other fresh fruits affected by blue mould rot, as well as in derived juices and jams.  相似文献   

13.
The genera ofMicrogaster Latreille 1804 andHygroplitis Thomson 1895 from China are presented systematically in this paper. Thirty-two species ofMicrogaster and three species ofHygroplitis are known in China. Diagnosis, character variation, distribution and host of each species among the two genera are presented, including its host and distribution. Keys to the species ofMicrogaster andHygroplitis are given. http://www.phytoparasitica.org posting Dec. 19, 2006.  相似文献   

14.
Plant Viruses Transmitted by Whiteflies   总被引:18,自引:0,他引:18  
One-hundred and fourteen virus species are transmitted by whiteflies (family Aleyrodidae). Bemisia tabaci transmits 111 of these species while Trialeurodes vaporariorum and T. abutilonia transmit three species each. B. tabaci and T. vaporariorum are present in the European–Mediterranean region, though the former is restricted in its distribution. Of the whitefly-transmitted virus species, 90% belong to the Begomovirus genus, 6% to the Crinivirus genus and the remaining 4% are in the Closterovirus, Ipomovirus or Carlavirus genera. Other named, whitefly-transmitted viruses that have not yet been ranked as species are also documented. The names, abbreviations and synonyms of the whitefly-transmitted viruses are presented in tabulated form together with details of their whitefly vectors, natural hosts and distribution. Entries are also annotated with references. Whitefly-transmitted viruses affecting plants in the European–Mediterranean region have been highlighted in the text.  相似文献   

15.
Broad bean mottle virus (BBMV) was transmitted from infected to healthy faba-bean plants by the curculionid weevilsApion radiolus Kirby,Hypera variabilis Herbst,Pachytychius strumarius Gyll,Smicronyx cyaneus Gyll, andSitona lineatus L. The latter appeared to be an efficient vector: acquisition and inoculation occurred at the first bite, the rate of transmission was c. 41%, and virus retention lasted for at least seven days.S. lineatus transmitted the virus from faba bean to lentil and pea, but not to the three genotypes of chickpea tested. This is the first report on the generaHypera, Pachytychius, andSmicronyx as virus vectors, and onA. radiolus, H. variabilis, P. strumarius, andS. cyaneus as vectors of BBMV.Out of 351 samples of food legumes with symptoms suggestive of virus infection, 16, 11, 19, and 17% of the samples of chickpea, lentil, pea, and common bean, respectively, were found infected when tested for BBMV in DAS-ELISA. This is the first report on the natural occurrence of BBMV in chickpea, lentil, pea, and common bean. The virus should be regarded as a food-legume virus rather than a faba-bean virus solely, and is considered an actual threat to food legume improvement programmes.  相似文献   

16.
A collection of 38 PVY isolates from seed potato batches, originating from several Western European countries, was characterized by using current biological, serological and molecular tools differentiating PVY strains and groups. The correlation between the three kinds of tests was good but not absolute. No single serological or PCR method was able to discriminate among the five isolate groups found. Twenty-nine isolates belonged to the PVYN strain and six to the PVYO strain. No PVYC was found. Two other isolates reacted serologically like PVYO, but were unable to elicit a hypersensitive response from the Nytbr gene and probably represent the PVYZ group. At the molecular level, these two isolates showed a combination of both PVYO and PVYN and could be recombinants of these strains. Another isolate reacted serologically like PVYO, but induced vein necrosis in tobacco, like PVYN-Wilga. Some PVYN isolates caused tuber ring necrosis in glasshouse conditions. These might belong to the PVYNTN group. The PVYNTN, PVYN-Wilga and PVYZ groups probably represent pathotypes within strains PVYN and PVYO, respectively. The present study also confirms previous reports showing a high genetic variation at the 5 end within the PVYN strain.  相似文献   

17.
The phenology of the autumn leafroller,Syndemis musculana, a local pest of apple, was studied in order to forecast larval emergence. From 1983–1986, peak flight as determined with sexpheromone traps was always between 13–18 May. The duration of embryonic development was determined at various constant temperatures and used to estimate the periods of egg hatch in these four years. Each year, most eggs should have hatched in the second decade of June.Differences in attack rates between apple cultivars seem to be explained largely by the variation in picking time. Larvae are only half grown at the beginning of harvest (cv. James Grieve), and have gone into hibernation when the latest variety (cv. Golden Delicious) is picked. Moreover, the varieties Cox's Orange Pippin and Belle de Boskoop, picked about half time, are liable to receive additional damage by caterpillars brought with the picked fruits into storage.Various hymenopterous parasites were reared from caterpillars. As the only leafroller in the orchard which hibernates as mature larva,S. musculana may promote winter survival of some parasitoids, like the eulophidColpyclypeus florus.Samenvatting De fenologie van de herfstbladroller (Syndemis musculana Hübner), een incidentele plaag op appel, werd nader bepaald met het doel het uitkomen van de eieren te kunnen voorspellen. In 1983–1986 viel de piekvlucht, bepaald met behulp van feromoonvallen, steeds tussen 13 en 18 mei.De ontwikkelingsduur van de eieren bij verschillende constante temperaturen werd gebruikt om de periode van uitkomen te schatten. De meeste eieren zullen ieder jaar in de eerste helft van juni uitkomen.Geconstateerde verschillen in schade tussen appelrassen blijken goeddeels terug te voeren op verschillen in pluktijdstip. De rupsen van de herfstbladroller zijn pas half-was als de eerste appels eind augustus geplukt worden, terwijl tegen het einde van de oogst begin oktober de meeste al in winterslaap zijn. Met name tussentijdse rassen, als Cox's Orange Pippin and Schone van Boskoop, lopen extra schade op doordat grotere rupsen met de geplukte vruchten in de kist terecht komen.Uit de rupsen werden negen, al van andere boomgaardbladrollers bekende, sluipwespen gekweekt, Omdat deze bladrollersoort, als enige in de boomgaard, als volgroeide rups overwintert, lijkt zij bij uitstek geschikt als winterwaard.This study was carried out at the Experimental Orchard De Schuilenburg, Schuilenburg 3, 4041 BK Kesteren, the Netherlands, to which address correspondence should be addressed.  相似文献   

18.
In the summer of 2004 an epidemic of sclerotinia blight of peanut, a disease caused by Sclerotinia minor, occurred in Texas in fields where the disease was never previously detected. The disease was observed on many plants within one of the fields (>3000 disease foci), although most foci were <1 m. It is hypothesized that these observations were inconsistent with the recent introduction of a monocyclic pathogen, even if disease developed under conducive environmental conditions. The pattern of disease is most suggestive of the presence of foliar (ascospore) infections, although air temperature was above the known limits for apothecia development if the pathogen had arrived in the field in 2004 peanut seed. To further examine this epidemic, 232 isolates were collected, across a variety of spatial scales spanning this field and other Texas peanut fields, and evaluated for aggressiveness, fungicide sensitivity and genotypic diversity. There was wide variation among isolates for the phenotypic characteristics measured, but there was no evidence that a genotypically unique, highly aggressive, and fungicide resistant isolate had been introduced or evolved. The predominant genotype, TX1, which contained 154 isolates, was found in every county and field population.  相似文献   

19.
Four species so far classified in Pseudocercosporella or Ramulispora (hyphomycetes) are associated with eyespot disease symptoms of cereals. Two of these have been linked to teleomorphs that were described in Tapesia. Sequence data derived from the Internal Transcribed Spacer region (ITS1, 5.8S and ITS2) of the rDNA operon showed, however, that the eyespot fungi associated with Tapesia are not congeneric with Ramulispora sorghi, the type of Ramulispora. The genus name Tapesia is now rejected in favour of the conserved name Mollisia, which appears to comprise heterogeneous fungi. Tapesia yallundae is not closely related to the type of Mollisia, M. cinerea, but clusters separately, being more closely allied to species with Cadophora anamorphs. A new holomorph genus, Oculimacula, is therefore proposed for teleomorphs of the eyespot fungi, while the anamorphs are accommodated in Helgardia gen. nov.  相似文献   

20.
In 1975 many tumours were observed in plants ofBegonia Schwabenland grown in Aalsmeer. Submersion of the roots ofNicotiana megalosiphon seedlings in a homogenate of tumorous tissue, induced tumours after two weeks. Short periods of submergence yielded results similar to those obtained after longer periods. Tumour homogenates lost their infectivity after ten min at 50°C. Aphids transmitted the infectious agent.Treatment with propylene oxide did not inhibit infectivity completely. Filtration through a 450 nm filter removed the infectious agent.Tobacco tumor virus or a viroid could not be isolated. Cultures ofCorynebacterium fascians, isolated from tumours ofN. megalosiphon were highly infectious and induced tumours in healthyN. megalosiphon andBegonia. Tumorous tissue homogenates ofPelargonium zonale, Dahlia sp.,Gladiolus sp., andLilium sp. also caused tumours inN. megalosiphon, from whichC. fascians was isolated. It was not possible to produce tumours inN. megalosiphon with homogenates from roses with symptoms of bud proliferation.Samenvatting In 1975 werden vele tumoren waargenomen inBegonia Schwabenland op Aalsmeerse bedrijven (Fig. 1). De infectiositeit van tumorweefsel kon goed en snel worden vastgesteld door de wortels van zaailingen vanNicotiana megalosiphon in een homogenaat van tumorweefsel te dompelen. Tumoren ontstonden na twee weken, de eindbeoordeling geschiedde na een maand (Fig. 2). Ook verschillende andereNicotiana spp.,Melilotus officinalis (Fig. 3) enPisum odoratum (Fig. 4) werden aangetast.Bij de infectiositeitstoets gaven zeer korte dompeltijden even goede resultaten als langere (Tabel 1). Infectieus sap verloor zijn infectievermogen na 10 min verhitting bij 50°C. Bladluizen brachten de smetstof over. Propyleenoxide verminderde de infectiositeit wel, doch onderdrukte deze niet totaal. Bij filtratie door een 450 nm filter bleef het infectieuse agens op het filter achter. Het tumor-inducerende agens was ook aanwezig in die delen van planten met tumoren welke gezond leken en het ging voor een gering deel over met zaad (Tabel 2).Uit tumoren konden wij geen tabakstumorvirus of een viroïde isoleren. Culturen vanCorynebacterium fascians, geïsoleerd uit tumoren vanN. megalosiphon bleken zeer infectieus en veroorzaakten tumoren inN. megalosiphon enBegonia. Homogenaten van tumorweefsel vanPelargonium zonale, dahlia (Fig. 5), gladiool (Fig. 6) enLilium Mid Century Hybrid Enchantment (Fig. 7) veroorzaakten ook tumoren opN. megalosiphon, waaruitC. fascians werd geïsoleerd. Met sap van kroeskopzieke rozen konden wijN. megalosiphon niet besmetten.  相似文献   

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