Interdecadal Modulation of the Influence of La Nina Events on Mei-yu Rainfall over the Yangtze River Valley   总被引：2，自引：0，他引：2  

WANG Xin  WANG Dongxiao  ZHOU Wen  LI Chongyin 《大气科学进展》2012,29(1):157-168

The aim of this study was to investigate changes in the relationship between mei-yu rainfall over East China and La Nin a events in the late 1970s,a period concurrent with the Pacific climate shift,using meiyu rainfall data and the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis.This relationship was modulated by the climate shift:Before the 1977/1978 climate shift and after the 1992/1993 climate shift,mei-yu rainfall levels were above normal in most La Nin a years,whereas during the period 1979-1991,mei-yu rainfall was usually below normal levels in La Nin a years.Both composite analyses and results from an atmospheric general circulation model show remarkable detail in terms of La Nin a’s impacts on mei-yu rainfall in the late 1970s due to the change in the mean climatic state over the tropical Pacific.After the late 1970s,the tropical Pacific SSTs were warmer,and the mean state of low-level anticyclone circulation over the western North Pacific (WNP) weakened.Superimposed on La Nin a-related cyclonic anomaly over the WNP,anticyclonic circulation weakened.Prior to the late 1970s,the mean state of low-level anticyclone circulation over the WNP was stronger and was less affected by La Nin a-related anomalous cyclones.Anticyclone circulation may have brought moisture to the Yangtze River valley,leading to above-normal rainfall.  相似文献   

2011年秋季华西秋雨异常及成因分析   总被引：9，自引：2，他引：7  

柳艳菊  孙冷  孙丞虎  王遵娅  王艳姣  袁媛 《气象》2012,38(4):456-463

本文对2011年秋季我国的降水异常特征及成因进行了分析,结果表明2011年秋季,华西秋雨较为典型,主要呈现以下3个特点：多雨区位置较常年偏东、偏北,阴雨日数偏多;秋雨阶段性显著;极端性强。2011年华西秋雨异常突出表现为对2011年9月开始的La Nina事件响应的特征。此外,年代际的变化也可能是造成华西秋雨异常的重要原因之一。  相似文献   

Early Cretaceous fish trails from La Rioja, Spain     

Loïc Costeur  Rubn Ezquerra 《Cretaceous Research》2009,30(4):1027-1030

We report a new find of the fish trail Undichna unisulca in fluvial sediments of the Lower Cretaceous Oliván Group of the Cameros Basin (Aptian-Albian; Valtrujal, La Rioja, northern Spain). It is the second Mesozoic record of Undichna unisulca after the first discovery in the Lower Cretaceous of central Spain (Las Hoyas, Cuenca, central Spain). The trails are characterized by single sinusoidal waves which in this case are often surrounded by well-preserved lateral levees that rule out an undertrail hypothesis.The continental depositional setting, a floodplain fluvial system, reflects the known broad palaeoenvironmental distribution of Undichna and confirms its occurrences in freshwater settings.  相似文献   

厄尔尼诺与拉尼娜     

魏东岩 《化工矿产地质》2001,23(3):165-168

厄尔尼诺与拉尼娜现象是当前预报全球气候系统异常的最强信号 ,前者对全球气候不利影响要比后者大得多。史前记录表明 ,厄尔尼诺与拉尼娜现象不是近几十年才出现的 ,而是至少在15 0 0 0aB .P前就已存在了。从厄尔尼诺与拉尼娜现象演变来看 ,其出现的频率趋于愈加频繁之势  相似文献   

近40年秦岭南北地区气候变化及与El Nino/La Nina事件相关性分析   总被引：11，自引：0，他引：11  

殷淑燕 《山地学报》2002,20(4):493-496

通过对近40年来秦岭南北地区气候变化及与El Nino/Ln Nina事件相关性研究发现，秦岭南北地区气温与降水同步波动，但波动幅度有差别。二者都有暖干化趋势，秦岭以北变暖程度超过秦岭以南，而秦岭以南年降水量的绝对减少量大于秦岭以北，两地年平均气温降水量差值有缩小趋势。Ln Nina事件对秦岭南北地区的影响大于El Ninona事件，La Nina年年平均气温明显下降，超过极显著相关水平，而降水增多。El Nino年气温略有升高趋势，降水略有减少趋势，但达不到统计上的相关水平。  相似文献   

Air–Sea Flux Estimates And The 1997–1998 Enso Event     

A. Birol Kara  Peter A. Rochford  Harley E. Hurlburt 《Boundary-Layer Meteorology》2002,103(3):439-458

Bulk formulae for wind stress, sensible and latent heat flux are presented that are suitable for strong mesoscale events such as westerly wind bursts that contribute to the El Niño-Southern Oscillation (ENSO). Their exchange coefficients for heat and momentum have a simple polynomial dependence on wind speed and a linear dependence on air–sea temperature difference. The accuracy of these formulae are validated with respect to air–sea fluxes estimated using the standard algorithm adopted by the Tropical Ocean-Global AtmosphereCoupled-Ocean Atmosphere Response Experiment (TOGA COARE). The comparison ismade for observations from 96 Tropical Atmosphere Ocean (TAO) array and National Oceanographic Data Center (NODC) moorings in the equatorial and North Pacific Ocean spanning years 1990–1999. The bulk formulae are shown to have very small median root–mean-square differences with respect to the TOGA COARE estimates: 0.003 N m^-2, 1.0 W m^-2, and 10.0 W m^-2 for the wind stress, sensible heat flux, and latent heat flux, respectively.The variability of air–sea fluxes during the 1997–1998 ENSO is also examined, along with a possible relationship between air–sea fluxes and surface ocean mixed layer depth (MLD). The wind stress and latent heat flux during the 1997 El Niño are found to be greater in the warm pool of the western Pacific than in the central Pacific where the ENSO is most clearly seen. These differences disappear upon the start of La Niña. The MLD in the equatorial Pacific is found to be moderately correlated to air–sea fluxes just before the start of the 1998 La Niña and poorly correlated otherwise.  相似文献   

厄尔尼诺事件的随机特征   总被引：1，自引：2，他引：1  

刘伟  杨学祥 《地球物理学进展》2003,18(2):357-362

厄尔尼诺事件与强潮汐、日食、月食、火山、地震以及洋流冷暖循环相关．统计资料表明，厄尔尼诺事件的发生具有明显的随机特征，当各因素的最大值相互叠加时，就会发生强厄尔尼诺事件．厄尔尼诺与火山地震活动密切相关，具有区域性强，能量变化大，活动频繁，有规律但无严格周期等特点．厄尔尼诺事件是多种因素形成的。因而更具有随机特征．  相似文献   

厄尔尼诺事件对商丘气候的影响   总被引：3，自引：0，他引：3  

常军  张云霞等 《河南气象》2002,(3):13-14

不仅厄尔尼诺事件不同的冷暖性质对商丘气候的影响不同，而且不同的起始时间、强度和持续时间对气候的影响也不同。利用1952－2000年气象资料，对厄尔尼诺的冷暖性质、发生特征进行分型，进而找到尼尔尼诺事件与本地降水和气温的统计相关关系。  相似文献   

El Nio、La Nia事件与太阳活动对河南省东亚飞蝗大发生的影响     

孔海江  陆维松  王晓丹  吕国强  王蕊 《气候与环境研究》2005,(1)

用研究灾变规律的关键时方法分析了El Nio、La Nia事件和太阳活动对河南省东亚飞蝗 (Locus ta migratoria manilensis Meyen) 的影响。结果发现, El No和La Nia事件不会促使河南省沿黄地区东亚飞蝗的大发生, 并得出El Ni no和La Ni na事件对飞蝗大发生的影响主要通过影响其发生地的天气、气候 (主要是降水), 从而影响飞蝗的大发生。在太阳黑子相对数高年的后一年, 河南省东亚飞蝗大发生的可能性超过90%。  相似文献   

The felsic complex of the Vallehermoso Caldera: interior of an ancient volcanic system (La Gomera, Canary Islands)     

J.A. Rodriguez-Losada  J. Martinez-Frias 《Journal of Volcanology and Geothermal Research》2004,137(4):261-284

  相似文献