Effects of intraseasonal oscillation on the anomalous East Asian summer monsoon during 1999   总被引：2，自引：0，他引：2  

孙颖  丁一汇 《大气科学进展》2008,25(2):279-296

The 1999 East Asian summer monsoon was very unusual for its weak northward advance and remarkably anomalous climate conditions. The monsoonal southwesterly airflow and related rain belt in East Asia were blocked south of the Yangtze River Valley. The monsoonal airflow and major moisture transport conduct shifted eastward and turned northward to Japan from the tropical western Pacific rather than to East China from the South China Sea （SCS） as in normal years. Severe and prolonged drought occurred over extensive areas of North China and heavy precipitation in South China and Japan. The investigation on the possible intrinsic mechanisms related to such an anomalous monsoon year has shown that the unique behavior of intraseasonal oscillation may play an essential role during this process. During this year, the northward propagation of 30-60-day anomalous low-level cyclone/anticyclone collapsed in the region around 20°N and did not extend beyond the latitudes of the Yangtze River basin due to the barrier of strong cold air intrusion from the mid-latitudes. The southwesterly moisture flux on the northwestern flank of the anticyclonic moisture transport system in the western North Pacific, which was regulated by the northward shift of 30-60-day cyclonic/anticyclonic moisture transport, also did not reach the region north of 30°N as well. Under this circumstance, the weak northward advance of the monsoon westerlies and associated northward moisture transport could not arrive in North China and led to the severe droughts there in 1999. The SCS and South China were mostly affected by the airflow in the southern and northern flanks of the same 30-60-day cyclones or anticyclones, respectively, and thus controlled by the nearly reverse zonal wind and moisture convergent/divergent conditions. The rainfall in the SCS and South China showed out-of-phase oscillation through the transient local Hadley circulation, with the rainfall maximum occurring in the SCS （South China） when the 30-60-day anticyclone （cyclone） r  相似文献   

赤点石斑鱼HSP60基因克隆及弧菌应激前后的组织表达特性分析          下载免费PDF全文

曲朦  施晓峰  张之文  丁少雄 《海洋学报》2011,33(1):111-120

HSP60(heat shock protein 60,热休克蛋白60)作为高度保守的热休克蛋白家族的一员,不仅可以在应激状态下帮助其他蛋白正确折叠并恢复天然构象,还可作为危险信号作用于天然免疫系统.基于HSP60的EST序列设计特异引物,采用RACE技术成功克隆获得赤点石斑鱼HSP60 cDNA全序列及基因组全序列....  相似文献   

WRF、EC和T639模式在福建沿海冬半年大风预报中的检验与应用     

曾瑾瑜  韩美  吴幸毓  林青  廖廓 《海洋科学》2015,39(7):75-85

基于福建省冬半年沿海和港湾岛屿自动站的逐时极大风观测资料和WRF(Weather Research and Forecast)、EC(European Centre for Medium-Range Weather Forecasts)细网格以及T639(TL639L60)三种模式预报的10 m 风场资料, 将模式预报的风向风速与观测资料进行对比检验, 结果表明: 福建省沿海冬半年大风的盛行风向以东北风为主, 大风的时空分布极为不均, 沿海风力的脉动性、跳跃性、局地性突出。从三种模式对风速风向的模拟效果来看, WRF 和EC 细网格的预报效果较好, 有可参考性, T639可参考性不高。对于风速, 模式预报结果相比实况极大风速偏小, 港湾岛屿代表站风速的平均绝对误差均小于沿海代表站, 预报平均误差由沿海向内陆逐渐减小, 由中部向南北逐渐减小。风向相比风速的预报效果要差, WRF 和EC 细网格的风向预报误差在45°～50°, 有一定的参考意义; 港湾岛屿代表站风向的平均绝对误差大于沿海代表站, 以浮标站的误差最大。当观测风速出现7 级及以上风速时, 若对大风进行分级检验, 则较低风速的预报平均绝对误差小于较高风速; 风向预报的平均绝对误差也大大降低, 且误差都在45°以内, 具有良好的参考性。  相似文献   

The evolution of BD+60°2522: with mass loss and overshooting     

D. N. Dawanas  A. Wardana  H. L. Malasan 《Astrophysics and Space Science》2007,312(1-2):23-25

The ionizing star BD+60°2522 is known as the central star of Bubble Nebulae NGC 7635—wind-blown bubble created by the interaction of the stellar wind of BD+60°2522 (O6.5 IIIef, V=8.7 mag, mass loss rate 10^−5.76 M _⊙/year) with the ambient interstellar medium. From the evolutionary calculations for the star with mass loss and overshooting, we find that the initial mass of the star is 60M _⊙, its present age is 2.5×10⁶ years, and the present mass is 45M _⊙.  相似文献   

An advanced irradiation facilities and its usage     

康兴伦  陈洪涛  江雪艳  宁劲松  于志刚  朱校斌  张卫国 《中国海洋湖沼学报》2006,24(2):212-214

1 INTRODUCTION Carrier type gamma irradiation, a new tech- nology have been developed rapidly in recent dec- ades in industry, agriculture, and science and tech- nology. In Qingdao Irradiation Center (QIC), a car- rier-type irradiator in overlapping sourc…  相似文献   

30-60-day Oscillations of Convection and Circulation Associated with the Thermal State of the Western Pacific Warm Pool during Boreal Summer   总被引：4，自引：0，他引：4  

REN Baohu  HUANG Ronghui 《大气科学进展》2003,20(5):781-793

This study focuses on the characteristics of the 30-60-day oscillation (MJO) associated with the interannual variability of the thermal state in the western Pacific warm pool. The composite results show that the amplitude of MJO convection over the tropical western Pacific tends to intensify (reduce) in the WARM (COLD) case. The negative correlations between MJO convection in the WARM and inthe COLD cases are examined to be significant over most of the Asian-Pacific region. The evolutions of MJO convection and lower circulation, on the one hand, exhibit larger differences between the WARM and COLD cases, but on the other hand, display a unique feature in that a well-developed MJO cyclone (anticyclone) is anchored over the Asian-Western Pacific domain at the peak enhanced (suppressed) MJO convection phase over the western Pacific warm pool, either in the WARM or in the COLD case. This unique feature of MJO shows a Gill-type response of lower circulation to the convection and is inferred to be an inherent appearance of MJO. The context in the paper suggests there may exist interactions between MJO and the interannual variability of the thermal state in the western Pacific warm pool.  相似文献   

Nonseparable stationary anisotropic space–time covariance functions     

E. Porcu  P. Gregori  J. Mateu 《Stochastic Environmental Research and Risk Assessment (SERRA)》2006,21(2):113-122

Obtaining new and flexible classes of nonseparable spatio-temporal covariances and variograms has resulted a key point of research in the last years. The goal of this paper is to introduce and develop new spatio-temporal covariance models taking into account the problem of spatial anisotropy. Recent literature has focused on the problem of full symmetry and the problem of anisotropy has been overcome. Here we propose a generalization of Gneiting’s (J Am Stat Assoc 97:590–600, 2002a) approach and obtain new classes of stationary nonseparable spatio-temporal covariance functions which are spatially anisotropic. The resulting structures are proved to have certain interesting mathematical properties, together with a considerable applicability.Work partially funded by grant MTM2004-06231 from the Spanish Ministry of Science and Education.  相似文献   

PROPAGATION OF 30-60 DAY LOW FREQUENCY OSCILLATIONS AND THEIR INFLUENCE UPON THE SUBTROPICAL WESTERLIES JET STREAM DURING NORTHERN HEMISPHERE WINTER^*     

Shi Yuguang  Li Qingquan 《Acta Meteorologica Sinica》1996,10(2):202-214

Based on daily ECMWF gridpoint data of two winters during 1981-1983 including an ENSO year,propagation of low frequency oscillations(LFO) during Northern Hemisphere winters and their influences upon 30-60 day oscillations of the subtropical jet stream are studied with the statistical methods as complex empirical orthogonal function(CEOF) and so on.Results show that in the winter of a normal year(1981-1982),30-60 day oscillations in the subtropical zone are mainly in the northern and southern flanks of exit region of jet stream.In the ENSO year(1982-1983),they are mainly in the vicinity of entrance and exit regions of jet stream.Intraseasonal changes of subtropical jet stream manifested themselves as latitudinal fluctuation or longitudinal progression or regression of about 40 day period.There are marked differences between propagating passages of low frequency modes responsible for changes of subtropical jet stream in the normal year(1981-1982) and in the ENSO year(1982-1983).Changes of oscillation amplitude show obvious phases.In general,the one in late winter is stronger than that in early winter,strongest one occurs in February.  相似文献   

不忘初心,砥砺奋进,为新时代国家生态安全和东北区域农业发展贡献科技力量——中国科学院东北地理与农业生态研究所建所60周年回顾     

何兴元  苏阳 《地理科学》2018,38(9):1397-1401

中国科学院东北地理与农业生态研究所（简称东北地理所）是中国科学院设立在东北地区的综合性地理科学、农业科学和环境科学研究机构和人才培养基地。2018年,东北地理所迎来了60周岁的生日。60 a来,东北地理所不断凝练科学目标,调整和完善学科布局与科研组织结构,推动了相关学科发展;强化人才引进和自主培养相结合,人才队伍结构和创新能力得到极大加强;瞄准世界科学前沿,取得了一批独具特色的重大基础研究成果,一大批有重要影响的技术成果取得突破并应用于国家生态建设与东北区域农业发展;发展和完善了绩效考评体系、成果转移转化机制和协同创新机制,和谐奋进的创新文化环境正在形成。  相似文献   

ANALYSIS ON THE SOURCE AND SINK OF KINETIC ENERGY OF ATMOSPHERIC 30-60 DAY PERIOD OSCILLATION AND THE PROBABLE CAUSES^*          下载免费PDF全文

Li Qingquan  Zhu Qiangen 《Acta Meteorologica Sinica》1995,9(4):420-431

Based on ECMWF daily grid point data in summer(May-August),1981,the distribution features of the source and sink of kinetic energy of atmosphere 30-60 day oscillation,including its horizontal distribution characteristics and its vertical structure characteristics,are investigated systematically with diagnostic analysis methods over a latitude belt between 80°N and 60°S.Also,the probable reasons for the existence of the source and sink of low frequency kinetic energy(LFKE) are discussed preliminarily.Results show that the horizontal distribution of the sources and sinks of kinetic energy of atmospheric 30-60 day oscillation is extremely different.The significant sources and sinks of LFKE mainly exist in the oceans and the coastal regions of continents or islands in the mid-high latitudes.It is also found that,in the vertical direction,the sources and sinks of kinetic energy of 30-60 day oscillation display barotropic structure in the mid-high latitudes of both hemispheres,but dispaly baroclinic structure in the equtorial region,and in the horizontal direction,the sources and sinks mainly display zonal wave-like distribution.The source and sink of LFKE are determinded by ageostrophic wind effect,frictional effect,interaction between sub-grid-scale systems,nonlinear interaction,and the flux-divergence of LFKE transported by transient wind.There are some regional reasons for the generation of sources and sinks which are not completely identical in different areas.  相似文献