滇东北一次暴雪天气过程个例分析

利用常规观测资料和多普勒雷达回波资料,综合分析了2008年1月31日发生在滇东北的一次暴雪天气过程.结果表明:过程前期500 hPa南支槽加深东移,槽前西南急流把孟加拉湾的水汽源源不断地向高纬度输送,为暴雪区提供了充足的水汽条件.阻高崩溃横槽转竖引导槽后冷空气南下,准静止锋补充加强,叠加在低层西南暖湿气流上空,触发了不稳定能量的释放.Ω型能量系统的建立和维持为强降雪的发生提供了足够的能量条件,强降雪发生在下游低能舌内.径向速度图上低层零速度带在0.38 km高度间隔内出现180°的顺转说明对流层低层存在强暖切变.西南方和东北方大片速度模糊区的出现反映了强西南急流的存在,西南急流的建立、维持和减弱时间与降雪强度的变化有较好的对应关系.强暖平流的存在和对流层低层1.0~1.2 km高度强垂直风切变的长时间维持为强降雪的产生提供了充足的动力条件.     

俄罗斯核潜艇失事,印度受损

11月8日,俄罗斯太平洋舰队一艘核潜艇在试航时发生事故,造成20多人死亡,另有21人受伤,遇难者包括造船厂技术人员和水兵。据报道,事故由艇上灭火系统故障导致,潜艇核反应堆运转正常,核辐射指标也没有异常。发生事故时,艇上共有208人。其中有81名军人。俄造船专家认为。潜艇灭火系统故障可能由负责测试的技术人员违规操作导致。     

第五届全国油气储层学术研讨会在成都召开

2008年8月29～31日,由中国地质学会沉积地质专业委员会、中国矿物岩石地球化学学会沉积学专业委员会主办,成都理工大学承办,中国石油西南油气田分公司、中国石化西南油气分公司、中国石化勘探南方分公司等单位协办的第五届全国油气储层学术研讨会在成都市召开。出席此次学术研讨会的代表共272人,分别来自国内12家油田单位、16所高校、11家科研单位以及5家学术期刊出版单位。会议的宗旨是总结、交流近年来我国在油气储层及相关地质、地球化学及地球物理等研究领域的最新研究成果,讨论油气储层研究的现状、问题与发展趋势。     

Features of tropical cyclone landfalls over East Asia corresponding to three types of Pacific warming decaying phase

This study examines the tropical cyclone （TC） landfall activities over the East Asia in three types of decaying phase of warm sea surface temperature anomalies （SSTAs） over the equatorial central-eastern Pacific： eastern Pacific warming decaying to La Nifia, eastern Pacific warming decaying to a neutral E1 Nifio-Southern Oscilla- tion phase, and a central Pacific warming decaying year. Results show that, for the type of eastern Pacific wanning decaying to La Nifia, more TCs make landfall over Hainan Island and Beibu Gulf, whereas fewer TCs reach eastern China coast. In particular, the number of landfalling TCs remarkably decreases in the decaying phase of eastern Pacific E1 Nifio to a neutral year. During the decaying phase of central Pacific E1 Nifio events, more TCs tend to make landfall over southern China, Indochina Peninsula and the Philippines. The anomalies of atmospheric circu- lation and environmental conditions induced by the SSTAs over the tropical Pacific in the different decaying types are responsible for the evident variation in features of TC landfall.     

Climatic significance of n-alkanes and their compound-specific δD values from lake surface sediments on the Southwestern Tibetan Plateau

The content and hydrogen isotope ratios of n-alkanes extracted from recent lake surface sediments sampled from nine lakes in three different climate zones on the Southwestern Tibetan Plateau were analyzed. Values were compared with n-alkanes in plants from lake drain- ages, and δD values of meteoric water, lake water, and mean annual precipitation. The results showed that n-C23 was predominantly derived from aquatic plants, and n-C27- n-C33 from terrestrial higher plants. The average carbon chain length of n-C27-n-C33 （ACL27-33） was positively correlated with the mean annual precipitation. δD values of the long-chain n-alkanes n-C29 and n-C31 of terrestrial origin （varying between -214‰ and -169 ‰, and-226 ‰ and -185 ‰, respectively） were inversely correlated with mean annual precipitation; but in accordance with the average annual variations in δD （OIPC）, δD values of n-C31 were strongly related to the δD values of growing season meteoric water （R2 = 0.74）. The large difference between δD values of n-C23 of aquatic origin and n-C31 （an average of about 27 ‰） demonstrates the enrichment of the lake water δD compared to precipitation, caused by strong evaporation in the semiarid-arid areas of the southwestern Tibetan Plateau. Average value of εn-c25- 31/p （-95 ‰） is evidently higher than the value observed in European wet regions （-128 ‰）; besides, εn-C31 （about -116 ‰） is constant along the study transect （SD = 9）, which indicates that n-C31 is a useful proxy for the environment.     

Occurrence of two types of El Niño events and the subsurface ocean temperature anomalies in the equatorial Pacific

The relationships between the evolution of two types of E1 Nifio events and the subsurface ocean temperature anomaly （SOTA） in the equatorial Pacific are compared in this study. The results show that both types of E1 Nifio are negatively correlated to the SOTA in the equatorial western Pacific, but relationships are different in different phases of E1 Nifio. Furthermore, the occurrence of different types of E1 Nifio is related to different features of the equatorial thermocline, e.g. its zonal gradient, significant variation area, amplitude and duration of thermocline oscillation. The propagation of SOTA in the equator plays an important role during the evolution of both types of E1 Nifio, but shows dramatic differences in intensity, duration and phase reverse of warm SOTA. Moreover, the pathways of SOTA signal are different between these two types of E1 Nifio. The dominant pathway in the life cycle of Eastern Pacific （EP）-E1 Nifio lies on the equator and to its north, but there is no loop to the south of the equator. In contrast, the dominant pathway in Central Pacific （CP）-E1 Nifio is located on the equator and to its south, and the propagation signal of SOTA to the north of the equator is very weak. The relationships between the zonal wind anomalies and the two types of E1 Nifio are also preliminarily discussed. It is shown that EP-E1 Nifio is more likely to respond to the westerly anomalies over the equatorial central and western Pacific, while CP-E1 Nifio is more likely to respond to the westerly anomalies over the equatorial western Pacific and need the cooperation of easterly anomalies over the equa- torial eastern Pacific to certain extent.     

西南丘陵区高标准基本农田建设潜力测算及模式探讨

高标准基本农田建设直接关系国家粮食安全和重要农产品供给.本文依据相关规划和标准建立了西南丘陵区高标准基本农田建设潜力评价指标体系,以重庆市荣昌县为研究区,运用ArcGIS软件空间叠置分析工具和层次分析方法,对研究区高标准基本农田建设潜力进行了测算,并探讨了西南丘陵区高标准基本农田建设的适宜模式.结果发现,研究区高标准基本农田建设的潜力为35 241.85hm2,占区内基本农田总面积的72.34%;依托农业资源优势、农业产业现状和产业发展规划布局,区内高标准基本农田建设宜采用"粮油基地"、"蔬菜基地"、"城乡统筹示范村"、"西部生态农田"等4种不同的模式进行.研究认为,摸清区域高标准基本农田建设潜力,总结高标准基本农田建设的经验模式,是发挥区域农业水土资源优势,提升农业科技应用和农业机械化水平,促进农业持续增产稳产的一条可靠途径.     

“生态经济昆明高层论坛-海峡两岸生态经济理论与实践研讨会”将在昆明举行

"生态经济昆明高层论坛-海峡两岸生态经济理论与实践研讨会"将于2008年9月19-21日在昆明举办。该论坛由云南省科学技术学会、中国生态经济学会、西南林学院、云南省生态经济学会、台湾开南大学联合主办,中国科协《科技导报》社、京港学术交流中心、澳门科学技术协进会、     

仪式环境中的空间造型艺术——以桑植高傩为个案分析

"还傩愿"是广泛流传在西南少数民族当中的民间宗教信仰.以湖南桑植高傩为个案研究,阐述高傩仪式环境中的空间造型艺术的研究方法、研究范围、分类特点,造型艺术在神圣空间构建中的作用,以及仪式环境对造型艺术的影响.     

西南民族研究中值得进一步研究的几个问题

西南民族史所涉及民族众多、民族关系错综复杂、历史变迁缤纷多样,因此西南民族史研究中难点颇多,对其进行深入研究的历史与现实价值也很大。全文仅选择秦汉“西南夷”藏缅语族诸民族的族源、滇国与夜郎国民族关系、南诏政权后期对唐用兵原因诸问题进行探讨,以达到抛砖引玉的目的。