大气对外强迫低频遥响应的数值模拟 II:对欧亚中高纬“寒潮”异常的响应

本文通过用IAP GCM所作的数值模拟研究了欧亚大陆中高纬度地区的外强迫在全球大气中激发的响应.结果清楚表明,同赤道地区的热源强迫一样,中高纬度地区的外强迫也可以在全球大气中产生低频遥响应;通过低频波列EAP,欧亚大陆中高纬度地区的寒潮异常可以对赤道中西太平洋地区的大气运动及全球大气环流有重要影响.对30—60天振荡的强迫激发来讲,地球大气的气候基本态是极为重要的,热带大气对于全球大气的低频振荡活动具有尤为突出的作用.     

Orogenic evolution of the External Dinarides in the NE Adriatic region: a model constrained by tectonostratigraphy of Upper Cretaceous to Paleogene carbonates

Mesozoic to Cenozoic evolution of the central part of the Adriatic plate (External Dinarides and Adriatic foreland) is still a matter of debate. This is expressed by opposing paleogeographic models: single carbonate platform (Adriatic or Adriatic-Dinaridic) versus two carbonate platforms (Adriatic and Dinaridic) separated by the inter-platform Budva-Cukali basin. Estimates of shortening during Adria NE subduction, that resulted in the development of the Dinaric Alps, differ substantially. The single-platform model involves minor shortening achieved by folding and faulting along steep reverse faults. The two-platform model involves significant shortening achieved mainly by thrust stacking, which resulted in almost complete underthrusting of the intervening basinal deposits.Analysis of Upper Cretaceous to Paleogene stratigraphical data from both outcrops and boreholes allows regional correlation and the interpretation of major lithostratigraphic units. As a result, a few tectonostratigraphic units are recognized. The tectonostratigraphy is used as a basis for a new model on the late Mesozoic to Cenozoic evolution of the region.Generally, Adriatic and Dinaridic segments acted as major regional crustal entities of Adria. The upper portions of the sedimentary cover were differentially affected by progressive, southwestward verging thin-skinned deformations during the Paleocene to Eocene (Miocene?). The Adriatic foreland stayed out of the deformations, and is characterized predominantly by wrench and salt tectonics. The regional tectonic map shows arcuate thrust fronts of the External Dinarides. They could be a consequence of both, differential propagation of early-orogenic thin-skinned deformations over crustal fragments separated by transversal faults, and/or differential (isostatic?) movements of the fragments. The collision zone of the Adriatic and Dinaridic segments is characterized by late-orogenic (Oligocene to Miocene) thick-skinned compressional uplift (exhumation), related gravity gliding, and still active escape tectonics (wrenching). These processes masked primary thin-skinned deformations. A significant amount of shortening within and between the thin-skinned sedimentary covers is proposed. Therefore, the question of the general paleogeography of the region and the original NW extent of the Budva-Cukali basin (NE Adriatic trough) remains open.     

20世纪90年代末东亚冬季风年代际变化的外强迫因子分析

使用NCEP/NCAR、英国气象局哈德莱中心(Met Office Hadley Center)Had ISST以及NOAA提供的再分析资料分析了海温、海冰及雪盖异常对20世纪90年代末我国冬季气温和东亚冬季风(EAWM)年代际跃变的外部强迫作用,同时也对比分析了20世纪90年代EAWM年代际跃变与20世纪80年代EAWM年代际跃变特征和成因的一些差异。结果表明:20世纪80年代中期EAWM的年代际变化特征主要表现为全国一致偏冷型,同时中国近海的海温也偏低;该年代际变化的主要原因来自大气内部动力过程,而海温和海冰的作用不显著。20世纪90年代末EAWM年代际变化的特征表现为东亚北方气温显著偏冷而南方偏暖的南北反相变化分布;EAWM在20世纪90年代末的年代际变化受北大西洋海温和热带太平洋海温的共同影响。北大西洋显著的异常暖海温,激发一个向下游传播的波列,使得西伯利亚高压加强,EAWM加强,从而导致我国北方气温下降;同时,秋冬季北极海冰异常偏少和秋季欧亚雪盖偏多对东亚冬季风的增强也有一定的作用。此外,热带西太平洋的暖海温异常会导致在海洋性大陆地区有异常的辐合和对流增强,引起大气环流的Gill型响应,对流西侧的异常气旋在孟加拉湾至我国西南地区出现南风异常,使得东亚南部地区温度偏高。因此,20世纪90年代末之后东亚温度呈现南暖北冷的分布特征。     

土质边坡震裂机制物理模拟研究

为了研究地震中土质边坡(包括覆盖层边坡)在强震作用下破裂的成因机制,以"5·12"汶川特大地震为背景资料,采用震动台模拟试验进行了研究.模拟试验结果表明:斜坡震裂变形破坏与斜坡外形结构特征具有相关性.坡面转折点应力最易集中,破坏的可能性较大.震动条件下土质边坡完全破坏也具有一般性的规律,即以"一垮到底"的方式堆积于坡脚...     

对大灰厂台形变异常的再认识

按照文献[1]的思路和方法,利用历史观测数据,通过建立大灰厂台形变资料动态预估方程,对唐山地震前后两次形变异常重新作了分析。结果表明,1975年前后和1980年前后的两次形变异常情况类似,且具有较好的预估关系,其它年份的资料也有重复的特点。其特点与地震孕育引起的地壳形变关系不大。因此把1975年形变异常作为唐山地震的前兆信息依据不足,两次异常都是由于干扰因素影响所致。     

A note on the economics of Swedish Baltic Sea fisheries

The cod stocks in the Baltic Sea are important not only for fisheries but for the entire ecosystem utilized by numerous stakeholders around the coast. All such activities have economic values. In this note the economics of the Swedish Baltic Sea cod fishery is estimated in relation to the sector's interaction with other users of the Baltic Sea ecosystem. The results show a negative resource rent for the fishery, € −5 million without public expenses (subsidies and administrative costs), and € −13 million including public expenses. The interactions between the fisheries and tourism, seal population, carbon dioxide emissions, recreational fishing, and discards are discussed, and when monetary estimates are available these are related to the estimated resource rent.     

An Ecosystem Based Fisheries Management framework: the efficient,regional-level planning tool for management agencies

The value of applying a regional level, Ecosystem Based Fisheries Management (EBFM) framework, which is a step-wise, hierarchical, risk-based approach, was tested on the West Coast Bioregion of Western Australia. With structured stakeholder input, over 600 ecological, social, economic and governance issues were initially identified for the region. This complexity was reduced to a level useful for management by consolidating the individual risks into 60 regional-level risks, with a multi-criteria analysis used to integrate the ecological, social and economic risks into just 24 Departmental-level priorities, which ranged from very low to urgent. Given this success, EBFM-based priorities now form the basis for the Department’s budget planning process, plus the framework is providing a critical link between fishery level issues and the broader processes undertaken by other marine based agencies. The EBFM framework is a significant step forward for the integrated management of natural resources by enabling all assets and issues relevant to stakeholders and government to be holistically considered at a regional level.     

全型涡度方程和经典涡度方程比较

在简要回顾经典涡度方程和全型涡度方程推导的基础上 ,比较了两种涡度方程的异同。集中讨论全型涡度方程新的物理内涵 ,证明了与稳定度和斜压性变化 (锋生、锋消过程 )相联系的内部强迫以及与摩擦耗散和非绝热加热相联系的外部强迫所诱发的涡度发展的机制。最后 ,指出了全型涡度方程的天气和气候应用前景。     

Gabbro-derived granulites from External liguride units (northern Apennine,Italy): implications for the rifting processes in the western Tethys

In Santonian-Early Campanian sedimentary melanges of the External Liguride units (northern Apennine), slide blocks of subcontinental mantle and MOR basalts are associated with lithologies derived from the continental crust. One of these sedimentary melanges, the Mt. Ragola complex, is characterized by the close association of mantle ultramafic, mafic and quartzo-feldspathic granulites. Mafic granulites show a wide compositional range. They generally display a marked metamorphic layering, but undeformed rocks which preserve a gabbroic fabric are found locally. The most frequent lithologies are Al-spinel gabbronorites, generally containing minor olivine, and Fe-Ti oxidebearing gabbronorites. Troctolites, olivine gabbronorites and anorthosites were also recovered. Relics of primary textures as well as mineral and bulk-rock compositional variations indicate a comagmatic intrusive origin for the protoliths of the mafic granulites. This intrusive mafic complex underwent a subsolidus reequilibration under granulite facies conditions, at 0.6–0.9 GPa and 810–920°C, and was derived from crystallization at intermediate levels of tholeiite-derived liquids, possibly affected by crustal contamination. Its primary features are similar to those of the upper zone of the Ivrea layered complex. The gabbroic protolith for the granulites of External Liguride units were probably crystallized into the extending Adria lithosphere in relation to the initial stages of the opening of the western Tethys.     

Cadomian basement of the palaeozoic platform in central Europe

Summary In central Europe, evidence for Cadomian basement occurs from the Midlands Massif in the United Kingdom to the Moesian Platform in Romania. The patchily exposed basement rocks either have survived almost intact through the Phanerozoic (e.g. Lusatia), overstepped by different Palaeozoic strata, or have been reworked to various degrees (e.g. Erzgebirge) and involved in Variscan structures (e.g. Sudetes, Moravia). In the Polish and German lowlands, undated subsurface basement occurs below the Permo-Mesozoic cover and Variscan molasse and flysch successions. The mutual relationships between the various Cadomian fragments occurring within and/or below the Palaeozoic, both orogenic and platform successions, are far from fully understood.