我国油气成藏机理与油气资源评价研究迈上新台阶——第四届油气成藏机理与油气资源评价国际学术研讨会在北京召开

由中国石油学会石油地质专业委员会、中国地质学会石油地质专业委员会、北京石油学会、国家自然科学基金委地学部、国土资源部油气资源战略研究中心和中国石油大学共同主办的“第四届油气成藏机理与油气资源评价国际学术研讨会”,于2006年10月14日-16日在中国北京顺利召开。共有260余位代表参加了这次大会,他们分别来自俄罗斯、加拿大、澳大利亚、英国、挪威、德国、韩国以及国内的18个科研院所和34个油田公司。这次大会提交的会议论文和摘要116篇,其中大会主题报告28篇,分会交流34篇。[第一段]     

High-frequency climatic oscillations during the last deglaciation as revealed by oxygen-isotope records of benthic organisms (Ammersee,southern Germany)

High-resolution oxygen-isotope records of benthic ostracods and molluscs from Ammersee, southern Germany, show high-frequency climatic changes during the last deglaciation and parallel in great detail published faunal and floral variations reconstructed from Norwegian Sea sediments and isotope variations in Greenland ice cores. The marine and the terrestrial records give evidence of a synchronous late glacial climatic development in Greenland, NW- and Mid-Europe. However,¹⁴C-ages of the supraregional climatic events and of two tephra layers in the marine sediments of the northeastern Atlantic Ocean are significantly older than the¹⁴C-ages of the corresponding horizons on land. These differences strongly suggest that major short-term events have affected the exchangeable carbon on earth during the dramatic environmental changes related to the deglaciation and in particular have affected the CO₂-distribution within the ocean and between ocean and atmosphere. Dating methods independent of climatic variations and of the global carbon budget should be given priority to refine the timescales of the marine and atmospheric processes during the last deglaciation.This is the fourth paper in a series of papers published in this issue on high-resolution paleolimnology. These papers were presented at the Sixth International Palaeolimnology Symposium held 19–21 April, 1993 at the Australian National University, Canberra, Australia. Dr. A. F. Lotter and Dr. M. Sturm served as guest editors for these papers.     

济阳坳陷中生代地层剥蚀厚度、原始厚度恢复及原型盆地研究

在采用各种地层剥蚀量的计算方法对济阳坳陷中生代各主要不整合面地层剥蚀厚度恢复的基础上,结合钻井及地震资料,对中生代各主要构造层的原始地层厚度进行了恢复。以此为切入点,对济阳坳陷区中生代盆地原型进行了初步探讨,将其划分为5期盆地原型：早-中三叠世为一大型内陆坳陷盆地;晚三叠世整体挤压抬升剥蚀;早-中侏罗世为弱挤压背景下的山间盆地;晚侏罗世-早白垩世为受正断层控制的断陷盆地;晚白垩世为断陷后的坳陷盆地。     

Mineralogical evidence for the derivation of metaluminous,potassic rocks from peralkaline precursors: The Cordon Syenite Complex (Philippines)

Summary Rocks from the Cordon Syenite Complex, located in the Philippine island arc, correspond to miaskitic (metaluminous) potassic lavas from the Roman Region and the Indonesian arc in terms of bulk rock chemistry. However, the mineral chemistry indicates a complex history of multiple equilibrations with liquids of different nature. T-site (Si + Al) occupancy in some clinopyroxenes and Ca contents of alkali feldspar phenocrysts indicate that these phases crystallized under the temperature-pressure subvolcanic regime from host liquids with progressively decreasing (Na + K)/Al ratio. In contrast to current views on the genesis of potassic rocks, it is suggested that differentiated leucite tephrite suites may be derived from peralkaline liquids by alkali loss. Magmas with affinities to lamproites may occur in the Philippine island arc, but a direct genetic relationship between subduction and alkaline/peralkaline magmatism remains questionable.

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Mineralogische Hinweise auf die Entstehung subalkalischer, K-reicher gesteine aus, peralkalischen Vorläufern: Der Syenit Komplex von Cordon (Philippinen)

Zusammenfassung Die Magmatite des im philippinischen Inselbogen gelegenen Syenitkomplexes von Cordon entsprechen in ihrem Gesamtgesteinschemismus den miaskitischen, K-reichen Vul kaniten der Romanischen Provinz und des indonesischen Inselbogens. Die chemische Zusammensetzung einzelner Mineralphasen deutet auf eine komplexere Genese unter Beteiligung von Magmen unterschiedlicher Alkalinität hin. Die Variation in der Besetzung der T-Position (Si + Al) in Klinopyroxenen und der Ca-Gehalte in Alkalifeldspäten wird dahingehend interpretiert, daß diese Phasen unter subvulkanischen Bedingungen aus Schmelzen mit abnehmenden (Na + K)/Al-Verhältnissen kristallisierten. Im Gegensatz zu gängigen Auffassungen wird daher angenommen, daß differenzierte Leucit-Tephrite aus mild-peralkalischen Magman hervorgehen können. Obwohl die K-reichen Magmatite des Syenitkomplexes von Cordon in einem Inselbogen gebildet wurden, ist ein direkter Zusammenhang mit Anreicherungsvorgängen im Bereich der Subduktionszone fraglich.

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Paper presented at the General Assembly of the International Association of Volcanology and Chemistry of the Earth Interior, Santa Fe, New Mexico, 1989.

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With 6 Figures     

The tropospheric distribution of formaldehyde during TROPOZ II

A series of 149 measurements of the HCHO mixing ratio were made between 0 and 10 km altitude and 70° N to 60° S latitude during TROPOZ II. The data show a vertical decrease of the HCHO mixing ratio with altitude at all latitudes and a broad latitudinal maximum in the HCHO mixing ratio between 30° N and 30° S at all altitudes. The measured mixing ratios of HCHO are considerably higher than those expected from CH₄ oxidation alone, but agree broadly with the average latitude by altitude distribution of HCHO derived by a 2D model including emissions of C₁–C₇ hydrocarbons. A number of the regional scale deviations of the measured HCHO distribution from the average modelled one can be explained in terms of the local wind field.     

酒泉绿洲夏季大气边界层加热(冷却)特征初探

利用“绿洲系统能量与水分循环过程观测与数值研究”的观测资料和酒泉站的地面和探空气象资料,计算了酒泉绿洲夏季大气边界层的加热（冷却）率,分析了酒泉绿洲近地面层和行星边界层的大气加热（冷却）率逐日变化,研究了不同典型天气下大气加热（冷却）率的变化特征。结果表明,酒泉绿洲近地面层和行星边界层内,大气加热（冷却）率具有明显的逐日变化特征;近地面层和行星边界层及整个大气层白天的大气加热率和夜晚的大气冷却率基本相当,大气能量基本守恒;日照时数、云量和特殊天气过程（如冷空气活动、沙尘天气和降水等）对大气加热（冷却）率有很大影响。     

An Improved Three-Dimensional Simulation of the Diurnally Varying Street-Canyon Flow

The impact of diurnal variations of the heat fluxes from building and ground surfaces on the fluid flow and air temperature distribution in street canyons is numerically investigated using the PArallelized Large-eddy Simulation Model (PALM). Simulations are performed for a 3 by 5 array of buildings with canyon aspect ratio of one for two clear summer days that differ in atmospheric instability. A detailed building energy model with a three-dimensional raster-type geometry—Temperature of Urban Facets Indoor-Outdoor Building Energy Simulator (TUF-IOBES)—provides urban surface heat fluxes as thermal boundary conditions for PALM. In vertical cross-sections at the centre of the spanwise canyon the mechanical forcing and the horizontal streamwise thermal forcing at roof level outweigh the thermal forces from the heated surfaces inside the canyon in defining the general flow pattern throughout the day. This results in a dominant canyon vortex with a persistent speed, centered at a constant height. Compared to neutral simulations, non-uniform heating of the urban canyon surfaces significantly modifies the pressure field and turbulence statistics in street canyons. Strong horizontal pressure gradients were detected in streamwise and spanwise canyons throughout the day, and which motivate larger turbulent velocity fluctuations in the horizontal directions rather than in the vertical direction. Canyon-averaged turbulent kinetic energy in all non-neutral simulations exhibits a diurnal cycle following the insolation on the ground in both spanwise and streamwise canyons, and it is larger when the canopy bottom surface is paved with darker materials and the ground surface temperature is higher as a result. Compared to uniformly distributed thermal forcing on urban surfaces, the present analysis shows that realistic non-uniform thermal forcing can result in complex local airflow patterns, as evident, for example, from the location of the vortices in horizontal planes in the spanwise canyon. This study shows the importance of three-dimensional simulations with detailed thermal boundary conditions to explore the heat and mass transport in an urban area.     

Investigation of seasonal droughts and related large-scale atmospheric dynamics over the Potwar Plateau of Pakistan

As a result of climate change and unsustainable land use management in the recent past, droughts have become one of the most devastating climatic hazards whose impacts may prolong from months to years. This study presents analysis of droughts for two major cropping seasons, i.e., Kharif (May–September) and Rabi (October–April), over the Potwar Plateau of Pakistan. The analysis is performed using various datasets viz. observational, reanalysis, and Regional Climate Models (RCMs), for the past (1981–2010) and future (2011–2100) time periods. The following two methods for the identification of dry and wet years, also referred to as drought and wetness, are applied: (1) the percentile rank approach and (2) the drought indices, Standardized Precipitation Index (SPI) and Reconnaissance Drought Index (RDI). Future projections of droughts are investigated using RCM (RegCM4.4 and RCA4) outputs from CORDEX South Asia domain under two Representative Concentration Pathway (RCP) scenarios, RCP4.5 and RCP8.5. Generally, the indices show non-significant decreasing trends of drought severity in the recent past for all cases; however, significant increasing trends are observed for annual (0.006) and Kharif (0.007) cases under RCP4.5 scenario. The analysis of large-scale atmospheric dynamics suggests the significant role of low-level geopotential height anomalies over Tibetan Plateau (northwest of Pakistan) during Kharif (Rabi) season in controlling drought occurrence by transporting moisture from the Bay of Bengal (Arabian Sea). Moreover, composites of vertically integrated moisture transport, moisture flux convergence/divergence, and precipitable water anomalies show their marked contribution in maintaining the drought/wetness conditions over the Potwar region.     

Principal Components Analysis of Rainfall and Associated Synoptic Models of the Southwest Monsoon over India

Summary  The summer monsoon circulation shows various spatial and temporal oscillations and often a combination of systems produces an integrated effect. In this study phases of the southwest (SW) monsoon have been identified in an objective manner with the help of T-mode principal component analysis (PCA) of weekly rainfall anomalies. Mean composite charts have been prepared utilising all available upper air data (1977–1986) for each category of the SW monsoon epochs identified by the PCA. These sets of charts have been constructed for both the strong and weak phases associated with the first four significant principal components (PCs). A well defined east-west oriented trough system, extending from about 28° N Latitude/65° E Longitude to 20° N Latitude/90° E Longitude, in the lower levels, has been the main feature associated with the strong phase of the monsoon corresponding to PC I. The trough in the lower levels is more marked in the eastern half compared to the western half in both the sets of charts associated with strong phases of the monsoon related to the PC II and PC III. With PC II, the position of the troughs in the lower levels is further north of its location in PC III. The east-west trough system associated with the strong phase of PC IV has a large southward tilt with height. The charts corresponding to the weak phases of these PCs have synoptic features, such as the position of the trough close to the foothills of the Himalayas, and the shifting of middle and upper tropospheric anticyclones to the south. The study suggests an objective method of interpretation of principal components by utilising synoptic data. In addition, synoptic models and data sets corresponding to different phases of the monsoon can also be prepared in an objective manner by such PCA. Received July 18, 1997 Revised April 30, 1999     

A comprehensive model inter-comparison study investigating the water budget during the BALTEX-PIDCAP period

Summary A comparison of 8 regional atmospheric model systems was carried out for a three-month late summer/early autumn period in 1995 over the Baltic Sea and its catchment area. All models were configured on a common grid using similar surface and lateral boundary conditions, and ran in either data assimilation mode (short term forecasts plus data assimilation), forecast mode (short term forecasts initialised daily with analyses) or climate mode (no re-initialisation of model interior during entire simulation period). Model results presented in this paper were generally post processed as daily averaged quantities, separate for land and sea areas when relevant. Post processed output was compared against available analyses or observations of cloud cover, precipitation, vertically integrated atmospheric specific humidity, runoff, surface radiation and near surface synoptic observations. The definition of a common grid and lateral forcing resulted in a high degree of agreement among the participating model results for most cases. Models operated in climate mode generally displayed slightly larger deviations from the observations than the data assimilation or forecast mode integration, but in all cases synoptic events were well captured. Correspondence to near surface synoptic quantities was good. Significant disagreement between model results was shown in particular for cloud cover and the radiative properties, average precipitation and runoff. Problems with choosing appropriate initial soil moisture conditions from a common initial soil moisture field resulted in a wide range of evaporation and sensible heat flux values during the first few weeks of the simulations, but better agreement was shown at later times. Received September 8, 2000 Revised April 3, 2001