关于大陆构造的思考

大陆动力学与全球动力学是当代地学的重在前沿领域。本文在研究青藏高原与周缘盆地的同步演化规律和综合前人最新研究成果的基础上，分析了大陆构造的１０个基本问题，并进一步阐述了层流构造模式，其内容包括：（１）深部层流导致浅部隆陷；（２）层流隆陷构造系统的物质循环过程；（３）大陆层块结构与地温场，应力场的关系；（４）层流构造的阶段发展与复合叠加；（５）层流构造的深部过程及动力学源，特别强调指出应当区大分陆隆     

Potentialities,uncertainties and complexities in the response of coral reefs to future sea-level rise

Coral islands formed of largely unconsolidated sands only a few metres above sea level are thought to be particularly vulnerable to sea-level rise consequent upon global warming. However, scenarios which predict catastrophic flooding and loss of island area need reassessment, particularly in the light of the continued downwards revision of projected rates of future sea-level rise. Revised questions concern the interactions between reef growth and sea-level change, biophysical constraints on coral growth, and the importance to reef systems of potential changes in the magnitude, frequency and location of tropical cyclones and hurricanes. It is clear that most reefs have the growth potential to meet even the highest of future sea-level rise scenarios, but too little is known about physiological and physical constraints to reef growth to adequately evaluate the importance of these two factors in constraining this potential at the present time. Future sea-level rise in the tropical oceans, and coral reef responses, will take place against a backdrop of inter-regional differences in Holocene sea levels, resulting from the varying interaction of eustatic and hydro-isostatic processes. These differences have generated varying constraints on the development of modern reefs and varying inherited topographies upon which future sea-level changes will be superimposed. These controls are particularly important in assessing differences in vulnerability to future sea-level rise for reef islands in the Pacific Ocean and the Caribbean Sea.     

全球旋回地层学

全球旋回地层学是指在对全球沉积岩进行综合系统研究之基础上，通过估算沉积盆地中源于物源区的沉积物类型和沉积环境条件变化，来预测地层学特征的一种过程一结果模型。其研究内容包括对全球地质演化时期全球海平面变化、全球气候条件、全球构造运动、全球古地理背景、全球沉积环境特征、全球古生物事件及全球矿产形成过程进行动态模拟，强调古气候在地质记录中的意义，注重沉积记录的全球同时性研究；强调各种事件在沉积作用中的意     

古新统─始新统界线与事件沉积

深海钻探揭示的古新统—始新统界线上许多全球性变化引起了地质学家的普遍关注。这些变化包括：岩性上从海绿石石英砂岩变化到粘土岩、粘土矿物组合从伊利石／蒙脱石为主变化为高岭石为主、大陆植物群的绝灭和迁移、钙质超微化石物种更新速度加快、底栖有孔虫绝灭和分异度降低、碳氧同位素强烈负异常、大陆哺乳动物演化发生变化、大气环流强度减弱、海洋环流模式改变、海平面上升、海底热液活动呈１～２个数量级加强。通过对古新世—始新世的地层沉积学、古生物学、古气候学和古海洋学研究，确认古新统—始新统地层界线是全球构造事件的结果，表现为全球板块边界重组、扩张中心和转换断层模式改变、海底热液活动呈１～２个数量级加强。     

Emission of aliphatic amines from animal husbandry and their reactions: Potential source of N2O and HCN

We measured the emissions of volatile aliphatic amines and ammonia produced by the manure of beef cattle, dairy cows, swine, laying hens and horses in livestock buildings. The amine emissions consisted almost exclusively of the three methylamines and correlated with those of ammonia. The molar emission ratios of the methylamines to ammonia, and data on NH₃ emissions from animal husbandry in Europe, together with global statistics on domestic animals, were used to estimate the global emissions of amines. Annual global methylamine-N input to the atmosphere from animal husbandry in 1988 was 0.15±0.06 TgN (Tg=10¹² g). Almost 3/4 of these emissions consisted of trimethylamine-N. This represents about half of all methylamine emissions to the atmosphere. Other sources are marine coastal waters and biomass burning.Possible reaction pathways for atmospheric methylamines are shown. Among various speculative but possible products N₂O and HCN are of interest because the emission of methylamines could contribute to the global budgets of these compounds. Maximum atmospheric N₂O production from methylamines are below 0.4 Tg N/year, which is less than 10% of the annual N₂O growth rate. Although we do not expect the methylamine emissions to contribute in a major way to the atmospheric N₂O budget, more studies are needed to establish this conclusion beyond doubt. Similar conclusions hold for HCN.     

诱发前震预报方法的检验——1981—992年中国大陆地震活动图象

大强固区之间的相互作用和震后运动可以引起触发,强固区破裂引起相邻强固区加载。震后运动可以在大范围内发生并引起相邻区域的不均匀应变积累。观测表明大震后首先发生中等地震的地点正好是下次大震的位置,所以任何一个大地震发生都提供了一个探寻临界破裂区的良好时机。依据1960—1980年资料总结的中期地震危险性估测方法称为“诱发前震图象”,1981—1992年的地震资料完全证实了该方法的可靠性。     

A new theoretical solution of the effect of atmospheric pressure on water level

Based on the partial differential equation governing the effect of atmospheric pressure on water level of confined well, deriving the boundary condition and considering the seepage water between well and aquifer, the author obtained the analytical solution of water level change in time domain under the action of an atmospheric pressure history with the Laplace transform method. This solution is composed of two terms:stable and retarded terms. The stable term is the multiplication of barometric efficiency and simultaneous atmospheric pressure, and it implies the value of water level after infinite time when the atmospheric pressure is a constant from the time in question. The retarded term is the transient process due to the time lag of water exchange between well and aquifer. From the solution, it is obtained that the interference of atmospheric pressure on water level is the integral superimposition of the contribution of all atmospheric pressure changes before the time in question. So that, we further found out the response function of pulsive atmospheric pressure history. Calculation shows: (1) The pulsive response function starts from zero and tends to a steady value, which is proportional to the barometric efficiency, when the time tends to infinity; (2) The retarded time depends on the mechanical property of aquifer and the radius of well. The larger the seepage coefficient, the smaller the radius of well and the thicker the aquifer, then the shorter the retarded time gets. This solution can be used as the theoretical basis for further analysis of the atmospheric effect and practical correcting method in the future.     

1994年全球地震活动综述

１９９４年全球地震活动属于高水平，有４次大深震和４次浅源大地震。全球全年共发生６级以上地震１３４次，超过１９９３年。全球地震活动中心仍在太平洋西北边缘地震带。１０月４日的千岛群岛地震是最大的浅源地震；６月９日的玻利维亚地震是最大的深源地震。１９９４年全球地震活动开始转折，揭开强烈活动期的序幕。各大地震带的Ａ（ｂ）值几乎按同一比例上升，显示全球地震整体性增强。全球地震Ａ（ｂ）值在６月和１０月有两次高     

MONITORING OF 1991 EASTERN CHINA FLOODING WITH POLAR ORBITING METEOROLOGICAL SATELLITES FY-1 AND NOAA

With polar orbiting meteorological satellites FY-1 and NOAA,flooding was monitored in the areas of the HuaiheRiver basin and the Taihu Lake region during June and July 1991.All satellite images from FY-1 and NOAA for concerned areas before and during flooding were examined.Thoseof cloud-free,with small amount of cumulus or thin cirrus were selected to exam the situation.Navigation and projec-tion were carefully performed,to ensure the projected images at different time overlap accurately with each other in 1—2pixels.Channel 1 (CH1) and Channel 2 (CH2) data of FY-1 and NOAA satellites with wavelength of 0.58—0.68μm and0.725—1.1μm were used to monitor the flooding.Albedo of Channel 2 and normalized vegetation index (NDVI) wereadopted as indicators to identify water body from land.With histogram and man-machine interactive methods,analysiswas done.In cloud-free condition,the two indicators identified the same area and scope of the water body.Totally cloud-free image in a large area is quite rare.To understand flood process,it is necessary to use more fre-quent images.It was investigated to distinguish water from land in partly cloudy condition.The result showed that whenthere is small amount of cumulus or thin cirrus,satellite images are still valuable in monitoring water body.In case ofmonitoring area covered with cirrus,vegetation index is useful,and while there is small amount of cumulus on land,albedo of Channel 2 can be used.Ten images from May 16 to August 18 of 1991 were examined.The results show that in the Lixiahe area,JiangsuProvince,the area submerged in total was the largest;along main stream of the Huaihe River,the Chuhe River,andaround the Chaohu Lake,a large percentage of area submerged;while in the Taihu Lake area,less field submerged.Flood monitoring was performed for 87 counties in the region concerned.These counties were put in order accord-ing to the percentage of submerged area in total.This order showed the extent of disaster at one view point.     

ANALYSIS OF SURFACE AIR TEMPERATURE RECORDED IN LAHORE AND MIANWALI OVER THE PAST THREE DECADES

Surface air temperatures recorded over the past three decades at the weather stations located in Lahore (anindustrialized and densely populated city) and Mianwali (a small and sparsely populated city) were analyzed in order tostudy their climatic trend.Lahore,where meteorological data are recorded at two weather stations (city station and air-port station) indicates a cooling trend,of about 0.5℃ per record period of 1953—1992,for the airport station (31°31′N,74°24′E) and a slight warming trend,of about 0.2℃,for the city station (31°33′N,74°20′E) for the record period of 1950—1992.The Mianwali weather station (32°33′N,71°31′E) also shows a slight cooling trend,of about 0.4℃ per recordperiod of 1959—1992.The climatic variability at these stations was studied by computing seasonal and annual tempera-ture anomalies.The results are explained in terms of the local environmental conditions.