我国历史时期的湖泊围垦与湖泊退缩

根据历史资料记载,我国历史时期的湖泊围垦可分为三个时期,即魏晋——南北朝、南宋和明末清初。近乎90％的古湖泊消失于这些时期。大多数学者认为,人口增长导致湖泊围垦、退缩。本文进一步的研究表明,湖泊田垦时期与气候干旱期、黄河和长江的低水位期相吻合:与此同时,湖泊也处于低水位期。     

全新世中期以来黄土高原中部生物多样性研究

根据孢粉分析、古文献记载、生物地名考证以及对现今物种群多样性等方面的研究资料，结合气候变迁，论述了全新世以来，在自然和人为因素影响下，黄土高原中部地区景观和生物多样性的演变过程及其恢复和保护措施。     

硝酸盐矿床及其盐湖形成机理初探

分析了硝酸盐的多种可能来源。认为硝酸盐矿床及其盐湖的形成与地质事件关系密切。地质事件所产生的高温、高压和触媒 ,能将 H2 、N2 合成 NH3 ,NH3 氧化成硝酸盐及亚硝酸盐 ,并提供运移通道、储矿场所和积累条件。     

强震蕴育过程中区域垂直形变场多种动态信息演化特征

以区域精密水准重复观测资料为依据,用定性与定量相结合的方法,研究了发生于我国大陆板内的１９９６年丽江７．０级等几次强震过程中区域垂直形变速率、剪切变形率、扩张变形率和体积变化率等形变场多种信息的动态演化特征。结果显示：强震蕴育过程中,区域垂直形变场在空间和时间上均会出现不同程度的非均匀态特征。在此基础上,结合区域构造,进一步研究了判定强震危险区的形变前兆场多种信息异常综合标志,得出了一些用大地形变进行强震预测的初步结论。     

Evolution of the great river systems of southern Asia during the Cenozoic India–Asia collision: Rivers draining north from the Pamir syntaxis

During uplift of the Tibetan plateau and surrounding ranges, tectonic processes have interacted with climatic change and with local random effects (such as landslides) to determine the development of the major river systems of Asia. Rivers draining northward from the Pamir syntaxis have three distinctive patterns that are controlled by different tectonic and climatic regimes. West of the Pamir, the rivers have moderate but irregular gradients and drain northwards to disappear into arid depressions. Relatively steady uplift of the Hindu Kush in northern Afghanistan allowed rivers to cut across the rising ranges, modified by the shear along the Harirud fault zone, local faulting, and by increasing rain-shadow effects from the rising Makran. In the transition to the Pamir the rivers have steeper but more even gradients suggesting more even flow and downcutting during uplift, possibly related to larger glacial sources. In the central Pamir, only one antecedent river, the Pyandzh appears to have kept its northward course with compression and uplift of the indenter, and its course strangely corresponds with a major geophysical boundary (a distorted subducted slab) but not a geological boundary: the other rivers are subsequent rivers developed along deformation fronts during development and northward displacements of the Pamir structural units. The above areas have sources north of the Cretaceous Karakorum–South Pamir Andean margin. On the eastern flank of the Pamir, in the Kunlun and northern Tibetan plateau, the rivers rise similarly north of the Cretaceous Andean margin of southern Tibet, but then flow with low gradients across the plateau, before cutting and plunging steeply down across the Kunlun to disappear into the arid Tarim. These steep profiles are the result of late Neogene uplift of the northern Tibetan plateau and Kunlun possibly modified by glacial diversion and river capture. The drainage history of the Pamir indenter can be reconstructed by restoring the gross movements of the plates and the tectonic displacements, uplift, and erosion of individual tectonic units. Most important changes in drainage took place in the last 10 million years, late Miocene to Quaternary times, as the Pamir syntaxis developed.     

滇西“三江”地区新生代地质构造格局及其演化

新生代构造演化主要经历了陆内裂陷、断裂走滑活动及会聚构造带的形成、陆内岩浆活动、强烈的抬升第一系列构造运动。     

河北蔚县九宫口断层重叠带的断层生长、位移转移和演化

对河北蔚县九宫口断层重叠带进行了地质和地貌观察、年龄测定和断层落差分析。结果表明,伴随重叠带内的断层生长,位移发生转移,而且,原来两个独立的断层段演化成为互相关联的单一断层。岩浆活动和掀斜作用是该重叠带演化的原因     

台湾地形对海棠台风影响的数值模拟研究

应用美国国家大气研究中心(NCAR)研发的WRF(Weather Research and Forecasting)气象模式,研究海棠台风(2005)接近并登陆台湾岛的过程中的强度、结构的演变,以及地形强迫作用对台风的影响.对模拟结果的评估表明,在整个海棠台风(2005)模拟实验期间,WRF模式很好地抓住了台风海棠强风,低中心气压的高强度特征.对引起台风降水的中尺度系统的分析表明,一方面台风环流与中央山脉地形共同作用激发出垂直次级环流在降水区域产生强烈的上升运动;另一方面,水平风场源源不断给该地区输送暖湿空气,为对流发展提供充足的水汽.分析结果表明中央山脉地形与台风环流场之间的配置形势对台风降水有着重要的影响.     

Divergent evolution of Earth and Venus: Influence of degassing,tectonics, and magnetic fields

Knowledge of the earliest evolution of Earth and Venus is extremely limited, but it is obvious from their dramatic contrasts today that at some point in their evolution conditions on the two planets diverged. In this paper we develop a geophysical systems box model that simulates the flux of carbon through the mantle, atmosphere, ocean, and seafloor, and the degassing of water from the mantle. Volatile fluxes, including loss to space, are functions of local volatile concentration, degassing efficiency, tectonic plate speed, and magnetic field intensity. Numerical results are presented that demonstrate the equilibration to a steady state carbon cycle, where carbon and water are distributed among mantle, atmosphere, ocean, and crustal reservoirs, similar to present-day Earth. These stable models reach steady state after several hundred million years by maintaining a negative feedback between atmospheric temperature, carbon dioxide weathering, and surface tectonics. At the orbit of Venus, an otherwise similar model evolves to a runaway greenhouse with all volatiles in the atmosphere. The influence of magnetic field intensity on atmospheric escape is demonstrated in Venus models where either a strong magnetic field helps the atmosphere to retain about 60 bars of water vapor after 4.5 Gyr, or the lack of a magnetic field allows for the loss of all atmospheric water to space in about 1 Gyr. The relative influences of plate speed and degassing rate on the weathering rate and greenhouse stability are demonstrated, and a stable to runaway regime diagram is presented. In conclusion, we propose that a stable climate-tectonic-carbon cycle is part of a larger coupled geophysical system where a moderate surface climate provides a stabilizing feedback for maintaining surface tectonics, the thermal cooling of the deep interior, magnetic field generation, and the shielding of the atmosphere over billion year time scales.     

不同类型日冕物质抛射事件的比较

依据二维磁流体力学方程组 ,在子午面内分别数值模拟了与动量扰动和温度扰动相关的日冕物质抛射事件 （CME） ,并将二者结果进行对比 .结果认为 :二者在事件的空间结构 ,前沿激波的演化 ,暗腔的形成及作用 ,扰动后近日面新喷发物质的特征等方面是相似的 ;但在前沿激波的传播速度 ,强度和径向演化进程 ,暗腔的行为和磁感应强度以及后随等离子体团的密度等方面却不相同 .