杭州湾庵东浅滩现代沉积物中的生物遗迹

杭州湾庵东浅滩沉积物中发现有多种造迹生物,主要有蝼蛄、泥甲虫、宁波泥蟹、珠带拟蟹守螺、泥螺、弹涂鱼、蚂蚁和鸟类等,营造的生物遗迹主要为觅食迹、居住迹和爬行迹(爬迹、拖迹和鸟足迹)等。分析表明,浅滩不同亚环境的造迹生物及其遗迹的主要类型和分布特征具有明显的差异性: (1)在潮上带植被茂密的草滩环境中,以层面上的生物觅食迹、居住迹和鸟足迹为主,造迹生物主要有蝼蛄、泥甲虫、蚂蚁和鸟类等,其中以蝼蛄的潜穴最为丰富。(2)在高潮滩的积水泥沼环境中,有大量近海喜盐植物,生物遗迹主要有宁波泥蟹的“J”形、“W”形和“Y”形潜穴、弹涂鱼的羽状爬迹、珠带拟蟹守螺在层面上营造的弧形、圆圈状的觅食迹和“C”形的条带状生殖迹。(3)在中、低潮间带的粉砂质环境中,以层面上珠带拟蟹守螺不规则的觅食迹为主。生物遗迹的分布与浅滩沉积底质沉积物粒度与含水量等特征密切相关。本研究不仅丰富了杭州湾浅滩沉积的新遗迹学研究,而且对古代潮汐沉积及其环境研究有重要的借鉴意义。     

东北典型林区雪深反演算法的验证与分析

积雪对自然环境和人类活动都有极其重要的影响。积雪参数（雪面积、雪深和雪水当量）反演对水文模型和气候变化研究有着实际的意义。然而,目前森林区的雪深遥感反演精度一直有待于进一步提高。东北地区是我国最大的天然林区和重要的季节性积雪区之一,本文利用FY3B卫星微波成像仪（MWRI）L1级亮温数据和L2级雪水当量数据,以及东北典型林区野外实测雪深数据,对Chang算法、NASA 96算法和FY3B雪深业务化反演算法进行了验证与分析。结果表明：在东北典型林区的雪深反演中,Chang算法和NASA 96算法反演的雪深波动都比较大,当森林覆盖度f≤0.6时,NASA 96算法表现比较好,均方根误差值在3种算法中较小,但当f >0.6时,NASA 96算法失真严重。当考虑纯森林像元（f=1）时,Chang算法低估了雪深47%。当f≤0.3时,FY3B业务化算法始终优于Chang算法。整体上,FY3B业务化算法相对稳定,具有较高的精度。     

中国海相烃源岩发育控制因素

烃源岩的形成取决于生烃母质生物的生存环境和有机质良好的保存条件,这两大因素从根本上来说又取决于生物繁殖时和埋藏时的古气候、古洋流、古构造及古环境等各要素的良好匹配。海相高有机质丰度烃源岩的形成与大气中的中等含氧量、干热的气候、冰期-冰后期之交的气温快速转暖、冰川迅速融化所导致的海平面快速上升等密切相关。大洋环流的形成和演变也是控制海相高有机质丰度烃源岩形成的主要因素,上升洋流富磷、富硅、富铁族元素等营养盐和富绿硫细菌极大地促进了有机质生产力、埋藏率的激增。通过研究,建立了中国华南和塔里木盆地寒武系上升洋流分布模式、塔里木盆地上奥陶统良里塔格组台缘斜坡灰泥丘相源岩形成时的反气旋洋流分布模式。研究发现,优质烃源岩仅发育于被动大陆边缘背景下的裂谷、克拉通内裂谷、克拉通内坳陷盆地和克拉通边缘坳陷盆地。欠补偿盆地、蒸发潟湖、台缘斜坡(灰泥丘)和半闭塞—闭塞欠补偿海湾,是高丰度烃源岩发育的有利环境;低的无机物输入和低的沉积速率,有利于高有机质丰度烃源岩形成;呈斜坡的海底地貌,有利于烃源岩形成。     

黑河上游冰沟流域典型积雪期水文情势

综合研究了黑河上游祁连山冰沟流域2008年积雪期水文情势,以积雪-冻土-径流为框架详细分析了该地区积雪水文特征.采用物质平衡计算了冰沟流域雪蒸发和融水值,并分析了冻土水热变化过程和融雪径流变化特征.积雪期降水总量达到204.6 mm,雪而蒸发为140.8 mm,雪面蒸发在积雪期水文循环中占有重要的位置.3月12日融雪开始,引起3次人规模的融雪峰值;整个融雪季,冰沟流域融雪径流总嚣为3.98×106m3.冻土解冻始于4月12日左右,随着气温升高,土壤含水量变化明显.地形和风速相巨作用,造成积雪的大规模重新分布.     

利用地基微波辐射计验证积雪微波辐射传输模型

积雪雪水当量参数是水文、气候、水资源利用与管理模型中非常重要的输入参数,积雪辐射理论模型可以模拟积雪物理参数与微波辐射的关系.因此,准确模拟积雪辐射信息,验证积雪辐射模型显得尤为重要.采用改进的基于能量守恒的干雪微波辐射传输理论模型(DMRT-AIEM-MD),利用2008年3月24 日黑河地区联合实验获取的地面测量数据以及车载辐射计18.7 GHz和36.5 GHz两个频率的辐射亮温值,考虑地形的影响,分析积雪辐射散射特性以及验证该模型.结果表明:该模型模拟值与地面实测值吻合的比较好,该模型能较好的模拟中国地区自然地表积雪辐射信号.分析了部分模型模拟值和地面实测值偏差的可能原因,该积雪区是多次堆积形成,积雪垂直剖面的密度、温度不规则变化可能会引起偏差.     

Diagenesis and Restructuring Mechanism of Oil and Gas Reservoir in the Marine Carbonate Formation,Northeastern Sichuan:A Case Study of the Puguang Gas Reservoir

Abstract: Based on the technology of balanced cross-section and physical simulation experiments associated with natural gas geochemical characteristic analyses, core and thin section observations, it has been proven that the Puguang gas reservoir has experienced two periods of diagenesis and restructuring since the Late Indo-Chinese epoch. One is the fluid transfer controlled by the tectonic movement and the other is geochemical reconstruction controlled by thermochemical sulfate reduction (TSR). The middle Yanshan epoch was the main period that the Puguang gas reservoir experienced the geochemical reaction of TSR. TSR can recreate the fluid in the gas reservoir, which makes the gas drying index higher and carbon isotope heavier because C2+ (ethane and heavy hydrocarbon) and 12C (carbon 12 isotope) is first consumed relative to CH4 and 13C? (carbon 13 isotope). However, the reciprocity between fluid regarding TSR (hydrocarbon, sulfureted hydrogen (H2S)?, and water) and reservoir rock results in reservoir rock erosion and anhydrite alteration, which increases porosity in reservoir, thereby improving the petrophysical properties. Superimposed by later tectonic movement, the fluid in Puguang reservoir has twice experienced adjustment, one in the late Yanshan epoch to the early Himalayan epoch and the other time in late Himalayan epoch, after which Puguang gas reservoir is finally developed.     

An empirical formula to compute snow cover fraction in GCMs

There exists great uncertainty in parameterizing snow cover fraction in most general circulation models (GCMs) using various empirical formulae, which has great influence on the performance of GCMs. This work reviews the commonly used relationships between region-averaged snow depth (or snow water equivalent) and snow cover extent (or fraction) and suggests a new empirical formula to compute snow cover fraction, which only depends on the domain-averaged snow depth, for GCMs with different horizontal resolution. The new empirical formula is deduced based on the 10-yr (1978-1987) 0.5°× 0.5° weekly snow depth data of the scanning multichannel microwave radiometer (SMMR) driven from the Nimbus-7 Satellite. Its validation to estimate snow cover for various GCM resolutions was tested using the climatology of NOAA satellite-observed snow cover.     

A Modeling Study of the Effects of Anomalous Snow Cover over the Tibetan Plateau upon the South Asian Summer Monsoon

The effect of anomalous snow cover over the Tibetan Plateau upon the South Asian summer monsoon is investigated by numerical simulations using the NCAR regional climate model (RegCM2) into which gravity wave drag has been introduced. The simulations adopt relatively realistic snow mass forcings based on Scanning Multi-channel Microwave Radiometer (SMMR) pentad snow depth data. The physical mechanism and spatial structure of the sensitivity of the South Asian early summer monsoon to snow cover anomaly over the Tibetan Plateau are revealed. The main results are summarized as follows. The heavier than normal snow cover over the Plateau can obviously reduce the shortwave radiation absorbed by surface through the albedo effect, which is compensated by weaker upward sensible heat flux associated with colder surface temperature, whereas the effects of snow melting and evaporation are relatively smaller.The anomalies of surface heat fluxes can last until June and become unobvions in July. The decrease of the Plateau surface temperature caused by heavier snow cover reaches its maximum value from late April to early May. The atmospheric cooling in the mid-upper troposphere over the Plateau and its surrounding areas is most obvious in May and can keep a fairly strong intensity in June. In contrast, there is warming to the south of the Plateau in the mid-lower troposphere from April to June with a maximum value in May.The heavier snow cover over the Plateau can reduce the intensity of the South Asian summer monsoon and rainfall to some extent, but this influence is only obvious in early summer and almost disappears in later stages.     

建立海洋地理信息系统两个技术问题的探讨

在分析海洋数据特征的基础上,探讨了建立海洋地理信息系统的两个技术问题:海洋数据融合技术和海洋地理信息空间技术.分析了目前数据融合技术的发展方向以及在海洋上应用的缺陷,探讨了海洋地理信息空间技术的发展以及存在的问题.     

青藏高原积雪与广西降水的相关关系

利用青藏高原资料序列长度均在30年以上的54个台站(1967～1997年)的积雪日数和积雪深度资料,与广西降水进行相关统计和分析研究,找出两者之间的相关统计事实及存在的联系:不管是上一年还是当年的青藏高原积雪与广西当年降水都有一定的相关,但大多是分散的个别显著相关,少数属于区域显著相关,没有全区性的显著相关。