汶川地震重灾区泥石流沟内崩滑物空间分布的RS-GIS定量方法

汶川地震在山区引发大量崩塌、滑坡,形成大量的固体松散碎屑物质堆积在沟谷内(CLCAR,崩滑碎屑区),使得地震山区泥石流活动性增强。以岷江上游四川省汶川县银杏乡、映秀镇的15条泥石流沟的SPOT遥感影像为基础,利用GIS技术对CLCAR空间分布进行分析。建立CLCAR与流域高程、主沟侧距和沟口纵距的分布函数T(x)、M(x)和G(x),对CLCAR的空间分布特征进行描述;并计算其积分(DT、DM和DG)作为CLCAR空间分布特征的定量化参数。结果表明,函数T(x)、M(x)和G(x)能够较全面描述CLCAR的空间分布特征,DT、DM和DG能够作为CLCAR空间分布特征的定量化参数。泥石流沟谷内CLCAR的空间分布对泥石流的形成及规模具有一定的影响;在对灾区泥石流研究时有必要考虑泥石流沟内CLCAR空间分布特征。     

Impact of seasonal tide variation on saltwater intrusion in the Changjiang River estuary

An improved 3-D ECOM-si model was used to study the impact of seasonal tide variation on saltwater intrusion into the Changjiang River estuary, especially at the bifurcation of the North Branch (NB) and the South Branch (SB). The study assumes that the river discharge and wind are constant. The model successfully reproduced the saltwater intrusion. During spring tide, there is water and salt spillover (WSO and SSO) from the NB into the SB, and tidally averaged (net) water and salt fluxes are 985 m3/s and 24.8 ton/s, respectively. During neap tide, the WSO disappears and its net water flux is 122 m3/s. Meanwhile, the SSO continues, with net salt flux of 1.01 ton/s, much smaller than during spring tide. Because the tidal range during spring tide is smaller in June than in March, overall saltwater intrusion is weaker in June than in March during that tidal period. However, the WSO and SSO still exist in June. Net water and salt fluxes in that month are 622 m3/s and 15.35 ton/s, respectively, decreasing by 363 m3/s and 9.45 ton/s over those in March. Because tidal range during neap tide is greater in June than in March, saltwater intrusion in June is stronger than in March during that tidal period. The WSO and SSO appear in June, with net water and salt fluxes of 280 m3/s and 8.55 ton/s, respectively, increasing by 402 m3/s and 7.54 ton/s over those in March. Saltwater intrusion in the estuary is controlled by the river discharge, semi-diurnal flood-ebb tide, semi-monthly spring or neap tide, and seasonal tide variation.     

保康县地质特征及其对旅游资源景观的影响

着重阐述了湖北省保康县的地质特征及其对资源景观的影响;分析了保康县北部４个风景区的地层发特征,岩性特征、地质构造,并对其旅游资源进行了定性、定量分析,提出了今后开发的方向。     

Outburst risk of barrier lakes in Sichuan,China

34 barrier lakes induced by earthquake have been formed by wedged debris on the river channels after a massive earthquake happening on May 12 in Sichuan, China. Among them, the Tangjiashan Barrier Lake is the largest one. It faces very urgent risk of dam breaking when water level reaches the top and begins overflow in case of storm rainfalls and continually aftershocks, threatening already devastated cities and villages with about 1.5 million people downstream. The outburst of a similar barrier lake occurred in the Minjiang River in 1933, causing a catastrophic flood. Risk analysis indicates that not all barrier lakes are highly dangerous. Only those lakes with very high dams and water to be filled up in short period need to be dealt with immediately.     

长江口北支盐水倒灌的数值模型研究

20世纪80年代以来,国内对长江口盐水入侵进行了大量系统专门的研究,对长江口的盐水入侵规律有了一个比较基本的认识.但是,长江口特别是在南支及南北港的盐度变化规律极其复杂,主要有盐度的周日变化峰值与潮流变化关系不尽协调,落潮时盐度反而最大;盐度的纵向分布上游比下游高;盐度的半月变化峰值一般发生在小潮和寻常潮期间,而且各测点盐度峰值的发生时间不尽一致[1,2]等等.其中北支盐水向南支倒灌是引起长江口盐度变化异常复杂的主要原因[1-5].北支倒灌在长江口盐度变化中扮演了重要的角色,掌握北支倒灌是认识长江口盐水入侵规律特别是南支和南北港盐度变化规律的重要内容,同时也是长江口淡水咨源利用的一个重要方面.     

德州市浅层地温能资源潜力评价

随着我国社会经济的快速发展,对能源的需求大幅增加,供需矛盾越来越突出,煤炭、石油、天然气等常规能源的大量消耗对环境造成的压力也越来越大。浅层地温能是一种可再生的新型环保能源,逐步受到各级政府及社会各界的重视。通过对德州城区浅层地温能赋存条件的分析,利用试验测试数据对浅层地温能热容量进行了计算,并在适宜性分区在基础上,进行了浅层地温能资源潜力评价。结果表明,德州城区120 m深度内浅层地热容量为8.525×10~(13)k J/℃,相当于291万t标准煤。整个德州城区为地下水换热系统不适宜区,而适宜地埋管换热系统。在地埋管换热系统适宜区内,120 m深度范围内考虑土地利用系数,计算得出夏季换热功率为339.18万k W,冬季换热功率为343.22万k W。夏季可制冷面积4.845×10~7m~2,冬季可供暖面积6.240×10~7m~2。     

西北干旱地区大气降水δ18O的特征及水汽来源

In order to reveal the characteristics and climatic controls on the stable isotopic composition of precipitation over Arid Northwestern China, eight stations have been selected from Chinese Network of Isotopes in Precipitation (CHNIP). During the year 2005 and 2006, monthly precipitation samples have been collected and analyzed for the composition of δD and δ18O. The established local meteoric water line δD=7.42 δ18O+1.38, based on the 95 ob-tained monthly composite samples, could be treated as isotopic input function across the region. The deviations of slope and intercept from the Global Meteoric Water Line indicated the specific regional meteorological conditions. The monthly δ18O values were characterized by a positive correlation with surface air temperature (δ18O (‰) =0.33 T (℃)-13.12). The amount effect visualized during summer period (δ18O (‰) = -0.04P (mm)-3.44) though not appeared at a whole yearly-scale. Spatial distributions of δ18O have properly portrayed the atmospheric circulation background in each month over Arid Northwestern China. The quan-titative simulation of δ18O, which involved a Rayleigh fractionation and a kinetic fractionation, demonstrated that the latter one was the dominating function of condensation of raindrops. Furthermore, the raindrop suffered a re-evaporation during falling processes, and the pre-cipitation vapor might have been mixed with a quantity of local recycled water vapor. Multiple linear regression equations and a δ18O-T relation have been gained by using meteorological parameters and δ18O data to evaluate physical controls on the long-term data. The estab-lished δ18O-T relation, which has been based on the present-day precipitation, could be considered as a first step of quantitatively reconstructing the historical environmental climate.     

The study of s-process nucleosynthesis based on barium stars, CEMP-s and CEMP-r/s stars

In order to get a broader view of the s-process nucleosynthesis we study the abundance distribution of heavy elements of 35 barium stars and 24 CEMP-stars, including nine CEMP-s stars and 15 CEMP-r/s stars. The similar distribution of [Pb/hs] between CEMP-s and CEMP-r/s stars indicate that the s-process material of both CEMP-s and CEMP-r/s stars should have a uniform origin, i.e. mass transfer from their predominant AGB companions. For the CEMP-r/s stars, we found that the r-process should provide similar proportional contributes to the second s-peak and the third s-peak elements, and also be responsible for the higher overabundance of heavy elements than those in CEMP-s stars. Which hints that the r-process origin of CEMP-r/s stars should be closely linked to the main r-process. The fact that some small r values exist for both barium and CEMP-s stars, implies that the single exposure event of the s-process nucleosynthesis should be general in a wide metallicity range of our Galaxy. Based on the relation between C _r and C _s, we suggest that the origin of r-elements for CEMP-r/s stars have more sources. A common scenario is that the formation of the binary system was triggered by only one or a few supernova. In addition, accretion-induced collapse(AIC) or SN 1.5 should be the supplementary scenario, especially for these whose pre-AGB companion with higher mass and smaller orbit radius, which support the higher values of both C _r and C _s.     

陇中黄土高原土壤水分变化特征及其机理分析

基于兰州大学半干旱气候与环境观测站（SACOL）2010年全年的观测资料,对陇中黄土高原半干旱区土壤水分的年变化和日变化特征进行了研究,并通过计算水汽通量与蒸散量,探讨了土壤-地表-大气间水分的交换和运移机理。结果表明：土壤湿度的季节变化主要受降水影响,各季节的平均土壤湿度均呈现出表层和深层低、中间层高的特点,最高值出现在地下10 cm附近;在无降水的情况下,土壤5~20 cm处的含水量呈现出夜间逐渐降低、白天逐渐上升的波形变化,这种变化与土壤水汽通量具有很好的一致性,而水汽通量的方向则受温度梯度的影响;在白天,地表温度高于气温与较深层地温,水汽在向空气蒸散的同时也由地表流向土壤深部,夜晚地表温度则低于较深层地温,水汽由土壤深部流向地表。因此土壤内部的水分蒸发主要出现在夜晚,且主要发生在地表40 cm以内的土壤孔隙中,而白天地表的实际蒸发主要存在土壤浅层0~5 cm,5 cm以下土壤水分的蒸发十分微弱。本研究结果对于改进半干旱区陆面计算模式以及当地的生态环境建设具有一定的参考价值。     

近60年来长江河口河势变化及其对水动力和盐水入侵的影响I.河势变化

河势是影响河口水动力和盐水入侵基本因子。本文利用20世纪50和70年代长江河口海图,数值化岸线和水深,结合2012年长江河口实测水深资料,分析长江河口自50年代以来的河势变化。长江河口为分汊河口,50年代仅为二级分汊,至70年代才形成三级分汊,四口入海的河势格局。70年代相比于50年代,北支淤浅严重,其上、中、下段容积变化分别为-64.13×106、-306.60×106和-639.27×106 m3,对应的变化率分别为-16.30%、-22.74%和-25.69%,均显著减小;南支的上、中、下段容积变化分别为-28.61×106、-35.69×106和126.43×106 m3,相应的变化率分别为-1.30%、-2.12%和4.36%;北港由于崇明浅滩和横沙浅滩的淤浅,下段容积明显减小,其上段和下段容积变化分别为109.21×106和-797.14×106 m3,对应的变化率分别为5.01%和-15.25%;南港上段由于河道淤浅容积减小,下段北由于铜沙浅滩被冲开形成北槽,导致水深变深、容积增加,其上段、下段北和下段南容积变化分别为-238.95×106、203.58×106和153.34×106 m3,对应的变化率分别为-8.96%、6.85%和3.26%。2012年相比于70年代,北支由于大量淤浅和围垦容积大幅减小,其上、中、下段容积变化分别为-199.06×106、-504.61×106和-654.12×106 m3,对应的变化率分别为-60.45%、-48.44%和-35.38%;南支的上、中、下段容积变化分别为92.34×106、193.01×106和-163.62×106 m3,相应的变化率分别为4.24%、11.73%和-5.40%;北港上段青草沙水库的围垦和下段横沙东滩的围垦造成面积和容积减小,其上段和下段容积变化分别为-154.64×106和-511.79×106 m3,对应的变化率分别为-6.75%和-11.55%;南港由于上段河道刷深而下段九段沙以及南汇边滩淤浅、围垦,导致其容积上段增加,下段减小,上段、下段北和下段南容积变化分别为136.39×106、-658.28×106和-1266.11×106 m3,对应的变化率分别为5.62%、-20.73%和-26.06%。