八宝河流域土壤温度波动的时空分异

The Babao River Basin is the "water tower" of the Heihe River Basin.The combination of vulnerable ecosystems and inhospitable natural environments substantially restricts the existence of humans and the sustainable development of society and environment in the Heihe River Basin.Soil temperature(ST) is a critical soil variable that could affect a series of physical,chemical and biological soil processes,which is the guarantee of water conservation and vegetation growth in this region.To measure the temporal variation and spatial pattern of ST fluctuation in the Babao River Basin,fluctuation of ST at various depths were analyzed with ST data at depths of 4,10 and 20 cm using classical statistical methods and permutation entropy.The study results show the following: 1) There are variations of ST at different depths,although ST followed an obvious seasonal law.ST at shallower depths is higher than at deeper depths in summer,and vice versa in winter.The difference of ST between different depths is close to zero when ST is near 5℃ in March or –5℃ in September.2) In spring,ST at the shallower depths becomes higher than at deeper depths as soon as ST is above –5℃;this is reversed in autumn when ST is below 5℃.ST at a soil depth of 4 cm is the first to change,followed by ST at 10 and 20 cm,and the time that ST reaches the same level is delayed for 10–15 days.In chilling and warming seasons,September and February are,respectively,the months when ST at various depths are similar.3) The average PE values of ST for 17 sites at 4 cm are 0.765 in spring > 0.764 in summer > 0.735 in autumn > 0.723 in winter,which implies the complicated degree of fluctuations of ST.4) For the variation of ST at different depths,it appears that Max,Ranges,Average and the Standard Deviation of ST decrease by depth increments in soil.Surface soil is more complicated because ST fluctuation at shallower depths is more pronounced and random.The average PE value of ST for 17sites are 0.863 at a depth of 4 cm > 0.818 at 10 cm > 0.744 at 20 cm.5) For the variation of ST at different elevations,it appears that Max,Ranges,Average,Standard Deviation and ST fluctuation decrease with increasing elevation at the same soil depth.And with the increase of elevation,the decrease rates of Max,Range,Average,Standard Deviation at 4 cm are –0.89℃/100 m,–0.94℃/100 m,–0.43℃/100 m,and –0.25℃/100 m,respectively.In addition,this correlation decreased with the increase of soil depth.6) Significant correlation between PE values of ST at depths of 4,10 and 20 cm can easily be found.This finding implies that temperature can easily be transmitted within soil at depths between 4 and 20 cm.7) For the variation of ST on shady slope and sunny slope sides,it appears that the PE values of ST at 4,10 and 20 cm for 8 sites located on shady slope side are 0.868,0.824 and 0.776,respectively,whereas they are 0.858,0.810 and 0.716 for 9 sites located on sunny slope side.     

水位波动的幅度与频率对刺苦草(Vallisneria spinulosa)生物量和形态特征的影响

沉水植物是维持浅水湖泊清水稳态以及湖泊生态系统结构与功能的关键生物类群.近年来,气候变化和人类活动的双重作用造成湖泊水文情势的明显改变,对沉水植物的生长、繁殖和演替有着较大的影响.本文选取2个水位波动幅度与2个波动频率(逐渐改变水位),以恒定水位作为对照,研究湿地中具有重要生态功能的沉水植物刺苦草(Vallisneria spinulosa)的生物量及地上和地下营养器官形态结构对水位波动的响应.结果表明,相对于恒定水位,波动水位(低幅度低频率、低幅度高频率、高幅度低频率、高幅度高频率)对刺苦草的总生物量和获取限制资源相关器官有显著影响.相比于对照组,水位波动能够显著降低刺苦草分株数、叶片数、根数、根长、匍匐茎数、总匍匐茎长以及叶、根、地上和地下生物量,但会显著增加其株高和比叶面积.不同波动频率(低频率和高频率)和幅度(低幅度和高幅度)对光合器官的形态特征都没有显著影响,但叶和地上部分的生物量积累均受到波动幅度的显著影响.水位波动幅度显著改变了刺苦草的根数和根长,而波动频率的影响不显著.因此,对浅水湖泊受损刺苦草群落进行重建时,应避免较大幅度的水位波动,从而有利于增强植株快速恢复的能力.     

辽西医巫闾山海蚀地貌遗迹的发现及其意义

简要介绍医巫山闾山山区海蚀地貌遗迹的发现及其形态类型、形成的可能时代和机制.这不仅为定性及定量研究中国东部地区新构造运动上升和海平面变化幅度和速率提供科学依据,同时为医巫闾山风景区申报世界自然与文化遗产提供新的条件.     

库水升降条件下考虑饱和渗透系数空间变异性的白水河滑坡渗流变形分析

堆积层滑坡的岩土体渗透系数具有一定的不确定性,且渗透系数是饱和-非饱和渗流分析的重要参数,开展考虑其空间变异性的库岸堆积层滑坡渗流变形分析具有重要意义。以三峡库区中的白水河滑坡为研究对象,基于地面核磁共振技术获取的岩土体渗透系数,分析滑坡体渗透系数的空间变异特征,采用半变异函数方法求得滑坡体渗透系数的竖直波动范围,在此基础上建立渗透系数的非平稳随机场模型。以非侵入式随机有限元的方式开展库水升降两种工况下不确定模型与确定模型的流固耦合模拟,分析两种模型的渗流场、位移变形特征及其差异。结果表明：相比于确定模型,不确定模型孔压改变的滞后性更为明显,且库水下降工况下整体的变形更大,若忽略滑体渗透系数的非平稳空间变异特征将会低估滑坡的实际变形。     

Spatial and temporal variation of groundwater recharge in shallow aquifer in the Thepkasattri of Phuket,Thailand

Whether groundwater resources can be sustainably utilized is largely determined and characterized by hydrogeological parameters.Estimating the groundwater recharge is one of the essential parameters for managing water resources and protecting water resources from contamination.This study researched the spatial and temporal variation of groundwater recharge in the Thepkasattri sub-district through integrating chloride mass balance(CMB)and water table fluctuation(WTF)methods.The chloride content of representative rainfall and groundwater samples was analyzed.Besides,WTF method was adopted from groundwater level data from 2012 to 2015.According to the CMB method,the mean recharge was estimated to be 1172 mm per year,accounting for 47%of the annual rainfall.Moreover,the estimated recharge from the WTF method took 26%of annual rainfall in 2015.The recharge was underestimated according to the WTF method,because of the uncertainty in specific yield estimates and the number of representative wells in the study area.Moreover,the correlation between rainfall and water table fluctuation data indicated the positive linear relationship between two parameters.The spatial recharge prediction indicated that recharge was higher(1200-1400 mm/yr)in the eastern and western catchment,while that in the central floodplains was between 800 mm/yr and 1100 mm/yr.In addition,low recharge value between 450 mm/yr and 800 mm/yr was observed in the south-west part of Thepkasattri.The spatial variation of recharge partly reflects the influences of land use and land cover of the study area.     

南海台西南盆地南部海域TS6孔常量元素地球化学特征及其古环境意义

通过对南海台西南盆地南部海域TS6柱状样沉积物样品常量元素地球化学特征的分析,结合粒度和AMS14C测年分析结果,探讨了研究区末次冰消期以来的沉积环境及气候变化特征。常量元素垂向序列显示元素Mn在沉积物近表层大量自生富集,指示近现代底层水高度富氧,表明研究区水体环境条件十分有利于水成成因的铁锰结核发育;常量元素统计分析表明,Al、Fe、Mg、K、Ti代表了陆源元素组合;陆源常量元素比值Al2O3/TiO2、TFe2O3/TiO2、MgO/TiO2和MgO/Al2O3记录了研究区末次冰消期以来的部分气候波动事件,其中全新世9.8~9.4 kaBP和6.5~5.8 kaBP阶段发生了两次气候变冷事件,指示东亚夏季风强度明显减弱,并且6.5~5.8 kaBP阶段冷事件表现出“双峰”特征。各常量元素比值指示末次冰消期18.5和15.8 kaBP左右可能也出现了气候变冷事件,其中15.8 kaBP出现的冷事件应该对应于H1事件。     

Fluctuation in Ommastrephe bartrami yield in the North Pacific

The fluctuation in Ommastrephe bartrami yield from 1995 to 2001 in the North Pacific was shown obvious, on which this study was conducted using data of sea surface temperature (SST), chlorophyll-a (chl-a) and statistical production. The study shows that, cool water and low food abundance caused by abnormal Kuroshio resulted in the reduction in abundance of O. bartrami, which was worsened by excessive catch and the unawareness to local fishery resources protection.     

大布苏湖全新世沉积岩心的碳酸盐含量与湖面波动

大布苏湖是我国东北地区极为罕见的盐湖，通过对该湖现代湖盆碳酸盐沉积相的分析，以及钻孔岩心碳酸盐含量和^14C年代的测定,探讨了大布苏湖全新世湖面波动与环境演化的过程。结果表明，大布苏湖有两次高湖面时期，分别为10450－7260和5400－3600aBP，湖泊水位稳定在125m以上，这两个时期也是松嫩沙地古土壤集中发育的时期，晚全新世以来，大布苏湖明显萎缩，气候向干燥方向转化。     

福建沿岸6000年来的海平面波动

本文通过35个~(14)C测年数据进行评价,建立一条福建省沿岸过去6000年海平面变化曲线,该线表明海平面在现代位置上下呈振荡性变化,最高和最低海平面分别出现距今5000年前和4000年前左右,海平面高度分别为约+2m,-2m。     

Multifractal analysis of spatial distribution of microearthquakes in the Kanto region

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The spatial distribution of earthquakes is a fractal, which is characterized by a fractal dimension. However, if a spatial distribution has a heterogeneous fractal structure, a single value of fractal dimension [e.g. D_o (capacity dimension) or D ₂ (correlation dimension)] is not enough to characterize it. From a multifractal viewpoint, we analysed the spatial distribution of microearthquakes in the Kanto region by using a local density function. Generalized dimensions, D_q , of the spatial distribution were calculated from the slopes of generalized correlation integrals, C_q(r) versus distance r , on a log-log plot, examining the self-similarity of the spatial distribution of microearthquakes. Self-similar structures are held well at scales from 1.26 to 12.6 km. Our results suggest that the spatial distribution of microearthquakes in the Kanto region is not a homogeneous fractal structure but a heterogeneous one with generalized dimensions D₂ = 2.2 ≤ D ₃≤…≤ D _∞= 1.7. The value of D _∞, the lower limit of fractal dimension, is the fractal dimension of the most intensive clustering in the heterogeneous fractal set. The fractal dimension of the most intensive clustering of microearthquakes in the Kanto region is 1.7.