Effect of succession gaps on the understory water‐holding capacity in an over‐mature alpine forest at the upper reaches of the Yangtze River          下载免费PDF全文

Bin Wang  Fuzhong Wu  Sa Xiao  Wanqin Yang  Meta Francis Justine  Jiayi He  Bo Tan 《水文研究》2016,30(5):692-703

The water‐holding capacity (WHC) of the understory in the headwater regions of major rivers plays an important role in both the capacity of the forest water reservoir and water quality and quantity in the butted rivers. Although forest gaps could regulate water‐holding patterns in the understory by redistributing coarse woody debris (CWD), fine woody debris (FWD), non‐woody debris (NWD) and understory vegetation, little information is available on the effects of forest gaps on understory WHC. Therefore, we investigated the WHCs of CWD, FWD, NWD, herbaceous vegetation, mosses, epiphytes (including fern and lichen growing on the surface of logs) and soils from the gap centre to the adjacent closed canopy in an alpine forest at the upper reaches of the Yangtze River. The total WHC of the alpine forest understory components was approximately 300 mm. Soil layer had the largest contribution to the total understory WHC (90%), and among the aboveground components, CWD and mosses contributed 5% and 4% to the aboveground WHC, respectively. With the exception of that of the herbaceous layer, the WHC of the forest floor increased from the gap centre to the closed canopy. Although mosses had the lowest biomass allocation on the alpine forest floor, the water‐holding ratio (k) of mosses reached 485%. In conclusion, biomass is the parameter that most strongly and positively correlated with the WHC of the alpine forest understory, and forest gap formation decreases the understory WHC of alpine forest resulting from a decrease in organic soils, CWDs and mosses. Copyright © 2015 John Wiley & Sons, Ltd. Highlights

• The effects of gaps on the understory WHC were examined in an alpine forest.
• Gaps decreased the understory WHC by decreasing the amounts of the larger WHC components.
• The contribution of CWD and mosses to the aboveground WHC was large.
• The WHC of dead debris was higher than that of the vegetation.

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呼图壁地下储气库地表盖层变形的GPS研究     

王迪晋  李瑜  聂兆生  王坦  乔学军  李杰  余鹏飞  程瑞忠 《中国地震研究》2016,30(3):439-450

利用新疆呼图壁地下储气库地表盖层由13个点位组成的形变监测网的前5期GPS观测资料,研究地下储气库注采过程中地表盖层的变形响应。通过获取地下储气库运行过程中地表盖层形变的三维时间序列,并结合井口压力数据,区分地下储气库在不同过程中的变形信号。研究结果表明,地表盖层在储气库注采过程中水平方向上存在明显的“呼吸效应”,储气库每MPa气井压力变化在注、采周期内对地表变形造成的影响在水平方向上分别达到1.02、1.24mm,垂直方向分别达到-1.11、0.86mm。  相似文献   

初始震源深度对双差地震定位深度的影响分析   总被引：3，自引：0，他引：3  

闫俊岗  王利兵  谭青 《大地测量与地球动力学》2013,(Z1):41-44

利用随机生成的理论地震走时数据,取2、5、10、15 km作初始深度,对用双差定位法给出的定位深度结果进行分析。通过模拟计算,认为初始深度误差对双差定位法的空间位置影响较小,但对深度结果有一定影响。  相似文献   

绝对重力控制下的山西地震带2009—2012重力场动态变化     

冯建林  孙少安  秦建增  檀玉娟  黄帮武  李德庆 《大地测量与地球动力学》2013,(Z1):49-52

通过对山西地震带区域重力测网2009—2012年的绝对与相对重力资料的联合平差,获得了以太原绝对重力点为基准的区域重力场动态变化图像,并分析了太原绝对重力点起算值的选取问题。  相似文献   

Characterization of flounder (Paralichthys olivaceus) FoxD5 and its function in regulating myogenic regulatory factor     

谭训刚  张玉青  孙威  张培军  徐永立 《中国海洋湖沼学报》2012,30(2):286-294

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Crustal velocity structure off SW Taiwan in the northernmost South China Sea imaged from TAIGER OBS and MCS data     

Jia-Ming Deng  Tan K. Wang  Ben Jhong Yang  Chao-Shing Lee  Char-Shine Liu  Song-Chuen Chen 《Marine Geophysical Researches》2012,33(4):327-349

During TAiwan Integrated GEodynamics Research of 2009, we investigated data from thirty-seven ocean-bottom seismometers (OBS) and three multi-channel seismic (MCS) profiles across the deformation front in the northernmost South China Sea (SCS) off SW Taiwan. Initial velocity-interface models were built from horizon velocity analysis and pre-stack depth migration of MCS data. Subsequently, we used refracted, head-wave and reflected arrivals from OBS data to forward model and then invert the velocity-interface structures layer-by-layer. Based on OBS velocity models west of the deformation front, possible Mesozoic sedimentary rocks, revealed by large variation of the lateral velocity (3.1–4.8 km/s) and the thickness (5.0–10.0 km), below the rift-onset unconformity and above the continental crust extended southward to the NW limit of the continent–ocean boundary (COB). The interpreted Mesozoic sedimentary rocks NW of the COB and the oceanic layer 2 SE of the COB imaged from OBS and gravity data were incorporated into the overriding wedge below the deformation front because the transitional crust subducted beneath the overriding wedge of the southern Taiwan. East of the deformation front, the thickness of the overriding wedge (1.7–5.0 km/s) from the sea floor to the décollement decreases toward the WSW direction from 20.0 km off SW Taiwan to 8.0 km at the deformation front. In particular, near a turn in the orientation of the deformation front, the crustal thickness (7.0–12.0 km) is abruptly thinner and the free-air (?20 to 10 mGal) and Bouguer (30–50 mGal) gravity anomalies are relatively low due to plate warping from an ongoing transition from subduction to collision. West of the deformation front, intra-crustal interfaces dipping landward were observed owing to subduction of the extended continent toward the deformation front. However, the intra-crustal interface near the turn in the orientation of the deformation front dipping seaward caused by the transition from subduction to collision. SE of the COB, the oceanic crust, with a crustal thickness of about 10.0–17.0 km, was thickened due to late magmatic underplating or partially serpentinized mantle after SCS seafloor spreading. The thick oceanic crust may have subducted beneath the overriding wedge observed from the low anomalies of the free-air (?50 to ?20 mGal) and Bouguer (40–80 mGal) gravities across the deformation front.  相似文献   

2011年10月16日新疆精河县5.0级地震震害特征及原因   总被引：1，自引：0，他引：1  

陈建波  谭明  吴国栋  胡伟华  孙甲宁  张振斌 《震灾防御技术》2012,7(2):164-172

2011年10月16日新疆精河县5.0级地震震中位于博尔塔拉蒙古自治州精河县托里乡境内,极震区震中烈度为Ⅵ度.震害调查显示,灾区房屋主要以老旧的土坯房为主,地震使本身老旧的房屋裂缝加宽,破坏加重.其次,灾区房屋震害还具有明显的南北差异特性,场地条件差异是造成距离震中较远的部分房屋破坏较重的主要原因之一.  相似文献   

地震应急卫星通信系统的设计与应用.   总被引：6，自引：5，他引：1  

杨乐  曾薇  谭颖 《震灾防御技术》2012,7(1):100-109

地震应急通信是地震应急救援工作的基础和关键的组成部分.本文从地震应急卫星通信网络的组成及规模、站点配置、组网方式、工作模式、工作模式切换、通信方式、卫星信道规划、业务应用等方面,简要介绍了中国地震局“十五”期间建设并投入运行的地震应急卫星通信系统的设计以及在地震应急工作中的应用.  相似文献   

北秦岭东段二郎坪群火山岩锆石的LA-ICP-MS U-Pb定年及其地质意义   总被引：13，自引：0，他引：13  

赵姣  陈丹玲  谭清海  陈淼  朱小辉  郭彩莲  刘良 《地学前缘》2012,19(4):118-125

利用阴极发光（CL）技术和LA-ICP-MS原位分析方法,对北秦岭东段军马河、湾潭和湍河3个地区的二郎坪群基性火山岩进行了系统的锆石U Pb年代学研究。CL图像分析结果显示,三地火山岩中的锆石皆呈自形 半自形柱状形态和微弱的、宽的振荡环带结构。微量元素分析揭示,所有锆石都具有较高的稀土总量、重稀土和Th、U含量（ΣREE为(397.7~7 941.6)×10-6;ΣHREE为(376.7~7 774.2)×10-6;Th为(107.9~5 824.2)×10-6;U为(89.3~3 841.9)×10-6）以及轻稀土亏损、重稀土明显富集的左倾稀土配分曲线型式,所有锆石的Th/U比值皆大于0.4,显示典型岩浆锆石特征。LA-ICP-MS定年结果获得3地基性火山岩的形成年龄分别为(463±1.8) Ma、(475±1.5) Ma和(473±1.3) Ma,三者在误差范围内一致,表明北秦岭二郎坪群基性火山岩的形成时代为463~475 Ma。系统的岩石学和地球化学研究显示,二郎坪群火山岩具有弧后盆地火山岩的地球化学特征。研究获得的二郎坪基性火山岩463~475 Ma的结晶年龄明显晚于其南侧北秦岭超高压榴辉岩的原岩年龄(（791±6) Ma）以及变质年龄（(502±11) Ma）,而且榴辉岩的地球化学特征显示为板内玄武岩,也与二郎坪火山岩不同,因而指出北秦岭超高压榴辉岩与二郎坪火山岩没有直接成因联系。  相似文献   

构造电阻率差比值法识别火山岩裂缝地层天然气层     

谭锋奇  李洪奇  孙中春  欧阳敏  韩述一 《吉林大学学报(地球科学版)》2012,42(4):1199-1206

在基岩电阻率较高的硬地层中,除去泥质、孔隙和其他矿物等因素的影响后,地层电阻率与致密围岩电阻率的差异就被认为是裂缝以及地层孔隙中储存的流体性质引起的。选择相同岩性含气储层与致密围岩层的电阻率值,利用数值反演的方法确定出计算含气层段消除裂缝以及孔隙中流体性质影响以后的地层真电阻率公式,定义地层真电阻率和深侧向电阻率的差值与地层深侧向电阻率的比值为构造电阻率差比值,该参数主要反映裂缝以及孔隙中的流体性质对电阻率降低幅度的影响。因此,利用差比值法可以识别火山岩裂缝地层的流体性质,进而制作油层、气层和水层的判别图版,并结合其他测井曲线、油藏动态资料以及气测信息综合识别火山岩裂缝地层天然气层。该方法在准噶尔盆地研究区火山岩天然气层的识别中取得了很好的应用效果,解释结论与试油结果基本吻合。  相似文献