Channel geometry of mountain streams in New Zealand

A dataset of 21 study reaches in the Porter and Kowai rivers (eastern side of the South Island), and 13 study reaches in Camp Creek and adjacent catchments (western side of the South Island) was used to examine downstream hydraulic geometry of mountain streams in New Zealand. Streams in the eastern and western regions both exhibit well-developed downstream hydraulic geometry, as indicated by strong correlations between channel top width, bankfull depth, mean velocity, and bankfull discharge. Exponents for the hydraulic geometry relations are similar to average values for rivers worldwide. Factors such as colluvial sediment input to the channels, colluvial processes along the channels, tectonic uplift, and discontinuous bedrock exposure along the channels might be expected to complicate adjustment of channel geometry to downstream increases in discharge. The presence of well-developed downstream hydraulic geometry relations despite these complicating factors is interpreted to indicate that the ratio of hydraulic driving forces to substrate resisting forces is sufficiently large to permit channel adjustment to relatively frequent discharges.     

淀山湖太湖形成的古生物证据

通过对湖泊周围钻孔样品的微体古生物分析,根据化石群的生态特征,结合岩性、孢粉、¹⁴C等资料探讨晚更新世中期以来淀山湖、太湖沉积环境的演变过程,并比较其异同。现代湖泊的形成于全新世晚期。     

Trophic ecology of Pomatoschistus microps within an intertidal bay (Roscoff,France), investigated through gut content and stable isotope analyses

The diet of Pomatoschistus microps has been studied using both gut content and stable isotope analyses. In the Roscoff Aber Bay (Brittany, France), this fish is commonly found on sandy muddy intertidal flats. Gut content analyses were also interpreted using trophic indices. Owing to the large diversity of prey consumed, these indices emphasised the opportunistic feeding behaviour of P. microps. Here, this species fed mainly on endofauna with meiofauna being of high relative importance. The main biotic components of its trophic habitat, characterized by δ¹³C and δ¹⁵N, provided evidence of a major trophic pathway based on drift Enteromorpha sp. Trophic positions estimated by both diet analyses and isotopic analyses led to similar results. In this bay, P. microps is a first‐order predator with a low degree of omnivory. Despite a preferential consumption of the amphipod Corophium arenarium, we assumed that this goby behaves as a generalist feeding on a uniform variety of endofauna taxa.     

中蒙干旱半干旱区冬、夏季地面气温时空变化特征分析(Ⅱ):7月

为整体地分析中蒙干旱半干旱区(中蒙干旱区)夏季气温的时空变化特征,利用中蒙干旱区内分布相对均匀的104个站点(包括5个“人造站”)1961—1997年7月的平均地面气温资料等,首先分析了该区夏季的平均气温场、气温年较差及日较差等背景;然后,对标准化的7月平均气温距平资料分别作了EOF和REOF分析。结果表明:(1)中蒙干旱区夏季的热量资源充足。夏季气温场分布的区域性特色更明显。(2)受纬度、地形高度及远离海洋等的影响,中蒙干旱区地面气温的年较差大,日较差也大,呈典型大陆性气候(大陆度高)的特色,但是区内的夏季气温年际变化小。(3)根据气温的EOF分析,中蒙干旱区夏季气温异常可粗分为全区一致型、准东西差异型、准南北差异型及准东北—西南差异型等4种常见分布模态;再根据REOF分析,可将该区夏季气温异常进一步细分为青海高原、高原东北侧、南疆、北疆、陕西甘南区、蒙古国西北部及东南部等7个分区。(4)近37年来,中蒙干旱区夏季气温增暖主要出现在高原东北侧和南疆区,强度比冬春季弱;在青海高原及蒙古国东南部气温还在变凉,区内各分区夏季气温变化也约有3~4年的周期。     

赤道东太平洋SST强增温过程特征分析

本文利用太平洋海温距平场资料,对１９８６年以来发生的厄尔尼诺过程的开始时间、发展过程及强度等方面进行了分析。并与历史上的厄尔尼诺过程进行比较,结果表明,９０年代是厄尔尼诺事件的多发期,在１９９１￣９８年的８年中,间连续发生四次厄经诺事件,其中１９９７￣９８年的厄尔尼诺,成为有历史记录以来最强的一次过程。     

Evaluation of geochemical behavior and heavy metal distribution of sediments：The case study of the Tirumalairajan river estuary,southeast coast of India

The purpose of this study was to assess the chemical partitioning of selected heavy metals(Fe,Mn,Cu,Zn,Pb,Cr,Co and Ni) in 10 surface sediments at Tirumalairajan River Estuary in the southeastern coast of India.A five-step sequential extraction technique was used to assess the environmental status of heavy metals.Most of metals were considered to be immobile due to the high availability in the residual fraction of heavy metals.The sediments of Tirumalairajan River estuary had not been polluted by heavy metals,and they didn’t pose any high ecological risk.The seasonal variations of heavy metals were slightly higher in summer than in monsoon season.Factor analysis was also carned out to understand the associations of metals in different fractions with sand,silt,clay,organic matter,pH,salinity and other metals.The relationship between the Q-mode and R-mode cluster analyses was useful for identifying the pollution levels in both seasons.It was proved that the enrichment of heavy metals was related with geogenic and anthropogenic sources.The information on total metal concentrations in sediments was not sufficient for assessing the metal behavior in the environment,but the sequential extraction technique was more effective in estimating the environmental impact of contaminated sediments.     

磁纬20°以下地区哨声多台宽带定向观测及其初步结果

武汉大学哨声组与日本名古屋大学空电研究所合作于1988年1月在我国南方进行了哨声多台宽带定向测量。利用近两年研制的宽带数字化频率追踪定向分析系统,首次获得了磁纬20°以下地区哨声波出口区与偏振状态的实验结果。初步分析发现,在湛江附近（磁纬约10°N）存在一个比较稳定的哨声路径出口区,三台同时接收到的哨声大多从这同一出口区透射出来;有时存在两个出口区,一个仍位于湛江附近,另一个位于桂林和武昌之间;沿两条不同路径传播的同源哨声具有几乎相同的色散。本文所做的非导管射线追踪计算能比较满意地解释定向实验结果。另外,此次观测中还发现一些新的有意义的现象,如记录到近百例两跳、三跳及五跳回波等,这在低纬地区是非常少见的。     

福建漳浦前湖湾晚更新世的孢粉组合及其古环境意义

从孢粉角度对漳浦前湖湾古森林遗迹分布区所在的剖面QHP和钻孔QHZ～1的第四纪沉积物进行系统的分析．经过孢粉种属鉴定、孢粉浓度的统计,木本、草本、蕨类、藻类以及各科属孢粉百分比的不同,划分出7个孢粉组合带,剖面QHP自下而上为组合带Ⅲ、Ⅱ、Ⅰ,其中组合带Ⅲ推知属晚更新世的中期产物,组合带Ⅱ属晚更新世中期接近晚期的产物,组合带Ⅰ属晚更新世晚期的产物;钻孔QHZ-1自下而上为组合带Ⅳ、Ⅲ、Ⅱ、Ⅰ,其中组合带Ⅳ推知属晚更新世的早期的产物,组合带Ⅲ是一过渡层,组合带Ⅱ推知属晚更新世的中期的产物,组合带Ⅰ推知属晚更新世晚期的产物,而组合带Ⅰ以上的层位是全新世以来的产物．结合^14C测年和沉积地层岩性等资料,得出该地区晚更新世以来沉积环境及其古气候演化的4次变迁过程：晚更新世早期的寒冷干燥;晚更新世中期的温和热湿,期间发生2次明显的海侵事件;晚更新世晚期过渡到全新世的冷暖干湿的动荡期;全新世以来与现代气候较为接近的气候．     

Lateglacial and Holocene climate and soil erosion in southeastern France: A case study from Etang du Pourra,Provence

A synthesis of pollen evidence from Etang du Pourra, a small pond in Rhodanian Provence, France, complemented by new sedimentological, mineralogical and palynological data allow a reassessment of the Lateglacial-Holocene vegetation and climatic history of the area. The Etang du Pourra succession is shown to consist of two parts; the lower part dates from the Lateglacial and the upper reveals the Holocene pollen-stratigraphic succession typical of the region. In the Lateglacial, a humid and cooler phase is recorded before the Younger Dryas conditions progressively set in. In the Holocene succession, the consequences of human modifications on the environment are clearly visible in changes in mineralogy and pollen stratigraphy.     

Spatial distribution and susceptibility analyses of pre-earthquake and coseismic landslides related to the Ms 6.5 earthquake of 2014 in Ludian,Yunan, China

On 3 August 2014, an earthquake struck Ludian County, Yunnan Province, China, which has caused a large number of coseismic landslides. Visual interpretation permitted 284 and 1053 landslides before and after the event to be mapped, respectively. This work attempted to analyse these two kinds of landslides. Conditioning factors, such as slope angle, aspect, curvature, elevation, distance from drainages, intensity and lithology, and the index of Landslide Number Density (LND) were used to describe the spatial distribution of these landslides. Then, the pre-earthquake and coseismic landslide susceptibility maps were produced using the information value model. The areas under curve are 84.73 and 77.05%, for the pre-earthquake and coseismic landslides, respectively. The results show that the LND values as well as the information values of coseismic landslides are larger than those of the pre-earthquake case. This also indicates that this Ludian earthquake has a relatively larger ability to trigger landslides.