Indigenous perception of changes in climate variability and its relationship with agriculture in a Zoque community of Chiapas, Mexico

This study analyses the perceptions of Zoque indigenous men and women of changes in climate variability, indicated by rainfall and temperature records from the region. Peasant farmers perceive decreases in rainfall and increases in temperature as these factors are related to modifications in the corn planting season and the introduction of crops which were usually only found in hot regions. The climate changes in the zone are attributed to vegetation loss and the eruption of the Chichón volcano in 1982. The Zoque perception is structured according to cultural and individual experience, tied to agriculture and the annual weather calendar. The volcanic eruption offers a significant chronological reference point in order to explain different environmental transformations, such as climate, within Zoque territory. Perception is the mental picture of local climate variability changes and the responses in seasonal agriculture modifications, utilizing individual and cultural experiences which are vulnerable to economic and environmental change.     

Trace element distribution in annual stalagmite laminae mapped by micrometer-resolution X-ray fluorescence: Implications for incorporation of environmentally significant species

Stalagmite ER78, from Grotta di Ernesto cave in NE Italy displays clear annual lamination consistent with its shallow depth below a forest ecosystem subject to autumnal peaking of water infiltration. Synchrotron radiation scanning micro-X-ray fluorescence analyses of heavy elements at European Synchrotron Radiation Facility beamline ID22, and light elements at ID21, with 1-3 μm resolution has been combined with data from ion microprobe analyses to reveal chemical variability across the visible layers of these annual laminae. A series of elements display a symmetrical peak, centered around the thin, dark layer at the top of each lamina. The peak concentration is ordered Y > Zn, Cu and Pb > P and Br. This hierarchy is thought to reflect the selectivity of transport of these elements, possibly by organic colloids flushed from the soil zone during autumn infiltration. Ion microprobe analysis indicates Na and F also increase, as does H, the latter reflecting increased microporosity. Sr displays a trough around the dark and thin autumn layer implying that its incorporation may be limited by competition with other elements. Mg and S show a different pattern of annual variation and Fe displays none. The trace metals, Br and Y display peak abundance in the early 20th century, which appears to reflect a period of tree-felling rather than a climatic anomaly. The results demonstrate the power of the high spatial resolution and low detection limits of the synchrotron technique, and its ability to produce quantitative maps that allow distinction of layered structure from that of isolated particles, or irregular inhomogeneities.     

海冰在海气交换中的作用及其与海雾的关系

本文用了 1 999年夏季中国首次北极科学考察队对海冰、大气和海洋进行的同步和准同步的综合立体观测所获取的资料 ,研究海冰在海 气相互作用中扮演的角色。发现海冰的种类、分布、冰厚等变化对海气热交换都有重要影响。在浮冰区海洋以潜热的形式向大气输送热量 ,潜热通量与浮冰密集度的大小密切有关 ,浮冰越少潜热通量越大 ,潜热通量约为2 1～ 2 3 .6W /m2 ,潜热通量大于感热通量 ;在冰盖和大浮冰块上 ,大气以感热的形式向冰雪面上输送热量。新生的浮冰区或冰间湖是海气热交换最激烈的地方 ,是气候最敏感的区域 ,是北冰洋蒸汽雾生成的重要条件。用层结大气整体动力学输送法 ,计算了一次大范围的蒸汽雾过程的海气热交换 ,海洋向大气输送的热量总功率约为 1 4 8亿千瓦 ,相当于中国发电能力的 69倍 ,相当于大西洋向北冰洋输送热量平均功率的 1 / 2 0。北冰洋的夏季能够形成各种类型的海雾 :辐射雾、蒸汽雾和平流雾 ,其重要原因就是因为海冰的存在 ,使下垫面的性质复杂化 ,海气交换复杂化。     

杭州湾潮波三维数值模拟

采用“σ坐标下的三维数值模式”来模拟杭州湾三维潮波运动,水平方向上以较小尺度的差分网格覆盖计算区,垂直方向上给予均匀的分层,对占本湾水位谱总能量80％的半日潮波M_2和半日潮波m_1((K_1+O_1)/2)两类进行了数值模拟。水平流动和潮位的计算结果与相应的实测值拟合良好。计算表明,水平潮流具有明显的往复流性质,主要呈东-西方向;流速自湾口向湾顶增加,M_2分潮流最大可达270cm/s左右,m_1分潮流最大可达24cm/s左右。在太阴时1和13时,于湾的中部偏南存在一个弱的逆时针向的大涡旋;在7和19时于上述位置存在一个弱的顺时针向的大涡旋。垂直流速振幅一般为10~(-2)—2×10~(-2)cm/s,最大可达2.5×10~(-2)cm/s,位于乍浦附近的底层水域中。     

Vertical deformation partitioning across a collapsing large and hot orogen

Featuring 3 000-km-long large and hot orogen, the Mantiqueira Province provides a rare opportunity to study the process of gravitational collapse at mid to deep crustal levels. Distinct but contemporary (~500 Ma) post-collisional intrusions show structures and anisotropy of magnetic susceptibility (AMS) fabrics related to their emplacements, recording different flow patterns. In southern deep-seated intrusions, ellipsoidal-shaped roots with gabbroic-to-hybrid cores surrounded by granitic rocks show concentric patterns of AMS fabrics that cut across the NE-trending regional foliation. In contrast, northern intrusions, exposed as the upper sections of batholith-size bodies of coarse-grained granite emplaced at the shallow to mid-crust, show general NS-trending magnetic fabrics roughly parallel to strike of the orogen and the regional foliation of host rocks. These contrasting magnetic patterns from shallow to deeper crust suggest vertical magma migration from the overthickened orogenic core to be emplaced across its thinner stretched flanks during the gravitational collapse of the orogenic edifice.