Placing modern droughts in historical context in the Ohio Valley using tree-rings

The temporal variability and severity of pre-instrument record summer droughts in the Ohio River Valley (Illinois, Indiana, and Ohio, USA) are not well understood. This study attempts to help fill this gap in Ohio Valley drought knowledge by using tree-ring chronologies from Illinois, Indiana, and Ohio to reconstruct summer (June through August) PDSI. We found that recent meteorological droughts of 1988 and 2012 are not unusual in the context of those reconstructed for the interval of 1680–2012. Droughts prior to 1895 (when the instrument-based record began) were more severe and lasted, on average, 1.5 times longer than those after 1895. The North American Drought Atlas represents droughts well for this region, but we found that drought severity was not homogeneous across the three sites. This indicates drought in the Ohio River Valley should be examined at a sub-regional level and suggests a need for a finer spatial representation of tree-ring chronologies in the Ohio Valley. Given the context of historical drought variability, the reconstructions suggest this region should be prepared for droughts that may be more severe and longer lasting than those recently observed.     

南天山盲起苏花岗岩体的成因及构造意义：来自年代学、地球化学及Nd- Hf同位素证据

南天山造山带位于中亚造山带与塔里木克拉通的接壤地带,是了解克拉通及造山带构造演化的重要地区。但就南天山洋最终闭合和陆陆碰撞的时代目前还存在不同观点。盲起苏花岗岩体位于南天山造山带东段,是该区大型的复式花岗岩体,主要由东部黑云母花岗闪长岩、西部黑云母花岗岩和中部二云母花岗岩组成。LA ICP MS锆石U Pb定年结果显示,东部、西部和中部花岗岩的形成年龄分别为297±4 Ma、294±3 Ma和292±2 Ma。地球化学特征上,东部和西部花岗岩的SiO 2 含量为65. 34%~73. 12%,A/CNK为1. 00~1. 11（平均1. 05）,Na 2 O+K 2 O的含量为7. 26%~8. 52%,属高钾钙碱性弱过铝质岩石;中部花岗岩的SiO 2 含量为71. 97%~72. 84%,A/CNK为1. 09~1. 14（平均1. 12）,Na 2 O+K 2 O的含量为8. 36%~8. 80%,属钙碱性强过铝质岩石。稀土元素上,三者均富集轻稀土元素\[(La/Yb)N=9. 58~44. 94\],亏损重稀土元素（HREE,LREE/HREE=8. 00~22. 97）,并呈现不同程度的Eu负异常（东部 δ Eu=0. 67~0. 81;西部 δ Eu=0. 48~0. 78;中部 δ Eu=0. 44~0. 48）。微量元素上,三者均富集大离子亲石元素（K、Rb、Ba）,亏损高场强元素（Nb、Ta、Ti）。同位素特征上,锆石 ε Hf ( t )值分别为-11. 31~-1. 64（东部）、-5. 41~-0. 50（西部）和-14. 43~-2. 51（中部）,二阶段Hf模式年龄（ t DM2 ）均在1. 30~2. 20 Ga之间;东部岩体的 ε Nd ( t )的值为-6. 92~-10. 10,二阶段模式年龄 t DM2 (Nd)在1. 62~1. 88 Ga之间。综合区域地质和前人研究资料,表明盲起苏复式花岗岩体可能是后碰撞早期阶段由加厚的变质火成岩地壳发生部分熔融,经不同程度结晶分异所形成的,并暗示了南天山洋的闭合及陆陆碰撞的时间应发生于二叠纪之前。     

Creative destruction in urban planning procedures: the language of ‘renewal’ and ‘exploitation’21

This paper examines the language and phraseology of ‘creative destruction‘ (‘renewal‘ and ‘exploitation’) expressed in urban planning procedures concerning one particular house in West Jerusalem: 28 Radak Street. Through a forensic examination of the planning-related communications about this address, the work analyzes the various stages of the ’destruction’ and ’renewal’ of the property. It demonstrates how each of the various actors involved (Municipality, planning committees, legal courts, private entrepreneur and local residents) uses different language and phraseology to present their argument, while the voice of the original Palestinian owners of the house is entirely absent from the planning battle.     

Frontal compression along the Apennines thrust system: The Emilia 2012 example from seismicity to crustal structure

The evolution of the Apennines thrust-and-fold belt is related to heterogeneous process of subduction and continental delamination that generates extension within the mountain range and compression on the outer front of the Adria lithosphere. While normal faulting earthquakes diffusely occur along the mountain chain, the sparse and poor seismicity in the compressional front does not permit to resolve the ambiguity that still exists about which structure accommodates the few mm/yr of convergence observed by geodetic data. In this study, we illustrate the 2012 Emilia seismic sequence that is the most significant series of moderate-to-large earthquakes developed during the past decades on the compressional front of the Apennines. Accurately located aftershocks, along with P-wave and Vp/Vs tomographic models, clearly reveal the geometry of the thrust system, buried beneath the Quaternary sediments of the Po Valley. The seismic sequence ruptured two distinct adjacent thrust faults, whose different dip, steep or flat, accounts for the development of the arc-like shape of the compressional front. The first shock of May 20 (Mw 6.0) developed on the middle Ferrara thrust that has a southward dip of about 30°. The second shock of May 29 (Mw 5.8) ruptured the Mirandola thrust that we define as a steep dipping (50–60°) pre-existing (Permo-Triassic) basement normal fault inverted during compression. The overall geometry of the fault system is controlled by heterogeneity of the basement inherited from the older extension. We also observe that the rupture directivity during the two main-shocks and the aftershocks concentration correlate with low Poisson ratio volumes, probably indicating that portions of the fault have experienced intense micro-damage.     

内蒙古干旱半干旱带2012年“7·20”极端暴雨事件的特征及成因

2012年7月下旬, 处于内陆干旱-半干旱地带的内蒙古中-西部地区出现了有气象记录以来的极端降水事件, 使该区气象与气候预测面临新问题. 7月20日河套地区出现大范围暴雨天气, 其中两个台站日降水量超历史极值, 一个台站超历史阈值, 属极端天气事件. 利用常规及精细化监测资料和NCEP再分析资料对此次极端降水天气事件进行分析. 结果表明: 从天气背景看, 贝加尔湖低槽内冷空气侵入副高西侧的暖空气中, 在对流层低层激发出低涡系统, 低涡前侧的南风急流使南来水汽到达41°N以北, 并在河套地区聚集. 对流层低层水汽通量维持在8~10g·cm^-1·hPa^-1·s^-1, 大气比湿达12~17 g·kg^-1, 为极端降水事件提供了丰沛的水汽. 该事件是通过MCC强烈发展形成的, 河套西北部不断有中尺度对流系统MCS发展东移, 河套南部新生的β中尺度系统发展并入MCS中, MCS系统发展为中尺度对流复合体MCC, MCC中心的TBB值达-40~-83 ℃. 近地面雷达监测显示, 河套东北部、中部存在强雷达回波群, 回波群内对流单体中心的反射率因子均达到50~55 dbz, 构成超级对流单体. 地面上, 不断新生的中尺度辐合线长时间存在于河套东北部并促发对流性暴雨. 暴雨前期对流层低层增温作用显著, 中高层"干侵入"使大气不稳定能量进一步增加. 冷锋前暖空气强烈的上升运动促发了大气不稳定能量释放. 该事件很可能与当前全球变暖密切相关, 随着全球变暖, 北极冰量减少, 夏季风增强, 雨带北移, 使得中纬度内陆干旱-半干旱带发生前所未有的极端降水事件过程.     

2012年4月11日苏门答腊8.6级地震前后川滇地区波速变化研究

利用2012年1~6月川滇地区(21°～34°N, 97°～108°E)99个测震数字地震台的连续波形资料, 采用背景噪声层析成像方法反演了2012年4月11日苏门答腊8.6级地震前后川滇地区的波速变化, 同时研究了该地震前后川滇地区地震活动的变化特征。 结果表明, 川滇地区波速结构呈现龙门山断裂带南段至元谋—绿汁江断裂带和安宁河断裂带波速降低而两侧波速升高的特点。 同时, 波速变化与地震活动性变化具有明显的相关性: 在宁蒗—木里和乐山—雅安一带波速增高显著, 地震活动速率也增加; 在龙门山断裂带南段至安宁河断裂带上则表现为明显的波速降低, 而安宁河断裂带也是地震活动速率降低区域。 这表明本研究得到的波速变化的结果有一定的可信度, 也为背景噪声方法应用到地震预测提供了一种可能的途径。     

松潘- 甘孜造山带南部江浪穹隆中侏罗世花岗岩及构造意义

新火山和乌拉溪花岗岩体侵位于松潘-甘孜造山带南部的江浪穹隆中,是理解松潘-甘孜造山带的构造演化的重要窗口.锆石U-Pb定年结果表明新火山和乌拉溪花岗岩体的结晶年龄为162±1～170±0.5 Ma.岩体主要由石英、斜长石、钾长石和少量黑云母组成,具有低A/CNK(1.10～0.99)、TFeO/MgO(8.55～2.83)和K2O/Na2O(1.34～0.51),较低的Zr+Nb+Ce+Y浓度(平均258×10-6),Al2O3、P2O5与SiO2呈负相关,相当于I型花岗岩的特征.一些主微量元素具有明显的关联性,说明在岩浆演化过程中发生了分离结晶(例如:角闪石和钛铁矿).富集轻稀土和大离子亲石元素,亏损高场强元素,并具有较低的Mg#值(38.7～17.3)和Y/Nb值(0.45～0.16)以及多数为负的εHf(t)值(-24.8～-7.6),证明岩浆可能起源于古老地壳的部分熔融并受到幔源或者新生地壳熔融混染.松潘-甘孜地块的中侏罗世岩浆活动是在造山运动向陆内伸展这一构造体制转化背景下,由于地壳伸展造成了古老中基性地壳的部分熔融.     

From burden-sharing to opportunity-sharing: unlocking the climate negotiations

In conventional thinking on climate negotiations, traditional fossil fuel-based economic growth is coupled with carbon emissions, thus mitigation has been regarded as a burden on economic growth. The scarcity within the global emission budget and the interpretation of climate change as ‘global public goods’ have led climate change negotiations into a burden-sharing deadlock. However, some recent economics studies suggest that mitigation could actually promote local economic growth opportunities; consequently increasing the incentives for unilateral mitigation actions. This article highlights the implications for the strategies of unlocking the climate negotiations deadlock. Following an explanation of how climate change negotiations have led to a burden-sharing game and have become a deadlock, some new ways of thinking (based on the emerging literature) are used to suggest how mitigation could promote local economic growth.Policy relevanceOne policy implication is the need to change the current mindset in global climate change negotiations. The current framing of burden-sharing can be abandoned in favour of opportunity-sharing. This more positive approach will stimulate progress on climate action. Therefore, green growth should be situated at the heart of post-2020 climate change regime. A new two-track architecture is proposed for achieving the transformation as a combined top-down and bottom-up approach. A lower legally binding target based on equity principles of common but differentiated responsibilities (CBDR) could form a more politically realistic and inclusive basis for participation. To complement this, a green growth club would promote a higher voluntary global ambition and accelerate mitigation.     

北天山地区2011 年以来两次6 级地震前的地震学中短期异常特征

通过分析北天山地区历史强震、构造活动背景、区域应变能积累特征以及2011 年11月1 日尼勒克、巩留交界6. 0 级和2012 年6 月30 日新源、和静交界6. 6 级地震前区域地震活动异常特征等,探讨了这两次6 级地震前的地震学中短期异常特征。结果表明,2011 年6 月以来北天山地区中强以上地震处于加速活动状态,进入应变能释放阶段;尼勒克、巩留交界6. 0 级和新源、和静交界6. 6 级地震震前先呈6 级地震平静而后被打破、中强地震成组活动和空间迁移、条带和空区等较明显的中期异常;震前还出现了较为相似的4 级以上地震围空和5 级逼近地震,且逼近地震与主震发生时间间隔均为14 天,显示了较清晰的异常图像和较明显的中短期震兆特征。