“WOMEN IN GEOGRAPHY” REVISITED: PRESENT STATUS,NEW OPTIONS

The representation of women on geography faculties did not increase appreciably between 1971 and 1977, but women in other academic disciplines have fared somewhat better. The latter have improved their status primarily as a result of actions taken by professional associations representing their fields. When a professional association ignores its female constituency or refuses to commit itself to improving their circumstances, federal agencies now offer alternative channels for obtaining redress.     

Transnational Urbanism in Port of Spain: Returning Middle-Class Urban Elites

Port of Spain, Trinidad offers an ideal context in which to analyze pre-retirement return migration to a Global South urban realm, expanding transnational urban research beyond the conventional focus on Global North metropolitan destinations. In this article, we draw on the transnational narratives of a selected sample of relatively youthful Trinidadians, who have spent many years abroad acquiring education and professional experience, but who have then decided to return in mid-career to the capital region of the island nation of their birth, or of their parent(s). Theoretically, we position these returning professionals as members of a "middling" transnational urban class whose return is at least partly motivated by a desire to "make a difference." Our results contribute to a growing literature that documents the role of transnational middle-class urban elites returning elsewhere in the Carribbean: "middling" transnational urbanism is reshaping key facets of urbanization in the Global South.     

High‐precision Schmidt‐hammer exposure‐age dating of flood berms,Vetlestølsdalen,alpine southern Norway: first application and some methodological issues

Schmidt‐hammer exposure‐age dating (SHD) was applied to three flood berms in upper Vetlestølsdalen, southern Norway, using a local, high‐precision calibration curve that takes account of the colluvial origin of fluvial boulders in the youngest berm, which was deposited during the August 1979 flood. Precision of SHD dating for this berm was estimated as ±210 years, whereas predicted ages of the two older berms were 3195 ± 435 and 3405 ± 340 years, and subsections of the oldest berm yielded age ranges of ～900 years. The results demonstrate the feasibility of high‐precision SHD in the context of boulder landforms deposited by high‐magnitude floods, the requirement of a large sample of R values in the face of high natural variability, the necessity of an appropriate calibration curve to ensure accuracy, the usefulness of floods of known age for testing and improving calibration curves, and the potential effects of boulders of colluvial origin on R values (especially the susceptibility of young surfaces to roughness variations). The dated berms indicate a return period of ～1000–1500 years for floods of the magnitude of the 1979 flood event in the upper catchment. Thus, the long‐term persistence of flood boulder berms in the landscape has potential for reconstructing Holocene flood history and palaeohydrology from the geomorphic legacy of the most extreme Holocene floods.     

Temporal and spatial variation of annual rainfall on the island of Crete,Greece

Annual rainfall records from the island of Crete in Greece were used with the aid of a geographical information system (GIS) to study the temporal and spatial rainfall characteristics. The GIS was used to produce a digital elevation model, delineate watersheds and estimate the areal rainfall from a network of raingauges by using different interpolation schemes. The rainfall–elevation correlation was significant, suggesting an orographic type of precipitation for the island. The rainfall records for the majority of the stations were found to fit the normal distribution. Deviation from normal for the rest of the records was attributed to the wettest year of 1977–1978. The year 1989–1990 was the driest, and most rainfall records showed a decrease in rainfall over 30 years with higher negative rainfall gradients at the higher elevations. Frequency analysis of the rainfall records was used to estimate areal rainfall for the island of Crete and its main watersheds for return periods of 2, 5 and 10 years. Copyright © 2003 John Wiley & Sons, Ltd.     

A quantitative appraisal of earthquake hazard parameters computed from Gumbel I method for different regions in and around Turkey

Useful information concerning the earthquake hazard parameters distributed in Turkey and the adjacent areas are estimated in the present work. Based on Gumbel’s I distribution parameters we are able to estimate the hazard values of the investigated area which are the mean return periods, the most probable maximum magnitude in the time period of t-years and the probability for an earthquake occurrence of magnitude ≥M during a time span of t-years. Figures concerning the spatial distribution of probabilities and the return periods are plotted and we considered them of particular interest for mapping the earthquake hazard in Turkey and the surrounding areas. These figures effectively produce a brief earthquake hazard atlas. The quantitative appraisal of the hazard parameters is useful for engineers, planners, etc., because it provides a tool for earthquake resistant design.     

基于动态重现期的极端高温气候评估方法研究

利用全国754站逐日最高气温观测序列,在论证极端温度概率分布与非平稳性关系的基础上,构建和比较了多种非平稳广义极值模型,定义了极端高温的动态重现期和重现水平,提出了一种极端高温事件的新型评估思想和方法,并将其应用于极端气候变化研究。通过该方法可以更好地解释极端事件的真实极端性,有效地增强极端事件之间的可比性,从而保留更多历史极端气候事件的信息。动态重现期的变换运用可对当前极端事件发生的真实状态和趋势提出更准确评估。该方法的提出可有效澄清学术领域和公共舆论对于多年一遇极端事件的理解上长期混淆重现期的绝对值和概率性这一分歧和谬误。     

利用北极地区定时风观测资料推算年最大风速的重现期

北极地区风观测资料较少,工程气象参数的分析主要依靠国际交换站资料。但是,国际交换站资料为定时资料,并且存在较多质量问题。因此,在利用国际交换站资料时,需先对其进行质量控制,并且要考虑定时资料的转换。由于缺少其他参考资料,国际交换站资料的质量控制主要根据北极地区天气气候特征,通过时间一致性、空间一致性和要素间一致性检验进行。由于重现期风速需用年最大风速(通常是10 min平均风速)计算,鉴于定时资料中可能没有出现年最大风速,而目前又没有较好的定时资料向逐时资料转换的方法,因此,主要通过从定时资料统计得到的年最大值计算的重现期风速进行订正得到重现期风速。订正的方法是根据我国部分风速较大地区的观测结果,引入风速方差,建立定时资料与年最大风速资料计算的重现期风速之间的关系,然后利用此关系订正北极喀拉海和拉普捷夫海沿岸定时资料计算的重现期风速,得到了50年和100年一遇的风速。     

Modelling catchment‐scale shallow landslide occurrence and sediment yield as a function of rainfall return period

A model‐based method is proposed for improving upon existing threshold relationships which define the rainfall conditions for triggering shallow landslides but do not allow the magnitude of landsliding (i.e. the number of landslides) to be determined. The SHETRAN catchment‐scale shallow landslide model is used to quantify the magnitude of landsliding as a function of rainfall return period, for focus sites of 180 and 45 km² in the Italian Southern Alps and the central Spanish Pyrenees. Rainfall events with intensities of different return period are generated for a range of durations (1‐day to 5‐day) and applied to the model to give the number of landslides triggered and the resulting sediment yield for each event. For a given event duration, simulated numbers of landslides become progressively less sensitive to return period as return period increases. Similarly, for an event of given return period, landslide magnitude becomes less sensitive to event duration as duration increases. The temporal distribution of rainfall within an event is shown to have a significant impact on the number of landslides and the timing of their occurrence. The contribution of shallow landsliding to catchment sediment yield is similarly quantified as a function of the rainfall characteristics. Rainfall intensity–duration curves are presented which define different levels of landsliding magnitude and which advance our predictive capability beyond, but are generally consistent with, published threshold curves. The magnitude curves are relevant to the development of guidelines for landslide hazard assessment and forecasting. Copyright © 2011 John Wiley & Sons, Ltd.     

Extreme significant wave height climate in the Gulf of Guinea

This article investigates spatio-temporal trends for different return periods of extreme significant wave height (SWH) in the Gulf of Guinea (GG), northeastern tropical Atlantic Ocean, based on a 37-year (1980–2016) wave hindcast. High-resolution reanalysis windfield datasets were used to force the spectral wave model WAVEWATCH III. The wave hindcast information was validated using data gathered from the US National Data Buoy Center. The model performance was adequate. In a spatial analysis, the trends were less than 0.3 m decade^?1 in all parts of the GG, and were increasingly positive westwards, extending to the far western part of the GG; trends below 0.01 m decade^?1 dominated in the eastern part and some areas of the northern part of the gulf. Temporal analysis showed that the trends were negative in all cases. Spatio-temporal trends in the return periods for the 99th-percentile wave height were generally weak. Also, trends in the yearly, seasonal and monthly means of extreme SWH all generally increased from east to west in the GG. Furthermore, temporal trend analysis showed that extreme SWH exhibited an increasing trend of 0.0041 m y^–1 throughout the 37-year period; by season, it exhibited a declining trend of ?0.0005 m y^–1 in winter, and an increasing trend of 0.0048 m y^?1 in summer. The observed increasing positive trend of extreme SWH westward in the GG, however, suggests an increasing storminess towards the western part of the gulf, with potential implications for coastal flooding and erosion, and consequences for coastal structures.     

山东人工引发雷电综合观测实验及回击电流特征

山东人工引发雷电实验 （SHATLE) 自2005年开始, 六年来共成功引发负极性雷电22次, 包含大电流回击过程88次, 实验获取了包括雷电放电通道底部电流、近距离电磁场、 高速摄像等在内的高质量同步观测资料。对36次实测回击电流的统计分析表明, 回击峰值电流的几何平均值为12.1 kA, 最大值为41.6 kA, 最小值为4.4 kA。回击电流波形的半峰值宽度范围在1～68 μs之间, 电流10%～90%峰值的上升时间几何平均值为1.9 μs, 中和电荷量为0.86 C, 作用积分（action integral, 或称比能量) 为2.6 ×103A2?s。人工触发闪电峰值电流约16.5 kA的回击在30 m处产生的电场变化可达56.0 kV/m, 60 m处的磁场几何平均值为52 μT。一些强烈的M分量可以具有与回击相当的电流峰值和中和电荷量。人工引雷初始阶段上行正先导的发展速度约为0.96×105 m/s。