Palaeomagnetism and magnetic fabric in the Freetown Complex, Sierra Leone

About six separately orientated cores were collected at each of 14 sites distributed throughout the arcuate, west-dipping, 6  km thick, Freetown layered igneous complex. Alternating field and thermal demagnetization both isolate a stable component of remanent magnetism which corresponds to a palaeomagnetic south pole from 13 sites (nine reverse, four normal polarity) at 82.9°S, +32.7°E ( α ₉₅ = 5.6°). This is indistinguishable from that reported in 1971 based on alternating field demagnetization of cores from 10 orientated hand samples.
  The difference between the Freetown pole (age: 193 ± 3  Ma) and other mid-Jurassic poles from West Africa could be due to its greater age. The difference between the whole West African Jurassic pole group and the Karoo pole from southern Africa, however, suggests moderate (∼10°) differential rotation of West Africa relative to the Kaapvaal craton.
  A prevalent magnetic foliation fabric coincides generally with the petrological layering, as might be expected, but a ubiquitous magnetic lineation is predominantly down-dip. This is compatible with a down-dip pyroxene lineation reported to be present in some field outcrops, and interpreted in terms of late-stage deformation during the slow crystallization and cooling of the large igneous body. However, a fold test shows that the igneous layering had already achieved its present attitude before the Complex cooled to ∼570 °C (the maximum blocking temperature of the characteristic remanence).     

两汉侯国时空特征及其影响因素分析

运用重心迁移模型、标准差椭圆及多元Logistic回归分析,探讨了两汉794座侯国的时空演变特征,揭示了各历史时期侯国分布格局演变和社会经济、地理环境等要素的关系。结果表明：① 各历史时期中侯国数量及其占总量比重、频率基本呈现“高—低—高—低”波浪形起伏的变化趋势。② 各历史时期侯国分布格局均呈现高度集聚状态,分布重心走向经历了由西→东、由东→西的反转,在距离与移动速率上呈现东汉>西汉的规律;西汉标准差椭圆X轴、Y轴、面积呈不断减小趋势,东汉标准差椭圆X轴、Y轴、面积呈不断增大趋势。③ 微观地理选择上影响侯国设置最主要的因素是区位因子,说明两汉侯国设置时更多考虑分布于距离道路、都城、区域中心城市较近的区域,表现出明显的“社会经济指向性”。此外,地形因子与区位因子在方向性上的转变表明各因子对侯国设置的影响并非一成不变,而是伴随社会发展状况及政治体制动态变化,其与政治因素的关联度仍是主导性的。     

基于大数据的上海市共享汽车出行模式研究

共享汽车是城市交通发展的新潮流,论文基于2018年上海市共享汽车运营大数据和城市POI数据,研究共享汽车用户出行的空间、时间和频次特征,并对用户开展出行模式的K均值聚类分析,以期挖掘典型出行规律,为共享汽车运营优化提供依据。研究表明：① 工作日与休息日共享汽车使用行为差异显著,工作日共享汽车出行较集中于中心城区的混合功能区,早晚通勤高峰使用量大;休息日共享汽车出行空间布局较分散,使用量更高、平均单次使用时长更短且仅存在傍晚一个使用高峰。② 上海市共享汽车出行行为可分为工作日通勤的中高频模式,工作日夜间活动的高频模式,工作日偶尔用车晚餐及返家、偶尔用车远距离通勤和夜间长距离返家的低频模式,休息日日间休闲的高频模式、休息日傍晚离家休闲的中长途低频模式、休息日傍晚在休闲地之间穿梭的远距离低频模式、休息日日间加班的低频模式等10种模式。③ 中高频用户主要使用共享汽车实现远距离通勤和周末中长距离休闲活动,空间区域主要集中在中心城区和副中心区域;低频用户使用共享汽车多为夜间、长距离、休息日加班等公共交通难以满足需求、出租车成本过高的情景,空间分布也比较分散。可通过对用户提供差别化用车方案、优化车辆空间调度等方式推进超大城市共享汽车市场发展。     

Magnetic anisotropy produced by magma flow: theoretical model and experimental data from Ferrar dolerite sills (Antarctica)

Volcanic rocks forming sills, dykes or lava flows may display a magnetic anisotropy derived from the viscous flow during their emplacement. We model a sill as a steady-state flow of a Bingham fluid, driven by a pressure gradient in a horizontal conduit. The magma velocity as a function of depth is calculated from the motion and constitutive equations. Vorticity and strain rate are determined for a reference system moving with the fluid. The angular velocity and the orientation of an ellipsoidal magnetic grain immersed in the fluid are calculated as functions of time or strain. Magnetic susceptibility is then calculated for a large number of grains with a uniform distribution of initial orientations. It is shown that the magnetic lineation oscillates in the vertical plane through the magma flow direction, and that the magnetic foliation plane changes periodically from horizontal to vertical. The results are compared with the magnetic fabric of Ferrar dolerite sills (Victoria Land, East Antarctica) derived from low-field susceptibility measurements.     

The influence of geological fabric and scale on drainage pattern analysis in a catchment of metamorphic terrain: Laceys Creek, southeast Queensland, Australia

The relationship between geological fabric and drainage patterns in the 81.8 km² Laceys Creek sub-catchment of the North Pine River catchment, southeast Queensland, Australia, is analysed using a new channel–ordination system. The Laceys Creek catchment is situated on the South D'Aguilar Block, which underwent metamorphism, faulting and uplift from the Late Carboniferous to Late Triassic. The catchment drains exposures of two main rock units, the Neranleigh–Fernvale Beds and the Bunya Phyllite. Both units are composed of metamorphosed deep-sea sediments that accumulated as an accretionary wedge during late Palaeozoic subduction of the palaeo-Pacific plate under the eastern margin of the Australian craton. The new channel ordination system used in this study allows improved classification of stream segments of equal prominence or rank in comparison to previous schemes. A 10 m contour digital elevation model (DEM) was produced within which drainage channels were digitised. Planar geological features, including bedding, faults, joints and cleavage, were mapped in the field and collated with data from previous geological mapping programs.Regional and local trends of geological fabric are reflected in the variable orientation of channels of different rank in the catchment. Cleavage and fractures are the dominant planar features of the Bunya Phyllite and these correlate most closely with the orientation of middle-order incised stream segments. In contrast, middle-order channels on the Neranleigh–Fernvale Beds most closely correlate with bedding, which dominates the fabric of this unit. Although anthropogenic factors exert local influence and climatic processes exert broad influence on the catchment, this study focuses on structural and lithological fabrics, which are the apparent dominant controls on middle-order channel orientations. Identification of congruent patterns between bedrock fabric and channel ranks is variable, depending on the scale and number of channels included in the analysis. Many low-rank channels correspond closely to the orientation of fine-scale bedding and foliation and these influences may not be detected by coarse-scale mapping. Understanding the extent of geological controls on the morphology of a catchment may assist geo-hazard identification, land-use planning and civil-engineering projects.     

Regular spacing of drainage outlets from linear mountain belts

Abstract Straight sections of many actively uplifting mountain belts have simple patterns of drainage, transverse to their main structural trend. Streams rising near or beyond the topographic ridgepole of these sections are spaced at seemingly regular intervals. To test whether this regularity exists, morphometric aspects of drainage networks were measured in 11 mountain belts. The spacing of drainage basins can be expressed using a spacing ratio, which in effect is the ratio of the length and the width of the catchments under consideration. Average spacing ratios for most linear mountain belts are within a narrow range of values between 1.91 and 2.23. A linear relationship exists between the spacing of catchment outlets and the distance between the main divide and the front of the mountain belt in which they have developed. The Nepalese Himalaya form an exception to this regular pattern. In this mountain belt drainage is blocked and diverted by structures that have developed in relation to the Main Boundary Thrust. Structural complications cause drainage patterns to become less regular, introducing important non trans verse components. The linear relationship between spacing of catchment outlets and half-width of the mountain belt may be expressed in an equation of the same general form as Hack's law of stream length and drainage basin area. It seems likely that the mechanism underlying Hack's law also explains the consistent regularity of drainage spacing in active mountain belts. However, no generally accepted explanation for Hack's law has been offered. The narrow range of spacing ratios found for drainage networks in active orogens may represent an optimal catchment geometry that embodies a ‘most probable state’ in the uplift-erosion system of a linear mountain belt. The linear relationship between the half-width of a mountain belt and spacing of catchment outlets has profound implications for the modelling of erosion of orogenic topography, and for the formation and filling of foreland basins.     

长江下游分汊河型内部结构和空间效应的研究

本文从动力机制着手,对长江下游分汊河型的空间结构、衔接段的功能、动力轴线波模式、以及上下游效应等方面进行了分析研究。认为:分汊河型空间上具有独特的相关性;主流波是水流能量的载体、是上下游效应产生和传递的动力;点型衔接段是上下游效应的转换器;线型衔接可使上下游效应的强度或性质发生变异。长江下游分汊河段整治重点是控制上下游效应传递关键的衔接段。     

Statistics of Antarctic surface meteorology based on hourly data in 1957–2007 at Syowa Station

Statistical characteristics of the surface meteorology are examined at Syowa Station (69°00′S, 39°35′E), which is located on an island near the coastal region of the Antarctic continent, based on operational observations made over the 50-year period from February 1957 through January 2007, which includes missing periods equivalent to 5 years. Statistics are obtained for the surface temperature, sea level pressure (SLP), and horizontal winds in terms of frequency distribution, frequency power spectra, seasonal variation, diurnal variation, inter-annual variation, and trends, using hourly observation data, and several interesting characteristics are elucidated. The mean temperature, SLP, and wind speed over the 50-year period are −10.5 °C, 986 hPa, and 6.6 m s⁻¹, respectively. The frequency distribution of temperature is far from the normal one, because less variation exists in summer at higher temperatures. The predominant wind direction is northeasterly (southwestward), and a weak secondary peak is observed in the southerly (northward) direction in the frequency distribution. The directional constancy of winds is 0.78. The frequency spectra over a wide range of 2 h to 20 years exhibit clearly isolated peaks corresponding to annual and diurnal frequencies and their higher harmonics. An important finding is that the spectral shape is proportional to a power of the frequency with a transition frequency for all physical parameters. The transition frequencies correspond to about 5 days for temperature and winds and 3 days for SLP, most likely due to cyclonic activity. A peak in the 11-year solar cycle is not identified in any spectrum. Another interesting feature is the dominance of semi-annual and semi-diurnal variations in SLP, while annual and diurnal variations are dominant for temperature and winds. Statistically significant trends are not detected for annual mean surface temperature and SLP over the 50-year period, while a positive trend is significant for wind speed. These trends are also examined as a function of the months. The inter-annual variation of SLP is well correlated with that of the Antarctic Oscillation index, indicating that Syowa Station can be regarded as a typical Antarctic station. Furthermore, statistical analysis was conducted for blizzards (severe snow storms), in terms of duration, and seasonal and inter-annual variation in frequency of occurrence. It is shown that the blizzards are dominant in the period from late March to late October. No systematic variation in blizzard frequency was observed during the 50-year period. Instead, the frequency depends largely on the year with a minimum of nine in 1988 and a maximum of 42 in 1982. As a typical example, a synoptic chart is used to show the cause of a strong snow storm on 27 May 1996, when the absolute maximum gust was observed.     

Decadal‐Scale Changes of the Ödenwinkelkees,Central Austria,Suggest Increasing Control of Topography and Evolution Towards Steady State

Small mountain glaciers have short mass balance response times to climate change and are consequently very important for short‐term contributions to sea level. However, a distinct research and knowledge gap exists between (1) wider regional studies that produce overview patterns and trends in glacier changes, and (2) in situ local scale studies that emphasise spatial heterogeneity and complexity in glacier responses to climate. This study of a small glacier in central Austria presents a spatiotemporally detailed analysis of changes in glacier geometry and changes in glaciological behaviour. It integrates geomorphological surveys, historical maps, aerial photographs, airborne LiDAR data, ground‐based differential global positioning surveys and Ground Penetrating Radar surveys to produce three‐dimensional glacier geometry at 13 time increments spanning from 1850 to 2013. Glacier length, area and volume parameters all generally showed reductions with time. The glacier equilibrium line altitude increased by 90 m between 1850 and 2008. Calculations of the mean bed shear stress rapidly approaching less than 100 kPA, of the volume–area ratio fast approaching 1.458, and comparison of the geometric reconstructions with a 1D theoretical model could together be interpreted to suggest evolution of the glacier geometry towards steady state. If the present linear trend in declining ice volume continues, then the Ödenwinkelkees will disappear by the year 2040, but we conceptualise that non‐linear effects of bed overdeepenings on ice dynamics, of supraglacial debris cover on the surface energy balance, and of local topographically driven controls, namely wind‐redistributed snow deposition, avalanching and solar shading, will become proportionally more important factors in the glacier net balance.     

流动人口居留时长意愿的空间分异及影响因素

基于2018年中国流动人口动态监测数据,根据流动人口愿意在流入地居留时间的长短将居留意愿划分为短期居留意愿、长期居留意愿、永久居留意愿3种类型,运用空间分析技术和分层模型对中国地级及以上城市流动人口不同类型居留意愿的空间分异及影响因素进行对比分析。研究发现：具有短期和长期居留意愿的流动人口比例合计超过60%,表明两栖和多栖生计仍是流动人口的主导生计策略;短期和永久居留意愿在空间上存在明显的“一高一低”分布差异,短期居留意愿在东部地区最高,东北地区最低,永久居留意愿则呈完全相反的分布格局;中西部地区流动人口长期居留意愿最高。模型结果显示,流入地特征和流动人口个体特征共同影响着不同类型的居留意愿：在东部和中部、经济发达以及职工平均工资高的地区,流动人口短期和长期居留意愿较高,永久居留意愿较低;男性、农业户口、受教育程度和家庭月均收入低、在外流动时间短、跨省流动的流动人口倾向于短期和长期居留;而女性、非农业户口、受教育程度和家庭月均收入高、在省内流动、在外流动时间长的流动人口更愿意在流入地永久定居。     

内蒙古十大孔兑主河道纵剖面发育动力机制（英文）

The longitudinal profiles of main streams of ten kongdui basins within Inner Mongolian Autonomous Region of China were characterized in this study by analyzing a series of quantitative indexes that are relevant to tectonic activity and river action, and by establishing a series of multiple regression models. The results reveal that all longitudinal profiles are concave in shape, with a range of concavity between 1.1 and 3.1, increasing from west to east. Data also show that the concavity of the profiles is significantly negatively correlated with profile length, altitude difference, average altitude, drainage area and sediment load of the basins. Analysis reveals that kongdui basins have suffered from moderate-to-weak tectonic activity over time, again characterized by a west-to-east weakening trend. Stream power also varies along the main channels of the ten kongdui basins; average values in each case fall between 0.8 W/m and 8.4 W/m, generally higher within the middle reaches. This decreasing trend in stream power within the lower reaches of kongdui basins might provide one key explanation for sedimentation there. Data also show that the average stream power in western and central basins tends to be higher than that in eastern examples, even though both the highest and the lowest values are seen within two middle ones. This analysis shows that the longitudinal profile concavity values are mainly controlled by tectonic activity and that the effect of river action is insignificant.     

Origin of a complex and spatially diverse dune-field pattern, Algodones, southeastern California

The Algodones Dune Field of southeastern California shows a complex and spatially diverse dune-field pattern that is superimposed upon a series of topographic lineations. Analysis of dune-field pattern parameters (dune crest length, crest orientation, dune spacing and defect density) derived from aerial images indicates that the dune-field pattern represents two constructional generations. Prominent compound crescentic dunes formed during the first constructional generation. A younger generation consists of a variety of simple crescentic dunes, linear dunes and zibars. Statistical differences in the pattern parameters between the dune groups within the second generation are resolved through consideration of the boundary conditions under which the dune pattern evolved, and provide explanations for: (1) diversity of dune types, (2) range in implied constructional times, (3) range in crest orientations, and (4) the anomalous nature of the population of linear dunes. The boundary conditions that have modified pattern development include orographic effects, grain size, vegetation, areal extent and antecedent conditions. Topographic lineations in the Algodones range from the Western Ramp, which defines the field margin, to subtle features masked by the pattern of dunes. Imaging of the Western Ramp using Ground Penetrating Radar shows high-angle cross-strata migrating perpendicular to the lineation trend. The most plausible hypothesis for the origin of the lineations is as dune ridges sequentially shed from adjacent Lake Cahuilla, which is the source of Algodones sands. The overall geomorphic complexity of the Algodones originates from the emplacement of the dune ridges during stages of Lake Cahuilla, the two generations of dune-field construction, and the controls exerted by boundary conditions.     

Orthogonal to oblique rifting: effect of rift basin orientation in the evolution of the North basin, Malawi Rift, East Africa

The East African Rift system has long been considered the best modern example of the initial stages of continental rifting. The Malawi Rift is characteristic of the western branch of the East African Rift system, composed of half-grabens of opposing asymmetry along its length. There are striking similarities between basins within the Malawi Rift, and others along the western branch. Each exhibits similar bathymetry, border-fault length, rift zone width and fault segment length. The North Basin of the Malawi Rift differs from others in the rift only in its orientation: trending NW–SE as opposed to N–S. Although there is general agreement as to the geometry of the Malawi Rift; debate as to the amount of strike–slip vs. dip–slip deformation and the influence of underlying Pan-African foliation remains. This study presents new data from a closely spaced shallow [2 s two-way travel time (TWT)] seismic reflection data set integrated with basin-scale deeper (6 s TWT) seismic reflection data that document the structural evolution of the border and intra-basin faults. These data reveal that the different trend of the North Basin, most likely to have been influenced by the underlying Pan-African foliation, has played an extremely important role in the structural style of basin evolution. The border-fault and intra-basin structures nucleated during extension that was initially orthogonal (ENE). During this time (>8.6 to ∼0.5–0.4 Ma) intra-basin faults synthetic to the west-dipping border-fault nucleated, whereas strain was localised on the segmented border-fault early on. A later rotation of extension orientation (to NW) led to these established faults orienting oblique to rifting. This generated an overall dextral strike–slip setting that led to the development of transfer faults adjacent to the border-fault, and the generation of flower structures and folds over the greater displacement intra-basin faults.     

A STATISTICAL RELATIONSHIP BETWEEN EL NIÑO-SOUTHERN OSCILLATION AND FLORIDA WILDFIRE OCCURRENCE

Wildfires have long been an important environmental concern in Florida. Recent wildfires along the urban-rural interface of large cities in Florida have pointed to the need for an increased understanding of the physical and biological mechanisms that govern wildfire occurrence. Increased awareness of the relationships between global climate changes occurring in the tropics and their teleconnections outside the tropics dictate a reevaluation of the role of phenomena such as El Niño-Southern Oscillation on the risk of wildfire. One simple way of illustrating the relationship between ENSO and wildfire occurrence is the use of an Analysis of Variance (ANOVA) on wildfire data that has been categorized according to ENSO status (El Niño, La Niña, and neutral years). This research shows that a statistically significant relationship exists between ENSO conditions and annual wildfire occurrence in Florida when ENSO conditions are treated as a potential precursor to wildfire conditions. In particular, a statistically significant relationship exists between both acreage burned and average fire size, when the data are separated into El Niño and La Niña categories according to the previous year's ENSO status. This supports the idea that the climate from previous years has a measurable effect upon fire statistics in the years following the climate measurements, and that it may be possible to create a regional fire prediction model that incorporates ENSO information. [Key words: wildfire, natural hazards, ANOVA, Florida, ENSO.]     

上海及周边主要城镇城市用地扩展空间特征及其比较

基于多时段TM遥感影像资料,运用缓冲分析法对上海市区及其周边主要城镇城市用地扩展的时空特征进行了分析和比较。研究结果表明:1)区域城市土地利用扩展过程主要受距中心市区(CBD)的距离的影响;2)城市用地扩展在距CBD10km范围内主要表现为上海市区扩展的空间异向性,距CBD10km范围之外城市扩展的异向性则源于不同时期、不同方向上周边城镇的异速扩展过程,并受河流、渠系等小尺度地貌格局差异的影响;3)上海主要郊区城镇扩展可分为标准型、被动扩展型、平缓扩展型和不规则扩展型。     

1947-2006年东半球陆地干旱化特征——基于SPEI数据的分析

 利用1947—2006年逐月全球陆地高分辨率(0.5°×0.5°)标准化降水蒸散指数SPEI(Standardized Precipitation Evapotranspiration Index)资料,分析了过去60 a东半球(40°S—80°N,20°W—180°E)陆地的干旱化趋势和变率、干旱面积变化、干旱事件的持续性和周期性以及可能的变化成因等。结果显示,东半球80%的陆地上目前处于干旱化进程中,其中北非及中蒙边界等地干旱化趋势最为显著。干旱变率最大地区出现在非洲北部、中国青藏高原、中国西北东部及中蒙边界一带、俄罗斯中北部以及东北部。北非、中蒙边界中段及中国青藏高原地区也是持续性异常干旱事件出现频次最高的地区。基于功率谱的周期分析则显示,东半球大部分地区第一显著周期为1.5～3 a左右,中亚部分地区存在准4 a周期振荡,而北非地区存在准12 a周期的年代际变化。SPEI距平场的经验正交函数(EOF)分析第一模态反映了东半球陆地大部分地区干旱化总体上具有一致性,对应的时间函数与全球陆地气温距平相关系数高达0.81,表明全球变暖与东半球干旱化趋势有着紧密联系;第二模态对应的时间函数与超前8个月的南方涛动指数(SOI)的相关系数为0.60,因而大尺度的干旱周期性振荡受ENSO活动影响显著。     

A procedure for estimating lateral variations from low-frequency eigenspectra data

Summary. Expressions are derived for the zeroth and first moments of an isolated normal mode multiplet in the presence of rotational anisotropy, lateral heterogeneity and attenuation. It is demonstrated that, to first order, the zeroth moment is independent of the heterogeneity and the first moment is a linear functional of the heterogeneity. The location of the multiplet, defined in terms of the ratio of the first moment to the zeroth moment, is used to set up a linear inverse problem for lateral variations. The approximations employed in deriving the differential kernels are uniformly valid for all angular orders. In addition, formula for the differential kernels asymptotically valid in the limit of large angular order are developed, and the correspondence between these formulae and the geometrical optics approximation is established. It is shown that, in the limit of weak heterogeneity and large angular order, the location of the multiplet is the average of the local perturbation to the eigenfrequency over the great circular path containing the source and receiver.     

西南地区山洪灾害时空分布特征及其影响因素

山洪灾害时空特征和影响因素是山洪评估与管理的重要内容。根据1960-2015年中国西南地区历史山洪资料,采用线性回归、标准差椭圆、空间自相关和Logistic回归模型,深入分析了西南地区山洪灾害时空分布特征及其影响因素。结果表明：① 西南地区年度山洪灾害频次呈指数增长,年际变化呈现出稳定（1960-1980年）、缓慢波动增加（1981-1998年）、快速增加（1999-2015年）3个阶段;月际特征明显,山洪主要发生在每年6-8月,尤以7月频次最高;② 西南地区山洪灾害空间差异性显著,灾害高密度区主要集中于滇中高原地区、四川盆地和周边山地单元,山洪灾害数量分布呈显著的空间正相关,空间集聚特征明显（Moran's I指数为0.127、Z = 5.784、P = 0.007）;③ 西南地区历史灾害点的重心在年内存在明显的向正西方向移动的趋势,年内标准差椭圆转角均逐渐弱化,长轴逐渐变长,短轴逐渐变短;④ 降雨因子对山洪的影响度最高,人类活动因子次之,地表环境因子最低,降雨因子中1 h降雨量对山洪的影响最强,优势比值达到3.654。研究结果可为西南地区山洪灾害形成机理、监测预警研究,实施防灾减灾措施等提供科技支撑。     

陕北黄土高原沟道小流域形态特征分析

本文就黄土高原不同地貌类型区的小流域进行了形态量计分析。并以河网密度为地表切割程度指标,建立了河网密度与流域形态要素的复相关方程式。     

LINEAR MODELLING OF GLACIER LENGTH FLUCTUATIONS

In this contribution a linear first‐order differential equation is used to model glacier length fluctuations. This equation has two parameters describing the physical characteristics of a glacier: the climate sensitivity, expressing how the equilibrium glacier length depends on the climatic state, and the response time, indicating how fast a glacier approaches a new equilibrium state after a stepwise change in the climatic forcing. A prerequisite for the application of a linear model to a particular glacier is that length fluctuations over the period of interest are significantly smaller than the average length. The linear model is used to define and illustrate some concepts relevant to the study of glacier fluctuations. It is shown that glaciers are never in equilibrium with climate, and that a constant time lag between forcing and response cannot be expected. Next the linear glacier model is applied to real glaciers, showing how information on response times and a reconstruction of the climatic forcing can be extracted from length records. In the first application, two adjacent glaciers in the Oetztal Alps (Austria) are considered: Hintereisferner and Kesselwandferner. By optimizing the response times with a control method, reconstructed equilibrium‐line histories for these glaciers are almost identical. The corresponding response times are 31 years for Hintereisferner, and only 2.1 years for Kesselwandferner. In the second application, four glacier length records from the Oberengadin (Switzerland) are used to reconstruct equilibrium‐line histories. These appear to be mutually consistent, and the mean rise of the equilibrium line over the period 1894–2007 appears to be 1.4 m yr^?1. An equilibrium‐line history derived from data of a nearby climate station yields about the same trend over this period, but shows significant differences on the decadal time scale.