Hyperspectral boundary detection based on the Busyness Multiple Correlation Edge Detector and Alternating Vector Field Convolution snakes

Active contours, or snakes, are broadly used to detect linear features such as edges. However, they are often restricted in the delineation of regions of interest within the hyperspectral domain. In this paper, a new approach is presented, referred to as “Busyness Multiple Correlation Edge Detector”, that enables hyperspectral boundary detection using active contours such as “Alternating Vector Field Convolution” snakes. The combination of “Alternating Vector Field Convolution” snakes with the “Busyness Multiple Correlation Edge Detector” opens a broad set of applications by concurrent high convergence quality and speed. Furthermore, specific snake initialisations are tested. A series of examples are used to both demonstrate the approach and underline the benefits of the new methods.     

Observations of coastal cliff base waves,sand levels,and cliff top shaking

Concurrent observations of waves at the base of a southern California coastal cliff and seismic cliff motion were used to explore wave–cliff interaction and test proxies for wave forcing on coastal cliffs. Time series of waves and sand levels at the cliff base were extracted from pressure sensor observations programmatically and used to compute various wave impact metrics (e.g. significant cliff base wave height). Wave–cliff interaction was controlled by tide, incident waves, and beach sand levels, and varied from low tides with no wave–cliff impacts, to high tides with continuous wave–cliff interaction. Observed cliff base wave heights differed from standard Normal and Rayleigh distributions. Cliff base wave spectra levels were elevated at sea swell and infragravity frequencies. Coastal cliff top response to wave impacts was characterized using microseismic shaking in a frequency band (20–45 Hz) sensitive to wave breaking and cliff impacts. Response in the 20–45 Hz band was well correlated with wave–cliff impact metrics including cliff base significant wave height and hourly maximum water depth at the cliff base (r² = 0.75). With site‐specific calibration relating wave impacts and shaking, and acceptable anthropogenic (traffic) noise levels, cliff top seismic observations are a viable proxy for cliff base wave conditions. The methods presented here are applicable to other coastal settings and can provide coastal managers with real time coastal conditions. Copyright © 2016 John Wiley & Sons, Ltd.     

Proterozoic glaciations in eastern Brazil: A review

Earlier publications on proterozoic glaciations in eastern Brazil are reviewed and revised, based on recent investigations in the Serra do EspinhaÇo. The former “Lavras Series”, often cited as an example of an infracambrian glaciation, comprises units of different age. The older units (Sopa conglomerate in Minas Gerais, “Lavras Series” sensu strictu in Bahia) belong to the middle to early proterozoic Minas Supergroup. They show no indications of glaciation. The widespread and in part glacial MacaÚbas Group belongs to the basal SÃo Francisco Supergroup. According to stromatolites the latter has a minimum age of 950 m. y. The MacaÚbas Group might have an age of more than 1.650 m. y. An infracambrian glaciation is unknown from eastern Brazil.     

Urban Bias in Temperature Time Series – a Case Study for the City of Vienna, Austria

Compared with other large cities Vienna shows different urban development characteristics. The city has had a zero population growth during 1951–1995, a period of rapid growth elsewhere. In spite of its stagnating population of about 1,6 million Vienna has had development in other areas: a doubling of living floor space, a two and a half-fold increase in total energy consumption, a 60% rise of traffic area. In contrast, forests have been reduced by 20% and grasslands within the city borders by 30%. Of the 34 temperature recording stations in the study area of 1450 km², nine series passed the quality tests after careful homogenization. Three of these were in the rural environment and were used as reference series for the urban temperature excess at the other six stations in the urbanized area. The urban excess temperatures vary from site to site: from 0.2 K in suburban areas up to 1.6 K in densely built-up areas. The Vienna case study illustrates two features of more than local interest which should be considered in urban climatology as well as in time series studies where the urban temperature excess is regarded as a bias. Firstly, in a city with constant population the urban heat excess shows significant to strongly significant trends of up to 0.6 K in 45 years due to changes in urban morphology and energy consumption. Secondly, the urban heat island and its trend cannot be regarded simply for the city as a whole. There are different absolute levels, different annual variations and different increases of the urban temperature excess in different parts of a city. The urban effect is more strongly influenced by the local surroundings of the site than by the city as a whole. So, if possible, urban heat islands should not be described by a two station approach only (the typical airport-downtown comparison), nor should it rely on regression between population number and heat island.     

125 years of high-mountain research at Sonnblick Observatory (Austrian Alps)—from “the house above the clouds” to a unique research platform

Mountain observatories around the world are unique sites for monitoring and investigating variations, trends, forcings and feedbacks in the climate system, which are of utmost interest for understanding global climate change. From the small number of these research platforms, Sonnblick Observatory (Austrian Alps) stands out because of its long time series dating back to 1886 at an elevation of 3,100?m a.s.l. The paper describes the contribution of mountain observatories to climatology by the example of Sonnblick Observatory. The observatory's scientific evolution is summarised, starting from the original idea of upper air atmospheric measurements to its recent role as an atmospheric background station and interdisciplinary research site.     

Monthly, seasonal and annual temperature reconstructions for Central Europe derived from documentary evidence and instrumental records since AD 1500

Monthly temperature series for Central Europe back to AD 1500 are developed from documentary index series from Germany, Switzerland and the Czech Republic (1500–1854) and 11 instrumental temperature records (1760–2007). Documentary evidence from the Low Countries, the Carpathian Basin and Poland are used for cross-checking for earlier centuries. The instrumental station records are corrected for inhomogeneities, including insufficient radiation protection of early thermometers and the urban heat island effect. For overlapping period (1760–1854), the documentary data series correlate with instrumental temperatures, most strongly in winter (86% explained variance in January) and least in autumn (56% in September). For annual average temperatures, 81% of the variance is explained. Verification statistics indicate high reconstruction skill for most months and seasons. The last 20 years (since 1988) stand out as very likely the warmest 20-year period, accounting for the calibration uncertainty and decreases in proxy data quality before the calibration period. The new reconstruction displays a previously unobserved long-term decrease in DJF, MAM and JJA temperature variability over last five centuries. Compiled monthly, seasonal and annual series can be used to improve the robustness of gridded large-scale European temperature reconstructions and possible impact studies. Further improvement of the reconstruction would be achieved if documentary data from other European countries are further developed.     

The early instrumental warm-bias: a solution for long central European temperature series 1760–2007

Instrumental temperature recording in the Greater Alpine Region (GAR) began in the year 1760. Prior to the 1850–1870 period, after which screens of different types protected the instruments, thermometers were insufficiently sheltered from direct sunlight so were normally placed on north-facing walls or windows. It is likely that temperatures recorded in the summer half of the year were biased warm and those in the winter half biased cold, with the summer effect dominating. Because the changeover to screens often occurred at similar times, often coincident with the formation of National Meteorological Services (NMSs) in the GAR, it has been difficult to determine the scale of the problem, as all neighbour sites were likely to be similarly affected. This paper uses simultaneous measurements taken for eight recent years at the old and modern site at Kremsmünster, Austria to assess the issue. The temperature differences between the two locations (screened and unscreened) have caused a change in the diurnal cycle, which depends on the time of year. Starting from this specific empirical evidence from the only still existing and active early instrumental measuring site in the region, we developed three correction models for orientations NW through N to NE. Using the orientation angle of the buildings derived from metadata in the station histories of the other early instrumental sites in the region (sites across the GAR in the range from NE to NW) different adjustments to the diurnal cycle are developed for each location. The effect on the 32 sites across the GAR varies due to different formulae being used by NMSs to calculate monthly means from the two or more observations made at each site each day. These formulae also vary with time, so considerable amounts of additional metadata have had to be collected to apply the adjustments across the whole network. Overall, the results indicate that summer (April to September) average temperatures are cooled by about 0.4°C before 1850, with winters (October to March) staying much the same. The effects on monthly temperature averages are largest in June (a cooling from 0.21° to 0.93°C, depending on location) to a slight warming (up to 0.3°C) at some sites in February. In addition to revising the temperature evolution during the past centuries, the results have important implications for the calibration of proxy climatic data in the region (such as tree ring indices and documentary data such as grape harvest dates). A difference series across the 32 sites in the GAR indicates that summers since 1760 have warmed by about 1°C less than winters.     

Adapting to climate change in The Netherlands: an inventory of climate adaptation options and ranking of alternatives

In many countries around the world impacts of climate change are assessed and adaptation options identified. We describe an approach for a qualitative and quantitative assessment of adaptation options to respond to climate change in the Netherlands. The study introduces an inventory and ranking of adaptation options based on stakeholder analysis and expert judgement, and presents some estimates of incremental costs and benefits. The qualitative assessment focuses on ranking and prioritisation of adaptation options. Options are selected and identified and discussed by stakeholders on the basis of a sectoral approach, and assessed with respect to their importance, urgency and other characteristics by experts. The preliminary quantitative assessment identifies incremental costs and benefits of adaptation options. Priority ranking based on a weighted sum of criteria reveals that in the Netherlands integrated nature and water management and risk based policies rank high, followed by policies aiming at ‘climate proof’ housing and infrastructure.     

Superposition of burial and hydrothermal events: post‐Variscan thermal evolution of the Erzgebirge,Germany

The post‐Variscan thermal history of the Erzgebirge (Germany) is the result of periods of sedimentary burial, exhumation and superimposed hydrothermal activity. The timing and degree of thermal overprint have been analysed by zircon and apatite (U–Th)/He and apatite fission track thermochronology. The present‐day surface of the Erzgebirge was exhumed to a near‐surface position after the Variscan orogeny. Thermal modelling reveals Permo‐Mesozoic burial to temperatures of up to 80–100 °C, although the sedimentary cover thins out towards the north resulting in maximum burial temperatures of less than 40 °C. This thermal pattern was locally modified by Cretaceous hydrothermal activity that reset the zircon (U–Th)/He thermochronometer along ore veins. The thermal models show no significant regional exhumation during Cenozoic times, indicating that the peneplain‐like morphology of the basement is a Late Cretaceous feature.     

Thermal microstructural changes of grain-supported limestones

The microstructure of grainstone, grain-supported limestone, samples representing different geographic and stratigraphic intervals in Egypt were examined before and after calcination at 950°C for 0.25, 0.5, 1 and 2?h. The examination utilized are X-ray diffraction (XRD), X-ray fluorescence (XRF), transmitted light microscopy (TLM), scanning electron microscopy (SEM) and X-ray micro tomography (??-CT). Both the free lime content and reactivity of the produced quicklime were measured. The quicklime produced at 950°C for 0.25 and 0.5?h is un-reactive (R_DIN < 10) due to its low content of free lime. However, quicklime produced at 1 and 2?h conditions is highly reactive (R_DIN > 30) with variable reactivity due to the differences in the lime microfabric. The grainstones enriched in nummulites resulted in quicklime of higher reactivity than those dominated by foraminifera, peloids and miliolids. This is mainly attributed to the preservation of the intraparticle pores of the original limestone and the development of pinhole and fracture micropores. The shape of pores and not their amount is the main controlling variable in the quicklime reactivity. The grainstones enriched in fracture pores showed more reactive lime, whereas those with compact structures are less reactive post calcination.