Northwest-southeast Orientation Research Articles

Spatial Pattern and Influencing Factor Analysis of Attended Collection and Delivery Points in Changsha City, China

Attended collection and delivery points are vital components of ‘last-mile logistics’. Based on point of interest (POI) data for Cainiao Stations and China Post stations in Changsha City, China, this paper provides a detailed exploration of the basic features, spatial distribution, and location influencing factors of attended collection and delivery points. Specifically, analyses of the types, service objects and location distributions of the attended collection and delivery points alongside a discussion of their spatial pattern and influencing factors provides a reference for their general geographic layout and characteristics. The findings of this study indicate that: 1) The main mode of operation of attended collection and delivery points is franchises, with other modes of operation rely on supermarkets and other individual shop types. 2) The main service targets of attended collection and delivery points are communities, schools, and businesses, followed by townships, enterprises, scenic spots, and administrative units. 3) Approximately 77.44% of the attended collection and delivery points are located near the exits of service areas; others are situated in the centre of the service areas. For the Cainiao Stations, 80% are located within 125 m of the exit; for the China Post stations, 80% are located within 175 m of the exit. 4) The spatial distribution of the attended collection and delivery points in Changsha is unbalanced, with ‘more centre and fewer surrounding’. The centre is an ‘inverted triangle’, and the edge is an ‘orphan’, showing a northwest-southeast orientation and symmetrical along the axis. The layout of the attended collection and delivery points forms three core areas, and the number of sites decreases with the distance from the core. 5) The number and distribution of the attended collection and delivery points are strongly consistent with the regional economic development level, population, and roadway system traffic convenience. Most attended collection and delivery points are on residential, scientific and educational, and commercial and financial land.

Fracture systems and petrophysical properties of tight sandstone undergoing regional folding: A case study of the Cretaceous reservoirs in the Kuqa foreland thrust belt, Tarim Basin

Abstract The Kuqa foreland thrust belt of the Tarim Basin hosts a prolific hydrocarbon system. The main reservoirs are characterized by tight sandstone with low-porosity and ultra-low permeability, buried presently at more than 5000 m depth. Natural fracture systems have a significant impact on reservoir performance, and it may form paths for fluid flow in tight sandstone reservoirs, and therefore plays an essential role in controlling high production rates. With the aim of analyzing the distribution of favorable reservoir, we studied subsurface fracture patterns and petrophysical properties of the Bashijiqike Formation with data collected from Dabei structure and Keshen structure. We document the presence of four fracture systems whose distribution is related to far-field stress, thrusting and folding. In the Keshen anticlines, higher fracture intensities are observed in the limbs, with principal east-west (hinge-parallel fracture system) direction. The hinge-parallel fracture system includes a moderate-dipping fracture set and a vertical fracture set. Crosscutting relationships stress field inversion and fracture surface textures suggest that the moderate-dipping fracture set consists of shear fractures and can be explained by intra-layer shear caused by thrusting. The vertical fracture set may be formed due to the local outer arc extension during folding. The oblique fracture system shows scattering in strike, and is supposed to be related to a shear event of locally left-lateral strike-slip. Whereas, in the Dabei anticlines, the major system is hinge-perpendicular fracture system (NW-SE), showing a trending of increasing fracture intensity from limbs to hinge. The hinge-perpendicular fractures system in the Dabei anticlines consist of shear fractures and tension fractures. Stress inversion result shows it corresponds to northwest-southeast orientation compression stage. Besides, we analyzed petrophysical properties include porosity, permeability, Young's module, Poisson ratio and compressive strength of the Bashijiqike Formation concerning their structural position within folds. It indicates that the highest porosity and permeability are associated with dissolution and fracturing. The compressive strength of different structural positions also restrict the variations of mechanical properties of rocks. The best reservoir quality is suggested in the hinge zone and areas close to thrust. The findings have given maybe helpful for providing favorable reservoir targets for prospecting in the compressional basin.

Four-dimensional filtering of InSAR persistent scatterers elucidates subsidence induced by tunnel excavation in the Sri Lankan highlands

During construction of the Uma Oya Multipurpose Development Project, excavation of a headrace tunnel through highly tectonized metamorphic rock was slowed by repeated major water ingress events. In total, these events resulted in an estimated aquifer depletion of over 9 million m3, causing widespread surface subsidence. Persistent scatterer (PS) time series analysis of interferometric synthetic aperture radar (InSAR) scenes acquired by Sentinel-1 between July 28, 2016, and January 7, 2018, has revealed an ∼15 km2 area of subsidence near reported water ingress locations, with a maximum line-of-sight subsidence value of 4.3 cm. A four-dimensional (4-D) filtering method based on averaging spatial and temporal pixel neighbors was applied to the unwrapped PS pixels, significantly reducing noise from sources that appear randomly in spatial and temporal domains and increasing the ability to accurately identify the onset of subsidence and track surface volume loss over time. A maximum average subsidence rate of 0.15 mm / day coincides with maximum tunnel discharge measurements, indicating that rock mass consolidation occurred as a result of rapid pore-pressure drawdown within an interconnected discontinuity network and led to fracture closure. The observed subsidence is punctuated by localized maxima and extends in a northwest–southeast orientation, suggesting that the extent of subsidence is governed by previously mapped structural trends of similar orientations. These results highlight the value of the 4-D filtering approach in processing InSAR PS data to help determine the magnitude and extent of surface subsidence.

Role of the East Asian trough on the eastern Mediterranean temperature variability in early spring and the extreme case of 2004 warm spell

This study investigates the potential influence of the East Asian trough (EAT) on the eastern Mediterranean temperature variability in early spring. In connection with this, it also examines the extreme case of the year 2004 when anomalous warming of the eastern Anatolia resulted in unprecedented snowmelt runoff amounts in the Euphrates and Tigris basins in early March. In the analyses, we used reanalysis data, gridded products of surface temperature and snow cover, river discharge data and satellite imagery. We employed an intensity index for the EAT and a trough displacement index for the Mediterranean trough (MedT) to explore the relationship between the strength of the EAT and the displacement of the MedT at pentad resolution. Our analysis shows that there are statistically significant correlations (at 99% confidence level) between the strength of the EAT and the zonal shift of the MedT on some pentads (e.g., 3rd, 13th, 37th and 59th), but that the highest correlation occurs on the 13th pentad of the year corresponding to the early days of March. It seems that, on this pentad, when the EAT is strong, the MedT tends to be located in the west of its climatological position (about $$30\hbox {$-$}35^{\circ }\hbox {E}$$ ) which causes warmer conditions over the eastern Mediterranean. In 2004, which appears to be an extreme year for this phenomenon, the MedT is positioned and deepened in the central Mediterranean (about $$10\hbox {$-$}15^{\circ }\hbox {E}$$ ), and extended towards central Africa during the early days of March. This synoptic pattern provided favorable conditions for the development of a tropical plume/atmospheric river with a southwest-northeast orientation, carrying warm tropical African air towards the eastern Mediterranean and Anatolian highlands resulting in rapid melting of the snowpack as well as severe precipitation, and thus flooding events, in the eastern Anatolia. A key finding in our analysis is that the strengthening of the EAT was instrumental to the increased amplitude of the ridge-trough system over the Euro-Mediterranean region in the early days of 2004 spring. We highlight that the response of surface and upper level meteorological conditions to the amplitude of the ridge-trough system enhanced by the strength of the EAT might be crucial in the understanding of some of the extreme hydrometeorological events in the eastern Mediterranean region.

The JCMT BISTRO Survey: The Magnetic Field in the Starless Core ρ Ophiuchus C

We report 850~$\mu$m dust polarization observations of a low-mass ($\sim$12 $M_{\odot}$) starless core in the $\rho$ Ophiuchus cloud, Ophiuchus C, made with the POL-2 instrument on the James Clerk Maxwell Telescope (JCMT) as part of the JCMT B-fields In STar-forming Region Observations (BISTRO) survey. We detect an ordered magnetic field projected on the plane of sky in the starless core. The magnetic field across the $\sim$0.1~pc core shows a predominant northeast-southwest orientation centering between $\sim$40$^\circ$ to $\sim$100$^\circ$, indicating that the field in the core is well aligned with the magnetic field in lower-density regions of the cloud probed by near-infrared observations and also the cloud-scale magnetic field traced by Planck observations. The polarization percentage ($P$) decreases with an increasing total intensity ($I$) with a power-law index of $-$1.03 $\pm$ 0.05. We estimate the plane-of-sky field strength ($B_{\mathrm{pos}}$) using modified Davis-Chandrasekhar-Fermi (DCF) methods based on structure function (SF), auto-correlation (ACF), and unsharp masking (UM) analyses. We find that the estimates from the SF, ACF, and UM methods yield strengths of 103 $\pm$ 46 $\mu$G, 136 $\pm$ 69 $\mu$G, and 213 $\pm$ 115 $\mu$G, respectively. Our calculations suggest that the Ophiuchus C core is near magnetically critical or slightly magnetically supercritical (i.e. unstable to collapse). The total magnetic energy calculated from the SF method is comparable to the turbulent energy in Ophiuchus C, while the ACF method and the UM method only set upper limits for the total magnetic energy because of large uncertainties.

Large-Scale Flow Patterns Associated with Extreme Precipitation and Atmospheric Rivers over Norway

AbstractA climatology of extreme cold season precipitation events in Norway from 1979 to 2014 is presented, based on the 99th percentile of the 24-h accumulated precipitation. Three regions, termed north, west, and south are identified, each exhibiting a unique seasonal distribution. There is a proclivity for events to occur during the positive phase of the NAO. The result is statistically significant at the 95th percentile for the north and west regions. An overarching hypothesis of this work is that anomalous moisture flux, or so-called atmospheric rivers (ARs), are integral to extreme precipitation events during the Norwegian cold season. An objective analysis of the integrated vapor transport illustrates that more than 85% of the events are associated with ARs. An empirical orthogonal function and fuzzy cluster technique is used to identify the large-scale weather patterns conducive to the moisture flux and extreme precipitation. Five days before the event and for each of the three regions, two patterns are found. The first represents an intense, southward-shifted jet with a southwest–northeast orientation. The second identifies a weak, northward-shifted, zonal jet. As the event approaches, regional differences become more apparent. The distinctive flow pattern conducive to orographically enhanced precipitation emerges in the two clusters for each region. For the north and west regions, this entails primarily zonal flow impinging upon the south–north-orientated topography, the difference being the latitude of the strong flow. In contrast, the south region exhibits a significant southerly component to the flow.

Correlation Between Fracture Azimuth, Surface Lineaments and Regional Tectonics: A case study from Belik District, Central Java, Indonesia

Two major strike-slip faults with northeast-southwest and northwest-southeast orientation have shifted the southern Central Java, including Belik District. Consequently, many smaller faults that have the same direction as the major faults and west-east direction folding systems were emerged. The orientation of these geologic structures could be observed from morphological features such as ridge and river. A quantitative approach was carried out to unravel the impacts of those geologic structures on the geomorphology of the study area, which is located between Slamet Mountain and Sindoro Mountain, Central Java province. The method used in this research was the structural geology analysis, including the interpretation of ridge and river lineament, the distribution of fractures, and statistical analysis. The research location is divided into four different segments based on its lineament and morphology. The lineament that has similar characteristics was tested using normality test of Kolmogorov-Smirnov. The Spearman test was used to obtain the correlation between surface lineament and fracture azimuth. All fracture azimuth, ridges and rivers tend to have northwest-southeast and northeast-southwest direction. These results show similar direction with strike-slip regional structural pattern. The statistical calculation and field observation indicate the influence of external factor on the change of the study area’s landform.

Stratigraphy and Structure of Dhamtaur Area, District Abbottabad, Eastern Hazara, Pakistan

Pre-Cambrian to Paleocene age sedimentary rocks predominantly characterize the fold and thrust belt of eastern Hazara division. The Hazara Slate Formation is the oldest rock unit which represents the Precambrian sequence. The Permian and Triassic sequences are missing. The Jurassic sequence comprises Samana Suk Formation whereas the Cretaceous exposed is Chichali and Lumshiwal formations. The Eocene sequence consists of Nammal and Sakessar formations. The structural fabric of the area is mainly attributed to a series of northwest trending parallel to en echelon anticlines and synclines. Most of these folds are found to be asymmetric and are Northwest facing. Several thrust faults verging both to the north have been mapped that generally dissect the forelimbs of the anticlinal structures. But the following study going to be focus on surface structural features as well as subsurface projections of folds and faults. Study of such structural features has get prime importance in economic geology such as petroleum geology, mining geology and engineering geology. In our study area subsurface projection of folds and faults along the structural transects of the area suggests that these structures have formed as a result of shortening associated with ramping from a regional basal decollement. All the structures clearly demonstrate that the eastern Hazara area has been subjected to compressional deformation/stresses oriented northeast southwest. The repetition of rock units indicates, folding in the area and thrusting of Pre-Cambrian Hazara Formation over younger Paleocene Lockhart Formation, evidence of thrust fault. There are unconformable contacts between Hazara and Samana Suk, Chichali and Lumshiwal, Kawagarh and Hangu and Lockhart formations indicate fluctuation in the environment of deposition. The Bagnotar Fault, Dhamtaur syncline and Thai anticline are the major structural features identified and reported in the study area.

Lacustrine carbonate platforms: Facies, cycles, and tectonosedimentary models for the presalt Lagoa Feia Group (Lower Cretaceous), Campos Basin, Brazil

Studies of lacustrine carbonate rocks in continental rifts have received huge interest in recent years because of their great economic value in the South Atlantic. However, most existing facies and tectonosedimentary models for carbonate platforms are based on marine carbonate systems, whereas models for nonmarine systems are scarce. The main aim of this paper is to establish such models and to further our understanding of the hydrocarbon-bearing late synrift Lower Cretaceous carbonate successions of the Campos Basin, Brazil. This paper is based on a proximal to distal industrial data set of three-dimensional (3-D) seismic, cores, and well logs from the Coqueiros Formation (Coquina), southern Campos Basin. The dominant carbonate facies in the Coqueiros Formation are mollusk-rich grainstones, rudstones, and floatstones, which form the main reservoir facies. The 3-D seismic interpretations show an oblique extensional rift system, characterized by a series of grabens, half grabens, accommodation zones, and horsts oriented northeast–southwest to north–northeast-south–southwest. Three tectonic domains are recognized based on structural style, stretching factors, and subsidence rates as well as facies and different types of lacustrine carbonate platforms. Proximal rift margin areas are characterized by a series of half grabens with footwall and hanging-wall dip slopes of shallow lacustrine carbonates and fluviodeltaic mixed carbonate and siliciclastic deposits in marginal, hanging-wall basins. Central areas are carbonate rich with platforms established over horst blocks surrounded by deeper-water carbonate facies. Distal areas have the highest amount of stretching and subsidence and accumulate the thickest carbonate successions over a template of buried horsts and grabens. The entire carbonate succession underlies a thick layer of Aptian salt, which forms the seal to this prolific hydrocarbon system.

Mapping the subsurface structures of a lost medieval village in South‐Western Romania by combining conventional geophysical methods

AbstractThe medieval fortification of Mașloc, known as the ‘Șanțul Turcilor’ (Turkish ditch) is one of the best preserved archaeological sites in the Banat region, Romania. To reconstruct the subsurface archaeological features at the Mașloc site we combined three different geophysical methods: magnetometry, ground‐penetrating radar (GPR) and electrical resistivity tomography (ERT) and we used SfM (structure‐from‐motion) to achieve a detailed digital elevation model and an orthophoto mosaic also. Six hectares were investigated by magnetometry in order to define the basic outline of the medieval settlement, which gradually developed around the fortification. Several GPR and ERT profiles were constructed over the ramparts and ditches of the fortification to determine their extent and the internal structure of the ramparts, ditches and the houses within. The interpretation of these profiles shows for the first time the existence of a second ditch around the fortification: this is not visible in the field. The geophysical mapping precisely identifies the dwellings within the site, which shows the spatial organization of the village. Houses were developed along its main street, oriented northeast–southwest (NE–SW), which were constructed using well‐established rules and must have been planned by a local administration. Such organization demonstrates the importance of the village in medieval times, due probably to its location near to the road between two important towns: Timișoara and Lipova. The geophysical results now allow us to associate this settlement with the lost Machalaka, an important village mentioned in the medieval documents. The geophysical investigation demonstrates how this method can delineate village boundaries and the planimetry of internal archaeological features.

Near-Global Covariability of Hourly Precipitation in Space and Time

Abstract A detailed analysis of hourly precipitation from 60°N to 60°S for the covariability is performed at 0.25° resolution using the new CMORPH dataset. For all points, correlations are computed with surrounding points both concurrently and for various leads and lags up to a day. Results are more coherent over the oceans than land; the contours of constant correlation tend to be elliptical, oriented northeast–southwest in the northern extratropics and southeast–northwest in the southern extratropics. An ellipse is fitted to the correlation pattern, and major and minor axis vectors and eccentricity are mapped. Based upon both the isotropic correlations and ellipse, points are allocated to one of 20 clusters, and 16 are documented. Over the main extratropical ocean storm tracks, correlations exceed 0.8 for points 50 km distant and fall to about 0.3 at about 5° radius. In the tropics values drop to 0.65 within 50 km and 0.2 at 5° radius. Over land, values are lower in summer and drop to 0.1 at 5° radius. Decorrelation e-folding distances range from less than 50 km over land to 200 km over extratropical ocean storm tracks. The movement of precipitation is compared with mean atmospheric winds. The lead–lag relationships indicate movement of systems but reveal the relatively short lifetimes of precipitation, of less than 12 h, even taking movement into account. The orientation of the ellipse reflects the structures of rain phenomena (fronts, etc.) rather than movement. These statistics demonstrate that daily averages fail to capture the essential character of precipitation.

Identification the geothermal system using 1-D audio-magnetotelluric inversion in Lamongan volcano field, East Java, Indonesia

Tiris village, Probolinggo, East Java, is one of geothermal potential areas in Indonesia. This area is located in a valley flank of Mount Lamongan and Argopuro volcanic complex. This research aimed to identify a geothermal system at Tiris area, particularly the fluid pathways. The geothermal potential can be seen from the presence of warm springs with temperature ranging 35-45°C. The warm spring locations are aligned in the same orientation with major fault structure in the area. The fault structure shows dominant northwest-southeast orientation. We used audio-magnetotelluric data in the frequency range of 10 Hz until 92 kHz. The total magnetotelluric sites are 6. From the data analysis, most of the data orientation were 2-D with geo-electrical direction north-south. We used 1-D inversion using Newton algorithm. The 1-D inversion resulted in low resistive anomaly that corresponds to Lamongan lavas. Additionally, the depth of the resistor are different between the area to the west (i.e. 75 m) and to the east (i.e. 25 m). This indicates that there is a fault around the aligned maar (e.g. Ranu Air).

Biophysical interactions in perennial biomass alley cropping systems

Understanding the nature and degree of competition between trees and co-planted crops in agroforestry systems can inform management decisions, future species selection, and system design. We measured variation in herbaceous biomass yield, photosynthetically active radiation (PAR), soil water potential, and residual soil NO3 in alley cropping systems consisting of prairie cordgrass (Spartina pectinata) or an 11-species native grass-forb-legume polyculture planted between rows of shrub willow (Salix purpurea L. ‘Fish Creek’) at two Minnesota sites. At Empire, biomass yield increased with distance from the tree row for both alley crops, as did PAR and NO3 availability. At Granada, no spatial pattern in crop yield was evident, despite reduced PAR and NO3 availability adjacent to tree rows. At both sites, patterns in soil water potential suggested that trees competed with crops for soil water within 2.4 m of tree rows, but had a facilitative effect on crop water use at 4.8 m. Alleys had differing cardinal orientations at the two sites, and light availability was lower in a north–south alley (Empire) than in west–east and northwest-southeast orientations (Granada). At Empire, mixed effects analysis indicated that competition for light and soil water were responsible for reductions in crop yield. For every 100 μmol m−2 s−1 increase in PAR, model estimated herbaceous crop yield increased by 623 kg DM ha−1. For every 20 kPa increase in average daily water potential, crop yield increased by 1038 kg DM ha−1. The relative impact of competition on biomass yield was similar for both crops, though prairie cordgrass had higher average yields at Empire. Similar alley systems should avoid north–south alley orientations to minimize competition for light.

Temuan Kubur di Situs Bawahparit (Limapuluh Koto) Corak Penguburan Megalitik Masa Transisi

AbstractsBuried is one of some activities in human life, which have been doing if someone died. In Indonesia, since arrival of Islamic influence, the prehistoric buried in several places have been developed and change with new phenomenon. In other site, some places have indication with two signs of prehistoric and Islamic buried. That facts, we can find in Bawahparit site that have location on Kototinggi District, Limapuluhkoto regent’s, West Sumatera. In this site, we could find a hundred of the up right stones as a sign of buried and human skeletons were setting in cavity and putting down in northwest-southeast orientation. It is the same with Islamic buried.

PEBBLES IN THE TARKWAIAN BANKET CONGLOMERATE: INFERENCE OF GOLD GRADE AND PALEO-TRANSPORT DIRECTION

TarkwaianBanket conglomerateat Tarkwa area contains rounded to sub-rounded quartz pebbles ofwhich theB reef horizon haslarger pebble sizes, showed preferred northeast-southwest orientation with their longest axes in the north to northwest andprobably ofSEpaleo-transport direction. Interestingly, samplesfrom zones with pebblestrending in northeast-southwest directionshave higher gold grades.Pebbles ofthe B reef,trendtowards the northwestand probably came from the east,and characterizehighest average gold gradeof 2.50 g/t whilethose with the averagetrendof SW were associatedwithlowest average gradeof 1.95 g/t. Pebbles in theC reef trend towards the north to northwest and could have travelledfrom the east; those withthe averagetrendof SEhad a higheraverage grade of 1.12 g/t compared tothelower grade variety of 0.73 g/t which trends NW.

A climatological northern boundary index for the East Asian summer monsoon and its interannual variability

A long-term perspective on the spatial variation of the northern boundary of the East Asian summer monsoon (EASM) and the related physical mechanisms is important for understanding past climate change in Asia and for predicting future changes. However, most of the meteorological definitions of the EASM northern boundary do not correspond well to the actual geographical environment, which is problematic for paleoclimatic research. Here, we use monthly CMAP and GPCP precipitation data to define a new EASM northern boundary index by using the concept of the global monsoon, which is readily applicable to paleoclimatic research. The results show that the distribution of the 2 mm day−1 precipitation isoline (i.e., 300 mm precipitation) has a good relationship with the spatial distribution of modern land cover types, the transitional climate zone and the potential natural vegetation types, in China. The locations of the precipitation isolines also correspond well to the locations of major shifts in wind direction. These results suggest that the 2 mm day−1 isoline has a clear physical significance since the climatic, ecological, and geographical boundary can be used as the northern boundary index of the EASM (which we call the climatological northern boundary index). The index depicts the northeast-southwest orientation of the climatological (1981−2010) EASM northern boundary, along the eastern part of the Qilian Mountains-southern foothills of the Helan Mountains-Daqing Mountains-western margin of the Greater Khingan Range, from west to east across Northwest and Northeast China. The interannual change of the EASM northern boundary from 1980 to 2015 covers the central part of Gansu, the northern part of Ningxia, the eastern part of Inner Mongolia and the northeastern region in China. It can extend northward to the border between China and Mongolia and retreat southward to Shangdong-central Henan. There is a 200−700 km fluctuation range of the interannual EASM northern boundaries around the locations of the climatological northern boundary. In addition, the spatial variation of the interannual EASM northern boundaries gradually increases from west to east, whereas the trend of north-south fluctuations maintains a roughly consistent location in different regions.

Late Ordovician glacial and glacio-fluvial paleovalley architecture and sedimentation in southeast Jordan and northwest Saudi Arabia

Four recently discovered glacio-fluvial paleovalleys in southeast Jordan and northwest Saudi Arabia are described for the first time. The paleovalleys formed as a result of glacial erosion by series of sub-parallel valley glaciers during the Late Ordovician (Hirnantian) southern hemisphere glaciation on the Arabian Plate. The southwest-northeast orientation of the paleovalleys, Proterozoic erratic clasts and paleocurrent vectors indicate the advance of glaciers and subsequent glacio-fluvial siliciclastics emanating from a paleo-ice sheet located to the south on the Arabian Shield. U-shaped, paleovalley cross-sectional morphologies and gently inclined longitudinal profiles indicate initial glacial erosion of the ‘finger-like’ paleovalleys, probably as wet-based valley glaciers, eroded up to 250 m depth into Late Ordovician marine bedrock formations. Paleovalley-fill sequences comprise a tripartite upwards succession: (a) basal sandstone-dominated tillite with well-rounded, grooved and striated granitoid and metamorphic basement clasts derived from the Proterozoic Arabian Shield together with locally derived, rounded and elongate boulders eroded from the local bedrock at the margins of the paleovalleys (Retrogradational Lowstand Sequence); (b) green chloritic siltstone (Zarqa Formation) deposited during a progradational sea-level rise with marine influence (Transgressive Sequence); (c) coarse-grained, trough cross-bedded sandstone (Sarah Formation) attributed to progradational fluvial sedimentation as glacial outwash. Rapid sea-level rise during latest Hirnantian to Early Llandovery time resulted in marine flooding of the glacio-fluvial alluvial plain and deposition of organic-rich mudstones representing transgressive and high-stand sequences.

Blocking features for two types of cold events in East Asia

Cold air outbreaks (CAOs) always hit East Asia during boreal winter and have significant impacts on human health and public transport. The amplitude and route of CAOs are closely associated with blocking circulations over the Eurasian continent. Two categories of CAOs are recognized, namely, the ordinary cold wave events (CWEs) and the extensive and persistent extreme cold events (EPECEs), with the latter having even stronger impacts. The blocking features associated with these two types of CAOs and their differences are investigated in this study on the intraseasonal timescale. What these two CAOs do have in common is that they are both preceded by the intensification and recurrence of a blocking high over the midlatitude North Atlantic. The difference between these events is primarily reflected on the spatial scale and duration of the corresponding blocking high. During the CWEs, blocking occurs around the Ural Mountains, and exhibits a regional feature. The resulting cold air temperature persists for only up to 8 days. In contrast, during the EPECEs, the blocking region is quite extensive and is not only confined around the Ural Mountains but also extends eastward into Northeast Asia in a southwest–northeast orientation. As a result, the cold air tends to accumulate over a large area and persists for a much longer time. The blocking activity is primarily induced by an increased frequency and eastward extension of the synoptic anticyclonic Rossby wave breaking (AWB). Compared with the CWEs, characterized by a regional and short-lived synoptic AWB frequency, the EPECEs tend to be accompanied by more recurrent and eastward extensions of the synoptic AWB.

Die jungneolithischen Erdwerke von Altheim

Zusammenfassung:Die Geländearbeiten an dem vor einem Jahrhundert entdeckten Erdwerk von Altheim wurden im Jahre 2012 wieder aufgenommen. Im Verlauf dieser Untersuchungen konnte nahe der altbekannten Einhegung im Südosten der Nachweis eines zweiten altheimzeitlichen Grabenwerkes erbracht werden. Beide Anlagen sind räumlich aufeinander bezogen. Im Bereich des nördlichen Grabenwerkes wurde ein Bodenabtrag von mehreren Dezimetern während des letzten Jahrhunderts beobachtet; die Substanz beider Bodendenkmäler erscheint damit akut gefährdet. Erste Radiokohlenstoffdatierungen an Proben von Haustierknochen ergeben eine Einordnung beider Anlagen in das 37./36. Jh. v. Chr. und Hinweise auf eine zeitliche Abfolge der Gräben. Die seinerzeitige Feststellung eines hohen Pfeilspitzenanteiles an den geschlagenen Steingeräten sowie eines sehr geringen Wildtieranteiles wurden durch die neuen Grabungen bestätigt. Die Längsachsen-Ausrichtung in nordwest-südöstlicher Richtung ermöglicht eine archäoastronomische Deutung; durch Beobachtung von Naturphänomenen gewonnenes Wissen wurde in Architektur umgesetzt. Zweifel an einer fortifikatorischen Interpretation der Anlagen werden durch die neuerlichen Arbeiten nachhaltig verstärkt.

Structural changes of an outer tropical cyclone rain band encountering the topography of northern Taiwan

This study utilized ground‐based Doppler radar observations to document the detailed structures of an outer tropical cyclone rain band (TCR) of Typhoon Longwang (2005) as the rain band passed over the topography of northern Taiwan on 1 October 2005. The TCR was oriented northeast–southwest and was roughly parallel to the mountain barrier with a higher (lower) terrain height in its southern (northern) landfalling segment. During the pre‐landfall stage, the TCR was characterized by convective precipitation on its inner side, where the front‐to‐rear flow met with the rear‐to‐front flow to lift air upward with overturning‐updraught‐like signatures. Significant (relatively minor) changes in the TCR's structures were evident in the southern (northern) landfalling segment during the landfalling stage. In particular, the southern landfalling segment exhibited a much stronger front‐to‐rear flow that passed through the region of the rain band, resulting in the absence of low‐level organized convergence and a relatively disorganized nature of precipitation. This structural change was shown to be closely related to a significant decrease in the cross‐barrier flow due to the orographic blocking that occurred as easterly ambient winds encountered local high mountains in the vicinity of the rain‐band segment. As the TCR propagated over the western side of the major topography, the low‐level rear‐to‐front flow reappeared due to the collapse of low‐level orographic blocking, and the convergence between the front‐to‐rear flow and the rear‐to‐front flow tended to rebuild a well‐organized convective circulation along the rain band. Results from this case‐study provide insight into processes that contribute to rapid structural changes in a landfalling TCR over mountainous regions.