Cryoplanation Terraces: Indicators of a Permafrost Environment

1976 ◽  
Vol 6 (1) ◽  
pp. 99-109 ◽  
Author(s):  
Richard D. Reger ◽  
Troy L. Péwé
Keyword(s):  
Mass Movement ◽  
Indirect Evidence ◽  
Summer Temperature ◽  
Climatic Data ◽  
Mass Wasting ◽  
Fine Grained ◽  
Permafrost Environment ◽  
Summer Temperatures ◽  
The Mean ◽  
July Temperature

Cryoplanation terraces are bedrock steps or terraces on ridge crests and hilltops. The tread or “flat” area is 10 to several hundred meters wide and long and slopes from 1 to 5° parallel to the ridge crests. Terrace scarps may be from 1 to 75 m high. Terraces are cut into all bedrock types and are best developed on closely jointed, fine-grained bedrock. The scarps and treads are covered with frost-rived rubble 1 to 2 m thick. The rubble on treads is perennially frozen at a depth of 1 to 2 m or less on sharp but inactive terraces in Alaska.Cryoplanation terraces exist in many parts of the world in present or past periglacial environments. They occur chiefly in nonglaciated regions and near the general altitude of snowline. Cryoplanation terraces form by scarp retreat as the result of nivation. Surficial debris is removed across the terrace tread by mass-wasting. Terrace morphology depends mainly upon climate, bedrock type, and terrace orientation.No climatic data are available from active terraces. Indirect evidence indicates that climatic requirements include low snowfall and cold summer temperatures. Shallow permafrost is necessary to provide moisture and a base for mass movement as well as a base for nivation.Hundreds of sharp but inactive terraces occur in some areas in Alaska where the summer temperature is colder than 10°C. When these terraces were active, temperatures were colder. Recent work in Alaska indicates that terraces were active in some areas when the mean July temperature was about 4°C. The mean annual air temperature probably was in the neighborhood of -12°C or colder.

Cores and Peripheries Revisited: The Mining Landscapes of Wadi Faynan (Southern Jordan) 5000 BC–AD 700

2007 ◽  
Author(s):  
Graeme Barker ◽  
David Mattingly
Keyword(s):  
Roman Empire ◽  
Iron Age ◽  
Summer Temperature ◽  
Research Interest ◽  
Annual Rainfall ◽  
Winter Temperatures ◽  
Mountain Front ◽  
Summer Temperatures ◽  
The Mean ◽  
Landscape Survey

One of Barry Cunliffe’s major areas of research interest has been societies in transition, especially in the context of core/periphery relationships between expanding states and societies on their margins. Much of this work has been on the relationships between Rome and the Iron Age societies of southern Britain on the northwestern margins of the empire, and the subsequent pathways of resistance, interaction, and transformation. In this chapter we focus on events and processes on the opposite margins of the Roman empire in the Levant, where the Nabataean state was formally incorporated into the Roman imperial system some sixty years after the Claudian invasion of Britain. We draw on the results of the Wadi Faynan Landscape Survey (1996–2000), an interdisciplinary and diachronic investigation of evidence of environmental and climatic change, settlement pattern, and human activity in the Wadi Faynan in southern Jordan (figure 7.1). Situated about 40 kilometres from the Nabataean capital of Petra, the Wadi Faynan lies in the hot and hyper-arid Jordanian Desert, at a distinctive and spectacular mountain front that reaches 1500m above the desert floor. This landform marks the eastern margin of the desert lowlands of the great Jordanian rift valley, with the trough of the Wadi ‘Arabah to the south and west, and the highlands of the Mountains of Edom and the Jordanian tablelands to the east and north (Bienkowski and Galor 2006). The mean summer temperature on the Jordanian tablelands is in the order of 178c, compared with winter temperatures of about 12ºc (Bruins 2006; Rabb’a 1994). Winter temperatures on the desert floor in the Wadi Faynan are much the same as on the plateau, but in summer temperatures frequently reach 40ºc. Seasonality is strong, with most rain falling between December and March and virtually no precipitation occurring between June and September. Annual rainfall in the lower Wadi Faynan is around 63mm and even less in theWadi ‘Arabah (‘Aqaba receives 30mm for example), whereas the Jordanian Tablelands have an average precipitation exceeding 200mm per year.

Lightweight detection algorithm for fine-grained surface defects of aerospace seal rings

2021 ◽  
pp. 1-18
Author(s):  
Hui Liu ◽  
Boxia He ◽  
Yong He ◽  
Xiaotian Tao
Keyword(s):  
Feature Extraction ◽  
Defect Detection ◽  
Surface Defect ◽  
Surface Defects ◽  
Detection Algorithm ◽  
Seal Ring ◽  
Fine Grained ◽  
Aerospace Applications ◽  
Surface Defect Detection ◽  
The Mean

The existing seal ring surface defect detection methods for aerospace applications have the problems of low detection efficiency, strong specificity, large fine-grained classification errors, and unstable detection results. Considering these problems, a fine-grained seal ring surface defect detection algorithm for aerospace applications is proposed. Based on analysis of the stacking process of standard convolution, heat maps of original pixels in the receptive field participating in the convolution operation are quantified and generated. According to the generated heat map, the feature extraction optimization method of convolution combinations with different dilation rates is proposed, and an efficient convolution feature extraction network containing three kinds of dilated convolutions is designed. Combined with the O-ring surface defect features, a multiscale defect detection network is designed. Before the head of multiscale classification and position regression, feature fusion tree modules are added to ensure the reuse and compression of the responsive features of different receptive fields on the same scale feature maps. Experimental results show that on the O-rings-3000 testing dataset, the mean condition accuracy of the proposed algorithm reaches 95.10% for 5 types of surface defects of aerospace O-rings. Compared with RefineDet, the mean condition accuracy of the proposed algorithm is only reduced by 1.79%, while the parameters and FLOPs are reduced by 35.29% and 64.90%, respectively. Moreover, the proposed algorithm has good adaptability to image blur and light changes caused by the cutting of imaging hardware, thus saving the cost.

scholarly journals Mudrock Microstructure: A Technique for Distinguishing between Deep-Water Fine-Grained Sediments

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 653
Author(s):  
Shereef Bankole ◽  
Dorrik Stow ◽  
Zeinab Smillie ◽  
Jim Buckman ◽  
Helen Lever
Keyword(s):  
Grain Size ◽  
Deep Water ◽  
Sedimentary Facies ◽  
X Ray Diffraction ◽  
Weak Current ◽  
Large Area ◽  
Fine Grained ◽  
Mean Size ◽  
The Mean ◽  
Water Facies

Distinguishing among deep-water sedimentary facies has been a difficult task. This is possibly due to the process continuum in deep water, in which sediments occur in complex associations. The lack of definite sedimentological features among the different facies between hemipelagites and contourites presented a great challenge. In this study, we present detailed mudrock characteristics of the three main deep-water facies based on sedimentological characteristics, laser diffraction granulometry, high-resolution, large area scanning electron microscopy (SEM), and the synchrotron X-ray diffraction technique. Our results show that the deep-water microstructure is mainly process controlled, and that the controlling factor on their grain size is much more complex than previously envisaged. Retarding current velocity, as well as the lower carrying capacity of the current, has an impact on the mean size and sorting for the contourite and turbidite facies, whereas hemipelagite grain size is impacted by the natural heterogeneity of the system caused by bioturbation. Based on the microfabric analysis, there is a disparate pattern observed among the sedimentary facies; turbidites are generally bedding parallel due to strong currents resulting in shear flow, contourites are random to semi-random as they are impacted by a weak current, while hemipelagites are random to oblique since they are impacted by bioturbation.

Interdecadal changes in the interannual variability of the summer temperature over Northeast Asia

2021 ◽  
pp. 1-50
Author(s):  
Ruidan Chen ◽  
Zhiping Wen ◽  
Riyu Lu ◽  
Wenjun Liu
Keyword(s):  
Interannual Variability ◽  
Northeast Asia ◽  
Tropical Indian Ocean ◽  
Summer Temperature ◽  
Atmospheric Variability ◽  
The Pacific ◽  
The Mean ◽  
Southeastern Tropical Indian Ocean ◽  
Interdecadal Changes ◽  
Mean State

AbstractThis study reveals the interdecadal changes in the interannual variability of the summer temperature over Northeast Asia (NEA), which presents an enhancement around the early 1990s and a reduction after the mid-2000s. The stronger NEA temperature variability after the early 1990s is favored by the enhanced influence of the Pacific–Japan (PJ) teleconnection, which is remotely modulated by the southeastern tropical Indian Ocean (SETIO). After the early 1990s, the mean state over the SETIO presents relatively warmer SST and ascending motion, favoring a good relationship between the local SST and convection. Therefore, the SETIO SST could prominently influence the local convection and subsequently modulate the convection over the western North Pacific (WNP) via a cross-equatorial overturning circulation. The abnormal convection over the WNP further triggers the PJ teleconnection to influence NEA. However, these ocean–atmosphere processes disappear before the early 1990s. In this period, the mean state over the SETIO features relatively colder SST and subsiding motion, accompanied by a poor relationship between the local SST and convection. Therefore, the variability of convection over the SETIO is weak, thus the atmospheric variability over the WNP is also weakened and the PJ teleconnection presents a different distribution that could not influence NEA. The reduced variability of NEA temperature after the mid-2000s is related to the feeble influence of the PJ teleconnection and the reduced variability of the SETIO SST, which is modulated by the SST over the tropical central–eastern Pacific during the preceding winter to spring.

scholarly journals Temperature Change and Its Elevation Dependency in the Source Region of the Yangtze River and Yellow River

2014 ◽  
Vol 6 (2) ◽  
pp. 124 ◽  
Author(s):  
Chongyi E ◽  
Hongchang Hu ◽  
Hong Xie ◽  
Yongjuan Sun
Keyword(s):  
Temperature Change ◽  
Minimum Temperature ◽  
Yangtze River ◽  
Yellow River ◽  
Source Region ◽  
Maximum Temperature ◽  
Climatic Data ◽  
The Yangtze River ◽  
Extreme Minimum Temperature ◽  
The Mean

The study of temperature change and its elevation dependency in the source region of the Yangtze River and Yellow River have been insufficient owing to the lack of adequate observation stations and long-term climatic data. In this study five temperature indices of 32 stations from 1961 to 2007 in and near the source region are used. The 32 stations all have experienced significant warming; the warming amplitudes are higher than the mean warming amplitude of the Qinghai-Tibetan plateau. The warming amplitudes and the numbers of stations showing significant warming trends in mean minimum temperature and extreme minimum temperature are higher than that of the mean maximum temperature and extreme maximum temperature. The elevation dependency of climatic warming and the amount of significant warming stations are not obvious; the influence of human activity and urbanization may be higher. The warming amplitudes of 26 stations above 3000 m tend to be uniform, and there is no significant law at 6 stations below 3000 m. On the contrary, the ratio of stations showing significant warming in minimum temperature above 4000 m is far less than that of the stations below 4000 m.

scholarly journals Discharge and Sediment Transport in a River Basin. Assessment Before and After the Construction of a Dam at the Upper Basin Boundary

2021 ◽  
Author(s):  
George Paschalidis ◽  
Ilias IIordanidis ◽  
Petros Anagnostopoulos
Keyword(s):  
Sediment Transport ◽  
Meteorological Data ◽  
Climatic Data ◽  
Northern Greece ◽  
Basin Boundary ◽  
Software Packages ◽  
Before And After ◽  
The Mean ◽  
Gis Interface ◽  
Good Agreement

Abstract The purpose of this study is the evaluation of runoff and sediment transport in the basin of the Nestos River (Northern Greece) downstream of the dam of Platanovrisi, constructed in 1998. The model used for the simulation was AGNPS, which is based on the Revised Universal Soil Loss Equation (RUSLE), combined with a GIS interface. Two different simulations were conducted, one for the years 1980-1990 and another for the period 2006-2030, before and after the construction of the dam respectively. For the simulation for the period 1980-1990 existing meteorological data were employed, and the results were in good agreement with those of a different study (Hrissanthou, 2002). The simulation for the period 2006-2030 was based on rainfall and climatic data generated from the software packages GlimClim and ClimGen. The mean runoff was by 5% lower and the mean annual sediment yield by 20% lower than the corresponding values for the period 1980-1990.

scholarly journals Loneliness and social interaction dynamics: An ambulatory assessment study in a student population

2021 ◽  
Author(s):  
Timon Elmer ◽  
Gerine M. A. Lodder
Keyword(s):  
Social Interaction ◽  
Social Interactions ◽  
Social Relationships ◽  
Sensor Data ◽  
Ambulatory Assessment ◽  
Survival Models ◽  
Qualitative And Quantitative ◽  
Fine Grained ◽  
The Mean

Loneliness is the feeling associated with a perceived lack of qualitative and quantitative aspects of social relationships. Loneliness is thus evidently intwined with individuals’ social behaviors in day-to-day life. Yet, little is known about the bidirectional pathways between loneliness and social interactions in daily life. In this study, we thus investigate (a) how loneliness predicts the frequency and duration of social interactions and (b) how frequency and duration of social interactions predict changes in loneliness. We examine these questions using fine-grained ambulatory-assessed sensor data of student’s social behavior covering 10 weeks (N_participants = 45, N_observations = 74,645). Before (T1) and after (T2) the ambulatory assessment phase, participants completed the UCLA loneliness scale, covering subscales on intimate, relational, and collective loneliness. Using multistate survival models, we show that T1 loneliness subscales are not significantly associated with differences in social interaction frequency and duration– only relational loneliness predicted shorter social interaction encounters. In predicting changes in loneliness subscales (T1-T2), only the mean duration of social interactions was negatively associated with collective loneliness. Thus, effects of loneliness on the structure of social interactions may be small or limited to specific forms of loneliness, implying that the quality of interactions may be more important.

scholarly journals How COVID-19 affects voting for incumbents: Evidence from local elections in France

2021 ◽  
Author(s):  
Davide Morisi ◽  
Héloïse Cloléry ◽  
Guillaume Kon Kam King ◽  
Max Schaub
Keyword(s):  
Propensity Score ◽  
Excess Mortality ◽  
Indirect Evidence ◽  
Mortality Data ◽  
Local Elections ◽  
Municipal Elections ◽  
Fine Grained ◽  
Dependent Variables ◽  
Left And Right ◽  
Fear And Anxiety

How do voters react to an ongoing natural threat? We address this question by investigating voters’ reactions to the early spread of COVID-19 in the 2020 French municipal elections. Using a novel, fine-grained measure of the circulation of the virus based on excess-mortality data, we find that support for incumbents increased in the areas that were particularly hit by the virus. Incumbents from both left and right gained votes in areas more strongly affected by COVID-19. The results are robust to a placebo test and hold across different methods, including regressions with lagged dependent variables, a differences-in-differences approach and propensity score matching. We also provide indirect evidence for two mechanisms that can explain our findings: an emotional channel related to feelings of fear and anxiety, and a prospective-voting channel, related to the ability of incumbents to act more swiftly against the diffusion of the virus than challengers.

scholarly journals Recent fluctuations of glaciers in Valtellina (Italian Alps) and climatic variations

1992 ◽  
Vol 38 (129) ◽  
pp. 309-313 ◽  
Author(s):  
Manuela Pelfini ◽  
Claudio Smiraglia
Keyword(s):  
Temperature Fluctuations ◽  
Winter Precipitation ◽  
Meteorological Station ◽  
Summer Temperature ◽  
Italian Alps ◽  
Climatic Variations ◽  
Alpine Glaciers ◽  
The Mean

AbstractValtellina, located in the Italian Alps of Lombardy, is extensively glaciated. Since 1925, terminal variations of the glaciers have been recorded. By analysing a significant sample of valley glaciers, we have recognized a rapid retreat of the termini which occurred between 1925 and the early 1970s. A period of advance followed, which stopped in the second half of the 1980s. The mean summer-temperature fluctuations at the meteorological station of Sondrio at the centre of Valtellina, show that the period 1925–52 was very warm, and then the temperatures dropped. The most intense winter precipitation occurred in the period 1925–37. The behaviour of these glaciers is similar to that of other Alpine glaciers, although time of response may be different.

Standardizing Instructions for Ice and Cold Pack Use Can Mitigate Summer Temperatures on Two Commercially Available Outdoor Courier Lockboxes

2021 ◽  
Vol 156 (Supplement_1) ◽  
pp. S119-S120
Author(s):  
S A Hart ◽  
J R Wiencek
Keyword(s):  
Extreme Temperatures ◽  
Direct Sunlight ◽  
Data Loggers ◽  
Summer Temperatures ◽  
The Mean ◽  
Using Data ◽  
Cold Pack ◽  
The Impact ◽  
And Storage

Abstract Introduction/Objective Clinical and Laboratory Standards Institute document GP44 recommends samples avoid temperatures >22°C during sample transport and storage. Outdoor courier lockboxes used in external sample transport can experience extreme temperatures (>40°C) in the summer. Ice (frozen at -20°C) and cold (refrigerated at 4-8°C) packs can be used to reduce internal lockbox temperatures during hot summer days. Unfortunately, there are no universally accepted instructions to maintain internal lockbox temperatures during these conditions. Therefore, our goal was to elucidate the impact of placing ice and cold packs at two specific time points to mitigate external summer temperatures in two commercially available outdoor courier lockboxes used at our institution. Methods/Case Report Two pairs of uniquely manufactured courier lockboxes (steel vs. urethane polymer) were placed outside in direct sunlight in Nashville, Tennessee during the second week of June 2021. Ambient outdoor and lockbox temperatures were monitored using data loggers during a four-day cycle. Each type of lockbox design had a control with no ice or cold packs. These controls were then compared to each experimental, paired lockbox with four ice packs placed at 8am and replaced with four cold packs at 4pm. Results (if a Case Study enter NA) The mean ambient outdoor temperature over these four days was 27.7°C (range: 22.2-39.8°C). Temperatures within the steel and urethane polymer lockboxes without ice or cold packs was 28.3°C (range: 22.4-40.8°C) and 31.6°C (range: 23.8-41.0°C), respectively. The addition of four ice packs at 8am and replaced with four cold packs at 4pm reduced temperatures in the steel box to 24.3°C (range: 17.4-27.9°C) whereas in the urethane polymer box temperatures were reduced to 13.4°C (range: 6.6-18.1°C). Conclusion Temperatures inside outdoor lockboxes can increase in summer commonly above the outdoor ambient temperature. Standardizing instructions for ice and cold packs can reduce internal outdoor courier lockbox temperatures during summer months, especially in urethane polymer lockboxes.

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