scholarly journals A ring-width-based reconstruction of June–July minimum temperatures since AD 1245 from white spruce stands in the Mackenzie Delta region, northwestern Canada

2013 ◽  
Vol 80 (2) ◽  
pp. 167-179 ◽  
Author(s):  
Trevor J. Porter ◽  
Michael F.J. Pisaric ◽  
Steven V. Kokelj ◽  
Peter deMontigny
Keyword(s):  
20Th Century ◽  
Large Scale ◽  
Ring Width ◽  
White Spruce ◽  
Mackenzie Delta ◽  
Delta Region ◽  
Late 20Th Century ◽  
Climate History ◽  
Study Region ◽  
June July

We present a reconstruction of June–July minimum temperatures since AD 1245 for the Mackenzie Delta region based on a 29-site network of white spruce (Picea glauca) ring-width series. Most but not all trees experienced a divergent temperature–growth response, similar to the divergence that has affected other white spruce trees across Yukon and Alaska. However, divergence in the study region began as early as AD 1900 and we have documented our methods to avoid including divergent signals in the reconstruction. Calibration/verification testing based on local temperature data, and multi-century coherence with nearby and large-scale temperature proxy records, confirm that our reconstruction is robust. The reconstruction shows cool conditions in the late 13th, early 18th and early 19th centuries, corresponding with solar minima and increased volcanism. These cool periods are interrupted by warm periods consistent with early to mid-20th century warmth. The late 20th century is the warmest interval, and the last decade is estimated to be 1.4°C warmer than any decade before the mid-20th century. The reconstructed climate history corroborates other proxy-based inferences and supports the notion that high-latitude regions such as the Mackenzie Delta have experienced rapid warming in recent decades that is exceptional in the last eight centuries.

scholarly journals Urban Policies and Large Projects in Central City Areas: The Example of Madrid (Spain)

Urban Science ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 42
Author(s):  
Dolores Brandis García
Keyword(s):  
Urban Planning ◽  
20Th Century ◽  
Large Scale ◽  
Central City ◽  
Global Market ◽  
Late 20Th Century ◽  
Public And Private ◽  
Urban Policies ◽  
Starting Point ◽  
The City

Since the late 20th century major, European cities have exhibited large projects driven by neoliberal urban planning policies whose aim is to enhance their position on the global market. By locating these projects in central city areas, they also heighten and reinforce their privileged situation within the city as a whole, thus contributing to deepening the centre–periphery rift. The starting point for this study is the significance and scope of large projects in metropolitan cities’ urban planning agendas since the final decade of the 20th century. The aim of this article is to demonstrate the correlation between the various opposing conservative and progressive urban policies, and the projects put forward, for the city of Madrid. A study of documentary sources and the strategies deployed by public and private agents are interpreted in the light of a process during which the city has had a succession of alternating governments defending opposing urban development models. This analysis allows us to conclude that the predominant large-scale projects proposed under conservative policies have contributed to deepening the centre–periphery rift appreciated in the city.

European Tapestries

2021 ◽  
Keyword(s):  
New York ◽  
Cultural History ◽  
20Th Century ◽  
Art History ◽  
Large Scale ◽  
Early Modern Period ◽  
Metropolitan Museum ◽  
Late 20Th Century ◽  
Art Form ◽  
New Research

Tapestry, the most costly and coveted art form in Renaissance and Baroque Europe, has long fascinated scholars. In the 19th and early 20th centuries, researchers delved into archival sources and studied extant tapestries to produce sweeping introductions to the medium. The study of tapestry, however, fell outside mainstream art history, with tapestry too often seen as a less important “decorative art” rather than a “fine art.” , Also, tapestry did not fit easily into an art history that prioritized one master, as the making of a set of large-scale tapestries required a team of collaborators, including the designer, cartoon painters, and weavers, as well as a producer/entrepreneur and, often, a patron. Scholarship on European tapestries in the Early Modern period, nevertheless, flourished. By the late 20th century art historians turned attention to the “decorative arts” and tapestry specialists produced exciting new research illuminating aspects of design, production, and patronage, as well as tapestry’s crucial role in the larger narrative of art and cultural history. In 2002, the Metropolitan Museum of Art’s landmark exhibition and catalogue, Tapestry in the Renaissance: Art and Magnificence, spotlighted the art form, introduced it to a broad audience, and brought new understanding of tapestry as art. A sequel, the Met’s 2007 exhibition and catalogue, Tapestry in the Baroque: Threads of Splendor, followed. Other major museums presented ambitious exhibitions, accompanied by catalogues with substantial new research. In addition, from the late 20th century, institutions have produced complete catalogues of their extraordinary European tapestry holdings, among them: the Metropolitan Museum of Art in New York; the Patrimonio Nacional in Spain; the Rijksmuseum in Amsterdam; the Art Institute of Chicago; and the Burrell Collection in Glasgow. At the same time, articles and books exploring specific designs, designers, producers, and patrons appeared, with some monographs published in the dedicated series, Studies in Western Tapestry, edited by leading scholars Guy Delmarcel and Koenraad Brosens, and produced by Brepols. Tapestry research has often focused on the works of well-known designers and their exceptionally innovative work, such as the artists Raphael (b. 1483–d. 1520) or Peter Paul Rubens (b. 1577–d. 1640). High-quality production at major centers, including Brussels or at the Gobelins Manufactory in France, has also captured scholars’ attention, as have important patrons, among them Henry VIII of England (b. 1491–d. 1547) or Louis XIV of France (b. 1638–d. 1715). Newer directions for research include the contributions of women as weavers and entrepreneurs, the practice of reweaving designs, and the international reach and appeal of Renaissance and Baroque tapestry beyond Europe.

Cessation of ice-wedge development during the 20th century in spruce forests of eastern Mackenzie Delta, Northwest Territories, Canada

2007 ◽  
Vol 44 (11) ◽  
pp. 1503-1515 ◽  
Author(s):  
S V Kokelj ◽  
M FJ Pisaric ◽  
C R Burn
Keyword(s):  
20Th Century ◽  
Ice Age ◽  
Spruce Forest ◽  
Mackenzie Delta ◽  
Study Region ◽  
Near Surface ◽  
Spruce Forests ◽  
Surface Temperatures ◽  
Forest Sites ◽  
Ice Wedge

Ice wedges are presently inactive in white spruce (Picea glauca) forests of eastern Mackenzie Delta as shown by the absence of vein ice above ice wedges, the maintenance of intact breaking cables, and the abundance of rootlets propagating across ridge–trough sequences. At spruce forest sites, near-surface ground cooling rates and minimum near-surface temperatures from the years 2003–2005 were above ice-wedge cracking thresholds. Ground thermal conditions associated with cracking were recorded at a tundra peatland with active ice wedges. Annual mean permafrost temperatures at the spruce forest sites ranged from –1.8 to –2.9 °C, whereas at the tundra peatland, the permafrost was colder than –6 °C. Although winter air temperatures are similar throughout the study region, deeper snow cover, thicker active layers, and warmer permafrost account for the more gradual seasonal cooling and warmer near-surface temperatures recorded at the subarctic forest sites. The subtle ridge to trough relief, 12–35 cm of permafrost above wedge ice, roots up to 80 years old grown across ice wedges, and negligible tritium levels in wedge ice indicate that thermal contraction cracking in the spruce forests has been infrequent throughout much of the last century. The proximity of wedge ice to the base of the aggrading permafrost table and the absence of old spruce roots spanning ice-wedge troughs suggest that ice-wedge cracking did occur in the forest environments during the cold and dry conditions associated with the Little Ice Age and early part of the 20th century. When these ice wedges cracked, minimum temperatures at the top of permafrost were probably at least 3–8 °C colder than presently observed and similar to present conditions at the tundra peatland.

scholarly journals How unusual was late 20th century El Niño-Southern Oscillation (ENSO)? Assessing evidence from tree-ring, coral, ice-core and documentary palaeoarchives, A.D. 1525-2002

2006 ◽  
Vol 6 ◽  
pp. 173-179 ◽  
Author(s):  
J. L. Gergis ◽  
A. M. Fowler
Keyword(s):  
20Th Century ◽  
Tree Ring ◽  
El Niño ◽  
Large Scale ◽  
El Nino ◽  
Southern Oscillation ◽  
Enso Event ◽  
Late 20Th Century ◽  
Enso Events ◽  
Proxy Records

Abstract. Multiple proxy records (tree-ring, coral, ice and documentary) were examined to isolate ENSO signals associated with both phases of the phenomenon for the period A.D. 1525-2002. To avoid making large-scale inferences from single proxy analysis, regional signals were aggregated into a network of high-resolution records, revealing large-scale trends in the frequency, magnitude and duration of pre-instrumental ENSO using novel applications of percentile analysis. Here we use the newly introduced coupled ocean-atmosphere ENSO index (CEI) as a baseline for the calibration of proxy records. The reconstruction revealed 83 extreme or very strong ENSO episodes since A.D. 1525, expanding considerably on existing ENSO event chronologies. Significantly, excerpts of the most comprehensive list of La Niña events complied to date are presented, indicating peak activity during the 16th to mid 17th and 20th centuries. Although extreme events are seen throughout the 478-year reconstruction, 43% of the extreme ENSO events noted since A.D. 1525 occur during the 20th century, with an obvious bias towards enhanced El Niño conditions in recent decades. Of the total number of extreme event years reconstructed, 30% of all reconstructed ENSO event years occur post-1940 alone suggesting that recent ENSO variability appears anomalous in the context of the past five centuries.

scholarly journals Consumption and teleoaffective formations: Consumer culture and commercial communications

2017 ◽  
Vol 20 (1) ◽  
pp. 61-82 ◽  
Author(s):  
Daniel Welch
Keyword(s):  
Public Relations ◽  
20Th Century ◽  
Consumer Culture ◽  
Large Scale ◽  
Sustainable Consumption ◽  
Social Ontology ◽  
Theoretical Concept ◽  
Cultural Resources ◽  
Late 20Th Century ◽  
Consumer Sovereignty

This article considers the potential of a novel practice theoretical concept – teleoaffective formation – for the study of consumption. The concept builds on Schatzki’s social ontology of practice. Teleoaffective formations are configurations across multiple practices that enjoin those practices to common ends, ordering their affective engagements and offering general understandings through which participants make sense of the projects they pursue. This article argues that the approach affords consideration of large-scale configurations of practice and discourse and, therefore, enables re-engagement, from a practice theory perspective, with an earlier generation of concerns with consumer culture – including issues of cultural intermediation, consumption norms and the motivational structures of consumption. The distinctive features of the approach are illustrated through three successive teleoaffective formations that link the field of commercial communications (advertising, marketing, public relations, etc.) with consumer culture. The first – ‘consumer sovereignty’ – originates in the 1920s and 1930s and finds its fullest expression in the mid-20th century. The second – ‘emancipatory consumerism’ – emerged in the late 1960s and came to characterise late 20th-century consumer culture. These are briefly sketched. The third, which I propose to call ‘promotional sustainable consumption’, is a nascent formation of discourse and practice relating brands, sustainability and consumption. This formation is explored in more depth. The periodisation should not be understood in terms of epochal shifts but as an ongoing, recombinatory process. The three formations represent reconfigurations between heterogeneous elements, inter alia: general understandings, teleological orientations and affective engagements. Each successive formation informs novel understandings of the consumer and provides cultural resources for transformations in consumption norms. Each also provides resources for capitalist legitimation. The article concludes with a brief discussion of some theoretical and methodological implications of the approach.

scholarly journals A history of biogeographical regionalisation in Australia

Zootaxa ◽  
2012 ◽  
Vol 3392 (1) ◽  
pp. 1 ◽  
Author(s):  
MALTE C. EBACH
Keyword(s):  
20Th Century ◽  
Large Scale ◽  
Biological Diversity ◽  
Short Term ◽  
Late 20Th Century ◽  
Biodiversity Crisis ◽  
History Of

The development of Australian biogeographical regionalisation since 1858 has been driven by colonial 19th-centuryexploration and by the late 20th-century biodiversity crisis. The intervening years reduced existing large scaleregionalisation into smaller taxon specific areas of vegetation or endemism. However, large scale biotic biogeographicalregionalisation was rediscovered during multi-disciplinary meetings and conferences, sparking short-term revivals whichhave ended in constant revisions at smaller and smaller taxonomic scales. In 1995 and 1998, the Interim BiogeographicRegionalisation for Australia and the Integrated Marine and Coastal Regionalisation of Australia, AustralianCommonwealth funded initiatives in order to “identify appropriate regionalisations to assess and plan for the protectionof biological diversity”, have respectively replaced 140 years of Australian biogeographical regionalisation schemes. Thispaper looks at the rise and slow demise of biogeographical regionalisation in Australia in light of a fractured taxonomic biogeographical community.

scholarly journals Climatic Signals in δ13C and δ18O of Tree-rings from White Spruce in the Mackenzie Delta Region, Northern Canada

2009 ◽  
Vol 41 (4) ◽  
pp. 497-505 ◽  
Author(s):  
Trevor J. Porter ◽  
Michael F. J. Pisaric ◽  
Steven V. Kokelj ◽  
Thomas W. D. Edwards
Keyword(s):  
Tree Rings ◽  
White Spruce ◽  
Mackenzie Delta ◽  
Delta Region ◽  
Northern Canada ◽  
Climatic Signals ◽  
Δ13c And Δ18o

scholarly journals Assessing Spatiotemporal Variations of Landsat Land Surface Temperature and Multispectral Indices in the Arctic Mackenzie Delta Region between 1985 and 2018

2019 ◽  
Vol 11 (19) ◽  
pp. 2329 ◽  
Author(s):  
Leon Nill ◽  
Tobias Ullmann ◽  
Christof Kneisel ◽  
Jennifer Sobiech-Wolf ◽  
Roland Baumhauer
Keyword(s):  
Land Surface ◽  
Large Scale ◽  
Vegetation Index ◽  
Google Earth ◽  
Influential Factors ◽  
The Arctic ◽  
Moisture Regime ◽  
Mackenzie Delta ◽  
Delta Region

Air temperatures in the Arctic have increased substantially over the last decades, which has extensively altered the properties of the land surface. Capturing the state and dynamics of Land Surface Temperatures (LSTs) at high spatial detail is of high interest as LST is dependent on a variety of surficial properties and characterizes the land–atmosphere exchange of energy. Accordingly, this study analyses the influence of different physical surface properties on the long-term mean of the summer LST in the Arctic Mackenzie Delta Region (MDR) using Landsat 30 m-resolution imagery between 1985 and 2018 by taking advantage of the cloud computing capabilities of the Google Earth Engine. Multispectral indices, including the Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI) and Tasseled Cap greenness (TCG), brightness (TCB), and wetness (TCW) as well as topographic features derived from the TanDEM-X digital elevation model are used in correlation and multiple linear regression analyses to reveal their influence on the LST. Furthermore, surface alteration trends of the LST, NDVI, and NDWI are revealed using the Theil-Sen (T-S) regression method. The results indicate that the mean summer LST appears to be mostly influenced by the topographic exposition as well as the prevalent moisture regime where higher evapotranspiration rates increase the latent heat flux and cause a cooling of the surface, as the variance is best explained by the TCW and northness of the terrain. However, fairly diverse model outcomes for different regions of the MDR (R2 from 0.31 to 0.74 and RMSE from 0.51 °C to 1.73 °C) highlight the heterogeneity of the landscape in terms of influential factors and suggests accounting for a broad spectrum of different factors when modeling mean LSTs. The T-S analysis revealed large-scale wetting and greening trends with a mean decadal increase of the NDVI/NDWI of approximately +0.03 between 1985 and 2018, which was mostly accompanied by a cooling of the land surface given the inverse relationship between mean LSTs and vegetation and moisture conditions. Disturbance through wildfires intensifies the surface alterations locally and lead to significantly cooler LSTs in the long-term compared to the undisturbed surroundings.

scholarly journals Reconstruction of June–July Temperatures Based on a 233 Year Tree-Ring of Picea jezoensis var. microsperma

Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 416 ◽  
Author(s):  
Yangao Jiang ◽  
Xue Yuan ◽  
Junhui Zhang ◽  
Shijie Han ◽  
Zhenju Chen ◽  
...  
Keyword(s):  
Correlation Analysis ◽  
Southern Oscillation ◽  
Ring Width ◽  
Temperature Series ◽  
Maximum Temperature ◽  
Limiting Factor ◽  
Picea Jezoensis ◽  
Study Region ◽  
Reconstructed Temperature ◽  
June July

In this study, ring-width chronology of Picea jezoensis var. microsperma from the Changbai Mountain (CBM) area, Northeast China, was constructed. Growth/climate responses suggested that mean maximum temperature (Tmax) was the limiting factor affecting radial growth of PJ trees in the study region. According to the correlation analysis between the ring-width index and meteorological data, a June–July mean maximum temperature (Tmax6–7) series between 1772 and 2004 was reconstructed by using the standard chronology. For the calibration period (1959–2004), the explained variance of the reconstruction was 41.6%. During the last 233 years, there were 36 warm years and 34 cold years, accounting for 15.5% and 14.7% of the total reconstruction years, respectively. Cold periods occurred in 1899–1913, 1955–1970, and 1975–1989, while warm periods occurred in 1881–1888. The reconstructed temperature series corresponded to the historical disaster records of extreme climatic events (e.g., drought and flood disasters) in this area. Comparisons with other temperature reconstructions from surrounding areas and spatial correlation analysis between the gridded temperature data and reconstruction series indicated that the regional climatic variations were well captured by the reconstruction. In addition, multi-taper method spectral analysis indicated the existence of significant periodicities in the reconstructed series. The significant spatial correlations between the reconstructed temperature series and the El Niño–Southern Oscillation (ENSO), solar activity, and Pacific Decadal Oscillation (PDO) suggested that the temperature in the CBM area indicated both local-regional climate signals and global-scale climate changes.

scholarly journals RAINFALL AND THE WIDTH OF ANNUAL RINGS IN PLANTED WHITE SPRUCE

1961 ◽  
Vol 37 (2) ◽  
pp. 96-101 ◽  
Author(s):  
Daniel Gagnon
Keyword(s):  
Picea Glauca ◽  
Annual Ring ◽  
Ring Width ◽  
White Spruce ◽  
Monthly Precipitation ◽  
Annual Rings ◽  
Annual Ring Width ◽  
The Past ◽  
The Mean ◽  
June July

The influence of monthly rainfall on the mean annual ring width in a 31-year-old plantation of white spruce, Picea glauca (Moench) Voss, on sandy soils near Grand'Mère, Quebec, was studied. Analysis carried out on 43 dominant trees growing without competition on a very poor dry site of coarse material indicated that current mean annual ring width is closely related to the mean monthly precipitation during June, July and August of the preceding year. Although this relationship was evident for the past 18 years, the possibility that other factors may act concurrently is recognized.

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