scholarly journals Changes in glacier dynamics in the northern Antarctic Peninsula since 1985

2018 ◽  
Vol 12 (2) ◽  
pp. 577-594 ◽  
Author(s):  
Thorsten Seehaus ◽  
Alison J. Cook ◽  
Aline B. Silva ◽  
Matthias Braun
Keyword(s):  
Antarctic Peninsula ◽  
West Coast ◽  
East Coast ◽  
Hierarchical Cluster ◽  
Flow Speed ◽  
Climatic Conditions ◽  
Surface Velocity ◽  
Ice Shelf ◽  
The West ◽  
Ice Dynamics

Abstract. The climatic conditions along the northern Antarctic Peninsula have shown significant changes within the last 50 years. Here we present a comprehensive analysis of temporally and spatially detailed observations of the changes in ice dynamics along both the east and west coastlines of the northern Antarctic Peninsula. Temporal evolutions of glacier area (1985–2015) and ice surface velocity (1992–2014) are derived from a broad multi-mission remote sensing database for 74 glacier basins on the northern Antarctic Peninsula ( <  65° S along the west coast and north of the Seal Nunataks on the east coast). A recession of the glaciers by 238.81 km2 is found for the period 1985–2015, of which the glaciers affected by ice shelf disintegration showed the largest retreat by 208.59 km2. Glaciers on the east coast north of the former Prince Gustav Ice Shelf extent in 1986 receded by only 21.07 km2 (1985–2015) and decelerated by about 58 % on average (1992–2014). A dramatic acceleration after ice shelf disintegration with a subsequent deceleration is observed at most former ice shelf tributaries on the east coast, combined with a significant frontal retreat. In 2014, the flow speed of the former ice shelf tributaries was 26 % higher than before 1996. Along the west coast the average flow speeds of the glaciers increased by 41 %. However, the glaciers on the western Antarctic Peninsula revealed a strong spatial variability of the changes in ice dynamics. By applying a hierarchical cluster analysis, we show that this is associated with the geometric parameters of the individual glacier basins (hypsometric indexes, maximum surface elevation of the basin, flux gate to catchment size ratio). The heterogeneous spatial pattern of ice dynamic evolutions at the northern Antarctic Peninsula shows that temporally and spatially detailed observations as well as further monitoring are necessary to fully understand glacier change in regions with such strong topographic and climatic variances.

scholarly journals Changes in glacier dynamics at the northern Antarctic Peninsula since 1985

2017 ◽  
Author(s):  
Thorsten Seehaus ◽  
Alison Cook ◽  
Aline B. Silva ◽  
Matthias H. Braun
Keyword(s):  
Antarctic Peninsula ◽  
East Coast ◽  
Temporal Trends ◽  
Climatic Conditions ◽  
Surface Velocity ◽  
Glacier Area ◽  
Ice Dynamics ◽  
Ice Shelves ◽  
Ice Surface ◽  
Glacier Dynamics

Abstract. The climatic conditions along the northern Antarctic Peninsula have shown significant changes within the last 50 years. Most studies have focused on the glaciers affected by the disintegration of the ice shelves along the east coast. However, temporally and spatially detailed observations of the changes in ice dynamics along both the east and west coastlines are missing. Temporal trends of glacier area (1985–2015) and ice surface velocity (1992–2014) changes are derived from a broad multi-mission remote sensing database for 74 glacier basins on the northern Antarctic Peninsula (

scholarly journals The retreat of Jones Ice Shelf, Antarctic Peninsula

2005 ◽  
Vol 51 (175) ◽  
pp. 555-560 ◽  
Author(s):  
Adrian J. Fox ◽  
David G. Vaughan
Keyword(s):  
Survey Data ◽  
Antarctic Peninsula ◽  
Climate Warming ◽  
West Coast ◽  
Climate Forcing ◽  
Ice Shelf ◽  
The West ◽  
Ice Shelves ◽  
East And West ◽  
The Antarctic

AbstractIn recent decades, several ice shelves along the Antarctic Peninsula have diminished in size as a result of climate warming. Using aerial photographic, satellite and survey data we document a similar retreat of Jones Ice Shelf, which was another small ice shelf on the west coast of the Antarctic Peninsula. This ice shelf was roughly stable between 1947 and 1969, but in the early 1970s it began to retreat and had completely disappeared by early 2003. Jones Ice Shelf has two ice fronts only a few kilometres apart and its retreat provides a unique opportunity to examine how different ice fronts retreat when subjected to similar climate forcing. We mapped the retreat of both the east and west ice fronts of Jones Ice Shelf and found that, although individual episodes of retreat may be related to particularly warm summers, the overall progress of retreat of the two ice fronts has been rather different. This suggests that in this case the course of retreat is controlled by the geometry of the embayment and location of pinning points as well as climatic events.

scholarly journals ENSO and Wintertime Extreme Precipitation Events over the Contiguous United States

2008 ◽  
Vol 21 (1) ◽  
pp. 22-39 ◽  
Author(s):  
Siegfried D. Schubert ◽  
Yehui Chang ◽  
Max J. Suarez ◽  
Philip J. Pegion
Keyword(s):  
United States ◽  
West Coast ◽  
Extreme Precipitation ◽  
East Coast ◽  
Daily Precipitation ◽  
Precipitation Variability ◽  
The West ◽  
Extreme Precipitation Events ◽  
The Impact ◽  
Precipitation Events

Abstract In this study the authors examine the impact of El Niño–Southern Oscillation (ENSO) on precipitation events over the continental United States using 49 winters (1949/50–1997/98) of daily precipitation observations and NCEP–NCAR reanalyses. The results are compared with those from an ensemble of nine atmospheric general circulation model (AGCM) simulations forced with observed SST for the same time period. Empirical orthogonal functions (EOFs) of the daily precipitation fields together with compositing techniques are used to identify and characterize the weather systems that dominate the winter precipitation variability. The time series of the principal components (PCs) associated with the leading EOFs are analyzed using generalized extreme value (GEV) distributions to quantify the impact of ENSO on the intensity of extreme precipitation events. The six leading EOFs of the observations are associated with major winter storm systems and account for more than 50% of the daily precipitation variability along the West Coast and over much of the eastern part of the country. Two of the leading EOFs (designated GC for Gulf Coast and EC for East Coast) together represent cyclones that develop in the Gulf of Mexico and occasionally move and/or redevelop along the East Coast producing large amounts of precipitation over much of the southern and eastern United States. Three of the leading EOFs represent storms that hit different sections of the West Coast (designated SW for Southwest coast, WC for the central West Coast, and NW for northwest coast), while another represents storms that affect the Midwest (designated by MW). The winter maxima of several of the leading PCs are significantly impacted by ENSO such that extreme GC, EC, and SW storms that occur on average only once every 20 years (20-yr storms) would occur on average in half that time under sustained El Niño conditions. In contrast, under La Niña conditions, 20-yr GC and EC storms would occur on average about once in 30 years, while there is little impact of La Niña on the intensity of the SW storms. The leading EOFs from the model simulations and their connections to ENSO are for the most part quite realistic. The model, in particular, does very well in simulating the impact of ENSO on the intensity of EC and GC storms. The main model discrepancies are the lack of SW storms and an overall underestimate of the daily precipitation variance.

scholarly journals Climatic conditions, mass balance and dynamics of Larsen B ice shelf, Antarctic Peninsula, prior to collapse

2004 ◽  
Vol 39 ◽  
pp. 557-562 ◽  
Author(s):  
Pedro Skvarca ◽  
Hernán De Angelis ◽  
Andrés F. Zakrajsek
Keyword(s):  
Mass Balance ◽  
Antarctic Peninsula ◽  
Satellite Image ◽  
Climatic Conditions ◽  
Strain Rates ◽  
Ice Shelf ◽  
Ice Flow ◽  
Ice Shelves ◽  
Additional Information ◽  
Significant Acceleration

AbstractFollowing the collapse of Larsen A in 1995, about 3200 km2 of Larsen B ice shelf disintegrated in early 2002 during the warmest summer recorded on the northeastern Antarctic Peninsula. Immediately prior to disintegration the last field campaign was carried out on Larsen B. Measurements included surface net mass balance, velocity and strain rate on a longitudinal transect along Crane Glacier flowline and over a remnant section confined within Seal Nunataks that survived the collapse. In addition, an automatic weather station located nearby allowed derivation of melt days relevant to the formation and extent of surface meltwater. Repeated surveys allowed us to detect a significant acceleration in ice-flow velocity and associated increasing strain rates along the longitudinal transect. It may be possible to use this acceleration as a predictor of imminent ice-shelf collapse, applicable to ice shelves subject to similar climatic conditions. Additional information on recent ongoing changes was provided by a visible satellite image acquired in early 2003.

RESEARCH ON PREMATURE INFANTS—SOME PERSPECTIVES

PEDIATRICS ◽  
1963 ◽  
Vol 32 (3) ◽  
pp. 319-325
Author(s):  
S. Z. LEVINE
Keyword(s):  
Clinical Research ◽  
Premature Infants ◽  
West Coast ◽  
East Coast ◽  
Good Friend ◽  
The West ◽  
Clinical Research Center ◽  
Principle Investigator ◽  
Long Time ◽  
The Many

THERE ARE A number of reasons why I appreciate deeply your invitation to join in these dedication exercises of the Clinical Research Center for Premature Infants. This Center for the care and study of premature infants extends to the West Coast a field of study in which I, on the East Coast, have been interested for many years. Equally gratifying is the circumstance that it will have Dr. Norman Kretchmer, my long-time colleague and good friend, as its Principle Investigator; and Dr. Sumner Yaffe, his distinguished associate, as its first Program Director. Under their direction and with a team of competent workers, with splendid facilities and an adequate budget, we are assured of imaginative exploration and new approaches to the many unknowns still awaiting solution.

Quantitative seismicity maps of India

1972 ◽  
Vol 62 (5) ◽  
pp. 1119-1132 ◽  
Author(s):  
K. L. Kaila ◽  
V. K. Gaur ◽  
Hari Narain
Keyword(s):  
Return Period ◽  
West Coast ◽  
Active Zone ◽  
East Coast ◽  
Indian Subcontinent ◽  
B Value ◽  
Tibet Plateau ◽  
The West ◽  
Period Map ◽  
A Value

Abstract Using the Kaila and Narain (1971) method, three quantitative seismicity maps have been prepared for the Indian subcontinent which are compared with regional tectonics. These are the A-value map, the b-value map and the return-period map for earthquakes with magnitude 6 and above where A and b are the constants in the cumulative regression curve represented by log N = A - bM. The A-value seismicity map shows that India can be divided into two broad seismic zones, the northern seismically highly active zone and the southern moderately active zone. In the northern active zone, a number of seismic highs have been delineated such as the Pamir high, the northwest-southeast trending Srinagar-Almora high, the Shillong massif high, the Arakan Yoma high and the West Pakistan highs. These seismic highs are consistent with the Himalayan tectonic trends. Contrary to this, two seismic highs fall in the Tibet plateau region which align transversely to the main Himalayan trend. In the southern moderately active zone, two seismic highs are clearly discernible, the east and the west coast high, the latter being seismically more active than the former. The least active zone encompasses the Vindhyan syncline and the areas of Delhi and Aravalli folding. Between this zone and the east coast high lies another moderately active zone which encloses the Godavari graben, western part of the Mahanadi graben and the Chattisgarh depression. The b-value seismicity map also demarcates the same active zones as are brought out on the A-value map. The return-period map of India for earthquakes with magnitude 6 and above shows a minimum return period of 100 years in the Pamirs, about 130 years in the various seismic highs in the northern active zone, 180 years on the west coast high, 200 years on the east coast high and about 230 years in the least active Vindhyan-Aravalli zone and the Hyderabad-Kurnool area. These quantitative seismicity maps are also compared with the seismic zoning map of Indian Standards Institution and seismicity maps of India prepared by other workers.

The I-4 Corridor

2019 ◽  
pp. 76-108
Author(s):  
Susan A. MacManus ◽  
David J. Bonanza ◽  
Anthony A. Cilluffo
Keyword(s):  
West Coast ◽  
Political Geography ◽  
East Coast ◽  
The West ◽  
Rural Counties

This chapter examines the critical political geography of Florida—the 130-mile expanse from Tampa on the west coast to Daytona Beach on the east coast known as the I-4 corridor.This mix of urban, suburban, and rural counties usually decides elections in Florida.

scholarly journals A Recent History of 14C, 137Cs, 210Pb, and 241Am Accumulation at Two Irish Peat Bog Sites: an East Versus West Coast Comparison

Radiocarbon ◽  
2001 ◽  
Vol 43 (2B) ◽  
pp. 517-525 ◽  
Author(s):  
D Gallagher ◽  
E J McGee ◽  
P I Mitchell
Keyword(s):  
West Coast ◽  
East Coast ◽  
Similar Sequence ◽  
The West ◽  
Nuclear Weapons Testing ◽  
History Of ◽  
The Difference ◽  
The Uk ◽  
Ombrotrophic Peat ◽  
Coast Site

Data on radiocarbon (14C), 137Cs, 210Pb, and 241Am levels in an ombrotrophic peat sequence from a montane site on the east coast of Ireland are compared with data from a similar sequence at an Atlantic peatland site on the west coast. The 14C profiles from the west and east coasts show a broadly similar pattern. Levels increase from 100 pMC or less in the deepest horizons examined, to peak values at the west and east coast sites of 117 ± 0.6 pMC and 132 ± 0.7 pMC, respectively (corresponding to maximal fallout from nuclear weapons testing around 1964), thereafter diminishing to levels of 110–113 pMC near the surface. Significantly, peak levels at the east coast site are considerably higher than corresponding levels at the west coast site, though both are lower than reported peak values for continental regions. The possibility of significant 14C enrichment at the east coast site due to past discharges from nuclear installations in the UK seems unlikely. The 210Pbex inventory at the east coast site (6500 Bq m−2) is significantly higher than at the west coast (5300 Bq m−2) and is consistent with the difference in rainfall at the two sites. Finally, 137Cs and 241Am inventories at the east coast site also exceed those at the west coast site by similar proportions (east:west ratio of approximately 1:1.2).

scholarly journals State of Balance of the Ice Sheet in the Antarctic Peninsula

1982 ◽  
Vol 3 ◽  
pp. 77-82 ◽  
Author(s):  
Christopher S. M. Doake
Keyword(s):  
Antarctic Peninsula ◽  
East Coast ◽  
Accumulation Rate ◽  
Level Line ◽  
Ice Shelf ◽  
High Accumulation ◽  
Glacier Recession ◽  
Valley Glacier ◽  
The Antarctic ◽  
Small Valley

Data from ice rises on the east coast of the Antarctic Peninsula can be interpreted as showing that the ice is thinning at rates of up 0.5 m a−1. However, a level line between two nunataks in Palmer Land showed no change in surface elevation over a period of 5 a. Melt rates on George VI Ice Shelf vary with position and may indicate that parts of the ice shelf are thickening at the rate of several m a−1, presumably in response to a higher accumulation rate over the peninsula a few hundred years ago. A small valley glacier, Spartan Glacier, is wasting away at about 0.27 m a−1. Ice fronts on both east and west coasts of the peninsula have been retreating for the last 30 a. It seems that there is general glacier recession in response to a wanner climate and decreased snowfall for at least the last 30 a, while parts of the peninsula are still thickening in response to a high accumulation rate several hundred years ago.

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