Iceberg

In his post-WWI and semi-autobiographical novel, entitled “A Farewell to Arms”, Ernest Hemingway wrote with the iceberg theory in mind. Using a psychological term such as the iceberg theory, which is usually only used to analyse a person’s behaviour and characteristics, Hemingway showed just how the same iceberg theory can be used in literature. And he even used his own literary work as a great example. This paper will be focusing on (1) what is the iceberg model / theory, (2) how Ernest Hemingway used the iceberg theory in his novel “A Road to Arms”, and (3) how the iceberg theory influence the readers.

Certains parlent des icebergs comme de simples blocs de glace, « gaspillés » sans avoir été utilisés lorsqu’ils fondent dans la mer. Malgré l’optimisme des années 1970, la technologie ne permet pas encore de faire verdir le désert avec des icebergs transportés de l’Antarctique. Les icebergs du Groenland, par contre, lorsqu’ils dérivent en eau internationale, sont déjà exploités à des fins d’embouteillage commercial. Or, plus qu’un habitat pour la faune marine, le processus de vêlage et de fonte des icebergs aurait aussi un impact certain sur les courants marins et le climat de la planète.

Artists of this early period of exploration often relied on familiar artistic tropes when creating visual representations of the Arctic.  Pictorial modes presently popular in England, such as the sublime and the picturesque, supplied artists with an accepted, reliable framework to which they could adapt the Arctic landscape.  This made the Arctic more comprehensible and palatable for their audience.  Rather than presenting realistic depictions, the artists heightened the picturesque, sublime, or fantastical elements therein. In applying these British conventions to the Arctic, artists declared their power over the landscape.

This paper deals with the integrated numerical analysis of iceberg collisions with ship sides. A nonlinear explicit commercial code LS-DYNA 971 was used in the analysis. The deformations and fracture of both the ship structure and iceberg are considered. The RTCL failure criterion is applied to simulate steel fracture, whereas the iceberg fracture model is simulated by a plastic strain and pressure-based empirical failure criterion. Material models for steel and iceberg are implemented in the commercial code through a user-defined subroutine. For simplicity, the ship-iceberg collision is split into external and internal mechanics. Thus, only part of the ship structure and iceberg is modelled in the numerical simulations. The ship structure is based on the drawings of an ice-strengthened FPSO, and only the side structure is modelled. The structure model has been enlarged to minimise boundary influences. Different shapes for the leading edges of the iceberg are proposed, namely so-called " sharp " , " blunt " and " intermediate " icebergs. The iceberg shapes are simply represented by revolving a parabolic or circular profile line about its symmetry axis. Four profiles are proposed. Three different collision locations were simulated as well. Rigid analyses have also been performed. Finally, 24 numerical simulations have been carried out. The results for the maximum deflection of the outer and inner shells and the total internal energy are presented. Discussions and conclusions based on the results are provided as well. Introduction Arctic waters are attracting researchers and engineers due to the large reserves of oil and gas and the potential for new sailing routes through this area. It is expected that ship traffic will increase in this area in the near future. Thus, the probability of ship/iceberg collision increases, and it is necessary to investigate ship and iceberg collision problems in Arctic and sub-Arctic waters. This paper presents a study on the numerical simulation of iceberg collisions with ship sides.

As a high-nutrient and low-chlorophyll region, the modern Gulf of Alaska (GoA) is strongly  impacted by the limitation of iron. Paleostudies along the Alaskan slope have mainly focused on reconstructing  environmental conditions over the past 18 ka. Based on micropaleontological, biogeochemical, and  sedimentological parameters, we explore a sediment record covering the past 54 ka at Integrated Ocean Drilling  Program Site U1419 to understand the impact of orbital- and suborbital scale climate variability on productivity  and sea-surface conditions. Close to the Cordilleran Ice Sheet (CIS), Site U1419 is ideally located to elucidate  how the evolution of a large ice mass and glacial processes affected orbital- and suborbital-scale changes in  nutrients (e.g., iron) supply. Meltwater discharge from the northern CIS impacted sea surface dynamics of GoA  coastal waters. The corresponding increases in bulk biogenic concentrations during Marine Isotope Stage (MIS)  3 and MIS 2 (54–17 ka) suggests a direct impact from iron fertilization. The lack of a consistent relationship  between productivity and SST suggests that cooling of surface waters was not the dominant control on primary  producers. The inundation of the subaerially exposed continental shelf during the last deglacial (17–10 ka)  warming could have served as a major micronutrient source, accounting for a deglacial peak in production. Low  productivity after the last deglaciation suggests reduced iron availability, which we link to reduced meltwater inputs from smaller ice masses onshore. Our multiproxy approach reveals a more comprehensive picture of  late Quaternary productivity variations compared to earlier studies along the Alaskan margin. The impact of  tidewater glaciers and meltwater discharge on past marine productivity and nutrient budget dynamics of high-latitude coastal regions is discussed.

The present paper considers numerical modelling of ship–iceberg collisions with emphasis on material modelling. A material model is proposed for ice. The model is pressure-dependent and strain rate-independent. The so called Tsai-Wu yield surface envelop is adopted, and plastic flow theory is used to derive the constitutive relationships. The ice is assumed to be isotropic, the temperature profile of icebergs is considered in the present model, and the influence of strain rate is discussed. A user-defined failure criterion is proposed; the criterion is based on effective plastic strain and hydrostatic pressure and enables crack initiation and damage evolution. The material model has been simulated using the commercial code LS-DYNA. Both local and global contact pressures have been investigated. Numerical examples show that the present model produces reasonably good results. It is applied to integrated analysis of iceberg impacts for the Accidental Limit State. Results from simulations of a head-on collision between a ship bow and icebergs are presented and discussed with respect to validity.

Lost Beauty: Icebergs investigates the history of how the project came together, the process of creating the painting,  the book designer's thought process in the layout of the publication, and the dramatic effects of climate change on the Breiđamerkurjökull glacier and the rest of the world.

Data warehousing is an environment which will allows the various categories of the source data in the formats of ERP, XML, Relational model, Flat Files (.DOCS, Excel sheets, .PPT...)which is in the area of Online Transaction Processing(OLTP),later the data will be integrated into the uniform format and stored into a data warehousing, Data Marts. Finally the data will be processed to produce the results in the form of Reports which is known as Online Analytical Processing (OLAP).The ultimate goal of data warehousing is to produce strategic decisions by making analysis in the huge amount of the data. Processing of the huge amounts of the data in the fastest manner is the mandatory requirement in the data warehousing. One of the possible and best solutions to handle faster data processing is the mechanism of Indexing. This research article gives the existing indexing techniques and their suitability with various categories and workloads. Identification of the dimension data with slowly changing dimension (SCD) property, and processing of TYPE-1, TYPE-2, TYPE-3, TYPE-4 and TYPE-6. The article also provides the research issues in the establishment of the indexing mechanism on relational, web based and Flat file kinds of the data. The paper describes the available indexes and process of selecting new index techniques according to workloads and category of the data and there is a requirement of new encoding technique for handling bitmap indexing technique, we will give the presentation of algorithm which is dealing with amounts of the data, categories of the data. Another issue is regarding with uncertain data which is a big challenge in data processing. With the usage of softest computing we can handle the uncertain data in the data warehousing indexing mechanisms. The research article deals with the preprocessing considerations in the handling of Bitmap indexing creation, which will help the processing of the data warehousing data in effective and efficient manner.

Future iceberg and meltwater discharge from the Antarctic ice sheet (AIS) could substantially exceed present levels, with strong implications for future climate and sea levels. Recent climate model simulations on the impact of a rapid disintegration of the AIS on climate have applied idealized freshwater forcing scenarios 1,2 rather than the more realistic iceberg forcing. Here we use a coupled climate-iceberg model to determine the climatic effects of combined iceberg latent heat of fusion and freshwater forcing. The iceberg forcing is derived from an ensemble of future simulations conducted using the Penn State ice-sheet model 3. In agreement with previous studies , the simulated AIS meltwater forcing causes a substantial delay in greenhouse warming in the Southern Hemisphere and activates a transient positive feedback between surface freshening , subsurface warming and ice-sheet/shelf melting, which can last for about 100 years and may contribute to an accelerated ice loss around Antarctica. However, accounting further for the oceanic heat loss due to iceberg melting considerably increases the surface cooling effect and reduces the subsur-face temperature feedback amplitude. Our findings document the importance of considering realistic climate-ice sheet-iceberg coupling for future climate and sea-level projections. Recent ice-sheet simulations suggest that future AIS discharge could increase substantially towards the end of this century, attaining values of >1 Sv (1 Sv = 10 6 m 3 s-1 ≈ 31,500 Gt yr-1 ≈ 0.087 m sea-level equivalent (SLE) yr-1) 3-6. With AIS discharge causing reduced Southern Hemisphere surface temperatures 1,7-12 , freshwater forcing of this magnitude could delay Southern Hemisphere greenhouse warming by up to several decades 2. Moreover, AIS discharge has been shown to lead to increased subsurface ocean temperatures around Antarctica, which may provide a positive feedback to AIS melting 1,2,4,6,12-14. Previous simulations have applied either climate forcing to ice-sheet models 3 or ice-sheet freshwater forcing to climate models 2. Important feedbacks among atmosphere, ocean and the AIS are therefore not properly resolved. Moreover, the amplitude of future AIS discharge remains highly uncertain, even in response to specific warming scenarios 15. Processes such as hydrofractur-ing, ice-cliff instability and basal melting are observationally not well constrained 5. Resulting uncertainties translate into uncertainties in global sea-level projections and AIS discharge, which are reflected in substantial discrepancies between different state-of-the-art estimates of future contributions to sea-level changes from the AIS 2,3,5,6,15. Models also do not agree well on the partition between basal melting and calving fluxes 6,16. In more realistic scenarios, calving icebergs are advected by ocean currents and winds, influencing the ocean, sea ice and climate along their trajectories by continuously changing freshwater and heat fluxes 17,18. Iceberg melting is also modulated seasonally, as sea ice, winds, ocean currents and temperatures change dramatically around Antarctica 19. This fundamental process has not been properly included in future climate and sea-level projections. To improve our understanding of the climatic response to future changes in the AIS, we use the earth system model of intermediate complexity (LOVECLIM, see Methods) under the representative concentration pathway (RCP) 4.5 and 8.5 GHG emission scenarios (RCP4.5 and RCP8.5, respectively). We further apply a wide range of freshwater and iceberg forcing scenarios derived from ice-sheet model simulations conducted with the Penn State ice-sheet model 16. The low computational cost of LOVECLIM allows us to conduct a large number of ensemble simulations with varying AIS meltwater/ iceberg discharge amplitude (Fig. 1; Methods). The thermodynamic and dynamic impacts of icebergs are tested by varying the implementation of AIS forcing in different experiments using the same AIS forcing scenario (Supplementary Table 1). Here, the thermo-dynamic effect of icebergs describes the consequences of energy consumption by the melting processes to account for latent heat. Icebergs can travel large distances before melting entirely, thereby generating spatiotemporally varying meltwater patterns that extend across the Southern Ocean 19,20. This process is, henceforth, referred to as the dynamic iceberg effect. To isolate its climatic impact, simulations are compared to idealized experiments with spatially homogeneous freshwater forcing. The oceanic response to Antarctic meltwater discharge is well documented in climate models 1,2,7-12. By freshening the Southern Ocean surface water and lowering its density, AIS meltwater strengthens Southern Ocean stratification 1,7-12. The latter acts as a barrier for deep convection, Antarctic bottom water formation and vertical heat fluxes, enhancing Southern Hemisphere sea-ice production and causing surface cooling and subsurface ocean warming around Antarctica 1,12,21. The impact on global ocean circulation 22-24 then results in an interhemispheric asymmetry in surface temperature 25 , a northward displacement of the intertropical convergence zone and global precipitation changes 22,26,27. The response of LOVECLIM to freshwater forcing 1,6,7 is very similar to that recently reported using more sophisticated coupled general circulation models 2,22. In control experiments with greenhouse forcing, but without AIS forcing, global surface air

IL-1 is a potent pro-inflammatory cytokine that activates intracellular signaling cascades some of which may involve IL-1 receptor associated kinase-1 (IRAK1). Psoriasis is a T cell dependent chronic inflammatory condition of the skin of unknown cause. IL-1 has been implicated in psoriasis pathology, but the mechanism has not been elucidated. Interestingly, expression of IRAK1 is elevated in psoriatic skin. To identify a potential link between IL-1, keratinocytes and T cells in skin inflammation we employed pathway-focused microarrays to evaluate IL-1 dependent gene expression in keratinocytes. Several candidate mRNAs encoding known T cell chemoattractants were identified in primary keratinocytes and the stable keratinocyte cell line HaCaT. CCL5 and CCL20 mRNA and protein levels were confirmed up-regulated by IL-1 in concentration and time-dependent manners. Furthermore IL-1 synergized with IFN-γ and TNF-α. Expression of CXCL9, CXCL10 and CXCL11 mRNAs was also increased in response to IL-1, but protein could only be detected in medium from cells treated with IFN-γ alone or in combination with IL-1. Over-expression of IRAK1 led to increased constitutive and cytokine induced production of CCL5 and CCL20. Inhibition of IRAK1 activity through RNAi or expression of a dominant negative mutant blocked production of CCL5 and CCL20 but had no effect upon the IL-1 enhancement of IFN-γ induced CXCL9, CXCL10 and CXCL11 production. In conclusion IL-1 regulates T cell targeting chemokine production in keratinocytes through IRAK1 dependent and independent pathways. These pathways may contribute to acute and chronic skin inflammation.

The surface velocity field of Devon Ice Cap, Nunavut, Canada, was mapped using interferometric synthetic aperture radar (InSAR). Ascending European Remote-sensing Satellite 1 and 2 (ERS-1/-2) tandem mode data were used for the western and southeast sectors, and 3 day repeat pass ERS-1 imagery for the northeast sector. Speckle-tracking procedures were used with RADARSAT 1 imagery to obtain surface velocities over the terminus of Belcher Glacier (a major calving front) where decorrelation between ERS data occurred. The InSAR data highlight a significant contrast in ice-flow dynamics between the east and west sides of the ice cap. Ice movement west of the main north south divide is dominated by relatively uniform 'sheet' flow, but three fast-flowing outlet glaciers that extend 14 23 km beyond the ice-cap margin also drain this region. Several outlet glaciers that extend up to 60 km inland from the eastern margin drain the eastern side of the ice cap. The dominant ice-flow regimes were classified based on the relationship between the driving stress (averaged over a length scale of ten ice thicknesses) and the ratio of surface velocity to ice thickness. The mapped distribution of flow regimes appears to depict the spatial extent of basal sliding across the ice cap. This is supported by a close relationship between the occurrence of flow stripes on the ice surface and flow regimes where basal sliding was found to be an important component of the glacier motion. Iceberg calving rates were computed using measured surface velocities and ice thicknesses derived from airborne radio-echo sounding. The volume of ice calved between 1960 and 1999 was estimated to be 20.5 ± 4.7 km3 (or 0.57 km3 a-1). Approximately 89% of this loss occurred along the eastern margin. The largest single source is Belcher Glacier, which accounts for ˜50% of the total amount of ice calved.

Summer profiles of sea-water temperature, salinity and flow were obtained on George VI Ice Shelf near its northern ice front. At each depth, temperature salinity and density show little variation between sites. Their respective variation to 250 m depth confirms a linear temperature-salinity dependence. This is the first place in the world where observations confirm precisely the form of the T-S diagram predicted for fresh ice melting in sea-water. Both tidal and residual flow are small, except at the western margin of the ice front, where a strong outflow is concentrated immediately beneath the ice shelf. The observations lead to a simple circulation model for the ice-shelf regime. Warm Deep Water flows southwards into George VI Sound, replacing the colder water that spreads northwards in the surface outflow. Thermohaline exchanges beneath the ice shelf determine the salinity profile, which itself provides evidence of upwelling. Estimates can be made of the basal melt rate of the ic...

The surface velocity field of Devon Ice Cap, Nunavut, Canada, was mapped using interferometric synthetic aperture radar (InSAR). Ascending European Remote-sensing Satellite 1 and 2 (ERS-1/-2) tandem mode data were used for the western and southeast sectors, and 3 day repeat pass ERS-1 imagery for the northeast sector. Speckle-tracking procedures were used with RADARSAT 1 imagery to obtain surface velocities over the terminus of Belcher Glacier (a major calving front) where decorrelation between ERS data occurred. The InSAR data highlight a significant contrast in ice-flow dynamics between the east and west sides of the ice cap. Ice movement west of the main north–south divide is dominated by relatively uniform ‘sheet’ flow, but three fast-flowing outlet glaciers that extend 14–23km beyond the ice-cap margin also drain this region. Several outlet glaciers that extend up to 60 km inland from the eastern margin drain the eastern side of the ice cap. The dominant ice-flow regimes were c...

Records of iceberg-rafting and palaeohydrography from two East Greenland shelf cores (JM96-1206/1-GC and JM96-1207/1-GC) are reported. Benthic foraminifera, stable isotopes and IRD fluxes indicate a shift toward colder, lower-salinity ‘polar’ conditions c. 5 cal. ka. A new proxy of iceberg-rafting on the East Greenland Shelf is the flux of calcium carbonate (TIC) thought to be derived from glacial erosion of Cretaceous calcareous mudstones. A change in the regularity and spacing of carbonate flux peaks at c. 4.7 cal. ka in JM96-1207 coincides with the onset of Neoglacial cooling in the Renland ice core δ18O record. We propose that the carbonate flux peaks between 4.7 and 0.4 cal. ka are related to sea-surface coolings associated with increased flux of polar water and sea ice in the East Greenland Current. These peaks are synchronous with sea-surface coolings interpreted from North Atlantic deep-sea cores, but additional peaks centred around 2.4 and 3.8 cal. ka in JM96-1207 suggest t...

The surface velocity field of Devon Ice Cap, Nunavut, Canada, was mapped using interferometric synthetic aperture radar (InSAR). Ascending European Remote-sensing Satellite 1 and 2 (ERS-1/-2) tandem mode data were used for the western and southeast sectors, and 3 day repeat pass ERS-1 imagery for the northeast sector. Speckle-tracking procedures were used with RADARSAT 1 imagery to obtain surface velocities over the terminus of Belcher Glacier (a major calving front) where decorrelation between ERS data occurred. The InSAR data highlight a significant contrast in ice-flow dynamics between the east and west sides of the ice cap. Ice movement west of the main north–south divide is dominated by relatively uniform ‘sheet’ flow, but three fast-flowing outlet glaciers that extend 14–23km beyond the ice-cap margin also drain this region. Several outlet glaciers that extend up to 60 km inland from the eastern margin drain the eastern side of the ice cap. The dominant ice-flow regimes were c...

The surface velocity field of Devon Ice Cap, Nunavut, Canada, was mapped using interferometric synthetic aperture radar (InSAR). Ascending European Remote-sensing Satellite 1 and 2 (ERS-1/-2) tandem mode data were used for the western and southeast sectors, and 3 day repeat pass ERS-1 imagery for the northeast sector. Speckle-tracking procedures were used with RADARSAT 1 imagery to obtain surface velocities over the terminus of Belcher Glacier (a major calving front) where decorrelation between ERS data occurred. The InSAR data highlight a significant contrast in ice-flow dynamics between the east and west sides of the ice cap. Ice movement west of the main north south divide is dominated by relatively uniform 'sheet' flow, but three fast-flowing outlet glaciers that extend 14 23 km beyond the ice-cap margin also drain this region. Several outlet glaciers that extend up to 60 km inland from the eastern margin drain the eastern side of the ice cap. The dominant ice-flow regimes were classified based on the relationship between the driving stress (averaged over a length scale of ten ice thicknesses) and the ratio of surface velocity to ice thickness. The mapped distribution of flow regimes appears to depict the spatial extent of basal sliding across the ice cap. This is supported by a close relationship between the occurrence of flow stripes on the ice surface and flow regimes where basal sliding was found to be an important component of the glacier motion. Iceberg calving rates were computed using measured surface velocities and ice thicknesses derived from airborne radio-echo sounding. The volume of ice calved between 1960 and 1999 was estimated to be 20.5 ± 4.7 km3 (or 0.57 km3 a-1). Approximately 89% of this loss occurred along the eastern margin. The largest single source is Belcher Glacier, which accounts for ˜50% of the total amount of ice calved.