Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
32,047
result(s) for
"Sea ice"
Sort by:
Improved Simulation of Antarctic Sea Ice by Parameterized Thickness of New Ice in a Coupled Climate Model
Sea ice formation over open water exerts critical control on polar atmosphere‐ocean‐ice interactions, but is only crudely represented in sea ice models. In this study, a collection depth parameterization of new ice for flux polynya models is modified by including the sea ice concentration and ice growth rate as additional factors. We evaluated it in a climate model BCC‐CSM2‐MR and found that it improves simulation of Antarctic sea ice concentration and thickness in most of Indian and Atlantic sectors. Disagreement between the observed Antarctic sea ice expansion during 1981–2014 and the modeled decline still exists but is mitigated when the modified scheme is implemented. Further analysis indicates that these improvements are associated with the overcoming of premature closure of open water, which enhances the response of ocean to surface wind intensification during 1981–2014, and consequently slowdowns the sea surface temperature increase and the resulting Antarctic sea ice reduction. Plain Language Summary Open water ice formation critically modulates sea ice variations and the associated polar atmosphere‐ocean interaction, but is not well represented in sea ice models. In this study, a modified collection depth parameterization of new ice based on an existing scheme is presented after including sea ice concentration and ice growth rate as additional factors. We evaluated this modified scheme in BCC‐CSM2‐MR and found that it can improve the simulation of mean Antarctic sea ice thickness and concentration in winter as well as Antarctic sea ice expansion from 1981 to 2014. Further analysis implies that these improvements can be attributed to the overcoming of the premature closure of open water areas in model simulations. Key Points A modified collection thickness parameterization of new ice suitable for large‐scale climate simulations is presented It improves the simulation of Antarctic sea ice thickness and concentration, as well as Antarctic sea ice expansion during 1981–2014 The improved simulations can be attributed to the overcoming of the premature closure of open water areas where new ice forms
Journal Article
Large Decreases in Sea Ice Strength and Pressure Along Major Arctic Shipping Routes Projected for the Next Two Decades
The observed decline of sea ice in the Arctic, if it persists into the future, can create more favorable conditions for shipping activity in the region. To estimate possible changes in key sea ice characteristics over the next two decades, we use high‐resolution climate models. The focus is on two shipping routes: the Northwest Passage and the Northeast Passage. In addition to more traditionally analyzed ice concentration and thickness, we present projected changes in ice strength and pressure, which are especially relevant for shipping hazards. Along both routes, the mean September values of ice strength and pressure, projected for the period 2041–2050, decrease by an order of magnitude relative to the period 2015–2024. The decrease is largely driven by changes in ice concentration, rather than thickness or velocity. Increasing ocean resolution from eddy‐present to eddy‐rich leads to less reduction of sea ice area, volume and strength with global warming. Plain Language Summary We use a suite of high‐resolution climate models to explore changes in sea ice area, thickness, strength and pressure over the next two decades along two major Arctic shipping routes: the Northwest Passage and Northeast Passage. We show that these quantities are simulated to decline substantially under strong warming. If these changes are to occur, this will make shipping activity along both routes much less difficult than it currently is. Key Points In two decades, sea ice strength and pressure are projected to decrease by an order of magnitude along two major Arctic shipping routes The strength and pressure changes are driven more by changes in sea ice concentration than in thickness or velocity In one model, increasing ocean resolution from eddy‐present to eddy‐rich leads to less reduction of ice strength with global warming
Journal Article
Melting ice
\"Giant icebergs are cracking off ice shelves and splashing into the oceans below. Ice sheets are melting, sending more and more water rushing into the sea. What on Earth is causing this melting ice? As Earth's climate is changing, rising temperatures are causing catastrophic melting. Uncover the problems of climate change, explore its impact on Earth's ice, and dive into what we can do to help. Approachable text and engaging images bring this timely topic to life\"-- Provided by publisher.
Book
Sea Ice Heterogeneity as a Result of Ocean Eddy Activity During the Ice Growth Season
Mesoscale eddies, generated by lateral gradients in salinity and temperature in the Arctic marginal ice zone, are known to modulate the melting of sea ice. Yet, it remains unclear if eddies modify sea ice growth during the freezing season. Here, we use idealized spin‐down simulations of a front to explore the sea ice growth above an eddying ocean. In the presence of eddies, mixing of the sea surface temperature and salinity induces spatial variability in the heat and salt fluxes at the ice‐ocean interface, imprinting spatial variability on the sea ice thickness. Sea ice thickness shows an order of magnitude more spatial variability in our simulations with strong eddies compared to those without. Increased spatial heterogeneity in the sea ice could make it more brittle and affect its evolution. This effect may become more pronounced as the Arctic transitions to a summer open‐ocean regime and the eddy field intensifies. Plain Language Summary Lateral variations of salinity and temperature in the Arctic Ocean caused by the melting or freezing of ice can result in ocean eddies (vortex‐like features up to ∼100${\\sim} 100$km in size). Previous studies have focused on how these eddies affect sea ice melting. However, it is not clear if eddies also play a role when the ice forms. Here, we use numerical simulations to see how these eddies influence the growth of sea ice. Eddies affect the temperature and salinity distributions at the ocean surface, which, in turn, modulate the thickness of sea ice as it forms. This eddy effect in the sea ice is important because it could impact the transitional zone between the open ocean and ice covered Arctic. Understanding these eddy‐sea ice interactions is crucial to better understand the current and future states of the Arctic sea ice as it transitions to a summer ice free ocean. Key Points Mesoscale ocean eddies imprint heterogeneity on sea‐ice thickness during the freezing season Eddies induce heterogeneity in sea‐ice thickness by locally changing heat and salt fluxes at the ice‐ocean interface An increase in eddy field intensity leads to an increase in sea ice heterogeneity
Journal Article
Physical and morphological properties of first-year Antarctic sea ice in the spring marginal ice zone of the Atlantic-Indian sector
This study presents the first dataset of physical and textural properties of sea ice collected in the South Atlantic and Indian Ocean sector of the Antarctic marginal ice zone (MIZ). Observations of sea ice from this region in the austral spring 2019, including sea-ice core temperature, salinity, crystal size, texture, oxygen isotopes and stratigraphy, were used in conjunction with a Lagrangian back-tracking algorithm and atmospheric reanalyses. This method relates the reconstructed synoptic conditions to sea-ice growth along the transect. A significant difference was found between the stratigraphy of consolidated pack ice samples collected at the same latitude and spanning over 550 km eastwards. The eastward group was found to have more disturbances in their stratigraphy which is attributed to the highly variable atmospheric and sea-ice conditions together with varying wave penetration through the sea-ice pack, notably during the passage of an intense polar cyclone, while the westward group showed no signs of disturbance or deformation. These results indicate that consolidated Antarctic sea-ice floes of similar thickness and from the same latitude in the MIZ have distinct stratigraphic properties, which will influence their physical and biogeochemical features.
Journal Article
Vanishing ice : glaciers, ice sheets, and rising seas
\"The Arctic is thawing. Vanishing Ice is a powerful depiction of the dramatic transformation of the cryosphere--the world of ice and snow--and its consequences for the human world. Delving into the major components of the cryosphere, including ice sheets, valley glaciers, permafrost, and floating ice, Vivien Gornitz gives an up-to-date explanation of key current trends in the decline of ice mass. Drawing on a long-term perspective gained by examining changes in the cryosphere and corresponding variations in sea level over millions of years, she demonstrates the link between thawing ice and sea-level rise to point to the social and economic challenges on the horizon. Gornitz highlights the widespread repercussions of ice loss, which will affect countless people far removed from frozen regions, to demonstrate why the big meltdown matters to us all\"-- Provided by publisher.
BOOK
The Future of Sea Ice Modeling
Earth system models (ESMs) include a sea ice component to physically represent sea ice changes and impacts on planetary albedo and ocean circulation (Manabe and Stouffer 1980). Most contemporary sea ice models describe the sea ice pack as a continuum material, a principle laid by the Arctic Ice Dynamics Joint Experiment (AIDJEX) group in the 1970s (Pritchard 1980). Initially intended for climate studies, the sea ice components in ESMs are now used across a wide range of resolutions, including very high resolutions more than 100 times finer than those they were designed for, in an increasingly wide range of applications that challenge the AIDJEX model foundations (Coon et al. 2007), including operational weather and marine forecasts. It is therefore sensible to question the applicability of contemporary sea ice models to these applications. Are there better alternatives available? Large advances in high-performance computing (HPC) have been made over the last few decades and this trend will continue. What constraints and opportunities will these HPC changes provide for contemporary sea ice models? Can continuum models scale well for use in exascale computing?
Journal Article