Snow depth on Antarctic sea ice: a Lagrangian model-based approach 

2021 ◽  
Author(s):  
Isobel R. Lawrence ◽  
Andy Ridout ◽  
Andrew Shepherd
Keyword(s):  
Sea Ice ◽  
Snow Depth ◽  
Global Climate ◽  
Lagrangian Model ◽  
The Arctic ◽  
Balance Model ◽  
The Past ◽  
Antarctic Sea Ice ◽  
Regional Trends ◽  
The Antarctic

<p>Snow on Antarctic sea ice is an important yet poorly resolved component of the global climate system. Whilst much attention over the past few years has been dedicated to producing reanalysis-forced models of snow on sea ice in the Arctic, none currently exist for the Southern Hemisphere. Here we present a Lagrangian-framework model of snow depth on Antarctic sea ice, in which “parcels” of ice accumulate snow as they drift around the ocean according to daily ice motion vectors. Snow accumulates from two sources; (i) snowfall from ERA5 atmospheric reanalysis and (ii) snow blown off the Antarctic continent, which we estimate using the RACMO2 ice sheet mass balance model. Ice parcels lose snow via wind-redistribution into leads and through snow-ice formation. We validate our dynamic snow product against ship-based measurements from the ASPeCT data archive, and we compare our long-term climatology against estimates derived from passive microwave (AMSR-E/2) satellites. Finally, we assess regional trends in snow depth over the past four decades and investigate whether these are driven by changes in snowfall or divergence/convergence of the Antarctic sea ice pack. </p>

The role of Antarctic sea ice in global climate change

1996 ◽  
Vol 20 (4) ◽  
pp. 371-401 ◽  
Author(s):  
Edward Hanna
Keyword(s):  
Climate Change ◽  
Sea Ice ◽  
Global Climate Change ◽  
Global Climate ◽  
The Arctic ◽  
Antarctic Sea Ice ◽  
Current State ◽  
Ocean Models ◽  
State Of Research ◽  
The Antarctic

Taking a distinct interdisciplinary focus, a critical view is presented of the current state of research concerning Antarctic sea-ice / atmosphere / ocean interaction and its effect on climate on the interannual timescale, with particular regard to anthropogenic global warming. Sea-ice formation, morphology, thickness, extent, seasonality and distribution are introduced as vital factors in climatic feedbacks. Sea-ice / atmosphere interaction is next discussed, emphas izing its meteorological and topographical influences and the effects of and on polar cyclonic activity. This leads on to the central theme of sea ice in global climate change, which contains critiques of sea-ice climatic feedbacks, current findings on the representation of these feedbacks in global climatic models, and to what extent they are corroborated by observational evidence. Sea-ice / ocean interaction is particularly important. This is discussed with special reference to polynyas and leads, and the use of suitably coupled sea-ice / ocean models. A brief review of several possible climatic forcing factors is presented, which most highly rates a postulated ENSO-Antarctic sea-ice link. Sea-ice / atmosphere / ocean models need to be validated by adequate observations, both from satellites and ground based. In particular, models developed in the Arctic, where the observational network allows more reasonable validation, can be applied to the Antarctic in suitably modified form so as to account for unique features of the Antarctic cryosphere. Benefits in climatic modelling will be gained by treating Antarctic sea ice as a fully coupled component of global climate.

Cryosphere

2004 ◽  
Author(s):  
Kenneth M. Hinkel ◽  
Andrew W. Ellis
Keyword(s):  
Sea Ice ◽  
Snow Cover ◽  
Global Climate ◽  
Ice Sheets ◽  
Past Century ◽  
High Latitudes ◽  
Ice Shelves ◽  
The Past ◽  
Third Assessment Report ◽  
The Antarctic

The cryosphere refers to the Earth’s frozen realm. As such, it includes the 10 percent of the terrestrial surface covered by ice sheets and glaciers, an additional 14 percent characterized by permafrost and/or periglacial processes, and those regions affected by ephemeral and permanent snow cover and sea ice. Although glaciers and permafrost are confined to high latitudes or altitudes, areas seasonally affected by snow cover and sea ice occupy a large portion of Earth’s surface area and have strong spatiotemporal characteristics. Considerable scientific attention has focused on the cryosphere in the past decade. Results from 2 ×CO2 General Circulation Models (GCMs) consistently predict enhanced warming at high latitudes, especially over land (Fitzharris 1996). Since a large volume of ground and surface ice is currently within several degrees of its melting temperature, the cryospheric system is particularly vulnerable to the effects of regional warming. The Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) states that there is strong evidence of Arctic air temperature warming over land by as much as 5 °C during the past century (Anisimov et al. 2001). Further, sea-ice extent and thickness has recently decreased, permafrost has generally warmed, spring snow extent over Eurasia has been reduced, and there has been a general warming trend in the Antarctic (e.g. Serreze et al. 2000). Most climate models project a sustained warming and increase in precipitation in these regions over the twenty-first century. Projected impacts include melting of ice sheets and glaciers with consequent increase in sea level, possible collapse of the Antarctic ice shelves, substantial loss of Arctic Ocean sea ice, and thawing of permafrost terrain. Such rapid responses would likely have a substantial impact on marine and terrestrial biota, with attendant disruption of indigenous human communities and infrastructure. Further, such changes can trigger positive feedback effects that influence global climate. For example, melting of organic-rich permafrost and widespread decomposition of peatlands might enhance CO2 and CH4 efflux to the atmosphere. Cryospheric researchers are therefore involved in monitoring and documenting changes in an effort to separate the natural variability from that induced or enhanced by human activity.

scholarly journals The Arctic and Antarctic Sea-Ice Area Index Records versus Measured and Modeled Temperature Data

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Nicola Scafetta ◽  
Adriano Mazzarella
Keyword(s):  
Sea Ice ◽  
General Circulation ◽  
General Circulation Models ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Climate Indices ◽  
Area Index ◽  
Antarctic Sea Ice ◽  
Arctic Sea ◽  
The Antarctic

Here we study the Arctic and Antarctic sea-ice area records provided by the National Snow and Ice Data Center (NSIDC). These records reveal an opposite climatic behavior: since 1978 the Arctic sea-ice area index decreased, that is, the region has warmed, while the Antarctic sea-ice area index increased, that is, the region has cooled. During the last 7 years the Arctic sea-ice area has stabilized while the Antarctic sea-ice area has increased at a rate significantly higher than during the previous decades; that is, the sea-ice area of both regions has experienced a positive acceleration. This result is quite robust because it is confirmed by alternative temperature climate indices of the same regions. We also found that a significant 4-5-year natural oscillation characterizes the climate of these sea-ice polar areas. On the contrary, we found that the CMIP5 general circulation models have predicted significant warming in both polar sea regions and failed to reproduce the strong 4-5-year oscillation. Because the CMIP5 GCM simulations are inconsistent with the observations, we suggest that important natural mechanisms of climate change are missing in the models.

scholarly journals Antarctic regional modelling of atmospheric, sea-ice and oceanic processes and validation with observations

2000 ◽  
Vol 31 ◽  
pp. 348-352 ◽  
Author(s):  
David A. Bailey ◽  
Amanda H. Lynch
Keyword(s):  
Sea Ice ◽  
Global Climate ◽  
Regional Climate ◽  
Climate System ◽  
The Arctic ◽  
Small Scale ◽  
Atmospheric Conditions ◽  
Regional Modelling ◽  
Climate System Model ◽  
The Antarctic

AbstractHigh-latitude interactions of local-scale processes in the atmosphere-ice-ocean system have effects on the local, Antarctic and global climate. Phenomena including polynyas and leads are examples of such interactions which, when combined, have a significant impact on larger scales. These small-scale features, which are typically parameterized in global models, can be explicitly simulated using high-resolution regional climate system models. As such, the study of these interactions is well suited to a regional model approach and is considered here using the Arctic Regional Climate System Model (ARCSyM). This model has been used for many simulations in the Arctic, and is now implemented for the Antarctic. Observations of such processes in the Antarctic are limited, which makes model validation difficult. However, using the best available observations for an annual cycle, we have determined a suite of model parameterization which allows us to reasonably simulate the Antarctic climate. This work considers a fine-resolution (20 km) simulation in the Cosmonaut Sea region, with the eventual goal of elucidating the mechanisms in the formation and maintenance of the sensible-heat polynya which is a regular occurrence in this area. It was found in an atmosphere-sea-ice simulation that the ocean plays an important role in regulating the sea-ice cover in this region in compensating for the cold atmospheric conditions.

scholarly journals A Regime Shift in Seasonal Total Antarctic Sea Ice Extent in the 20th Century

2021 ◽  
Author(s):  
Ryan Fogt ◽  
Amanda Sleinkofer ◽  
Marilyn Raphael ◽  
Mark Handcock
Keyword(s):  
Sea Ice ◽  
20Th Century ◽  
Climate Models ◽  
Historical Context ◽  
The Arctic ◽  
Sea Ice Extent ◽  
Antarctic Sea Ice ◽  
Coupled Climate Models ◽  
High Degree ◽  
The Antarctic

Abstract In stark contrast to the Arctic, there have been statistically significant positive trends in total Antarctic sea ice extent since 1979, despite a sudden decline in sea ice in 2016(1–5) and increasing greenhouse gas concentrations. Attributing Antarctic sea ice trends is complicated by the fact that most coupled climate models show negative trends in sea ice extent since 1979, opposite of that observed(6–8). Additionally, the short record of sea ice extent (beginning in 1979), coupled with the high degree of interannual variability, make the record too short to fully understand the historical context of these recent changes(9). Here we show, using new robust observation-based reconstructions, that 1) these observed recent increases in Antarctic sea ice extent are unique in the context of the 20th century and 2) the observed trends are juxtaposed against statistically significant decreases in sea ice extent throughout much of the early and middle 20th century. These reconstructions are the first to provide reliable estimates of total sea ice extent surrounding the continent; previous proxy-based reconstructions are limited(10). Importantly, the reconstructions continue to show the high degree of interannual Antarctic sea ice extent variability that is marked with frequent sudden changes, such as observed in 2016, which stress the importance of a longer historical context when assessing and attributing observed trends in Antarctic climate(9). Our reconstructions are skillful enough to be used in climate models to allow better understanding of the interconnected nature of the Antarctic climate system and to improve predictions of the future state of Antarctic climate.

scholarly journals Processes Controlling Arctic and Antarctic Sea Ice Predictability in the Community Earth System Model

2018 ◽  
Vol 31 (23) ◽  
pp. 9771-9786 ◽  
Author(s):  
Ana C. Ordoñez ◽  
Cecilia M. Bitz ◽  
Edward Blanchard-Wrigglesworth
Keyword(s):  
Sea Ice ◽  
Mixed Layer ◽  
Ocean Dynamics ◽  
System Model ◽  
The Arctic ◽  
Earth System ◽  
Ice Volume ◽  
Antarctic Sea Ice ◽  
The Antarctic ◽  
Area And Volume

Sea ice predictability is a rapidly growing area of research, with most studies focusing on the Arctic. This study offers new insights by comparing predictability between the Arctic and Antarctic sea ice anomalies, focusing on the effects of regional differences in ice thickness and ocean dynamics. Predictability in simulated regional sea ice area and volume is investigated in long control runs of an Earth system model. Sea ice area predictability in the Arctic agrees with results from other studies, with features of decaying initial persistence and reemergence because of ocean mixed layer processes and memory in thick ice. In pan-Arctic averages, sea ice volume and the area covered by thick ice are the best predictors of September area for lead times greater than 2 months. In the Antarctic, area is generally the best predictor of future area for all times of year. Predictability of area in summer differs between the hemispheres because of unique aspects of the coupling between area and volume. Generally, ice volume only adds to the predictability of summer sea ice area in the Arctic. Predictability patterns vary greatly among different regions of the Arctic but share similar seasonality among regions of the Antarctic. Interactive ocean dynamics influence anomaly reemergence differently in the Antarctic than the Arctic, both for the total and regional area. In the Antarctic, ocean dynamics generally decrease the persistence of area anomalies, reducing predictability. In the Arctic, the presence of ocean dynamics improves ice area predictability, mainly through mixed layer depth variability.

scholarly journals Influence of North Pacific decadal variability on the western Canadian Arctic over the past 700 years

2017 ◽  
Vol 13 (4) ◽  
pp. 411-420 ◽  
Author(s):  
François Lapointe ◽  
Pierre Francus ◽  
Scott F. Lamoureux ◽  
Mathias Vuille ◽  
Jean-Philippe Jenny ◽  
...  
Keyword(s):  
Climate Variability ◽  
Sea Ice ◽  
North Pacific ◽  
Decadal Variability ◽  
Global Climate ◽  
Canadian Arctic ◽  
Summer Precipitation ◽  
The Arctic ◽  
Past Century ◽  
The Past

Abstract. Understanding how internal climate variability influences arctic regions is required to better forecast future global climate variations. This paper investigates an annually-laminated (varved) record from the western Canadian Arctic and finds that the varves are negatively correlated with both the instrumental Pacific Decadal Oscillation (PDO) during the past century and also with reconstructed PDO over the past 700 years, suggesting drier Arctic conditions during high-PDO phases, and vice versa. These results are in agreement with known regional teleconnections, whereby the PDO is negatively and positively correlated with summer precipitation and mean sea level pressure respectively. This pattern is also evident during the positive phase of the North Pacific Index (NPI) in autumn. Reduced sea-ice cover during summer–autumn is observed in the region during PDO− (NPI+) and is associated with low-level southerly winds that originate from the northernmost Pacific across the Bering Strait and can reach as far as the western Canadian Arctic. These climate anomalies are associated with the PDO− (NPI+) phase and are key factors in enhancing evaporation and subsequent precipitation in this region of the Arctic. Collectively, the sedimentary evidence suggests that North Pacific climate variability has been a persistent regulator of the regional climate in the western Canadian Arctic. Since projected sea-ice loss will contribute to enhanced future warming in the Arctic, future negative phases of the PDO (or NPI+) will likely act to amplify this positive feedback.

Farewell to IceBridge: 10 years of polar sea ice remote sensing

2020 ◽  
Author(s):  
Linette Boisvert ◽  
Joseph MacGregor ◽  
Brooke Medley ◽  
Nathan Kurtz ◽  
Ron Kwok ◽  
...  
Keyword(s):  
Sea Ice ◽  
The Arctic ◽  
Ice Thickness ◽  
Sea Ice Thickness ◽  
Antarctic Sea Ice ◽  
Ice Drift ◽  
Laser Altimeters ◽  
Sea Ice Drift ◽  
To Come ◽  
The Antarctic

<p>NASA’s Operation IceBridge (OIB) was a multi-year, multi-platform, airborne mission which took place between 2009-2019. OIB was designed and implemented to continue monitoring the changing sea ice and ice sheets in both the Arctic and Antarctic by ‘bridging the gap’ between NASA’s ICESat (2003–2009) and ICESat-2 (launched September 2018) satellite missions. OIB’s instrument suite most often consisted of laser altimeters, radar sounders, gravimeters and multi-spectral imagers. These instruments were selected to study polar sea ice thickness, ice sheet elevation, snow and ice thickness, surface temperature and bathymetry. With the launch of ICESat-2, the final year of OIB consisted of three campaigns designed to under fly the satellite: 1) the end of the Arctic growth season (spring), 2) during the Arctic summer to capture many different types of melting surfaces, and 3) the Antarctic spring to cover an entirely new area of East Antarctica. Over this ten-year period a coherent picture of Arctic and Antarctic sea ice and snow thickness and other properties have been produced and monitored. Specifically, OIB has changed the community’s perspective of snow on sea ice in the Arctic. Over the decade, OIB has also been used to validate other satellite altimeter missions like ESA’s CryoSat-2. Since the launch of ICESat-2, coincident OIB under flights with the satellite were crucial for measuring sea ice properties. With sea ice constantly in motion, and the differences in OIB aircraft and ICESat-2 ground speed, there can substantial drift in the sea ice pack over the same ground track distance being measured.Therefore, we had to design and implement sea ice drift trajectories based on low level winds measured from the aircraft in flight, adjusting our plane’s path accordingly so we could measure the same sea ice as ICESat-2. This was implemented in both the Antarctic 2018 and Arctic 2019 campaigns successfully. Specifically, the Spring Arctic 2019 campaign allowed for validation of ICESat-2 freeboards with OIB ATM freeboards proving invaluable to the success of ICESat-2 and the future of sea ice research to come from these missions.</p><p> </p>

scholarly journals Contrasting the Antarctic and Arctic Atmospheric Responses to Projected Sea Ice Loss in the Late Twenty-First Century

2018 ◽  
Vol 31 (16) ◽  
pp. 6353-6370 ◽  
Author(s):  
Mark England ◽  
Lorenzo Polvani ◽  
Lantao Sun
Keyword(s):  
Sea Ice ◽  
Climate Model ◽  
Arctic Sea Ice ◽  
First Century ◽  
The Arctic ◽  
Minor Role ◽  
Systems Model ◽  
Antarctic Sea Ice ◽  
Twenty First Century ◽  
The Antarctic

Abstract Models project that Antarctic sea ice area will decline considerably by the end of this century, but the consequences remain largely unexplored. Here, the atmospheric response to future sea ice loss in the Antarctic is investigated, and contrasted to the Arctic case, using the Community Earth Systems Model (CESM) Whole Atmosphere Coupled Climate Model (WACCM). Time-slice model runs with historic sea ice concentrations are compared to runs with future concentrations, from the late twenty-first century, in each hemisphere separately. As for the Arctic, results indicate that Antarctic sea ice loss will act to shift the tropospheric jet equatorward, an internal negative feedback to the poleward shift associated with increased greenhouse gases. Also, the tropospheric response to Antarctic sea ice loss is found to be somewhat weaker, more vertically confined, and less seasonally varying than in the case of Arctic sea ice loss. The stratospheric response to Antarctic sea ice loss is relatively weak compared to the Arctic case, although it is here demonstrated that the latter is still small relative to internal variability. In contrast to the Arctic case, the response of the ozone layer is found to be positive (up to 5 Dobson units): interestingly, it is present in all seasons except austral spring. Finally, while the response of surface temperature and precipitation is limited to the southern high latitudes, it is nonetheless unable to impact the interior of the Antarctic continent, suggesting a minor role of sea ice loss on recent Antarctic temperature trends.

scholarly journals A spurious jump in the satellite record: has Antarctic sea ice expansion been overestimated?

2014 ◽  
Vol 8 (4) ◽  
pp. 1289-1296 ◽  
Author(s):  
I. Eisenman ◽  
W. N. Meier ◽  
J. R. Norris
Keyword(s):  
Sea Ice ◽  
Ice Cover ◽  
Current Data ◽  
The Arctic ◽  
Sea Ice Extent ◽  
Data Set ◽  
Antarctic Sea Ice ◽  
Ice Retreat ◽  
Bootstrap Algorithm ◽  
The Antarctic

Abstract. Recent estimates indicate that the Antarctic sea ice cover is expanding at a statistically significant rate with a magnitude one-third as large as the rapid rate of sea ice retreat in the Arctic. However, during the mid-2000s, with several fewer years in the observational record, the trend in Antarctic sea ice extent was reported to be considerably smaller and statistically indistinguishable from zero. Here, we show that much of the increase in the reported trend occurred due to the previously undocumented effect of a change in the way the satellite sea ice observations are processed for the widely used Bootstrap algorithm data set, rather than a physical increase in the rate of ice advance. Specifically, we find that a change in the intercalibration across a 1991 sensor transition when the data set was reprocessed in 2007 caused a substantial change in the long-term trend. Although our analysis does not definitively identify whether this change introduced an error or removed one, the resulting difference in the trends suggests that a substantial error exists in either the current data set or the version that was used prior to the mid-2000s, and numerous studies that have relied on these observations should be reexamined to determine the sensitivity of their results to this change in the data set. Furthermore, a number of recent studies have investigated physical mechanisms for the observed expansion of the Antarctic sea ice cover. The results of this analysis raise the possibility that much of this expansion may be a spurious artifact of an error in the processing of the satellite observations.

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