scholarly journals A 40-y record reveals gradual Antarctic sea ice increases followed by decreases at rates far exceeding the rates seen in the Arctic

2019 ◽  
Vol 116 (29) ◽  
pp. 14414-14423 ◽  
Author(s):  
Claire L. Parkinson
Keyword(s):  
Sea Ice ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Antarctic Sea Ice ◽  
Ice Coverage ◽  
Yearly Average ◽  
Precipitous Decline ◽  
The One ◽  
The Antarctic

Following over 3 decades of gradual but uneven increases in sea ice coverage, the yearly average Antarctic sea ice extents reached a record high of 12.8 × 106 km2 in 2014, followed by a decline so precipitous that they reached their lowest value in the 40-y 1979–2018 satellite multichannel passive-microwave record, 10.7 × 106 km2, in 2017. In contrast, it took the Arctic sea ice cover a full 3 decades to register a loss that great in yearly average ice extents. Still, when considering the 40-y record as a whole, the Antarctic sea ice continues to have a positive overall trend in yearly average ice extents, although at 11,300 ± 5,300 km2⋅y−1, this trend is only 50% of the trend for 1979–2014, before the precipitous decline. Four of the 5 sectors into which the Antarctic sea ice cover is divided all also have 40-y positive trends that are well reduced from their 2014–2017 values. The one anomalous sector in this regard, the Bellingshausen/Amundsen Seas, has a 40-y negative trend, with the yearly average ice extents decreasing overall in the first 3 decades, reaching a minimum in 2007, and exhibiting an overall upward trend since 2007 (i.e., reflecting a reversal in the opposite direction from the other 4 sectors and the Antarctic sea ice cover as a whole).

scholarly journals Antarctic sea ice variability and trends, 1979–2010

2012 ◽  
Vol 6 (2) ◽  
pp. 931-956 ◽  
Author(s):  
C. L. Parkinson ◽  
D. J. Cavalieri
Keyword(s):  
Indian Ocean ◽  
Sea Ice ◽  
Ross Sea ◽  
Ice Cover ◽  
Weddell Sea ◽  
The Arctic ◽  
Future Research ◽  
Positive Trend ◽  
Antarctic Sea Ice ◽  
Ice Coverage

Abstract. In sharp contrast to the decreasing sea ice coverage of the Arctic, in the Antarctic the sea ice cover has, on average, expanded since the late 1970s. More specifically, satellite passive-microwave data for the period November 1978–December 2010 reveal an overall positive trend in ice extents of 17 100 ± 2300 km2 yr−1. Much of the increase, at 13 700 ± 1500 km2 yr−1, has occurred in the region of the Ross Sea, with lesser contributions from the Weddell Sea and Indian Ocean. One region, that of the Bellingshausen/Amundsen Seas, has, like the Arctic, instead experienced significant sea ice decreases, with an overall ice extent trend of −8200 ± 1200 km2 yr−1. When examined through the annual cycle over the 32-yr period 1979–2010, the Southern Hemisphere sea ice cover as a whole experienced positive ice extent trends in every month, ranging in magnitude from a low of 9100 ± 6300 km2 yr−1 in February to a high of 24 700 ± 10 000 km2 yr−1 in May. The Ross Sea and Indian Ocean also had positive trends in each month, while the Bellingshausen/Amundsen Seas had negative trends in each month, and the Weddell Sea and Western Pacific Ocean had a mixture of positive and negative trends. Comparing ice-area results to ice-extent results, in each case the ice-area trend has the same sign as the ice-extent trend, but differences in the magnitudes of the two trends identify regions with overall increasing ice concentrations and others with overall decreasing ice concentrations. The strong pattern of decreasing ice coverage in the Bellingshausen/Amundsen Seas region and increasing ice coverage in the Ross Sea region is suggestive of changes in atmospheric circulation. This is a key topic for future research.

scholarly journals Antarctic sea ice variability and trends, 1979–2010

2012 ◽  
Vol 6 (4) ◽  
pp. 871-880 ◽  
Author(s):  
C. L. Parkinson ◽  
D. J. Cavalieri
Keyword(s):  
Indian Ocean ◽  
Sea Ice ◽  
Ross Sea ◽  
Ice Cover ◽  
Weddell Sea ◽  
The Arctic ◽  
Future Research ◽  
Positive Trend ◽  
Antarctic Sea Ice ◽  
Ice Coverage

Abstract. In sharp contrast to the decreasing sea ice coverage of the Arctic, in the Antarctic the sea ice cover has, on average, expanded since the late 1970s. More specifically, satellite passive-microwave data for the period November 1978–December 2010 reveal an overall positive trend in ice extents of 17 100 ± 2300 km2 yr−1. Much of the increase, at 13 700 ± 1500 km2 yr−1, has occurred in the region of the Ross Sea, with lesser contributions from the Weddell Sea and Indian Ocean. One region, that of the Bellingshausen/Amundsen Seas, has (like the Arctic) instead experienced significant sea ice decreases, with an overall ice extent trend of −8200 ± 1200 km2 yr−1. When examined through the annual cycle over the 32-yr period 1979–2010, the Southern Hemisphere sea ice cover as a whole experienced positive ice extent trends in every month, ranging in magnitude from a low of 9100 ± 6300 km2 yr−1 in February to a high of 24 700 ± 10 000 km2 yr−1 in May. The Ross Sea and Indian Ocean also had positive trends in each month, while the Bellingshausen/Amundsen Seas had negative trends in each month, and the Weddell Sea and western Pacific Ocean had a mixture of positive and negative trends. Comparing ice-area results to ice-extent results, in each case the ice-area trend has the same sign as the ice-extent trend, but the magnitudes of the two trends differ, and in some cases these differences allow inferences about the corresponding changes in sea ice concentrations. The strong pattern of decreasing ice coverage in the Bellingshausen/Amundsen Seas region and increasing ice coverage in the Ross Sea region is suggestive of changes in atmospheric circulation. This is a key topic for future research.

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 Impact of sea ice on the marine iron cycle and phytoplankton productivity

2014 ◽  
Vol 11 (17) ◽  
pp. 4713-4731 ◽  
Author(s):  
S. Wang ◽  
D. Bailey ◽  
K. Lindsay ◽  
J. K. Moore ◽  
M. Holland
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Phytoplankton Production ◽  
Iron Cycle ◽  
Surface Ocean ◽  
Antarctic Sea Ice ◽  
Iron Concentrations

Abstract. Iron is a key nutrient for phytoplankton growth in the surface ocean. At high latitudes, the iron cycle is closely related to the dynamics of sea ice. In recent decades, Arctic sea ice cover has been declining rapidly and Antarctic sea ice has exhibited large regional trends. A significant reduction of sea ice in both hemispheres is projected in future climate scenarios. In order to adequately study the effect of sea ice on the polar iron cycle, sea ice bearing iron was incorporated in the Community Earth System Model (CESM). Sea ice acts as a reservoir for iron during winter and releases the trace metal to the surface ocean in spring and summer. Simulated iron concentrations in sea ice generally agree with observations in regions where iron concentrations are relatively low. The maximum iron concentrations simulated in Arctic and Antarctic sea ice are much lower than observed, which is likely due to underestimation of iron inputs to sea ice or missing mechanisms. The largest iron source to sea ice is suspended sediments, contributing fluxes of iron of 2.2 × 108 mol Fe month−1 in the Arctic and 4.1 × 106 mol Fe month−1 in the Southern Ocean during summer. As a result of the iron flux from ice, iron concentrations increase significantly in the Arctic. Iron released from melting ice increases phytoplankton production in spring and summer and shifts phytoplankton community composition in the Southern Ocean. Results for the period of 1998 to 2007 indicate that a reduction of sea ice in the Southern Ocean will have a negative influence on phytoplankton production. Iron transport by sea ice appears to be an important process bringing iron to the central Arctic. The impact of ice to ocean iron fluxes on marine ecosystems is negligible in the current Arctic Ocean, as iron is not typically the growth-limiting nutrient. However, it may become a more important factor in the future, particularly in the central Arctic, as iron concentrations will decrease with declining sea ice cover and transport.

Mapping Antarctic sea ice albedo properties from MISR fused with MODIS

2020 ◽  
Author(s):  
Jan-Peter Muller ◽  
Said Kharbouche
Keyword(s):  
Sea Ice ◽  
Processing System ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
National Academy Of Sciences ◽  
Antarctic Sea Ice ◽  
Ice Coverage ◽  
Time Period ◽  
Arctic Sea ◽  
Academy Of Sciences

<p>In [1] a new method is described for fusing spectral BRF and derived albedo at 1.1km within the 7 minutes that MISR acquires images of a surface point with coincident MODIS nadir spectral data processed into a 1km sea ice mask. NetCDF products were produced in polar stereographic projection and produced on daily, weekly, fortnightly and monthly from November to February each year from 2000-2016. Arctic sea ice albedo has been previously presented and in this presentation, Antarctic time series, will be presented covering the same time period. This area has less complete coverage than the Arctic due to data outages due to telecommunications issues. [2] has recently pointed out that sea ice coverage  has  reduced dramatically since 2014, mainly one quadrant centred on the Wendell sea and the spectral albedo for this area will be highlighted.</p><p>Acknowledgements: Support was provided by EU-FP7 QA4ECV (Quality Assurance for Essential Climate Variables) under Project Number 607405 for the development of the processing system.</p><p>References:<br>[1] Kharbouche, S.; Muller, J.-P. Sea Ice Albedo from MISR and MODIS: Production, Validation, and Trend Analysis. Remote Sens. 2019, 11, 9. doi: https://doi.org/10.3390/rs11010009</p><p>[2] Parkinson, C. A 40-y record reveals gradual Antarctic sea ice increases followed by decreases at rates far exceeding the rates seen in the Arctic. Proceedings of the National Academy of Sciences. 2019, 116 (29) 14414-14423; DOI: 10.1073/pnas.1906556116</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 The Transient versus the Equilibrium Response of Sea Ice to Global Warming

2013 ◽  
Vol 26 (15) ◽  
pp. 5624-5636 ◽  
Author(s):  
Chao Li ◽  
Dirk Notz ◽  
Steffen Tietsche ◽  
Jochem Marotzke
Keyword(s):  
Sea Ice ◽  
Co2 Concentration ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Concentration Change ◽  
Antarctic Sea Ice ◽  
Equilibrium Response ◽  
Arctic Sea ◽  
Rapid Transition

Abstract To examine the long-term stability of Arctic and Antarctic sea ice, idealized simulations are carried out with the climate model ECHAM5/Max Planck Institute Ocean Model (MPI-OM). Atmospheric CO2 concentration is increased over 2000 years from preindustrial levels to quadrupling, is then kept constant for 5940 years, is afterward decreased over 2000 years to preindustrial levels, and is finally kept constant for 3940 years. Despite these very slow changes, the sea ice response significantly lags behind the CO2 concentration change. This lag, which is caused by the ocean's thermal inertia, implies that the sea ice equilibrium response to increasing CO2 concentration is substantially underestimated by transient simulations. The sea ice response to CO2 concentration change is not truly hysteretic and is in principle reversible. The authors find no lag in the evolution of Arctic sea ice relative to changes in annual-mean Northern Hemisphere surface temperature. The summer sea ice cover changes linearly with respect to both CO2 concentration and temperature, while the Arctic winter sea ice cover shows a rapid transition to a very low sea ice coverage. This rapid transition of winter sea ice is associated with a sharply enhanced ice–albedo feedback and a sudden onset of convective-cloud feedback in the Arctic. The Antarctic sea ice cover retreats continuously without any rapid transition during the warming. Compared to Arctic sea ice, Antarctic sea ice shows a much more strongly lagged response to changes in CO2 concentration. It even lags behind the surface temperature change, which is caused by a different response of ocean deep convection during the warming and the cooling periods.

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.

scholarly journals Antarctic sea ice types from active and passive microwave remote sensing

2022 ◽  
Author(s):  
Christian Melsheimer ◽  
Gunnar Spreen ◽  
Yufang Ye ◽  
Mohammed Shokr
Keyword(s):  
Time Series ◽  
Sea Ice ◽  
Microwave Remote Sensing ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Distribution Data ◽  
Synthetic Aperture Radar Data ◽  
Current Time ◽  
Antarctic Sea Ice ◽  
The Antarctic

Abstract. Polar sea ice is one of the Earth’s climate components that has been significantly affected by the recent trend of global warming. While the sea ice area in the Arctic has been decreasing at a rate of about 4 % per decade, the multi-year ice (MYI), also called perennial ice, is decreasing at a faster rate of 10 %–15 % per decade. On the other hand, the sea ice area in the Antarctic region was slowly increasing at a rate of about 1.5 % per decade until 2014 and since then it has fluctuated without a clear trend. However, no data about ice type areas are available from that region, particularly of MYI. Due to differences in physical and crystalline structural properties of sea ice and snow between the two polar regions, it has become difficult to identify ice types in the Antarctic. Until recently, no method has existed to monitor the distribution and temporal development of Antarctic ice types, particularly MYI throughout the freezing season and on decadal time scales. In this study, we have adapted a method for retrieving Arctic sea ice types and partial concentrations using microwave satellite observations to fit the Antarctic sea ice conditions. The first circumpolar, long-term time series of Antarctic sea ice types; MYI, first-year ice and young ice is being established, so far covering years 2013–2019. Qualitative comparison with synthetic aperture radar data, with charts of the development stage of the sea ice, and with Antarctic polynya distribution data show that the retrieved ice types, in particular the MYI, are reasonable. Although there are still some shortcomings, the new retrieval for the first time allows insight into the evolution and dynamics of Antarctic sea ice types. The current time series can in principle be extended backwards to start in the year 2002 and can be continued with current and future sensors.

scholarly journals New estimates of Arctic and Antarctic sea ice extent during September 1964 from recovered Nimbus I satellite imagery

2013 ◽  
Vol 7 (2) ◽  
pp. 699-705 ◽  
Author(s):  
W. N. Meier ◽  
D. Gallaher ◽  
G. G. Campbell
Keyword(s):  
Sea Ice ◽  
Satellite Imagery ◽  
Arctic Sea Ice ◽  
Passive Microwave ◽  
The Arctic ◽  
Sea Ice Extent ◽  
Antarctic Sea Ice ◽  
1960S And 1970S ◽  
The 1960S ◽  
The Antarctic

Abstract. Visible satellite imagery from the 1964 Nimbus I satellite has been recovered, digitized, and processed to estimate Arctic and Antarctic sea ice extent for September 1964. September is the month when the Arctic sea ice reaches its minimum annual extent and the Antarctic sea ice reaches its maximum. Images from a three-week period were manually analyzed to estimate the location of the ice edge and then composited to obtain a hemispheric estimate. Uncertainties were based on limitations in the image analysis and the variation of the ice cover over the three-week period. The 1964 Antarctic extent is higher than estimates from the 1979–present passive microwave record, but is in accord with previous indications of higher extents during the 1960s. The Arctic 1964 extent is near the 1979–2000 average from the passive microwave record, suggesting relatively stable summer extents during the 1960s and 1970s preceding the downward trend since 1979 and particularly the large decrease in the last decade. These early satellite data put the recently observed record into a longer-term context.

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