Transition Periods Between Sea Ice Concentration and Sea Surface Air Temperature in the Arctic Revealed by an Abnormal Running Correlation

Global warming in the recent decades has been accompanied by a rapid recline of the Arctic sea ice area most pronounced in summer (10% per decade). To understand the relative contribution of external forcing and natural variability to the modern and future sea ice area changes, it is necessary to evaluate a range of long-term variations of the Arctic sea ice area in the period before a significant increase in anthropogenic emissions of greenhouse gases into the atmosphere. Available observational data on the spatiotemporal dynamics of Arctic sea ice until 1950s are characterized by significant gaps and uncertainties. In the recent years, there have appeared several reconstructions of the early 20th century Arctic sea ice area that filled the gaps by analogue methods or utilized combined empirical data and climate model&#8217;s output. All of them resulted in a stronger that earlier believed negative sea ice area anomaly in the 1940s concurrent with the early 20th century warming (ETCW) peak. In this study, we reconstruct the monthly average gridded sea ice concentration (SIC) in the first half of the 20th century using the relationship between the spatiotemporal features of SIC variability, surface air temperature over the Northern Hemisphere extratropical continents, sea surface temperature in the North Atlantic and North Pacific, and sea level pressure. In agreement with a few previous results, our reconstructed data also show a significant negative anomaly of the Arctic sea ice area in the middle of the 20th century, however with some 15% to 30% stronger amplitude, about 1.5 million km2 in September and 0.7 million km2 in March. The reconstruction demonstrates a good agreement with regional Arctic sea ice area data when available and suggests that ETWC in the Arctic has been accompanied by a concurrent sea ice area decline of a magnitude that have been exceeded only in the beginning of the 21st century.

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The Role of Moist Intrusions in Winter Arctic Warming and Sea Ice Decline

Journal of Climate ◽

10.1175/jcli-d-15-0773.1 ◽

2016 ◽

Vol 29 (12) ◽

pp. 4473-4485 ◽

Cited By ~ 122

Author(s):

Cian Woods ◽

Rodrigo Caballero

Keyword(s):

Sea Ice ◽

Barents Sea ◽

Surface Air Temperature ◽

The Arctic ◽

Positive Trend ◽

Sea Ice Concentration ◽

Local Conditions ◽

The Barents Sea ◽

Strong Inversion ◽

Ice Concentration

Abstract This paper examines the trajectories followed by intense intrusions of moist air into the Arctic polar region during autumn and winter and their impact on local temperature and sea ice concentration. It is found that the vertical structure of the warming associated with moist intrusions is bottom amplified, corresponding to a transition of local conditions from a “cold clear” state with a strong inversion to a “warm opaque” state with a weaker inversion. In the marginal sea ice zone of the Barents Sea, the passage of an intrusion also causes a retreat of the ice margin, which persists for many days after the intrusion has passed. The authors find that there is a positive trend in the number of intrusion events crossing 70°N during December and January that can explain roughly 45% of the surface air temperature and 30% of the sea ice concentration trends observed in the Barents Sea during the past two decades.

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Dynamics and drivers of extreme seasons in the Arctic region

10.5194/egusphere-egu21-1521 ◽

2021 ◽

Author(s):

Katharina Hartmuth ◽

Lukas Papritz ◽

Maxi Boettcher ◽

Heini Wernli

Keyword(s):

Climate Change ◽

Sea Ice ◽

Surface Temperature ◽

Sea Surface ◽

The Arctic ◽

Polar Regions ◽

Sea Surface Temperatures ◽

Sea Ice Concentration ◽

Surface Temperatures ◽

Ice Concentration

Single extreme weather events such as intense storms or blocks can have a major impact on polar surface temperatures, the formation and melting rates of sea-ice, and, thus, on minimum and maximum sea-ice extent within a particular year. Anomalous weather conditions on the time scale of an entire season, for example resulting from an unusual sequence of storms, can affect the polar energy budget and sea-ice coverage even more. Here, we introduce the concept of an extreme season in a distinct region using an EOF analysis in the phase space spanned by anomalies of a set of surface parameters (surface temperature, precipitation, surface solar and thermal radiation and surface heat fluxes). To focus on dynamical instead of climate change aspects, we define anomalies as departures of the seasonal mean from a transient climatology. The goal of this work is to study the dynamical processes leading to such anomalous seasons in the polar regions, which have not yet been analysed. Specifically, we focus here on a detailed analysis of Arctic extreme seasons and their underlying atmospheric dynamics in the ERA5 reanalysis data set.We find that in regions covered predominantly by sea ice, extreme seasons are mostly determined by anomalies of atmospheric dynamical features such as cyclones and blocking. In contrast, in regions including large areas of open water the formation of extreme seasons can also be partially due to preconditioning during previous seasons, leading to strong anomalies in the sea ice concentration and/or sea surface temperatures at the beginning of the extreme season.Two particular extreme season case studies in the Kara-Barents Seas are discussed in more detail. In this region, the winter of 2011/12 shows the largest positive departure of surface temperature from the background warming trend together with a negative anomaly in the sea ice concentration. An analysis of the synoptic situation shows that the strongly reduced frequency of cold air outbreaks compared to climatology combined with several blocking events and the frequent occurrence of cyclones transporting warm air into the region favored the continuous anomalies of both parameters. In contrast, the winter of 2016/17, which shows a positive precipitation anomaly and negative anomaly in the surface energy balance, was favored by a strong surface preconditioning. An extremely warm summer and autumn in 2016 caused strongly reduced sea ice concentrations and increased sea surface temperatures in the Kara-Barents Seas at the beginning of the winter, favoring increased air-sea fluxes and precipitation during the following months.Our results reveal a high degree of variability of the processes involved in the formation of extreme seasons in the Arctic. Quantifying and understanding these processes will also be important when considering climate change effects in polar regions and the ability of climate models in reproducing extreme seasons in the Arctic and Antarctica.

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Spatial and Temporal Variability of Minimum Brightness Temperature at the 6.925 GHz Band of AMSR2 for the Arctic and Antarctic Oceans

Remote Sensing ◽

10.3390/rs13112122 ◽

2021 ◽

Vol 13 (11) ◽

pp. 2122

Author(s):

Young-Joo Kwon ◽

Sungwook Hong ◽

Jeong-Won Park ◽

Seung Hee Kim ◽

Jong-Min Kim ◽

...

Keyword(s):

Sea Ice ◽

Brightness Temperature ◽

Seasonal Variability ◽

Sea Surface ◽

The Arctic ◽

Transfer Model ◽

Concentration Data ◽

Sea Ice Concentration ◽

Significant Difference ◽

Ice Concentration

The minimum brightness temperature (mBT) of seawater in the polar region is an important parameter in algorithms for determining sea ice concentration or snow depth. To estimate the mBT of seawater at 6.925 GHz for the Arctic and Antarctic Oceans and to find their physical characteristics, we collected brightness temperature and sea ice concentration data from the Advanced Microwave Scanning Radiometer 2 (AMSR2) for eight years from 2012 to 2020. The estimated mBT shows constant annual values, but we found a significant difference in the seasonal variability between the Arctic and Antarctic Oceans. We calculated the mBT with the radiative transfer model parameterized by sea surface temperature (SST), sea surface wind speed (SSW), and integrated water vapor (IWV) and compared them with our observations. The estimated mBT represents the modeled mBT emitted from seawater under conditions of 2–5 m/s SSW and SST below 0 °C, except in the Arctic summer. The exceptional summer mBT in the Arctic Ocean was related to unusually high SST. We found evidence of Arctic amplification in the seasonal variability of Arctic mBT.

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Impacts of early autumn Arctic sea ice concentration on subsequent spring Eurasian surface air temperature variations

Climate Dynamics ◽

10.1007/s00382-017-4026-x ◽

2017 ◽

Vol 51 (7-8) ◽

pp. 2523-2542 ◽

Cited By ~ 15

Author(s):

Shangfeng Chen ◽

Renguang Wu

Keyword(s):

Sea Ice ◽

Air Temperature ◽

Surface Air Temperature ◽

Arctic Sea Ice ◽

Sea Ice Concentration ◽

Temperature Variations ◽

Early Autumn ◽

Arctic Sea ◽

Ice Concentration ◽

Air Temperature Variations

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The impact of a warm moist air intrusion on dynamic and thermodynamic sea ice tendencies in the Arctic.

10.5194/egusphere-egu2020-8418 ◽

2020 ◽

Author(s):

Evelien Dekker

Keyword(s):

Sea Ice ◽

Radiative Forcing ◽

Surface Air Temperature ◽

Longwave Radiation ◽

Arctic Sea Ice ◽

The Arctic ◽

Moist Air ◽

Sea Ice Concentration ◽

Ice Concentration ◽

The Impact

Atmospheric blocking events in the Northern Hemishpere have been related to regional Arctic sea ice decline. During blocking events, pulses of warm and moist air enhance the radiative forcing on the sea ice in winter due to the increased longwave radiation associated with clouds. Several studies have shown that such events are related to regional sea ice concentration decline. Daily sea ice output with the latest version of CICE from the coupled Regional Arctic System model is used to study sea ice tendencies during January-February 2014. In this period there was a follow-up of a Atlantic warm moist air insturion and a Pacific warm moist air intrusion associated with surface air temperature perturbations up to 20 degrees locally.A decline in sea ice concentration during wintertime does not neccesarily mean that ice melt has occurred. The goal of this case study is to distinguish the sea ice response between a dynamic and a thermodynamic component. In this way, we learn how much of the sea ice is advected into another region during such an event and how much the sea ice is lost due to the enhanced forcing and temperature increase.&#160;&#160;&#160;

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Influences of Summertime Arctic-Dipole Atmospheric Circulation on Sea Ice Concentration Variations in the Pacific Sector of the Arctic During Different Pacific Decadal Oscillation Phases

Journal of Climate ◽

10.1175/jcli-d-19-0843.1 ◽

2021 ◽

pp. 1-43

Author(s):

Haibo Bi ◽

Yunhe Wang ◽

Yu Liang ◽

Weifu Sun ◽

Xi Liang ◽

...

Keyword(s):

Sea Ice ◽

Atmospheric Circulation ◽

Air Temperature ◽

Pacific Decadal Oscillation ◽

Satellite Observations ◽

Specific Humidity ◽

The Arctic ◽

Sea Ice Concentration ◽

The Pacific ◽

Ice Concentration

AbstractAtmospheric circulation associated with the Arctic Dipole (AD) pattern plays a crucial role in modulating the variations of summertime sea ice concentration (SIC) within the Pacific Arctic sector (PAS). Based on reanalysis data and satellite observations, we found that the impacts of atmospheric circulation associated with AD+ on SIC change over different regions of the PAS (including East Siberian Sea (ESS), Beaufort and Chukchi Seas (BCS), and Canadian Arctic Archipelago (CAA)), are dependent on the phase shifts of Pacific Decadal Oscillation (PDO). Satellite observations reveal that SIC anomalies, influenced by AD+ during PDO- relative to that during PDO+, varies significantly in summer by 4.9%, -7.3%, and -6.4% over ESS, BCS, and CAA, respectively. Overall, the atmospheric anomalies over CAA and BCS in terms of specific humidity, air temperature, and thereby downward longwave radiation (DLR), are enhanced (weakened) in the atmospheric conditions associated with AD+ during PDO- (PDO+). In these two regions, the larger (smaller) increases in specific humidity and air temperature, associated with AD+ during PDO- (PDO+), are connected to the increased (decreased) poleward moisture flux, strengthened (weakened) convergence of moisture and heat flux, and partly to adiabatic heating. As a consequence, the DLR and surface net energy flux anomalies over the two regions are reinforced in the atmospheric scenarios associated with AD+ during PDO- compared with that during PDO+. Therefore, smaller SIC anomalies are identified over CAA and BCS in the cases related to AD+ during PDO- than during PDO+. Essentially, the changes of the DLR anomaly in CAA and BCS are in alignment with geopotential height anomalies, which are modulated by the anticyclonic circulation pattern in association with AD+ during varying PDO phases. In contrast, the SIC changes over ESS is primarily attributed to the variations in mechnical wind focring and sea surface temperature (SST) anomalies. The cloud fraction anomalies associated with AD+ during different PDO phases are found not to be a significant contributor to the variations of sea ice anomaly in the studied regions. Given the oscillatory nature of PDO, we speculate that the recent shift to the PDO+ phase may temporarily slow the observed significant decline trend of the summertime SIC within PAS of the Arctic.

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Improved Estimation of Proxy Sea Surface Temperature in the Arctic

Journal of Atmospheric and Oceanic Technology ◽

10.1175/jtech-d-19-0177.1 ◽

2020 ◽

Vol 37 (2) ◽

pp. 341-349 ◽

Cited By ~ 6

Author(s):

Viva Banzon ◽

Thomas M. Smith ◽

Michael Steele ◽

Boyin Huang ◽

Huai-Min Zhang

Keyword(s):

Sea Ice ◽

Open Water ◽

Cold Season ◽

Sea Surface ◽

The Arctic ◽

Random Errors ◽

Sea Ice Concentration ◽

Arctic Sea ◽

Ice Concentration ◽

Almost All

AbstractArctic sea surface temperatures (SSTs) are estimated mostly from satellite sea ice concentration (SIC) estimates. In regions with sea ice the SST is the temperature of open water or of the water under the ice. A number of different proxy SST estimates based on SIC have been developed. In recent years more Arctic quality-control buoy SSTs have become available, allowing better validation of different estimates and the development of improved proxy estimates. Here proxy SSTs from different approaches are evaluated and an improved proxy SST method is shown. The improved proxy SSTs were tested in an SST analysis, and showed reduced bias and random errors compared to the Arctic buoy SSTs. Almost all reduction in errors is in the warm melt season. In the cold season the SIC is typically high and all estimates tend to have low errors. The improved method will be incorporated into an operational SST analysis.

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Increasing cloudiness in Arctic damps the increase in phytoplankton primary production due to sea ice receding

Biogeosciences Discussions ◽

10.5194/bgd-9-13987-2012 ◽

2012 ◽

Vol 9 (10) ◽

pp. 13987-14012 ◽

Cited By ~ 12

Author(s):

S. Bélanger ◽

M. Babin ◽

J.-E. Tremblay

Keyword(s):

Sea Ice ◽

Primary Production ◽

Arctic Ocean ◽

Sea Surface ◽

The Arctic ◽

Diagnostic Model ◽

Arctic Seas ◽

Sea Ice Concentration ◽

Phytoplankton Primary Production ◽

Ice Concentration

Abstract. The Arctic Ocean and its marginal seas are among the marine regions most affected by climate change. Here we present the results of a diagnostic model used to elucidate the main drivers of primary production (PP) trends over the 1998–2010 period at pan-Arctic and local (i.e. 9.28 km resolution) scales. Photosynthetically active radiation (PAR) above and below the sea surface was estimated using precomputed look-up tables of spectral irradiance and satellite-derived cloud optical thickness and cloud fraction parameters from the International Satellite Cloud Climatology Project (ISCCP) and sea ice concentration from passive microwaves data. A spectrally resolved PP model, designed for optically complex waters, was then used to produce maps of PP trends. Results show that incident PAR above the sea surface (PAR(0+)) has significantly decreased over the whole Arctic and sub-Arctic Seas, except over the perrennially sea ice covered waters of the Central Arctic Ocean. This fading of PAR(0+) (+8% decade–1) was caused by increasing cloudiness May and June. Meanwhile PAR penetrating the ocean (PAR(0–)) increased only along the sea ice margin over the large Arctic continental shelf where sea ice concentration declined sharply since 1998. Overall, PAR(0–) slightly increased in the Circum Arctic (+3.4% decade–1), while it decreased when considering both Arctic and sub-Arctic Seas (–3% decade–1). We showed that rising phytoplankton biomass (i.e. chlorophyll a) normalized by the diffuse attenuation of photosynthetically usable radiation (PUR) by phytoplankton accounted for a larger proportion of the rise in PP than did the increase in light availability due to sea-ice loss in several sectors and particularly in perrennially and seasonally open waters. Against a general backdrop of rising productivity over Arctic shelves, significant negative trends were observed in regions known for their great biological importance such as the coastal polynyas of Northern Greenland.

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Increasing cloudiness in Arctic damps the increase in phytoplankton primary production due to sea ice receding

Biogeosciences ◽

10.5194/bg-10-4087-2013 ◽

2013 ◽

Vol 10 (6) ◽

pp. 4087-4101 ◽

Cited By ~ 92

Author(s):

S. Bélanger ◽

M. Babin ◽

J.-É. Tremblay

Keyword(s):

Sea Ice ◽

Primary Production ◽

Arctic Ocean ◽

Sea Surface ◽

The Arctic ◽

Diagnostic Model ◽

Arctic Seas ◽

Sea Ice Concentration ◽

Phytoplankton Primary Production ◽

Ice Concentration

Abstract. The Arctic Ocean and its marginal seas are among the marine regions most affected by climate change. Here we present the results of a diagnostic model used to assess the primary production (PP) trends over the 1998–2010 period at pan-Arctic, regional and local (i.e. 9.28 km resolution) scales. Photosynthetically active radiation (PAR) above and below the sea surface was estimated using precomputed look-up tables of spectral irradiance, taking as input satellite-derived cloud optical thickness and cloud fraction parameters from the International Satellite Cloud Climatology Project (ISCCP) and sea ice concentration from passive microwaves data. A spectrally resolved PP model, designed for optically complex waters, was then used to assess the PP trends at high spatial resolution. Results show that PP is rising at a rate of +2.8 TgC yr−1 (or +14% decade−1) in the circum-Arctic and +5.1 TgC yr−1 when sub-Arctic seas are considered. In contrast, incident PAR above the sea surface (PAR(0+)) has significantly decreased over the whole Arctic and sub-Arctic Seas, except over the perennially sea-ice covered waters of the Central Arctic Ocean. This fading of PAR(0+) (−8% decade−1) was caused by increasing cloudiness during summer. Meanwhile, PAR penetrating the ocean (PAR(0−)) increased only along the sea ice margin over the large Arctic continental shelf where sea ice concentration declined sharply since 1998. Overall, PAR(0−) slightly increased in the circum-Arctic (+3.4% decade−1), while it decreased when considering both Arctic and sub-Arctic Seas (−3% decade−1). We showed that rising phytoplankton biomass (i.e. chlorophyll a) normalized by the diffuse attenuation of photosynthetically usable radiation (PUR), accounted for a larger proportion of the rise in PP than did the increase in light availability due to sea-ice loss in several sectors, and particularly in perennially and seasonally open waters. Against a general backdrop of rising productivity over Arctic shelves, significant negative PP trends and the timing of phytoplankton spring-summer bloom were observed in regions known for their great biological importance such as the coastal polynyas of northern Greenland.

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