Polar Sea Research Articles

SVM-Based Sea Ice Extent Retrieval Using Multisource Scatterometer Measurements

This study aims to explore the joint usage of multisource scatterometer measurements in polar sea water and ice discrimination. All radar backscatter measurements from current operating satellite scatterometers are considered, including the C-band ASCAT scatterometer on board the MetOp series satellites, the Ku-band scatterometer on board the HY-2B satellite (HSCAT), and the Ku-band scatterometer on board the CFOSAT satellite (CSCAT). By performing seven experiments that use the same support vector machine (SVM) classifier method but with different input data, we find that the SVM model with all available HSCAT, CSCAT, and ASCAT scatterometer data as inputs gives the best performance. In addition to the SVM outputs, we employ the image erosion/dilation techniques and area growth method to reduce misclassifications of sea water and ice. The sea ice extent obtained in this study shows a good agreement with the National Snow and Ice Data Center (NSIDC) sea ice concentration data from the years 2019 to 2021. More specifically, the sea ice areas are closer to the sea ice areas calculated using 15% as the threshold for NSIDC sea ice concentration data in both Arctic and Antarctic. The sea ice edges acquired by the multisource scatterometer show a close correlation with sea ice edges from the Sentinel-1 Synthetic Aperture Radar (SAR) images. In addition, we found that the coverage of multisource scatterometer data in a half-day is usually above 97%, and more importantly, the sea ice areas obtained on the basis of half-day and daily multisource scatterometer data are very close to each other. The presented work can serve as guidance on the usage of all available scatterometer measurements in sea ice monitoring.

Global distribution of marine microplastics and potential for biodegradation

Microplastics are a growing marine environmental concern globally due to their high abundance and persistent degradation. We created a global map for predicting marine microplastic pollution using a machine-learning model based on 9445 samples and found that microplastics converged in zones of accumulation in subtropical gyres and near polar seas. The predicted global potential for the biodegradation of microplastics in 1112 metagenome-assembled genomes from 485 marine metagenomes indicated high potential in areas of high microplastic pollution, such as the northern Atlantic Ocean and the Mediterranean Sea. However, the limited number of samples hindered our prediction, a priority issue that needs to be addressed in the future. We further identified hosts with microplastic degradation genes (MDGs) and found that Proteobacteria accounted for a high proportion of MDG hosts, mainly Alphaproteobacteria and Gammaproteobacteria, with host-specific patterns. Our study is essential for raising awareness, identifying areas with microplastic pollution, providing a prediction method of machine learning to prioritize surveillance, and identifying the global potential of marine microbiomes to degrade microplastics, providing a reference for selecting bacteria that have the potential to degrade microplastics for further applied research.

Direct measurements and CFD simulations on ice-induced hull pressure of a ship in floe ice fields

Floe ice fields are expected to replace level ice to be the most common environment for future polar sea transportation under the long-term trend of global warming. In this study, the authors aim to develop a viable analysis procedure to predict the ice-induced hull pressure characteristics for ships navigating in floe ice fields. A novel ice model test procedure is established, which is characterized by making use of non-refrigerated synthetic model ice and tactile pressure sensors to measure the hull pressure. The numerical tool is based on a state-of-the-art CFD-DEM numerical framework; a novel method to monitor the hull pressure during the interaction between the hull and ice floes during the CFD-DEM simulations. Statistical analysis indicates the probability distributions of the ice pressure from the experiment and the numerical results are comparable. Besides, the impacts of ship speed and ice floe concentration on the hull pressure distribution are also examined. Increasing speed and ice concentration will make the probability distribution of ice pressure shift towards the high-pressure going interval, resulting in an increased mean of ice pressure. It is also found that increased speed leads to a smaller variance, while increased ice concentration results in a larger variance.

Estimation of Arctic Sea Ice Thickness from Chinese HY-2B Radar Altimetry Data

Sea ice thickness (SIT) is an important parameter in the study of climate change. During the past 20 years, satellite altimetry has been widely used to observe sea ice thickness. The Chinese Haiyang-2B (HY-2B) radar altimeter, launched in October 2018, can provide data up to 80.6° latitude and can be used as a supplementary means to observe polar sea ice. Reliable HY-2B SIT products will contribute to the sea ice community. In this study, we aimed to assess the Arctic sea ice thickness retrieval ability of the HY-2B radar altimetry data. We processed the HY-2B radar altimetry data from January 2019 to April 2022 and used the processed data to retrieve the Arctic SIT. The Alfred Wegener Institute (AWI) CryoSat-2 (CS-2) SIT products were used to calibrate the HY-2B SIT estimates with a linear regression method. The Goddard Space Flight Center (GSFC) CS-2, Jet Propulsion Laboratory (JPL), and GSFC ICESat-2 (IS-2) SIT products were used to validate the HY-2B calibrated SIT estimates. The HY-2B calibrated SIT estimates have good, consistent spatial distributions with the CS-2 and IS-2 SIT products. The comparison with the IS-2 and IS-2 SIT products shows the root-mean-square error (RMSE) and bias for the HY-2B SIT estimates are significantly reduced after calibration. The HY-2B SIT estimates were also validated using the ice thickness data from Operation IceBridge (OIB) and the ice draft data from the Beaufort Gyre Exploration Project (BGEP). Finally, the monthly variations of the HY-2B SIT estimates were analyzed. Results show that the HY-2B calibrated SIT estimates are reliable, especially when the SIT values are lower than 3 m. The HY-2B altimetry data is a possible source for sea ice thickness data at lower latitudes and will help us better understand the sea ice response to climate change.

Antibacterial, Antifungal and Algicidal Activity of Phlorotannins, as Principal Biologically Active Components of Ten Species of Brown Algae.

Marine seaweeds synthesize a plethora of bioactive metabolites, of which phlorotannins of brown algae currently attract special attention due to their high antibiotic and cytotoxic capacities. Here we measured the minimum inhibitory concentrations (MICs) of several semi-purified phlorotannin preparations of different origins and molecular composition using a set of model unicellular organisms, such as Escherichia coli, Saccharomyces cerevisiae, Chlamydomonas reinhardtii, etc. For the first time, MIC values were evaluated for phlorotannin-enriched extracts of brown algae of the orders Ectocarpales and Desmarestiales. Phlorotannin extracts of Desmarestia aculeata, Fucus vesiculosus, and Ectocarpus siliculosus showed the lowest MIC values against most of the treated organisms (4-25 μg/mL for bacteria and yeast). Analysis of the survival curves of E. coli showed that massive loss of cells started after 3-4 h of exposure. Microalgae were less susceptible to activity of phlorotannin extracts, with the highest MIC values (≥200 µg/mL) measured for Chlorella vulgaris cells. D. aculeata, E. siliculosus, and three fucalean algae accumulate considerable amounts (4-16% of dry weight) of phlorotannins with MIC values similar to those widely used antibiotics. As these species grow abundantly in polar and temperate seas and have considerable biomass, they may be regarded as promising sources of phlorotannins.

Dataset for "Weakening of western disturbances in response to polar sea ice melt in climate model simulations"

Dataset for "Weakening of western disturbances in response to polar sea ice melt in climate model simulations"

Genomic diversity and ecological distribution of marine Pseudoalteromonas phages

Pseudoalteromonas, with a ubiquitous distribution, is one of the most abundant marine bacterial genera. It is especially abundant in the deep sea and polar seas, where it has been found to have a broad metabolic capacity and unique co-existence strategies with other organisms. However, only a few Pseudoalteromonas phages have so far been isolated and investigated and their genomic diversity and distribution patterns are still unclear. Here, the genomes, taxonomic features and distribution patterns of Pseudoalteromonas phages are systematically analyzed, based on the microbial and viral genomes and metagenome datasets. A total of 143 complete or nearly complete Pseudoalteromonas-associated phage genomes (PSAPGs) were identified, including 34 Pseudoalteromonas phage isolates, 24 proviruses, and 85 Pseudoalteromonas-associated uncultured viral genomes (UViGs); these were assigned to 47 viral clusters at the genus level. Many integrated proviruses (n = 24) and filamentous phages were detected (n = 32), suggesting the prevalence of viral lysogenic life cycle in Pseudoalteromonas. PSAPGs encoded 66 types of 249 potential auxiliary metabolic genes (AMGs) relating to peptidases and nucleotide metabolism. They may also participate in marine biogeochemical cycles through the manipulation of the metabolism of their hosts, especially in the phosphorus and sulfur cycles. Siphoviral and filamentous PSAPGs were the predominant viral lineages found in polar areas, while some myoviral and siphoviral PSAPGs encoding transposase were more abundant in the deep sea. This study has expanded our understanding of the taxonomy, phylogenetic and ecological scope of marine Pseudoalteromonas phages and deepens our knowledge of viral impacts on Pseudoalteromonas. It will provide a baseline for the study of interactions between phages and Pseudoalteromonas in the ocean.

First results of Antarctic sea ice type retrieval from active and passive microwave remote sensing data

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 for MYI. Due to differences in the 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 satellite retrieval scheme was ready to monitor the distribution and temporal development of Antarctic ice types, particularly MYI, throughout the freezing season and on timescales of several years. 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 core of the retrieval method is a mathematical scheme that needs empirical distributions of the microwave brightness temperature and backscatter input parameters for the different ice types. The first circumpolar, long-term time series of Antarctic sea ice types (MYI, first-year ice, and young ice) is being established, and so far covers the years 2013–2021. Qualitative comparison with (a) synthetic aperture radar data, (b) charts of the development stage of the sea ice, and (c) the 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 allows insight into the interannual evolution and dynamics of Antarctic sea ice types for the first time. 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.

Ice nucleating properties of the sea ice diatom Fragilariopsis cylindrus and its exudates

Abstract. In this study, we investigated the ice nucleation activity of the Antarctic sea ice diatom Fragilariopsis cylindrus. Diatoms are the main primary producers of organic carbon in the Southern Ocean, and the Antarctic sea ice diatom F. cylindrus is one of the predominant species. This psychrophilic diatom is abundant in open waters and within sea ice. It has developed several mechanisms to cope with the extreme conditions of its environment, for example, the production of ice-binding proteins (IBPs) and extracellular polymeric substances known to alter the structure of ice. Here, we investigated the ice nucleation activity of F. cylindrus using a microfluidic device containing individual sub-nanolitre (∼90 µm) droplet samples. The experimental method and a newly implemented Poisson-statistics-based data evaluation procedure applicable to samples with low ice nucleating particle concentrations were validated by comparative ice nucleation experiments with well-investigated bacterial samples from Pseudomonas syringae (Snomax®). The experiments reveal an increase of up to 7.2 ∘C in the ice nucleation temperatures for seawater containing F. cylindrus diatoms when compared to pure seawater. Moreover, F. cylindrus fragments also show ice nucleation activity, while experiments with the F. cylindrus ice-binding protein (fcIBP) show no significant ice nucleation activity. A comparison with experimental results from other diatoms suggests a universal behaviour of polar sea ice diatoms, and we provide a diatom-mass-based parameterization of their ice nucleation activity for use in models.

Spatio-temporal monitoring of the iceberg D28 using SCATSAT-1 data

Abstract The study of the icebergs and their movements is one of many applications of scatterometer data in the study of the ecosystems of polar regions. SCATSAT-1 is the Indian Space Research Organisation’s (ISRO’s) Ku-band (13.515625 GHz) scatterometer. Using enhanced resolution Gamma0H (horizontally polarised incidence angle normalised backscattering coefficient) data of SCATSAT-1, we observed the movement of iceberg D28 and its interaction with wind, ocean currents and sea ice for one and a half years of its journey (JD 269, 2019 to JD 051, 2021). The data sets used are as follows: (1) SCATSAT-1 level-4 Gamma0H; (2) OSCAR (Ocean Surface Current Analysis Real-time) third-degree resolution ocean surface currents; (3) hourly wind speed data of ERA5; 4) NSIDC (National Snow and Ice Data Center) sea ice concentration data; and (5) NSIDC Polar Path-finder Daily EASE-Grid Sea Ice Motion Vectors, Version-3. For this study, we divide the continent into five different regions/sectors. It is found that the trajectory of the iceberg is influenced by the resultant of the wind and ocean current, at different scales in these regions. Moreover, sea ice motion can also change the course of iceberg. From the on-screen digitisation of the iceberg, the average area of the iceberg is found to be approximately 1509.82 km2 with approximate dimensions of 27 km × 55.5 km. We conclude that spatial and temporal behaviours of the iceberg can be ascertained from the scatterometer data.

Asian States and the Arctic Ocean

Asian States and the Arctic Ocean Hide Sakaguchi According to solar physics data, the earth receives 7,400 quadrillion kilojoules (kJ) of energy from the sun each day. From this energy hitting the earth, it is estimated that roughly 80 trillion kJ is available to humans through the food chain from plants and animals. The amount of energy from food that each individual human needs each day is approximately 10 thousand kJ. Thus, solar energy can feed at most 8 billion people through the food chain from plants and animals. According to World Population Prospects 2022, the global population reached 8 billion in November 2022. The populations of China and India are each more than 1.4 billion, and other Asian countries such as Indonesia, Pakistan, Bangladesh, Japan, the Philippines, Vietnam, and Thailand are also among the top twenty largest countries by population. The sum of the populations in these nine countries alone is 3.9 billion. Thus, we should be aware that world population has already reached earth's capacity, and 50% of these people are concentrated in Asia. And yet, world population is projected to continue growing at a high rate for several decades, so we must intensify food production. However, doing so requires huge amounts of energy—in fact, 4% of global electric energy currently consumed is to produce nitrogen fertilizer in support of food production. Consequently, population, food, resources, energy, and the environment are all interrelated global problems, and we are now at a critical point. However, there exists a buffer to alleviate some of the tension of these problems—the oceans. The oceans can work to produce food and energy. At the same time, science has proven that the oceans can support carbon and nitrogen fixation, enabling these elements to support plant life and be used in fertilizers. The Arctic Ocean, especially, has great potential for those purposes. The Arctic Ocean is considered a large polar sea surrounded by the following five coastal states: Canada, Denmark (via Greenland), Norway (via Svalbard), Russia, and the United States (via Alaska). In terms of economic exclusive zones (EEZs), the largest area of Arctic Ocean by country belongs to Canada, 5.3 million square kilometers, while the second-largest belongs to Russia at 4.3 million square kilometers. Therefore, to address the global problems mentioned above, collaboration and cooperation between Asian states, which are largely driving global population growth, and the Arctic states, especially Canada with the largest share of the Arctic Ocean within its EEZ, are essential. International cooperation must be carried out through the development and conservation of the Arctic Ocean. In this context, projects to introduce the [End Page 3] ocean and its development potential to Asian states to attract investment, scientific research, and technological development are of the highest importance. This ocean is truly the last frontier and may be key to our last stand to save the earth. [End Page 4] Hide Sakaguchi President Ocean Policy Research Institute of the Sasakawa Peace Foundation Copyright © 2023 The National Bureau of Asian Research, Seattle, Washington

Gas flares and modern degasation processes in the Arctic seas (on the frequency resonance results-based)

The newly obtained results of the frequency-resonance (FR) technologies application for the study of the sources and processes of seeps and pockmarks formation in the Arctic Region (Norwegian, Barents Sea) and the North Sea are considered. The experimental study of the seepage processes' source formation was carried out using modified methods of the FR-processing, and decoding of satellite images and photographs with the vertical scanning of the cross-sections. The study results of the methane seeps and pockmarks fields show that the intensity and dynamics of their formation partly depend on the inflow of gas fluids from deep sources because of active degassing processes. The use of FR-sounding technologies allows us to remotely determine the spatial regularities of zones of intense gas emission formation and the geological sources of migration probable depth. The study of seep and pockmark field results confirms the significant, but insufficiently taken into account, the influence of crust-mantle gas fluids on the nature and degassing processes features in the structures of the continental margins. New results confirm the crust-mantle gas fluids influence on the nature and degassing processes features in the scan points of Polar marginal structures. These data are important arguments in favor of the "volcanic model" of various structural elements formation in this Region. The FR- technologies data also showed a possibility of seeps and pockmarks use as shallow and deep hydrocarbon field indicators in gas emission areas. These independent data can be used in modeling the deep lithosphere structure and possible mechanisms of abiogenic hydrocarbon formation in Arctic margin structures. We suppose that hydrocarbons through deep channels migrate (from 57 km deep) to the upper crustal horizons where can form hydrocarbon fields. During this migration, gas seeps and pockmarks are formed on the sea bottom and part of the gas can migrate into the atmosphere. Modern degassing centers' studies have confirmed the presence of zones of active migration of gases into the atmosphere, which is an important influencing factor in the dynamics of global climate change processes on Earth. The experience of FR- technologies used in the fields of methane seeps and pockmarks study found in the structures of the Arctic Polar seas showed versatility and the possibility of their use in the study of large gas emissions in structures of different regions.

‘The Admiralty has been keeping its pictures’: photography and the British Arctic Expedition, 1875–1876

ABSTRACT When the British Arctic Expedition of 1875 under command of George Nares left in search of the North Pole, they brought with them the most up-to-date photographic equipment available to the British Admiralty. Two crew members received instruction in photography from the astronomer, engineer and photographer, William Abney at Chatham, and Abney also sourced the wet and dry-plate equipment provided for the expedition. The expedition was unsuccessful in its ambitious geographical goal of reaching the North Pole, but it returned in 1876 with over 100 photographs. However, the Admiralty did not immediately release the photographs, which was a decision that was broadly criticized in the British periodical press. This was the first time an expedition had successfully returned with photographs taken in the high Arctic, so why did the Admiralty withhold the photographs? In this article, I use examples from the Illustrated London News and Nares’ official travel account Narrative of A Voyage to the Polar Sea (1878) to examine the use of photography in constructing specific ideals of exploration in the context of the British Arctic Exploration of 1875. I show that the use of photography in the Arctic had been an experiment, both in terms of using new technologies while travelling in the high north, and in incorporating this new medium into the visual archives and narrative storytelling of expeditions. The use of different forms of illustrations also speaks the construction of visual authority and narratorial control in the context of imperial expansionism in the North.

Global seaweed productivity.

The magnitude and distribution of net primary production (NPP) in the coastal ocean remains poorly constrained, particularly for shallow marine vegetation. Here, using a compilation of in situ annual NPP measurements across >400 sites in 72 geographic ecoregions, we provide global predictions of the productivity of seaweed habitats, which form the largest vegetated coastal biome on the planet. We find that seaweed NPP is strongly coupled to climatic variables, peaks at temperate latitudes, and is dominated by forests of large brown seaweeds. Seaweed forests exhibit exceptionally high per-area production rates (a global average of 656 and 1711 gC m−2 year−1 in the subtidal and intertidal, respectively), being up to 10 times higher than coastal phytoplankton in temperate and polar seas. Our results show that seaweed NPP is a strong driver of production in the coastal ocean and call for its integration in the oceanic carbon cycle, where it has traditionally been overlooked.

Cassini Bistatic Radar Experiments: Preliminary Results on Titan’s Polar Regions

In bistatic radar observations, reflected echoes from the surface of a target planet can be analyzed to infer its surface statistics and near-surface constituents. In this work, a preliminary inspection of two X-band bistatic radar observations gathered by the Cassini spacecraft about Titan’s polar regions is presented. Profiles of relative dielectric constant and root-mean-square (rms) surface slope are provided as outputs of the analysis, discussed, and compared with the present knowledge of Titan geomorphology. For the assessment of the rms slope, proportional to the spectral broadening of reflected echoes, a basic fitting procedure was applied to the received spectra using a Gaussian template, to later evaluate the full-width half-maximum of the fitting curve. The dielectric constant was computed from the power ratio between orthogonally circularly polarized components of signal reflections from Titan. Dielectric constant estimates are, on average, consistent with the expected materials covering the dry surfaces of the planet, while slightly low values were found over the seas. The rms slopes are generally low compared to past bistatic observations of other targets. Titan’s north polar seas are revealed to feature an unprecedented smoothness, with 0.01^circ of slope as an upper bound. Similar values were inferred for isolated spots in the southern pole, hinting at the possible presence of basins filled with liquid hydrocarbons. The main issues with the analysis are emphasized throughout the document, and some ideas for future work are presented in the conclusions.

Weakening of Indian Summer Monsoon Synoptic Activity in Response to Polar Sea Ice Melt Induced by Albedo Reduction in a Climate Model

AbstractThe effect of polar sea ice melt on low latitude climate is little known. To understand the response of the Indian summer monsoon (ISM) synoptic activity to the sea ice melt, we have run a suite of coupled and uncoupled climate model simulations. In one set of simulations, the albedo of sea ice is reduced so that it would melt due to increased absorption of solar radiation. The coupled model simulation with a reduced sea ice albedo resulted in an almost complete melting of the sea ice in summer in both hemispheres. A high‐resolution (50 km) atmospheric general circulation model (AGCM) is forced with the climatological annual cycles of sea surface temperature (SST) and sea ice concentrations (SIC) from the coupled model outputs to better resolve synoptic scale variability. In the high‐resolution AGCM simulations forced with SST and SIC from the sea ice melt experiments, the ISM circulation weakened substantially, and the monsoon low‐pressure systems (LPS) activity experienced an overall decline of 23%, with a widespread weakening in the south and a moderate strengthening over the north, in response to a decline of 78% (24%) in SIC over the Arctic (Antarctic) in the June–September season. The changes in the LPS activity in response to polar sea ice melt are found to be mostly driven by the changes in low‐level absolute vorticity and vertical shear over the Bay of Bengal.

Marine sediment as a likely source of methyl and ethyl iodides in subpolar and polar seas

The surface ocean is an important source of longer-lived volatile organic iodine compounds, such as methyl and ethyl iodide. However, their production in deep waters is poorly constrained. Here, we combine shipborne seawater and sediment core analyses to investigate the temporal and vertical distribution of methyl and ethyl iodide concentrations in the Bering and Chukchi Seas in July 2017 and 2018, and Funka Bay, Japan, between March 2018 and December 2019. We find the highest methyl and ethyl iodide concentrations in sediment porewaters and at the sediment surface. In Funka Bay, concentrations in the sediment and bottom waters strongly increased following the spring bloom and subsequent settling of phytodetritus to the seafloor. Dark incubation experiments suggest that diatom aggregates are a source of methyl and ethyl iodide to the ambient water. Our findings suggest that phytodetritus at the seafloor is a potential source of volatile organic iodine compounds to the water column in polar and subpolar coastal oceans.

Warmer western tropical South Atlantic during the Last Interglacial relative to the current interglacial period

The Last Interglacial (LIG, 129–116 thousand years ago) is an excellent case study for global warming scenarios and a target for proxy-model comparisons. The LIG global average sea surface temperature (SST) was ~0.5 °C higher than pre-industrial (PI). Contrary to the global average, tropical SST proxy compilations and model simulations show a negative anomaly in LIG SST relative to PI. Here, we present a LIG SST record from marine sediment core GL-1180 retrieved from the western tropical South Atlantic (WTSA). The SST record is based on Mg/Ca ratios of planktonic foraminifera Globigerinoides ruber (white). Our results indicate a warmer LIG in the WTSA relative to PI and Holocene conditions. We show that a positive LIG SST anomaly in tropical regions can be explained by polar sea ice loss during the LIG, which warms the ocean surface all the way into the tropics. The disagreement between proxy results and model simulations from the fourth phase of the Paleoclimate Modelling Intercomparison Project could result from uncertainties in our proxy for SST and/or limitations of numeric models in capturing transient forcings and feedbacks in Earth's climate system and imprecise boundary conditions. Additional studies are warranted to better constrain the LIG SST evolution in tropical regions.

Loss of Perennial Polar Sea Ice May Initiate Major Climate Change

Loss of Perennial Polar Sea Ice May Initiate Major Climate Change

Benefits and challenges of dynamic sea ice for weather forecasts

Abstract. The drive to develop environmental prediction systems that are seamless across both weather and climate timescales has culminated in the development and use of Earth system models, which include a coupled representation of the atmosphere, land, ocean and sea ice, for medium-range weather forecasts. One region where such a coupled Earth system approach has the potential to significantly influence the skill of weather forecasts is in the polar and sub-polar seas, where fluxes of heat, moisture and momentum are strongly influenced by the position of the sea ice edge. In this study we demonstrate that using a dynamically coupled ocean and sea ice model in the European Centre for Medium-Range Weather Forecasts (ECMWF) Integrated Forecasting System results in improved sea ice edge position forecasts in the Northern Hemisphere in the medium range. Further, this improves forecasts of boundary layer temperature and humidity downstream of the sea ice edge in some regions during periods of rapid change in the sea ice, compared to forecasts in which the sea surface temperature anomalies and sea ice concentration do not evolve throughout the forecasts. However, challenges remain, such as large errors in the position of the ice edge in the ocean analysis used to initialise the ocean component of the coupled system, which has an error of approximately 50 % of the total forecast error at day 9, suggesting there is much skill to be gained by improving the ocean analysis at and around the sea ice edge. The importance of the choice of sea ice analysis for verification is also highlighted, with a call for more guidance on the suitability of satellite sea ice products to verify forecasts on daily to weekly timescales and on meso-scales (< 500 km).