The Norwegian Computing Center, the Danish Meteorological Institute (DMI), the Technical University of Denmark (DTU), Polar View, the Nansen Environmental and Remote Sensing Center (NERSC), and ESA (European Space Agency) have created an extraordinary sea ice challenge, with the aim to bring together artificial intelligence (AI) and Earth observation players to address the challenge of automated sea ice mapping from Sentinel-1 synthetic aperture radar (SAR) data.

The objective of the AutoICE challenge is to advance the state of the art of sea ice parameter retrieval from SAR data, resulting in an increased capacity to derive more robust and accurate automated sea ice maps. In this challenge, we aim to push forward the new capability to retrieve multiple parameters, specifically, sea ice concentration, stage of development, and floe size (form). The relevance of these capabilities should also be seen in the context of the upcoming Copernicus next-generation Sentinel-1 SAR mission and the Copernicus Polar Expansion mission CIMR (Copernicus Imaging Microwave Radiometer).

The participants of the challenge are welcome to publish their results and approaches in a special issue dedicated to it. In addition, an overview paper will be published describing the challenge and summarizing the results.

Ice cores provide a wealth of information about past climate and environmental conditions as well as direct records of the composition of the atmosphere on timescales from decades to hundreds of millennia. This comprises deep ice cores from both polar ice sheets and from high-altitude glaciers, with the latter responding most sensitively to human interaction with the Earth system.

In October 2022 the 3rd Open Science Conference of the International Partnerships of Ice Core Sciences (IPICS) takes place in Crans-Montana, Switzerland, providing the opportunity to document the status quo of ice core research including comparative studies on other climate archives and climate models in this joint special issue of Climate of the Past and The Cryosphere: "Ice core science at the three poles".

Potential topics of contributions include the latest results from polar and high-altitude ice cores, integrative science on ice cores, climate models and other climate archives, new proxies, and other ice-core-related technology developments. In particular, we invite ice-core-related contributions on the following themes.

1. Glacial–interglacial dynamics, interglacials, and sea level
2. Holocene and the last 2000-year climate forcings and variability
3. Progress in proxy development and interpretation
4. Ice dynamics, ice sheet instability, and geophysics
5. High-alpine ice cores
6. Ice biology, basal ice, and subglacial lakes
7. Pollution records
8. Advances in drilling engineering and borehole observations
9. Timescales and methods for ice dating
10. Rapid changes and teleconnections
11. Biogeochemical cycles in the Earth system – data and models
12. New ice archives
13. The Oldest Ice challenge and the preservation of climatic signals in the deepest ice.

Studies of ice extent, volume, and dynamics during former glaciations are important for understanding past climates and evolution of the Earth's surface, and they also provide analogies for present-day and future ice sheets and their subglacial environments. The special issue (SI) "Icy landscapes of the past" brings together contributions from four Copernicus journals (Climate of the Past, The Cryosphere, Earth Surface Dynamics, and Earth System Science Data), reflecting the interdisciplinarity across scientific communities working with former glaciations from the perspectives of palaeoclimatology, glacial geomorphology, Quaternary geology, and numerical modelling, among others. It provides a platform from which field-based reconstructions and model simulations can be compared and contrasted, teasing out complex couplings between the changing cryosphere-induced topographic, freshwater, and sea level forcings and climate states of both warmer and colder epochs of the past. Through this SI, we aim to piece together the growing knowledge about regional responses of different geographic regions to past climate changes to obtain a global picture, thereby fostering emerging collaborations between previously disconnected geoscientific disciplines. We welcome contributions that shed light on ancient and more recent glaciations on Earth and their interaction with other components of the Earth system.

High-latitude regions are experiencing amplified anthropogenic global warming. Cryospheric changes (e.g. permafrost thaw, snow and ice accumulation, and melt) are strongly coupled with the hydrologic cycle and severely impact the amount and seasonality of groundwater recharge and streamflow generation and associated biogeochemical cycling. These widespread changes, in turn, affect ecological and human systems, with impacts evident even in the ocean. This special issue aims to foster knowledge exchange across communities to gain a better understanding of coupled processes between the cryosphere, hydrology, ecosystems, and humans. We welcome all contributions on topics related to cold-region hydrology with a focus on inter- and transdisciplinary approaches and particularly invite contributions targeting the following aspects:

• climate-change-induced cryospheric alterations and impacts on the water cycle in northern environments, e.g. changes in the snowpack, glacier recession, permafrost thaw, stream discharge, lake size, and wildfires;
• interdisciplinary research that furthers our understanding of the nexus between hydrological, biogeochemical, and ecosystem processes in cold-region environments;
• the impacts of current (e.g. mining, logging, dam building) and past (e.g. peatland drainage/restoration) land-use changes in high-latitude regions;
• transdisciplinary research, including knowledge of Indigenous communities and other interested parties, ideally aimed at sustainable co-development of climate change adaptation and mitigation strategies;
• studies providing open tools for the development and testing of transposable models in cold-region environments;
• studies providing information on or presenting new tools for the improvement and standardization of measurement techniques and network design in northern regions.

The glacial–interglacial cyclicity of the climate system varied in the past, most notably during the transition from a 40 ka to a 100 ka world in the mid-Pleistocene. Gases trapped in Antarctic ice are the most direct access available to investigate the composition of the paleo-atmosphere of that age and processes related to climate variability. The International Partnerships in Ice Core Sciences (IPICS) Oldest Ice endeavour aims at obtaining an undisturbed ice-core record older than 1 Ma. In addition to ice cores, time slices of paleo-records, available, for example, in Antarctic blue-ice fields, provide further valuable information, which complements continuous time series based on ice cores. This special issue will assemble contributions dedicated to the preparatory phase of this global effort to obtain ice samples and time series older than 700 000 years. This includes a consideration of glaciogical and geophysical settings which allow the presence of old ice, results from pre-site surveys and modelling studies, aspects of ice-core and other sampling techniques and analyses, and requirements for drilling and core handling.

Two closely coordinated groups (one from the USA and the other from Europe) are revisiting the Camp Century sub-ice sediment and the silty ice zone just above it using a wide variety of analytical techniques to make inferences about ice sheet behaviour, palaeo-climate, and palaeo-ecology as well as sediment transport and sourcing. The paper that kicked this off was in Proceedings of the National Academy of Sciences (PNAS) 2 years ago: "A multi-million-year-old record of Greenland vegetation and glacial history preserved in sediment beneath 1.4 km of ice at Camp Century" (Christ et al., 2021).

Talking among the 20+ lead investigators, we decided that the papers coming out of multiple, coordinated investigations of this historic (and still unique) ice core would be very useful to the broader community if they could be gathered into a special issue. Having these papers together would increase their impact and accessibility. Because of the wide variety of investigations being conducted on the core materials, a combined special issue including papers from both The Cryosphere and Climate of the Past will generate the most contributions and the largest readership.

Reference:

Christ, A. J., Bieman, P. R., Schaefer, J. M., Dahl-Jensen, D., Steffensen, J. P, Corbett, L. B., Peteet, D. M., Thomas, E. K., Steig, E. J., Rittenour, T. M., Tison, J.-L., Blard, P.-H., Perdrial, N., Dethier, D. P., Lini, A., Hidy, A. J., Caffee, M. W., and Southon, J.: A multi-million-year-old record of Greenland vegetation and glacial history preserved in sediment beneath 1.4 km of ice at Camp Century, P. Natl. Acad. Sci. USA, 118, e2021442118, https://doi.org/10.1073/pnas.2021442118, 2021.

Studies of ice extent, volume, and dynamics during former glaciations are important for understanding past climates and evolution of the Earth's surface, and they also provide analogies for present-day and future ice sheets and their subglacial environments. The special issue (SI) "Icy landscapes of the past" brings together contributions from four Copernicus journals (Climate of the Past, The Cryosphere, Earth Surface Dynamics, and Earth System Science Data), reflecting the interdisciplinarity across scientific communities working with former glaciations from the perspectives of palaeoclimatology, glacial geomorphology, Quaternary geology, and numerical modelling, among others. It provides a platform from which field-based reconstructions and model simulations can be compared and contrasted, teasing out complex couplings between the changing cryosphere-induced topographic, freshwater, and sea level forcings and climate states of both warmer and colder epochs of the past. Through this SI, we aim to piece together the growing knowledge about regional responses of different geographic regions to past climate changes to obtain a global picture, thereby fostering emerging collaborations between previously disconnected geoscientific disciplines. We welcome contributions that shed light on ancient and more recent glaciations on Earth and their interaction with other components of the Earth system.

High-latitude regions are experiencing amplified anthropogenic global warming. Cryospheric changes (e.g. permafrost thaw, snow and ice accumulation, and melt) are strongly coupled with the hydrologic cycle and severely impact the amount and seasonality of groundwater recharge and streamflow generation and associated biogeochemical cycling. These widespread changes, in turn, affect ecological and human systems, with impacts evident even in the ocean. This special issue aims to foster knowledge exchange across communities to gain a better understanding of coupled processes between the cryosphere, hydrology, ecosystems, and humans. We welcome all contributions on topics related to cold-region hydrology with a focus on inter- and transdisciplinary approaches and particularly invite contributions targeting the following aspects:

• climate-change-induced cryospheric alterations and impacts on the water cycle in northern environments, e.g. changes in the snowpack, glacier recession, permafrost thaw, stream discharge, lake size, and wildfires;
• interdisciplinary research that furthers our understanding of the nexus between hydrological, biogeochemical, and ecosystem processes in cold-region environments;
• the impacts of current (e.g. mining, logging, dam building) and past (e.g. peatland drainage/restoration) land-use changes in high-latitude regions;
• transdisciplinary research, including knowledge of Indigenous communities and other interested parties, ideally aimed at sustainable co-development of climate change adaptation and mitigation strategies;
• studies providing open tools for the development and testing of transposable models in cold-region environments;
• studies providing information on or presenting new tools for the improvement and standardization of measurement techniques and network design in northern regions.

The Norwegian Computing Center, the Danish Meteorological Institute (DMI), the Technical University of Denmark (DTU), Polar View, the Nansen Environmental and Remote Sensing Center (NERSC), and ESA (European Space Agency) have created an extraordinary sea ice challenge, with the aim to bring together artificial intelligence (AI) and Earth observation players to address the challenge of automated sea ice mapping from Sentinel-1 synthetic aperture radar (SAR) data.

The objective of the AutoICE challenge is to advance the state of the art of sea ice parameter retrieval from SAR data, resulting in an increased capacity to derive more robust and accurate automated sea ice maps. In this challenge, we aim to push forward the new capability to retrieve multiple parameters, specifically, sea ice concentration, stage of development, and floe size (form). The relevance of these capabilities should also be seen in the context of the upcoming Copernicus next-generation Sentinel-1 SAR mission and the Copernicus Polar Expansion mission CIMR (Copernicus Imaging Microwave Radiometer).

The participants of the challenge are welcome to publish their results and approaches in a special issue dedicated to it. In addition, an overview paper will be published describing the challenge and summarizing the results.

Two closely coordinated groups (one from the USA and the other from Europe) are revisiting the Camp Century sub-ice sediment and the silty ice zone just above it using a wide variety of analytical techniques to make inferences about ice sheet behaviour, palaeo-climate, and palaeo-ecology as well as sediment transport and sourcing. The paper that kicked this off was in Proceedings of the National Academy of Sciences (PNAS) 2 years ago: "A multi-million-year-old record of Greenland vegetation and glacial history preserved in sediment beneath 1.4 km of ice at Camp Century" (Christ et al., 2021).

Talking among the 20+ lead investigators, we decided that the papers coming out of multiple, coordinated investigations of this historic (and still unique) ice core would be very useful to the broader community if they could be gathered into a special issue. Having these papers together would increase their impact and accessibility. Because of the wide variety of investigations being conducted on the core materials, a combined special issue including papers from both The Cryosphere and Climate of the Past will generate the most contributions and the largest readership.

Reference:

Christ, A. J., Bieman, P. R., Schaefer, J. M., Dahl-Jensen, D., Steffensen, J. P, Corbett, L. B., Peteet, D. M., Thomas, E. K., Steig, E. J., Rittenour, T. M., Tison, J.-L., Blard, P.-H., Perdrial, N., Dethier, D. P., Lini, A., Hidy, A. J., Caffee, M. W., and Southon, J.: A multi-million-year-old record of Greenland vegetation and glacial history preserved in sediment beneath 1.4 km of ice at Camp Century, P. Natl. Acad. Sci. USA, 118, e2021442118, https://doi.org/10.1073/pnas.2021442118, 2021.

Ice cores provide a wealth of information about past climate and environmental conditions as well as direct records of the composition of the atmosphere on timescales from decades to hundreds of millennia. This comprises deep ice cores from both polar ice sheets and from high-altitude glaciers, with the latter responding most sensitively to human interaction with the Earth system.

In October 2022 the 3rd Open Science Conference of the International Partnerships of Ice Core Sciences (IPICS) takes place in Crans-Montana, Switzerland, providing the opportunity to document the status quo of ice core research including comparative studies on other climate archives and climate models in this joint special issue of Climate of the Past and The Cryosphere: "Ice core science at the three poles".

Potential topics of contributions include the latest results from polar and high-altitude ice cores, integrative science on ice cores, climate models and other climate archives, new proxies, and other ice-core-related technology developments. In particular, we invite ice-core-related contributions on the following themes.

1. Glacial–interglacial dynamics, interglacials, and sea level
2. Holocene and the last 2000-year climate forcings and variability
3. Progress in proxy development and interpretation
4. Ice dynamics, ice sheet instability, and geophysics
5. High-alpine ice cores
6. Ice biology, basal ice, and subglacial lakes
7. Pollution records
8. Advances in drilling engineering and borehole observations
9. Timescales and methods for ice dating
10. Rapid changes and teleconnections
11. Biogeochemical cycles in the Earth system – data and models
12. New ice archives
13. The Oldest Ice challenge and the preservation of climatic signals in the deepest ice.

The glacial–interglacial cyclicity of the climate system varied in the past, most notably during the transition from a 40 ka to a 100 ka world in the mid-Pleistocene. Gases trapped in Antarctic ice are the most direct access available to investigate the composition of the paleo-atmosphere of that age and processes related to climate variability. The International Partnerships in Ice Core Sciences (IPICS) Oldest Ice endeavour aims at obtaining an undisturbed ice-core record older than 1 Ma. In addition to ice cores, time slices of paleo-records, available, for example, in Antarctic blue-ice fields, provide further valuable information, which complements continuous time series based on ice cores. This special issue will assemble contributions dedicated to the preparatory phase of this global effort to obtain ice samples and time series older than 700 000 years. This includes a consideration of glaciogical and geophysical settings which allow the presence of old ice, results from pre-site surveys and modelling studies, aspects of ice-core and other sampling techniques and analyses, and requirements for drilling and core handling.