The MOSAiC ice floe: sediment-laden survivor from the Siberian shelf

In September 2019, the research icebreaker Polarstern started the largest multidisciplinary Arctic expedition to date, the MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) drift experiment. Being moored to an ice floe for a whole year, thus including the winter season, the declared goal of the expedition is to better understand and quantify relevant processes within the atmosphere–ice–ocean system that impact the sea ice mass and energy budget, ultimately leading to much improved climate models. Satellite observations, atmospheric reanalysis data, and readings from a nearby meteorological station indicate that the interplay of high ice export in late winter and exceptionally high air temperatures resulted in the longest ice-free summer period since reliable instrumental records began. We show, using a Lagrangian tracking tool and a thermodynamic sea ice model, that the MOSAiC floe carrying the Central Observatory (CO) formed in a polynya event north of the New Siberian Islands at the beginning of December 2018. The results further indicate that sea ice in the vicinity of the CO (<40 km distance) was younger and 36 % thinner than the surrounding ice with potential consequences for ice dynamics and momentum and heat transfer between ocean and atmosphere. Sea ice surveys carried out on various reference floes in autumn 2019 verify this gradient in ice thickness, and sediments discovered in ice cores (so-called dirty sea ice) around the CO confirm contact with shallow waters in an early phase of growth, consistent with the tracking analysis. Since less and less ice from the Siberian shelves survives its first summer (Krumpen et al., 2019), the MOSAiC experiment provides the unique opportunity to study the role of sea ice as a transport medium for gases, macronutrients, iron, organic matter, sediments and pollutants from shelf areas to the central Arctic Ocean and beyond. Compared to data for the past 26 years, the sea ice encountered at the end of September 2019 can already be classified as exceptionally thin, and further predicted changes towards a seasonally ice-free ocean will likely cut off the long-range transport of ice-rafted materials by the Transpolar Drift in the future. A reduced long-range transport of sea ice would have strong implications for the redistribution of biogeochemical matter in the central Arctic Ocean, with consequences for the balance of climate-relevant trace gases, primary production and biodiversity in the Arctic Ocean

Navigation track of Akademik Fedorov during pre-MOSAiC project phase with 1 minute interval for 21 September - 25 October 2019

Data contains recorded navigation track (geographical coordinates, time) and machine calculated course and speed of the Arctic and Antarctic Research Institute (AARI) research vessel Akademik Fedorov with 1 minute interval in CSV and shapefile formats for 21 September - 25 October 2019 (pre-MOSAiC phase). Coordinates are based on GPS positions of the vessels recorded continuously on the bridge by the DKart Navigator ECDIS. Navigation area - through the northern parts of Barents Sea, Kara Sea towards the initial area of the MOSAiC distributed network (DN) and Polarstern icebreaker central floe in the Arctic Basin (app 85N, 130E) and back. There is a couple of insignificant gaps in the row. Data are in compressed form as a single archive

Special sea ice observations aboard Akademik Fedorov MOSAiC leg 1, 2019-09-25 to 2019-10-20

Sea ice observations were routinely conducted by the Arctic and Antarctic Research Institute (AARI) group aboard AARI research vessel "Akademik Fedorov" during MOSAiC leg1 compaign, 25 September - 20 October 2019. Observations were conducted in accordance with AARI methodology. Special feature of the methodology is continuous estimation of sea ice parameters both along the track of navigation “on the route” (within the area around the ship of 2-3 widths of the hull) and “in the region” (within the range of eye visibility), with separation of recording into the zones with homogeneous ice characteristics [Manual on conduction of ice air reconnaissance / Rukovodstvo po proizvodstvu ledovoi aviarazvedki, 1981]. Observations were recorded in a form of an electronic log-book in accordance with the WMO Sea Ice Nomenclature (WMO-No.259) and WMO SIGRID-3 exchange format (SIGRID-3: A vector archive format for Sea Ice Georeferenced Information and Data - JCOMM TR-23, 2014). Column names, where applicable, correspond to SIGRID-3 naming convention for sea ice polygone field names (Tables A-2, B-2, B-3, C-2). Codes for the forms of ice fully correspond to SIGRID-3 "Table 3: Form of ice codes for variable identifiers FA, FB, FC, FP and FS"

TransArctic-2019 expedition ice thickness and snow height direct measurements at points of hydrological stations

Direct (contact) measurements of sea ice thickness, elevation and snow height performed at points of 59 hydrological (oceanographic) stations during the TransArctic-2019 expedition (28 March - 04 May 2019) are presented. Variables include time, geographical location (lat, lon) and measurements of minimum (imin, m) and maximum (imax, m) sea ice thickness, minimum (iemin, m) and maximum (iemax, m) sea ice elevation (above sea level), minimum (smi, m) and maximum (sma, m) snow height, hummock concentration (huct, in 1/10 of area coverage) and maximum hummocks height (humh, m). Data is presented in CSV, DBF and shapefile formats. TransArctic-2019 expedition was convened by the Arctic and Antarctic Research Institute (AARI) aboard AARI research vessel "Akademik Tryoshnikov" within the area of the Arctic Basin northward of the Franz-Josef Land archipelago. Points of the stations were the helicopter landing sites chosen on sufficiently level and thick ice along the sections at a distance of 10s-100s km from the drifting ship

Sea ice drift from autonomous measurements from buoy 2019P92, deployed during MOSAiC 2019/20

Sea ice drift was measured by Surface Velocity Profiler 2019P92, an autonomous platform, installed on drifting sea ice in the Arctic Ocean during MOSAiC (Leg 1) 2019/20. The time series describes the position and additional parameters of the buoy between 05 Oct 2019 and 13 August 2020 in sample intervals of 10 minutes. The data set has been processed, including the flagging of obvious inconsistencies in position. The position is flagged if the drift velocity exceeds a threshold (Quality flag, position = 1), if the position exceeds extreme values, such as longitutde > 360 deg (Quality flag, position = 2), and if the position is exactly 0.0 (Quality flag, position = 4). These quality flag values can be sums of each other

Sea ice drift from autonomous measurements from buoy 2019P91, deployed during MOSAiC 2019/20

Sea ice drift was measured by Surface Velocity Profiler 2019P91, an autonomous platform, installed on drifting sea ice in the Arctic Ocean during MOSAiC (Leg 1) 2019/20. The time series describes the position and additional parameters of the buoy between 07 Oct 2019 and 15 April 2020 in sample intervals of 10 minutes. The data set has been processed, including the flagging of obvious inconsistencies in position. The position is flagged if the drift velocity exceeds a threshold (Quality flag, position = 1), if the position exceeds extreme values, such as longitutde > 360 deg (Quality flag, position = 2), and if the position is exactly 0.0 (Quality flag, position = 4). These quality flag values can be sums of each other

Collection of data sets from autonomous platforms deployed during MOSAiC in 2019/2020

This bibliography unites the individual data collected by different types of autonomous platforms deployed during MOSAiC in 2019/2020

The YOPP Final Summit : Assessing Past and Forecasting Future Polar Prediction Research

The Year of Polar Prediction (YOPP) Final Summit What: One hundred eighty-seven scientists, stakeholders, and representatives from operational forecasting centers and international bodies assembled in person and online to review the accomplishments and impacts of YOPP and make recommendations on prediction-related priorities for future international polar research projects. Where: Montreal, Canada When: 29 August-1 September 2022

A New Structure for the Sea Ice Essential Climate Variables of the Global Climate Observing System

Author Posting. © American Meteorological Society, 2022. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Bulletin of the American Meteorological Society 103(6), (2022): E1502-E1521, https://doi.org/10.1175/bams-d-21-0227.1.Climate observations inform about the past and present state of the climate system. They underpin climate science, feed into policies for adaptation and mitigation, and increase awareness of the impacts of climate change. The Global Climate Observing System (GCOS), a body of the World Meteorological Organization (WMO), assesses the maturity of the required observing system and gives guidance for its development. The Essential Climate Variables (ECVs) are central to GCOS, and the global community must monitor them with the highest standards in the form of Climate Data Records (CDR). Today, a single ECV—the sea ice ECV—encapsulates all aspects of the sea ice environment. In the early 1990s it was a single variable (sea ice concentration) but is today an umbrella for four variables (adding thickness, edge/extent, and drift). In this contribution, we argue that GCOS should from now on consider a set of seven ECVs (sea ice concentration, thickness, snow depth, surface temperature, surface albedo, age, and drift). These seven ECVs are critical and cost effective to monitor with existing satellite Earth observation capability. We advise against placing these new variables under the umbrella of the single sea ice ECV. To start a set of distinct ECVs is indeed critical to avoid adding to the suboptimal situation we experience today and to reconcile the sea ice variables with the practice in other ECV domains.PH’s contribution was funded under the Australian Government’s Antarctic Science Collaboration Initiative program, and contributes to Project 6 of the Australian Antarctic Program Partnership (ASCI000002). PH acknowledges support through the Australian Antarctic Science Projects 4496 and 4506, and the International Space Science Institute (Bern, Switzerland) project #405.2022-12-0