ALBERT

Description: The fine spatial resolution of the ICESat-2 (IS2) satellite altimeter allows monitoring the evolution of sea ice thickness with detailed dynamic information (e.g. ridges and leads). In this study, we first assess the ability of IS2 to estimate thermodynamic ice growth and dynamic thickening during the ice-growing season in the central Arctic Ocean. As an indicator of the thermodynamic ice growth, we use 10 thermistor string-based sea ice mass balance array (SIMBA) buoys deployed at a scale of ~50 km from the Icebreaker Polarstern during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. We collect IS2 data within 20 km buffer distance from the individual buoys, and calculate the mode, median, and mean of the IS2-derived ice thickness. The IS2 modal thickness shows the least bias (−0.169 m) with the buoy ice thickness, representing level ice thickness. In addition, the increasing rate of the IS2 modal thickness is close to the thermodynamic ice growth with a small bias of −0.054 cm/day. However, the increasing rates of the IS2 median and mean thickness are greater than the thermodynamic ice growth by about 0.114 cm/day and 0.198 cm/day, respectively, because they also include ice growth caused by thickness redistribution during dynamic deformation. The dynamic contributions may account for 26.1 ± 10.3% and 34.4 ± 10.1% of the total increase of the IS2 median and mean thickness, respectively. Within a ~ 50 km radius area from the MOSAiC Central Observatory, IS2 measurements exhibit that the ridge fraction increased from 〈2% in November to ~4% in March (~0.029%/day of average increasing rate) and ridge height increased about 0.047 cm/day during the same period. However, lead formation does not show significant contributions to the dynamic ice thickening because leads are temporary features lasting only 2–3 days. Although there are considerable uncertainties in IS2 ice thickness estimation and IS2-buoy thickness comparison, this study emphasizes the importance of combining measurements by IS2 and SIMBA buoys to explain the regional sea ice mass balance with separating the thermodynamic and dynamic contributions.

Description: A thermistor string-based snow and ice mass balance apparatus (SIMBA) was deployed in the land-fast sea ice zone in Young sound, eastern Greenland, on 28 October 2020, and operated successfully until 10 April 2021. The SIMBA was manufactured by the Scottish Association for Marine Science (SAMS) (Jackson et al., 2013). Two types of temperatures were measured by the SIMBA. The temperature of air, snow, ice, and water where SIMBA thermistor sensors were placed, is named as SIMBA_ET. The temperature reading after each thermistor sensor was applied with an identical amount of heat, is named SIMBA_HT. The amount of heat was controlled by the duration of heating, often configured as the 30s and 120s, respectively. The SIMBA_ET and SIMBA_HT were measured four times per day and one time per day, respectively. So SIMBA_HT(30) and SIMBA_HT(120) represent the sensor temperature changes in air, snow, ice, and water after a heating cycle of the 30s and 120s, respectively. The length of the SIMBA thermistor chain is 4.8m. There are 240 thermistor sensors (DS28EA00, accurate to +/- 0.0625°C) with 0.02 m spacing. Combined with a SIMBA algorithm (Cheng et al., 2020) and manual analyses, snow depth and ice thickness can be derived from SIMBA_ET and SMMBA_HT observations. Overall, the measurement accuracy was 0.02 m for both the snow depth and ice thickness. The submitted data package includes 6 data files, i.e., SIMBA GPS position; snow depth; ice thickness; SIMBA_ET, as well as in situ snow depth and ice thickness measured by the local personnel.

Description: The Snow and Ice Mass Balance Array (SIMBA) is a thermistor string type IMB (Jackson et al., 2013) that measures the environment temperature SIMBA-ET and temperature change (SIMBA-HT) after an identical heating element is applied to each sensor. This SIMBA (FMI02) was deployed in the high Arctic during the Polarstern Arctic cruise (ARK-XXVII/3) on 22, September 2012. The SIMBA thermistor chain is 4.8 m long and equipped with 240 thermistors at 0.02 m spacing. Snow depth and ice thickness were derived manually by investigating the SIMBA_ET vertical temperature profiles. This SIMBA was deployed on 22 Sep 2012 at 15:15 UTC. The initial position was Latitude: 88.81287 N Longitude: 57.53883 E. The initial ice thickness was 1.44 m; Freeboard was 0.21 m and the snow depth was 0.03 m. The submitted data package includes 3 data files, i.e., SIMBA GPS position; SIMBA snow depth and ice thickness and SIMBA environmental temperature (SIMBA_ET).

Description: This is the SIMBA buoy (FMI0606) GPS position. The buoy was anchored in the ice floe. There was a sudden ice break drift in the first few days (30/Oct-3/Nov) before being relocated to a fixed location.

Description: This is SIMBA ice thickness (derived from temperature data). The values mean ice thickness growth below the initial reference surface (zero).

Description: This is SIMBA temperature data. The Tair (sensor1) was observed at a height of 1.5m above the initial ice surface. Sensor(2),,, sensor(241) are thermistor sensors attached to the thermistor string.

Description: The Snow and Ice Mass Balance Array (SIMBA) is a thermistor string type IMB (Jackson et al., 2013) that measures the environment temperature SIMBA-ET and temperature change (SIMBA-HT) after an identical heating element is applied to each sensor. This SIMBA (FMI02) was deployed in the high Arctic during the Polarstern Arctic cruise (ARK-XXVII/3) on 22, September 2012. The SIMBA thermistor chain is 4.8 m long and equipped with 240 thermistors at 0.02 m spacing. Snow depth and ice thickness were derived manually by investigating the SIMBA_ET vertical temperature profiles. This SIMBA was deployed on 22 Sep 2012 at 15:15 UTC. The initial position was Latitude: 88.81287 N Longitude: 57.53883 E. The initial ice thickness was 1.44 m; Freeboard was 0.21 m and the snow depth was 0.03 m. This dataset provides SIMBA GPS position.

Description: The Snow and Ice Mass Balance Array (SIMBA) is a thermistor string type IMB (Jackson et al., 2013) that measures the environment temperature SIMBA-ET and temperature change (SIMBA-HT) after an identical heating element is applied to each sensor. This SIMBA (FMI02) was deployed in the high Arctic during the Polarstern Arctic cruise (ARK-XXVII/3) on 22, September 2012. The SIMBA thermistor chain is 4.8 m long and equipped with 240 thermistors at 0.02 m spacing. Snow depth and ice thickness were derived manually by investigating the SIMBA_ET vertical temperature profiles. This SIMBA was deployed on 22 Sep 2012 at 15:15 UTC. The initial position was Latitude: 88.81287 N Longitude: 57.53883 E. The initial ice thickness was 1.44 m; Freeboard was 0.21 m and the snow depth was 0.03 m. This dataset provides snow depth and ice thickness derived from temperature data. The snow depth values mean snow accumulation above the reference surface (zero). The ice thickness values mean ice thickness growth below the initial reference surface (zero).

Description: The Snow and Ice Mass Balance Array (SIMBA) is a thermistor string type IMB (Jackson et al., 2013) that measures the environment temperature SIMBA-ET and temperature change (SIMBA-HT) after an identical heating element is applied to each sensor. This SIMBA (FMI02) was deployed in the high Arctic during the Polarstern Arctic cruise (ARK-XXVII/3) on 22, September 2012. The SIMBA thermistor chain is 4.8 m long and equipped with 240 thermistors at 0.02 m spacing. This SIMBA was deployed on 22 Sep 2012 at 15:15 UTC. The initial position was Latitude: 88.81287 N Longitude: 57.53883 E. The initial ice thickness was 1.44 m; Freeboard was 0.21 m and the snow depth was 0.03 m. This dataset provides SIMBA environmental temperature (SIMBA_ET).

Description: This is the in situ observed snow depth and ice thickness.