Description: Temperature and heating-induced temperature differences were measured along a chain of thermistors. SIMBA 2020T60 (a.k.a. HAVOC 0101) is an autonomous instrument that was installed on drifting sea ice in the Arctic Ocean during the 2nd leg of MOSAiC in February 2020. The thermistor chain was 10m long and included 250 sensors with a regular spacing of 4cm. The resulting time series describes the evolution of temperature and temperature differences after two heating cycles of 30 and 120 s as a function of place, depth and time between 08 Jan 2020 and 22 Apr 2020 in sample intervals of 6 hours for temperature and 24 hours for temperature differences. The buoy was installed on the ridge crest known as SIRO. In addition to temperature, geographic position, barometric pressure, air temperature measured 1m over the ice level, tilt and compass were measured. The data set has been processed as follows: obvious inconsistencies (missing values) have been removed and unrealistic values in position have been replaced by NaN (Not a Number). This instrument was deployed as part of the project "Ridges - Safe HAVens for ice-associated Flora and Fauna in a Seasonally ice-covered Arctic OCean" (HAVOC), funded by the Research Council of Norway, project number: 280292, "Coordinated Arctic Acoustic Thermometry Experiment" (CAATEX), funded by Norwegian Research Council, project number: 280531 and "Arctic Ocean ecosystems - Applied technology, Biological interactions and Consequences in an era of abrupt climate change" (Arctic ABC Development, Research Council of Norway, project number: 245923).