Temperature and heating-induced temperature differences were measured along a chain of thermistors. SIMBA 2019T58 (a.k.a. FMI_05_09, IRIDIUM number 300234065171790) is an autonomous instrument that was installed on drifting sea ice in the Arctic Ocean during the 1st leg of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) in October 2019. The buoy was deployed at M4 site with initial thicknesses of snow and ice of 0.08 and 0.84 m, respectively, on 7 October 2019. The thermistor chain was 5 m long and included 241 sensors with a regular spacing of 2 cm. The depths for the sensors are 64 to -414 cm, referring to the initial interface between snow and ice. The last sensor was used to measure the air temperature at 1 m above the initial snow surface. 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 depth and time between 7 October 2019 and 21 July 2020 in sample intervals of 6 hours for temperature and 24 hours for temperature differences. In addition to temperature, geographic position, barometric pressure, tilt and compass were measured.

The data set has been processed and contains quality flags for different kinds for erroneous data. Flag values are the sum of individual error codes. The value of 0 refers to no error. Quality flag, position: The geographic position is flagged +1 if the drift velocity, as derived from the GPS longitude and latitude, exceeds a threshold of 10 deg latitude or 50 deg longitude per time step; +2 if the position exceeds extreme values, such as longitude > 360 deg; +4 if the position is exactly 0.0.