Temperature and heating-induced temperature differences were measured along a chain of thermistors. SIMBA 2013T2 (a.k.a. Awi_21) is an autonomous instrument that was installed on drifting sea ice in the Antarctic Ocean during the expedition Polarstern PS81 (ANT29/6, AWECS) in 2013. The thermistor chain was 5 m long and included 240 sensors with a regular spacing of 2 cm. 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 location, depth and time between 2013-07-06 and 2014-05-23. Sample intervals are commonly between 1 and 24 hours, but most frequently hit intervals of 6 hours for temperature and 24 hours for temperature differences. The data set has been processed as follows: obvious inconsistencies (missing values) and unrealistic values in position have been removed. This instrument was deployed as part of the project Sea Ice Physics @ AWI (AWI_SeaIce).