I'm going to post a partial answer now, it will require some more reading to put together a complete explanation.
As described in the question there are two similar coils, one radiates the AC magnetic field ("transmitter") and the other picks up the weak radiated AC magnetic field produced by subsurface electrical currents induced by the primary field.
The wikipedia article List of weather records explicitly states
This list does not include remotely sensed observations such as satellite measurements, since those values are not considered official records.
Reference 1 in that article, a web archive link to a page on World Meteorological Organization Global Weather & Climate Extremes, adds that (...
Ultralow Surface Temperatures in East Antarctica
From Satellite Thermal Infrared Mapping:
The Coldest Places on Earth p. 6127 says:
Validation studies of MODIS c5 and c6 LST for nonpolar regions, while limited, suggest that the surface temperature data are generally within 1 °C of the in situ measured thermal emission temperature (Wan, 2014),
I suppose the answer depends on total lifecycle emissions as well as landfill environmental cost.
For plastic I assume PP or PETE.
For styrofoam production is based on polystyrene so some styrene emissions.
For lifecycle costs, emissions for manufacturing as well as energy (coal or gas power plant) need to be considered. Also are either recycled and in ...