  We present an analysis of recent high spatial and spectral resolution
ground-based infrared observations of H3+ spectra obtained with the 10-metre
Keck II telescope in April 2011. We observed H3+ emission from Saturn's
northern and southern auroral regions, simultaneously, over the course of more
than two hours, obtaining spectral images along the central meridian as Saturn
rotates. Previous ground-based work has derived only an average temperature of
an individual polar region, summing an entire night of observations. Here we
analyse 20 H3+ spectra, 10 for each hemisphere, providing H3+ temperature,
column density and total emission in both the northern and southern polar
regions simultaneously, improving on past results in temporal cadence and
simultaneity. We find that: 1) the average thermospheric temperatures are
527+/-18 K in northern Spring and 583+/-13 K in southern Autumn, respectively;
2) this asymmetry in temperature is likely to be the result of an inversely
proportional relationship between the total thermospheric heating rate (Joule
heating and ion drag) and magnetic field strength - i.e. the larger northern
field strength leads to reduced total heating rate and a reduced temperature,
irrespective of season, and 3) this implies that thermospheric heating and
temperatures are relatively insensitive to seasonal effects.
