We present an analysis of recent high spatial and spectral resolution ground-based infrared observations of H _ { 3 } ^ { + } spectra obtained with the 10-metre Keck II telescope in April 2011 .
We observed H _ { 3 } ^ { + } 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 H _ { 3 } ^ { + } spectra , 10 for each hemisphere , providing H _ { 3 } ^ { + } 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 \pm 18 K in northern Spring and 583 \pm 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 .