Abstract
Lower atmosphere variations in the martian water vapour and hydrogen
abundance during the Mars Year (MY) 34 C storm from
LS=326.1◦-333.5◦
and their associated effect on hydrogen escape are investigated using a
multi-spacecraft assimilation of atmospheric retrievals into a Martian
global circulation model. Elevation of the hygropause and associated
increase in middle atmosphere hydrogen at the peak of the MY 34 C storm
led to a hydrogen escape rate of around 1.4×109
cm−2s−1 , meaning the MY 34 C storm
enhanced water loss rates on Mars to levels observed during global-scale
dust storms.
The water loss rate during the MY 34 C storm (a loss of 15% of the
total annual water loss during only 5% of the year) was three times
stronger than the weak MY 30 C storm assimilation, demonstrating that
interannual variations in C storm strength must be considered when
calculating the integrated loss of water on Mars.