6. The polar jet stream: Each hemisphere has a persistent jet of air moving quickly from west to east, centered around 60N close to the tropopause (-10 km). The polar jet stream can reach speeds of 400 km h-?, but we'll assume a more standard velocity of 100 km h?. a) What is the magnitude & direction of the Coriolis acceleration acting on the jet stream? b) Assuming the flow is in geostrophic balance (a pretty safe assumption), what is the horizontal pressure gradient in the jet stream? You'll need to estimate the density of air in the jet, for which you can start with mean sea-level pressure and temperature and use the pressure scale height (7.4 km) and mean tropospheric temperature lapse rate (7 K km). What is the direction of this pressure gradient? c) If the pressure gradient is attributable entirely to a corresponding temperature gradient, what is the drop in temperature across a 1000 km wide jet stream