Why does the airflow in the mid-stratosphere of the northern hemisphere rotate FASTER than the earth? I have been playing around with this nice visualisation and noticed that in the mid-stratosphere (P=10hPa), the airflow around the equator and south of it is in the opposite direction to the earth's rotation [airflow relative to a fixed point on the surface], as one would expect.
In the northern hemisphere though (centered around Svalbard) the air flow is in the same direction as the rotation of the ground below and is at high velocity.  This seems somewhat counter-intuitive - what is the reason for it?

 A: There's all kinds of awesome and complicated stuff going on in that image... so let's look at a much simpler one to see what you mean (source):

At the equator, the predominant wind direction is easterly, or opposite the direction of Earth rotation. Away from the equator, north of 30 degrees, the winds are primarily westerly, with the direction of rotation, which means the atmosphere is moving faster there than the Earth. 
If we stopped the Earth from rotating, then the air would flow from the equator to the poles just based on temperature gradients. However, because the Earth is rotation, there is a Coriolis force that acts on the air as it moves. This causes northward motion to turn towards the east (generating westerly winds).
This is what causes the wind in the northern hemisphere to accelerate to the east. If you are closer to the equator, the wind will be coming from a more south-westerly direction because the Coriolis effect is weaker. If you are closer to the north pole, the wind will be coming from almost due west.
