Saturday, December 27, 2008

Convective cell: What radar sees

This is a very nice photograph taken by an astronaut while leaving the troposphere. Visual we can identify the overshooting, as a sign of strong updraft, the anvil, where the level of equilibrium of the air parcels lifted from the ground is, the very instable air that hangs is the altitude, on top of the updraft, where hail forms, sometimes as mamatus clouds. The overshootings are also very nice to be seen on visible channel satellite pictures, as satellite looks from up, down to the top of the clouds.

In coloured lines I wanted to show what a radar would see if would scan this cloud on vertical cross section, as reflectivity. The radar sees only a part of the cloud, but the most instense, that has more water and bigger particles (rain drops, hail, snowflakes). More than this, can see it from quite a long distance, and on 360 around the antenna.

The radar can track (see the evolution of) these cells and "tells" in time to the pilot what to avoid. What can happen if he gets into the updraft? He would be very lucky if he would remain alive and the aircraft would be destroyed by strong turbulence, big hailstones, thunders, iceing.

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