Hadley Cells and the jet stream

I want to mark this web site.  Atmospheric Circulation 

I have observed, from balloon flight planning and other projects that the mid-latitude  jet stream seems to divide the lower (polar?) tropopause, and the higher mid-latitude tropopause.  I think this goes part way to an explanation and expect to return to it to try to understand it.

Ice Cover on Lake Erie

The clouds parted today to give a satellite view of Lake Erie.

Other images can be found at the MODIS site.