In January, which two low-pressure cyclonic cells exist over the oceans around 60°N? How does this strengthen the high-pressure systems of the subtropics? How is the constant isobaric surface,...

In January, which two low-pressure cyclonic cells exist over the oceans around 60°N? How does this strengthen the high-pressure systems of the subtropics?

How is the constant isobaric surface, especially the ridges and troughs, related to surface-pressure systems? To divergence aloft and surface lows? To convergence aloft and surface highs?