In most areas of the world, except in the driest of deserts (and beneath glaciers), one can trace fairly easily on a topographic map the system of main streams and their tributaries. In some places st...In most areas of the world, except in the driest of deserts (and beneath glaciers), one can trace fairly easily on a topographic map the system of main streams and their tributaries. In some places streams “expand” into lakes, but the principle is the same.
Trajectories are the actual paths of the moving air parcels, and indicate both the direction and velocity of air parcels over time. Convergence is when the velocity of the air slows down in the direct...Trajectories are the actual paths of the moving air parcels, and indicate both the direction and velocity of air parcels over time. Convergence is when the velocity of the air slows down in the direction of the streamline. Divergence is when the velocity of the air speeds up in the direction of the streamline. The top figure is the horizontal view; the bottom figure shows the vertical motion of the trajectories.