Thanks for the question.
Indeed, the two methods are complementary and measure different things. The Brewer instrument is a land-based instrument. It sits on the ground and measures the total thickness of the ozone layer going up; while ozonesondes, which go up with a weather balloon, measure the ozone concentration as a function of altitude.
So the two methods are complementary. We use them also in collaboration or in combination with data from satellites, which we obtain from other sources, to then estimate, measure, predict, and monitor ozone as it's changing day in and day out, week in and week out across Canada.