Where does trough collide?

In macroeconomics, the trough is the turning point at the bottom of a business cycle: the month in which a contraction ends and expansion begins, marking the low of aggregate activity. Burns and Mitchell's 1946 Measuring business cycles defined the cycle as an alternation of expansions and contractions dated by their peaks and troughs, the framework later used to date recessions. The referent is a temporal turning point in economic activity, structurally unrelated to a dip in atmospheric pressure or a glacier-carved valley beyond the shared image of a low point.[1]

Unit

The dated low point between a contraction and the next expansion

Recovery means

The trough marks where recovery begins: activity turns upward from it

Measured by

Identified after the fact from the comovement of output, employment, and other activity series around their low

In meteorology, a trough is an elongated region of relatively low atmospheric pressure (an axis of minimum pressure or of minimum geopotential height aloft) without a closed circulation, often marking unsettled weather and where cyclones develop. Bluestein's Synoptic-dynamic meteorology in midlatitudes treats the structure of such troughs and ridges and their role in midlatitude weather systems. The referent is a spatial pressure pattern read off a weather map, a different construct from an economy's turning point or a glacial valley.[2]

Unit

An axis of minimum pressure or geopotential height

Recovery means

Not applicable

Measured by

Located on isobaric or constant-pressure charts as the axis of lowest pressure or height, often by contour curvature