Frequency of emergence vs. the unsigned flux of an emergence event (see Eq. (9) following Thornton & Parnell 2011). The values ϕ₀, ϕ_ER, ϕ_AR, and ϕ_limit represent the limit below which the local dynamo flux dominates, the minimum ephemeral region flux, the minimum active region flux, and the upper limit of the active region flux, respectively. The horizontal arrows mark the flux ranges corresponding to the internetwork (IN), ERs, ARs, and SSEs. The SSE range includes IN fields and ERs. The slope m of the distribution was derived by Thornton & Parnell (2011) by fitting various observations at different activity levels. Slopes m₁ and m₂ represent the corresponding distributions at maximum and minimum of solar activity levels for cycle 21, respectively (see main text for details).