Laboratory O2 clumped-isotope data (as D36 values measured at Rice University) for LOCK-IN firn air and air occluded in three ice different cores (SDM94, GISP2-D, and WDC06A) spanning gas ages of 1588 C.E. to 2016 C.E. Modeled atmospheric history from 1836 C.E. to 2016 C.E. using a firn- and ice-core inversion (constrained by the included trace-gas and bulk-isotope data), and from 1850 C.E. to 2016 C.E. via outputs of the GISS-E2.1 chemical transport model incorporated into a 2-box model of the atmosphere.

Supplement to: Yeung, Laurence Y; Murray, Lee T; Martinerie, Patricia; Witrant, Emmanuel; Hu, Huanting; Banerjee, Asmita; Orsi, Anais J; Chappellaz, Jérôme A (2019): Isotopic constraint on the twentieth-century increase in tropospheric ozone. Nature, 570, 224-227