Abstract:

In the 21st century, total column ozone (TCO) over Antarctica has been recovering. Based on the Bodeker Scientific Filled TCO (BS-TCO) datasets and ERA5 reanalysis datasets covered by 41 years (1979–2019), the main characteristics of Antarctic TCO and stratospheric circulation during the austral spring (September–November) are analyzed separately in the late 20th century (1979–1999, depletion period) and the early 21st century (2000–2019, recovery period). The relationship between stratospheric circulation anomalies and TCO and the possible effect of planetary waves on TCO variations are discussed in each period. Results indicate that (1) Antarctic TCO has strongly decreased during the depletion period, at a rate of 51.5 Du×(10 a)⁻¹, and continuously increased during the recovery period, by 14.2 Du×(10 a)⁻¹. Significant correlations are calculated between TCO and stratospheric each factor: polar stratospheric clouds (PSC) area, lower-stratospheric temperature, mid-stratospheric geopotential height, and mid-stratospheric zonal-mean zonal wind at 60°S, which all experience rapid variations during the depletion period and slow variations during the recovery period. (2) Over the total analysis period, relationships between TCO and temperature, geopotential height, and zonal wind are significant and consistent, with stronger correlations in the recovery period. (3) The stratospheric Eliassen-Palm (EP) flux, associated with EP flux convergence and large negative eddy heat flux in the middle and upper stratosphere, is stronger than in the depletion period and induces the increased temperatures, lower geopotential heights, lower zonal wind, and the smaller PSC area, thereby explaining the Antarctic TCO recovery.

Key words:

Antarctic total column ozone, recovery period, depletion period, stratospheric circulation, stratospheric clouds area, Eliassen-Palm flux