Sulfur dioxide in the Venus Atmosphere: II. Spatial and temporal variability

The vertical distribution of sulfur species in the Venus atmosphere has been investigated and discussed in Part I of this series of papers dealing with the variability of SO₂ on Venus. In this second part, we focus our attention on the spatial (horizontal) and temporal variability exhibited by SO₂. Appropriate data sets – SPICAV/UV nadir observations from Venus Express, ground-based ALMA and TEXES, as well as UV observation on the Hubble Space Telescope – have been considered for this analysis. High variability both on short-term and short-scale are observed. The long-term trend observed by these instruments shows a succession of rapid increases followed by slow decreases in the SO₂ abundance at the cloud top level, implying that the transport of air from lower altitudes plays an important role. The origins of the larger amplitude short-scale, short-term variability observed at the cloud tops are not yet known but are likely also connected to variations in vertical transport of SO₂ and possibly to variations in the abundance and production and loss of H₂O, H₂SO₄, and S_x.