Comparison of the Climatic Characteristics of Ozone Valley Over the Tibetan Plateau and the Rocky Mountains

This study compares the ozone valleys over the Tibetan Plateau (TP) and the Rocky Mountains (RM) using the ERA5 reanalysis data set. The dynamical transport of the ozone over these two regions is analyzed using the Lorenz circulation decomposition method. The ozone content valley over TP is observed around 200–50 hPa (upper troposphere and lower stratosphere, or UTLS), and that over RM is around 300–100 hPa. It is shown that the TP ozone content is smaller than that over RM. By analyzing the spatiotemporal distribution of the ozone content and the general circulation, the anticyclone over Southern Asian (SAH) plays a significant role in existence of the TP ozone valley, and the ozone content flux reaches its maximum in July. Large‐scale terrain and related general circulation determine the ozone valley appearance. Further analysis suggests that stationary transport has a larger impact on the ozone valley formation than the transient transport. The transport by the zonal circulation nearly cancels out most of that by the meridional circulation, due to the fact that the zonal transport magnitude is nearly equal to the meridional transport. The transport center over the RM is much weaker than that over the TP. Furthermore, the contrasts between transient and stationary transports are less evident over RM than over TP. The eddy‐driven stationary ozone transport flux significantly impacts the development of the two low ozone centers across these large terrains. Plain Language Summary Extremely low ozone content has been observed over the Arctic, Antarctic, and high‐terrain regions. Ozone absorbs most wavelengths of UV radiation, therefore understanding the formation of ozone valley plays an important role for climate research. We compared the climatic features of ozone valleys over two high‐terrain regions (i.e., Tibetan Plateau (TP) and Rocky Mountains (RM)). Dynamical transport is investigated using Lorenz circulation decomposition, and it shows the eddy stationary transport has a significant impact. The total dynamical transport of ozone over the RM is much weaker than that over the TP. This study advances our knowledge of ozone valley formation over these two regions. Key Points The ozone valleys exist over both the Tibetan Plateau (TP) and the Rocky Mountains (RM) The TP ozone valley is stronger and locates higher than that over the RM, consistent with the terrain contrast The stationary transport by the climatological eddies dominates the ozone budget for