Figure 5
![(a) Total production (solid lines), primary (photo) production (dashed lines) and secondary production (dot–dashed lines) and (b) production efficiency [kinetic model result (crosses), polynomial fit (solid line) and transition altitude (dashed line)] versus altitude (km). Production rates are in units of cm−3 s−1 versus altitude in km. Top left O++, top right CO+2, bottom left O+2, bottom right O++2.](https://oup.silverchair-cdn.com/oup/backfile/Content_public/Journal/mnras/400/1/10.1111_j.1365-2966.2009.15463.x/1/mnras0400-0369-f5.jpeg?Expires=1750154409&Signature=rlQ5Z-jZlNoZySO7obh9ldsRetV27ldhqJhazE3qEFFvDMvkcmir3Co-R4-VXZyVD6gG-2GogwE4dNmdeAs3NshEpjjGLoHYpsZG4foZkLImK5KrEIF6ex55LiJrLqnwr-Q8KlXah8ywv4K9lHBVDgG03iegIsbnqgCUP~STtdIcQ5BXXqr-a1d6H1X4dathaySLnFY7H0rwpM5TydI561pSwL9CCSxynwS9NXvC6P~tVStR9BPbZrBzcCA306VlfkFqEefkdECty14WRNsoXaTAbXn8K6Qua3i-pNtbmGBfojUdPgofESDrJCo1wKxeN6eBYu7lO6aknG5Q7SdehA__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
(a) Total production (solid lines), primary (photo) production (dashed lines) and secondary production (dot–dashed lines) and (b) production efficiency [kinetic model result (crosses), polynomial fit (solid line) and transition altitude (dashed line)] versus altitude (km). Production rates are in units of cm−3 s−1 versus altitude in km. Top left O++, top right CO+2, bottom left O+2, bottom right O++2.
