2.b. Mean altitude profiles
Altitude profiles of the mean P-O3 for the three tropical basins and the 4 deployments are compared in Figure 1b (for other regions and reactivities, see Figures S20-S27). For Central Pacific and Tropic Atlantic, the variation across deployments is not so large with values ~2 ppb/day throughout. ATom-1, however, shows slightly higher P-O3 (~3 ppb/day) below 4 km in both regions and also in the upper troposphere but only in the Atlantic.
In the Eastern Pacific, however, each deployment seems unique: ATom-2 is almost uniform at 2 ppb/day; ATom-134 show enhanced upper troposphere P-O3 probably from deep convection and lightning NOx over North America; ATom-13 show large mid-tropospheric production of ~3 ppb/day not seen in ATom-24; and ATom-4 finds a thick atmospheric layer, 1-3 km, with an astounding rate of P-O3, averaging ~10 ppb/day. The end of the biomass burning season in Central America (15°N-20°N) is probably the cause of the peak P-O3 in ATom-4 (May); while the start of the North American Monsoon season is probably the cause of the extensive deep-convection layer (8-12+ km) with high P-O3 in ATom-1 (August). With this high level of variability, it will be important to re-examine the time period of the ATom flights with a chemistry-transport model to assess the spatio-temporal scales of these incredible events. As expected from Figure 1a, the lowest P-O3 in all 3 tropical basins occurs in northern winter (ATom-2, February). For L-O3 and L-CH4, the Central Pacific and Tropical Atlantic show little variability across ATom-1234, but the Eastern Pacific shows the extremely high reactivities for ATom-14 as found in P-O3 (Figures S23-S25).
In the Arctic (Figure S26) ATom-14 show nearly identical and constant profiles for all 3 reactivities; while ATom-23 have negligible reactivities. P-O3 peaks at 8-12 km with values from 1-2 ppb/day. The reactivities in the Arctic, even in summer are less than the average over the Pacific and Atlantic oceans and thus have little impact on the global O3 or CH4 budgets. In the Antarctic (Figure S27), reactivities are much less than the Arctic and only reported for ATom-3.
2.c. Probability densities of photochemical reactivities
The probability densities (PDs) of the ATom reactivities have proven useful in testing model climatologies (see G2021). Here, we plot the PDs for the 4 deployments in the major oceanic regions for all 3 reactivities (Figures S28-S33). Overall, we find ATom-1 has more frequent high reactivities, and the East Pacific has the least conformity across ATom-1234. The Central Pacific and Tropical Atlantic provide a repeatable pattern that should provide an excellent test for CCM climatologies.