Flight 29

 

ln{[A]Dep/[A]Bgd} = - kCl

 

 

where = 7.3 x 109 molecule s cm-3

 

       1 day [Cl] ~ 8.4 x 104 molecules cm-3

       10 day [Cl] ~ 8.4 x 103 molecules cm-3

 

[O3]Bgd = 52.7 ppbv

 

[O3]Dep = 0.7 ppbv

 

 

For O3, kCl = 9.55 x 10-12 cm3 molecule-1 s-1

 

       Cl chemistry accounts for ~ 7% of O3 loss

dropping levels only to ~49.2 ppbv, not 0.7 ppbv

 

 

 

 

 

 

 

 

 

From ethyne deviation, we can determine [Br]

 

 

From Cl correlation linear regression line,

[C2H2]Dep/Cl = 249 pptv

 

[C2H2]Bgd/Cl = 462 pptv

 

From observations,

[C2H2]Dep/Obs = 34.6 pptv

 

[C2H2]Bgd/Obs = 462 pptv

 

Thus,

 

kBr = 2

= 1.3 x 1013 molecule s cm-3

 

       1 day [Br] ~ 1.8 x 108 molecules cm-3

       10 day [Br] ~ 1.8 x 107 molecules cm-3

 

For O3, kBr = 6.72 x 10-13 cm3 molecule-1 s-1

 

Expected [O3] ~ 0.1 ppbv

Observed was [O3] ~ 0.7 ppbv

 

Br atom chemistry accounts for the observed surface O3 loss