Flight 21

 

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

 

 

where = 5.9 x 109 molecule s cm-3

 

       1 day [Cl] ~ 6.8 x 104 molecules cm-3

       10 day [Cl] ~ 6.8 x 103 molecules cm-3

 

[O3]Bgd = 48.2 ppbv

 

[O3]Dep = 2.4 ppbv

 

 

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

 

       Cl chemistry accounts for ~ 6% of O3 loss

dropping levels only to ~45.6 ppbv, not 2.4 ppbv

 

 

 

 

 

 

 

 

 

From ethyne deviation, we can determine [Br]

 

 

From Cl correlation linear regression line,

[C2H2]Dep/Cl = 343 pptv

 

[C2H2]Bgd/Cl = 565 pptv

 

From observations,

[C2H2]Dep/Obs = 199 pptv

 

[C2H2]Bgd/Obs = 565 pptv

 

Thus,

 

kBr = 2

= 3.5 x 1012 molecule s cm-3

 

       1 day [Br] ~ 4.1 x 107 molecules cm-3

       10 day [Br] ~ 4.1 x 106 molecules cm-3

 

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

 

Expected [O3] ~ 4.2 ppbv

Observed was [O3] ~ 2.4 ppbv

 

Br atom chemistry accounts for the observed surface O3 loss