Download Stratospheric Ozone Hole Chemistry: Processes and Reactions and more Study notes Meteorology in PDF only on Docsity! The “Ozone Hole”
Total DU
Plate 14; Evolution between 1979 and 1997 of the total ozone column abundance (March average) measured by the Total
Ozone Mapping Spectrometer (TOMS) (Dobson Units). The figure highlights the substantial reduction in Arctic ozone during
the 1990's (courtesy of P. Newman, NASA/Goddard Space Flight Center)
Stratospheric ozone hole chemistry, |
TT Preriorerepe gy mT TTT 7 T-4J
S 1200 }- (a) 23 August | ~~ 3000 F (b) 16 September 7
a r 7 2 4
& a 4
2 °
<x re 7
S <
g 600 g 2000 7
S 4
° © 1
O O 1
0 1000 poten tis ty Ty
62 64 66 68 70 72 62 64 66 68 70 72
LATITUDE (°S) 2042:8,17:1/98:blm
Figure 8.10. Measurements of highly enhanced CIO concentrations in the Antarctic Polar
Vortex in 1987. The destruction of ozone during the period Aug. 23-Sept. 16 is evident, as is
the anticorrelation of O3 and ClO concentrations (adapted with permission from Anderson, J.
G., D. W. Toohey, and W. H. Brune (1991) Free radicals within the Antarctic vortex: The
role of CFCs in Antarctic ozone loss, Science 251, 39, ©1991, American Association for the
Advancement of Science).
Stratospheric ozone hole chemistry, III • Heterogeneous (surface) reactions: – Surfaces: H2SO4 H2SO4-H2O-HNO3 mix PSCs – Incorporation of HNO3/H2O with time “Denitrification” Dehumidification ClONO2 liquid/solid particles HCl liquid/solid particles ClONO2 + HCl Cl2 + HNO3 ClONO2 + H2O HOCl + HNO3 HOCl + HCl Cl2 + H2O HOBr + HCl BrCl + H2O Polar Stratospheric Clouds (PSCs) SAT = Sulfuric acid tetrahydrate NAT = nitric acid trihydrate Finlayson-Pitts and Pitts, AP 2000 0.1 - <5 µm 1-10 cm-3 5 - 50 µm 10-3 - 10-2 cm-3 Finlayson-Pitts and Pitts, AP 2000 Reaction probabilities on liquid/solid surfaces • increase with decreasing T • faster on liquid (or ice) than solid SAT/NAT surfaces 35
30
25
20
15
Altitude (km)
10
FIGURE 12.17 Vertical O3 profile before (August 23) and after
12) development of the ozone
Amundsen-Scott Station, South Pole, in 1993 (adapted from Hof-
(October
mann ef al., 1994a),
Antarctic ozone hole extent, |
*
- Aug 23, 1993
Oct 12, 1993
POT
1
VW
prretioirii tipi tiiig
Po, (mPa)
5 10 15 20
hole at the
100 hPa Temperature
Ozone layer temperature at Halley in 2005 - 2006
-30
-40 4
-50
-60 4 bi
-70 4
-80 4
- Dally values
‘4-day mean
Historic extreme
gore ss Historic mean
-100 I I I I i I
Aug Sep Oct
Nov
Dec
Jan Feb Mar Apr
May
Antarctic ozone hole extent, II
EP/TOMS Version 8 Total Ozone for Sep 20, 2005
GSFC/613.3
py @ w
a “s Oo WN
oa 6 a
Dobson Units
O01
—- = = wp
yan ©
a oa oqo
s2z
ose
Oo bB B PB AB
“NO MN G@ N
a oao a
aos
Dark Gray < 100 and > 500 DU
fotp mom oFoNG
2005 Southern Hemisphere Ozone Hole Area
NOAA SBUV2
Current Year Compared Against Past 10 Years
Million Sq Kin
Updated through Dec 2, 2005
August
September October November December
oe 2005 — 2004 —— 2003 += 95-04 Mean — 95-04 Max —— 95-04 Min
