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Guiding Recovery of Stratospheric Ozone NOAA/ESRL Global Monitoring Division Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery
Guiding Recovery of Stratospheric Ozone at GMD
GMD plays a central role in the global effort to monitor
stratospheric ozone, ozone-depleting gases, and other
processes affecting stratospheric ozone
Our focus:
– global-to-regional scale observations to assess global changes
and influences from specific processes and regions (e.g., U.S.)
– Diagnosing observed changes to clarify the relative influence of
policy decisions, other human behaviors, and natural processes
– To provide the highest-quality, policy-relevant science
Guiding the recovery of the ozone layer by informing Parties to
the Montreal Protocol on the progress of recovery
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery 2
SPO ozone, GMD Dobson
400
Stratospheric ozone depletion
Ozone Total Column (DU)
350
January a threat to life on Earth.
300
1950s: - NOAA begins measuring total column ozone
250
1970s: - Theory suggesting CFCs will deplete ozone
200 - NOAA and NASA begin measuring CFCs
150 1980s: - Severe ozone depletion reported in Antarctica
15 Oct - 30 Oct ave - Montreal Protocol controls CFC production
100 late October
January ave - Antarctic ozone hole attributed to CFCs and other chemicals
50
1960 1970 1980 1990 2000 2010 2020 1990s: - US Clean Air Act Amended:
SPO ozonesonde record NOAA and NASA
400 to monitor:
Ozone Total Column (DU)
350 January tropospheric chlorine & bromine, & stratospheric ozone
depletion
300
to project:
250 peak chlorine
200
late
the rate of chlorine decline after 2000
150 September the date when chlorine returns to two ppb
100 January Ave * 1996: tropospheric chlorine peaks (NOAA-GMD publication)
21 Sep-15 Oct ave
50 * 2003: tropospheric bromine peaks (NOAA-GMD publication)
1960 1970 1980
NOAA/ESRL Global Monitoring Division
1990 2000 2010 2020
Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery 3
Guiding Recovery of Stratospheric Ozone at GMD
A) Measuring chemicals that cause stratospheric ozone depletion
One of two global networks tracking long-term changes in ozone-depleting gases
B) Measuring long-term changes in stratospheric ozone
Providing reference-quality long-term measurements of stratospheric ozone
C) Advancing scientific understanding
Understanding causes of atmospheric composition change
and improving our understanding of atmospheric processes
D) Communicating results to a broader audience (stakeholders)
through simple indices, web presence, open data policies, publications,
and by contributing to national and international Scientific Assessments
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery 4
A) Measuring chemicals that cause stratospheric ozone depletion
• • + CCGG sites
••
BRW
ALT
• SUM
MHD • weekly
LEF • • hourly
• •• • •
(WLG) Tower CCGG
THD
NWR
HFM WIS
• • Aircraft
KUM
• MLO CCGG
• ~ 40 chemicals measured
••SMO
• Multiple techniques
8 km
• Data records up to 40 years long
updated regularly on web
• Addressing global and U.S.-centric issues
CGO•
PSA
• SPO
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018
• Guiding Ozone Layer Recovery 5
A) Measuring chemicals that deplete stratospheric ozone
− Concentrations of ozone-depleting chemicals for which PRODUCTION IS
CONTROLLED by the Montreal Protocol
265 260
CFC-11 HCFC-22
260 240
255 NH
220
All major ozone-
250
SH 200
depleting gases
245
are measured at
ppt
ppt
240 180
NH
235
160 NOAA/GMD.
230
140
225 SH
220 120 Emphasis is on
2000 2005 2010 2015 2020 2000 2005 2010 2015 2020
high precision and
100 11 accuracy.
CH3CCl3 10 NH CH3Br
NH the better the
9
ln(ppt)
SH measurement, the
ppt
10 8
more one can
7
SH
learn…
(log scale) 6
1 5 See talks by S. Montzka,
2000 2005 2010 2015 2020 2000 2005 2010 2015 2020
and by P. Yu
Recent related pubs: Montzka et al., 2015; 2018; Rigby et al., 2017
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery 6
A) Measuring chemicals that deplete stratospheric ozone
− Concentrations of halogenated chemicals NOT CONTROLLED by the
Montreal Protocol, but that can influence stratospheric ozone:
80 630
70 NH 610 CH3Cl NH Shorter-lived gases
60 CH2Cl2 590
also add chlorine
570
50
and bromine to the
ppt
ppt
550
atmosphere.
40
530
30
510
20 490 SH
10
SH 470 having human
0 450 and natural sources.
2000 2005 2010 2015 2020 2000 2005 2010 2015 2020
18 1.4 changing over
16
14
CHCl3 NH 1.2 SH time?
1.0
12
0.8
Also: N2O, COS
ppt
10
ppt
8 0.6 NH
6 SH
4
0.4
CH2Br2
2 0.2
0
2000 2005 2010 2015 2020
0.0
2000 2005 2010 2015 2020
See poster by G. Dutton
Recent related pubs: Hossaini et al., 2016; 2017
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery 7
A) Measuring chemicals that deplete stratospheric ozone
− Changes in “controlled” tropospheric chlorine and bromine:
Decline in total Chlorine Decline in total Bromine
3.8 GRL 2003
Science 1996; Nature 1999
Atmospheric Br (ppt)
17
Atmospheric Cl (ppb)
3.7
3.6
16
3.5
3.4
15
3.3
3.2 14
1990 1995 2000 2005 2010 2015 1990 1995 2000 2005 2010 2015
Sum of all controlled gases measured at GMD
directly addressing Congressional mandate
updated annually on NOAA web page:
ftp://ftp.cmdl.noaa.gov/hats/
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery 8
A) Measuring chemicals that deplete stratospheric ozone
– Distilling GMD measurements of controlled gases into a single index:
The Ozone Depleting Gas Index
Ozone Depleting Gas Index
Measuring progress in the decline of
100
ozone-depleting halogen back to 1980
95 concentrations (pre-ozone hole)
90
(ODGI)
85
ODGI
In 2017:
80
•Antarctic ODGI
75
was 80
70
65
•Mid-latitude ODGI
Antarctic
60
was 56
Mid-latitude
55
1990 1995 2000 2005 2010 2015
Annually updated at http://www.esrl.noaa.gov/gmd/aggi/
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery 9
A) Measuring substitute Hydrofluorocarbons
− Concentrations of chemicals for which PRODUCTION IS CONTROLLED by the
Montreal Protocol, but that do NOT deplete ozone
120 12
100 HFC-134a 10 HFC-152a Recently added to the
80 8 Montreal Protocol list of
controlled substances.
ppt
ppt
60 6
NH
40 NH 4
20 SH 2
These results enable a
SH tracking of radiative
0 0
2000 2005 2010 2015 2020 2000 2005 2010 2015 2020 forcing from ODS
1.2 1.6
substitution.
1.0 HFC-365mfc 1.4 HFC-227ea
1.2 Most substitute HFCs
0.8
NH 1.0 are measured at
NH
ppt
0.6 ppt 0.8
NOAA/GMD.
0.4 SH
0.6
SH
0.4
0.2
0.2
0.0 0.0
2000 2005 2010 2015 2020 2000 2005 2010 2015 2020
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery 10B) Measuring long-term changes in stratospheric ozone
Providing reference-quality long-term measurements of stratospheric ozone
Using a range of techniques to obtain:
Ozone total column density:
Dobson
Brewer
Ozone concentration vertical profile :
Ozone Sondes (highest vertical resolution)
Umkehr
Ozone concentrations near Earths surface
To allow an understanding of ozone concentration changes:
over time
developing and applying statistical models to provide trend estimates
as a function of altitude
stratospheric changes (upper vs lower stratosphere)
tropospheric changes (pollution-related or transported from stratosphere)
as a function of latitude
future ozone changes are expected to be latitude-dependent
aerosol, GHGs, circulation...
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery 11B) Measuring long-term changes in stratospheric ozone
NOAA-GMD Dobson ozone program:
- Forms a global backbone of robust,
calibrated total column ozone data
- Provides an essential reference for other
ozone measurements (satellites, other
Dobsons, etc.) through calibration transfers
- Maintains the WMO reference Dobson
instrument (#D083)
NOAA-GMD ozone sonde program:
- adds high vertical resolution (data were
recently homogenized)
- Strengthens and augments the SHADOZ
program for tropical ozone data
Recent Dobson- and sonde-related pubs: Petropavlovskikh et al. (2015), Nair et al., 2015; Evans et al., 2016, Thompson et al., 2017, Sterling et al, (2018)
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery 12B) Measuring long-term changes in stratospheric ozone
− To allow an understanding of ozone column changes by latitude (ODS+GHG+transport)
SPO PTH MLO FBK+BRW
SPO LDR SMO USA+OHP
All data 1998-2016
Sept-Oct
only
MLO 1979-1997
See posters by G. McConville, K. Miyagawa
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery 13B) Measuring long-term changes in stratospheric ozone
- To allow an understanding of ozone column changes by altitude (ODS+GHG+transport)
Boulder Umkehr, 40 km
Boulder total
column
Boulder
ozonesonde, 5 km LOTUS 2018 and Ozone
trend attribution Assessment 2018 used
GMD data and developed
statistical models to derive
trends in ozone profiles
and total column.
14
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018 Guiding Ozone Layer RecoveryB) Measuring long-term changes in stratospheric ozone
– To allow an understanding of ozone column changes by altitude (ODS+GHG+transport)
Is ozone in lower stratosphere still decreasing? Ball et al (2018) analyses are based on satellite records
40 % Sonde - SBUV 20⁰S-20 ⁰ N
30 %
25.45 - 16.06 hPa
20 %
10 %
0%
-10 %
-20 %
-30 %
-40 %
1982 1987 1992 1996 2002 2007 2012 2017 1982 1987 1992 1996 2002 2007 2012 2017
Homogenization for GMD (Sterling et al, 2018) and
SHADOZ (Witte et al, 2017) ozonesonde data -
improved records for future trend analyses
Trends in the low
Satellite and CCMI model
stratosphere will be soon
averaged trends (LOTUS,
assessed from homogenized
2018, Ozone Assessment)
ozone-sonde data in tropics
- disagreement between
and middle latitudes. 15
Oral presentation by Witte
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018
models and observations? Guiding Ozone Layer RecoveryB) Measuring long-term changes in stratospheric ozone
– Ozone, vertical profiles from ozone sondes on balloons
Pre-1971 (pre ozone-hole) Ozone-hole conditions Focus on depleted layer:
See talk by B. Johnson, poster by P. Cullis
Recent related pubs: Solomon et al. 2016 – ozone-sonde detected recovery, observed in September when dynamics are quiet.
Hofmann(2010)? Recovery after the September depletion rate is less than 2.7 DU/day
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery 16C) Advancing scientific understanding (Q3 & Q4 in New Research Plan)
Understanding the cause of atmospheric composition changes
sources, sinks, and transport
Improving our understanding of trace-gas sources and sinks
Sinks: Measuring the atmospheric oxidation capacity over time
budget analyses of long-lived gases
The exponential decline in CH3CCl3 Inferred [OH] inter-annual changes
40%
A) on [OH]G from:
Science 2000;
[OH] variability (% yr-1)
100 NH CH3CCl3
Science 2011;
30%
CH4 (constant emissions)
CH3CCl3 hemispheric
CH4 (v ary ing emissions)
20%
Prinn et al. (− − −) PNAS 2017
means (ppt)
SH
Bousquet et al ( )
10%
10
0%
-10%
M3 data
1
1992 1996 2000 2004 2008 2012 2016 2020 -20%
1985 1990 1995 2000 2005 2010
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery 17C) Advancing scientific understanding (Q3 & Q4 in New Research Plan)
Understanding the cause of atmospheric composition changes
sources, sinks, and transport
Improving our understanding of trace-gas sources and sinks
Sinks: Measuring the atmospheric oxidation capacity over time
budget analyses of long-lived gases
4 log transform
Alternative approaches to CH3CCl3:
* Deriving OH loss from consideration of NH
ln(CH2ClCH2Cl)
3
hemispheric mole-fraction differences
Long-lived gases 190
2
(Liang et al., 2017) 170 0 to 4 km
Short-lived gases 150 4 to 8 km SH
1:1
From network and 130 1
CH2Cl2 ppt)
kinetics-only (OH)
110
special projects (k1/k2) = 1.8
90
(e.g., Atom) 70 0
50 2.5 3.5 4.5 5.5
30
10
ln(CH2Cl2)
-90 -60 -30 0 30 60 90
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018
latitude Guiding Ozone Layer Recovery 18C) Advancing scientific understanding (Q3 & Q4 in New Research Plan)
Understanding the cause of atmospheric composition changes
sources, sinks, and transport
Improving our understanding of trace-gas sources and sinks
Sources, particularly U.S. contributions, but also on a global scale
Why are CCl4 emissions continuing now that CFC production is negligible?
SPARC Report focus in 2016
What we found:
US emissions are 10% of global
total
* associated with chemical industry
* this process likely accounts for
much of the remaining global
emissions
(Hu et al., 2016)
Other similar findings related to CFC-11 will be discussed in meeting
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery 19C) Advancing scientific understanding (Q3 & Q4 in Research Plan)
Understanding the cause of atmospheric composition changes
sources, sinks, and transport
Improving our understanding of trace-gas sources and sinks
Surface measurements are influenced by variations in sources and sinks:
100
Production or Emission (Gg/yr)
90 CFC-11 Stratosphere
80 Emission
70
altitude
60
Southern Northern
50 Hemisphere Hemisphere
40 Troposphere Troposphere
30
Reported
20
Production
10 Emission
0
latitude
1995 2000 2005 2010 2015
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery 20D) Communicating results
• Providing expertise to national and international Assessments
on Ozone and Climate:
– GMD scientists have been lead authors, co-authors, contributing authors,
and contributors to these Assessments
– GMD data are prominent in these Assessments
2016 2014 2013 2014
Also:
•UNEP/WMO, 2018 Scientific Assessment of Ozone Depletion—lead authors
•UNEP/WMO, Twenty questions and answers about the ozone layer, 2015
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery 21Guiding ozone layer recovery in the future at GMD:
• Continue ongoing programs to:
– Monitor effectiveness of the Montreal Protocol for diminishing ozone-depleting gases
– Accurately measure the response of stratospheric ozone to decreasing halogen and
increasing greenhouse gas concentrations
• Especially to address newly emerging issues:
– increases in CFC-11, CH2Cl2, & CH3Br; and in future for VSLS-bromine?
– HFCs and Kigali Amendment – locking in climate gains from the Montreal Protocol
– lower stratospheric ozone declines (Ball et al. 2018)? Assess better-positioned GMD
measurements (Unkehr; ozone-sonde)
• Add capabilities where possible:
– increased sampling frequency in tropics
– validation of new instruments (i.e. Pandora)
– validation of new operational NOAA satellite products (i.e., IPSS)
• Participate in periodic field campaigns to:
– extend an understanding of surface-based results vertically
– improve process-based understanding of the atmosphere
NOAA/ESRL Global Monitoring Division
– gauge the atmospheric response to increasing greenhouse gas concentrations
Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery 22Guiding Recovery of Stratospheric Ozone at GMD
GMD plays a central role in the global effort to monitor
stratospheric ozone, ozone-depleting gases, and other
processes affecting stratospheric ozone
Our focus:
– global-to-regional scale observations to assess global changes
and influences from specific processes and regions (e.g., U.S.)
– Diagnosing observed changes to clarify the relative influence of
policy decisions, other human behaviors, and natural processes
– To provide the highest-quality, policy-relevant science
Guiding the recovery of the ozone layer by informing Parties to
the Montreal Protocol on the progress of recovery
NOAA/ESRL Global Monitoring Division
Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery 23You can also read
