guiding recovery of stratospheric ozone · laboratory review, may 21-24, 2018 guiding ozone layer...

NOAA/ESRL Global Monitoring Division Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery

Guiding Recovery of Stratospheric Ozone

NOAA/ESRL Global Monitoring Division Laboratory Review, May 21-24, 2018 Guiding Ozone Layer Recovery 2

GMD plays a central role in the global effort to monitor stratospheric ozone, ozone-depleting gases, and other processes affecting stratospheric ozone

– 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

Our focus:

Guiding Recovery of Stratospheric Ozone at GMD


50

100

150

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250

300

350

400

1960 1970 1980 1990 2000 2010 2020

January Ave

21 Sep-15 Oct ave

SPO ozonesonde record

Ozo

ne T

otal

Col

umn

(DU

)

January

late September

50

100

150

200

250

300

350

400

1960 1970 1980 1990 2000 2010 2020

15 Oct - 30 Oct ave

January ave

SPO ozone, GMD Dobson O

zone

Tot

al C

olum

n (D

U)

January

late October

Stratospheric ozone depletion a threat to life on Earth.

1950s: - NOAA begins measuring total column ozone

1970s: - Theory suggesting CFCs will deplete ozone - NOAA and NASA begin measuring CFCs

1980s: - Severe ozone depletion reported in Antarctica - Montreal Protocol controls CFC production - Antarctic ozone hole attributed to CFCs and other chemicals

1990s: - US Clean Air Act Amended: NOAA and NASA to monitor: tropospheric chlorine & bromine, & stratospheric ozone depletion to project: peak chlorine the rate of chlorine decline after 2000 the date when chlorine returns to two ppb

* 1996: tropospheric chlorine peaks (NOAA-GMD publication) * 2003: tropospheric bromine peaks (NOAA-GMD publication)


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



•

•

ALT

BRW

KUM

SPO

NWR

MLO •

CGO

SMO

weekly hourly

• •

•

•

•

PSA

MHD

THD

SUM

Aircraft CCGG

8 km8 km8 km

Tower CCGG • •

•

• •

•

•

•

•

• •

•

• • LEF

HFM • WIS (WLG) •

+ CCGG sites

• ~ 40 chemicals measured

• Multiple techniques

• Data records up to 40 years long updated regularly on web

• Addressing global and U.S.-centric issues

A) Measuring chemicals that cause stratospheric ozone depletion


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265

2000 2005 2010 2015 2020120

140

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240

260

2000 2005 2010 2015 2020

1

10

100

2000 2005 2010 2015 20205

6

7

8

9

10

11

2000 2005 2010 2015 2020

CFC-11

CH3CCl3 CH3Br

HCFC-22 ln

(ppt

) pp

t

ppt

ppt

(log scale)

NH

SH

NH

SH

NH

SH

NH SH

6

A) Measuring chemicals that deplete stratospheric ozone − Concentrations of ozone-depleting chemicals for which PRODUCTION IS

CONTROLLED by the Montreal Protocol

All major ozone-depleting gases are measured at NOAA/GMD. Emphasis is on high precision and accuracy. the better the measurement, the more one can learn…

Recent related pubs: Montzka et al., 2015; 2018; Rigby et al., 2017

See talks by S. Montzka, and by P. Yu


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2

4

6

8

10

12

14

16

18

2000 2005 2010 2015 2020

450

470

490

510

530

550

570

590

610

630

2000 2005 2010 2015 2020

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

2000 2005 2010 2015 2020

0

10

20

30

40

50

60

70

80

2000 2005 2010 2015 2020

CHCl3

CH2Cl2

ppt

ppt

ppt

ppt

NH

SH

NH

SH

NH

SH

NH

SH

CH3Cl

CH2Br2

Recent related pubs: Hossaini et al., 2016; 2017

Shorter-lived gases also add chlorine and bromine to the atmosphere. having human and natural sources. changing over time? Also: N2O, COS

A) Measuring chemicals that deplete stratospheric ozone − Concentrations of halogenated chemicals NOT CONTROLLED by the

Montreal Protocol, but that can influence stratospheric ozone:

See poster by G. Dutton


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15

16

17

1990 1995 2000 2005 2010 2015

Atm

osph

eric

Br (

ppt)

3.2

3.3

3.4

3.5

3.6

3.7

3.8

1990 1995 2000 2005 2010 2015

Atm

osph

eric

Cl (

ppb)

Decline in total Chlorine Decline in total Bromine Science 1996; Nature 1999 GRL 2003

A) Measuring chemicals that deplete stratospheric ozone − Changes in “controlled” tropospheric chlorine and bromine:

Sum of all controlled gases measured at GMD

directly addressing Congressional mandate

updated annually on NOAA web page: ftp://ftp.cmdl.noaa.gov/hats/


556065707580859095

100

1990 1995 2000 2005 2010 2015

OD

GI

AntarcticMid-latitude

In 2017: •Antarctic ODGI was 80 •Mid-latitude ODGI was 56

Annually updated at http://www.esrl.noaa.gov/gmd/aggi/

O

zone

Dep

letin

g G

as In

dex

(O

DGI)

A) Measuring chemicals that deplete stratospheric ozone – Distilling GMD measurements of controlled gases into a single index:

The Ozone Depleting Gas Index Measuring progress in the decline of ozone-depleting halogen back to 1980 concentrations (pre-ozone hole)

http://www.esrl.noaa.gov/


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120

2000 2005 2010 2015 20200

2

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12

2000 2005 2010 2015 2020

0.0

0.2

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0.8

1.0

1.2

2000 2005 2010 2015 20200.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

2000 2005 2010 2015 2020

HFC-134a

HFC-365mfc HFC-227ea

HFC-152a

ppt

ppt

ppt

ppt

NH

SH

NH

SH

NH

SH

NH

SH

10

A) Measuring substitute Hydrofluorocarbons − Concentrations of chemicals for which PRODUCTION IS CONTROLLED by the

Montreal Protocol, but that do NOT deplete ozone

Recently added to the Montreal Protocol list of controlled substances. These results enable a tracking of radiative forcing from ODS substitution. Most substitute HFCs are measured at NOAA/GMD.


B) 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-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)

B) Measuring long-term changes in stratospheric ozone


MLO

B) Measuring long-term changes in stratospheric ozone − To allow an understanding of ozone column changes by latitude (ODS+GHG+transport)

13

SPO MLO FBK+BRW

USA+OHP PTH

LDR SPO

SMO

1998-2016

1979-1997

Sept-Oct only

All data

See posters by G. McConville, K. Miyagawa


B) Measuring long-term changes in stratospheric ozone - To allow an understanding of ozone column changes by altitude (ODS+GHG+transport)

14

LOTUS 2018 and Ozone Assessment 2018 used GMD data and developed statistical models to derive trends in ozone profiles and total column.

trend attribution

Boulder Umkehr, 40 km

Boulder ozonesonde, 5 km

Boulder total column


B) Measuring long-term changes in stratospheric ozone – To allow an understanding of ozone column changes by altitude (ODS+GHG+transport)

15

Is ozone in lower stratosphere still decreasing? Ball et al (2018) analyses are based on satellite records

Homogenization for GMD (Sterling et al, 2018) and SHADOZ (Witte et al, 2017) ozonesonde data - improved records for future trend analyses

Oral presentation by Witte

40 %

30 %

20 %

10 %

0 %

-10 %

-20 %

-30 %

-40 % 1982 1987 1992 1996 2002 2007 2012 2017 1982 1987 1992 1996 2002 2007 2012 2017

Sonde - SBUV 25.45 - 16.06 hPa

20⁰S-20 ⁰ N

Satellite and CCMI model averaged trends (LOTUS, 2018, Ozone Assessment) - disagreement between models and observations?

Trends in the low stratosphere will be soon assessed from homogenized ozone-sonde data in tropics and middle latitudes.


B) Measuring long-term changes in stratospheric ozone – Ozone, vertical profiles from ozone sondes on balloons

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

Pre-1971 (pre ozone-hole) Ozone-hole conditions Focus on depleted layer:

See talk by B. Johnson, poster by P. Cullis


C) 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

1

10

100

1992 1996 2000 2004 2008 2012 2016 2020

CH

3CC

l 3he

mis

pher

ic

mea

ns (p

pt)

NH

SH

Science 2000; Science 2011;

PNAS 2017

Inferred [OH] inter-annual changes

-20%

-10%

0%

10%

20%

30%

40% A) on [OH]G from: CH3CCl3

CH4 (constant emissions)

CH4 (v ary ing emissions)

Prinn et al. (− − −) Bousquet et al ( )

The exponential decline in CH3CCl3

M3 data

1985 1990 1995 2000 2005 2010

[OH]

var

iabi

lity

(% y

r-1)


0

1

2

3

4

2.5 3.5 4.5 5.50

1

2

3

4

2.5 3.5 4.5 5.5

kinetics-only (OH) (k1/k2) = 1.8

1:1

18


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

Alternative approaches to CH3CCl3: * Deriving OH loss from consideration of hemispheric mole-fraction differences Long-lived gases (Liang et al., 2017) Short-lived gases From network and special projects (e.g., Atom)

ln(C

H 2ClC

H 2Cl)

log transform

NH

SH

ln(CH2Cl2)

latitude

CH2C

l 2 ppt

)

10

30

50

70

90

110

130

150

170

190

-90 -60 -30 0 30 60 90

0 to 4 km

4 to 8 km



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


C) 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:

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100

1995 2000 2005 2010 2015

Prod

uctio

n or

Em

issio

n (G

g/yr

)

Reported Production

CFC-11 Emission

Northern Hemisphere Troposphere

Southern Hemisphere Troposphere

Emission

Stratosphere

latitude al

titud

e


• 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

Also: •UNEP/WMO, 2018 Scientific Assessment of Ozone Depletion—lead authors •UNEP/WMO, Twenty questions and answers about the ozone layer, 2015

2014 2016 2013 2014

D) Communicating results


Guiding 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 – gauge the atmospheric response to increasing greenhouse gas concentrations


GMD plays a central role in the global effort to monitor stratospheric ozone, ozone-depleting gases, and other processes affecting stratospheric ozone

– 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

Our focus:


guiding recovery of stratospheric ozone · laboratory review, may 21-24, 2018 guiding ozone layer...

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