Is St Stratosp ospheric O c Ozone Recover ering a ng as Ex - - PowerPoint PPT Presentation

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Is St Stratosp ospheric O c Ozone Recover ering a ng as Ex Expec pected ed? SPARC collaborators: I. Petropavlovskikh(1,2), S. Godin-Beekmann (3), D. Hubert (4), K.-L. Chang (5,2), K. Tourpali (6,7), R. Damadeo (6), V. Sofieva (8) and B.

slide-1
SLIDE 1

Is St Stratosp

  • spheric O

c Ozone Recover ering a ng as Ex Expec pected ed?

SPARC collaborators: I. Petropavlovskikh(1,2), S. Godin-Beekmann (3), D. Hubert (4), K.-L. Chang (5,2), K. Tourpali (6,7), R. Damadeo (6), V. Sofieva (8) and B. Hassler (9,10) GMD: K. Miyagawa (2), G. McConville(1,2), A. McClure (1,2), A. Jordan (1,2), B. Johnson(2), P. Cullis

(1) CIRES, University of Colorado, (2) NOAA ESRL/GMD, Boulder, (3) UVSQ/CNRS, Guyancourt, France, (4) Royal Belgian Institute for Space Aeronomy, Brussels, Belgium, (5) NOAA/GMD, National Research Council Post-Doc, Boulder (6)NASA Langley Research Center, (7) LASP, Aristotle University of Thessaloniki, Greece, (8) FMI, Helsinki, Finland, (9)Bodeker Scientific, Alexandra, New Zealand , (10) DLR, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany

WMO GAW, SPARC, NDACC, NOAA, and many observation and chemistry climate model data providers

1 GMD Review and GMAC 2018

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SLIDE 2

Ozon

  • ne’s

downs an and u ups

2

  • 1960s – NOAA ozone records
  • 1970s – NOAA ODS records
  • 1980s – Ozone hole is

discovered in Antarctica (Bryan

Johnson talk)

  • 1987: Montreal Protocol leads

to reductions in ozone depleting substances, now down 20-45% from the peak.

  • 2016: Signs of Antarctic ozone

layer healing, ground-based and model data (Solomon et al., 2016).

  • Is Stratospheric
  • zone recovering

globally?

WMO, 2014 Observed Predicted

GMD Review and GMAC 2018

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SLIDE 3

To address the differences between WMO/UNEP 2014 Ozone Assessment and SI2N initiative (Harris et al, 2015), a new WMO/SPARC LOTUS (Long-term Ozone Trends and Uncertainties in the Stratosphere) activity was initiated in 2016.

Histor

  • ry of
  • f WMO and

nd SP SPARC o C ozon

  • ne t

e trend end asses essmen ents

Harris s et et a

  • al. (2015

015) WMO ( (2014) 14)

Atmospheric pressure, hPa Trends after 2000

GMD Review and GMAC 2018 3

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SLIDE 4

Datase sets used ed i in LOTUS a and WMO Ozone a e asse sessmen ent 20 2018

  • Eight combined global

datasets created from multiple satellite records

  • Ground-based data,

total 43 ozone profile records.

  • Seven Model datasets

from Chemistry- Climate Model Initiative (Ref2 project)

4

GMD provided 7 ozonesonde (including SHADOZ), 6 Umkehr and 14 Dobson total column records for LOTUS and WMO 2018 trend assessments.

GMD Review and GMAC 2018

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SLIDE 5

Satellit llite r records: S Stabil ilit ity a and offsets ts

  • Use of ground-based data to assess drifts in satellite data
  • Remove offsets between satellite records to create combined datasets.

Aura MLS satellite differences from ozonesondes, Hilo

Anomaly of percentage difference SAT-GND wrt median difference in reference period, (Hubert et al, 2018) Posters by J. Witte, P. Cullis., K. Miyagawa, G. McConville

Satellites vs Dobson at Boulder

2004 2007 2010 2013 2016 40 30 20 10

Altitude, km

GMD Review and GMAC 2018 5

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SLIDE 6
  • Multiple linear regression
  • Natural variability effects:
  • 11-years solar cycle (Solar flux 10.7cm)
  • QBO (2 orthogonal components)
  • ENSO (El Nino/La Nino oscillations)
  • Stratospheric aerosols (Volcanic eruptions)
  • Dynamical proxies (Northern Annular Mode,

Southern Annular Mode, Eddy Heat Flux, tropopause pressure

Natural variability Normalized variability, %

Method hods fo for estimat ating ozo zone trends

1980 1990 2000 2010 2020

GMD Review and GMAC 2018 6

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SLIDE 7
  • “LOTUS” multiple regression

trend analyses applied to all datasets.

  • https://arg.usask.ca/docs/LOTUS_regression/
  • 8 combined satellite records

show similar trend patterns but clear discrepancies exist

  • Upper stratospheric trends

agree with CCMI model expectations, but lower stratospheric trends are varied and uncertain (Ball et al, 2018)

  • Resolving difference: revisiting

the merging process, i.e. using GMD ground-based data records

Trend Results: s: 7 7 C CCMI Model els a s and 8 8 S Satel ellite c e com

  • mbined r

records

CCMI models mean

GMD Review and GMAC 2018 7

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SLIDE 8

Trend Results: C Com

  • mparison of
  • f Sa

Satellites w with Grou

  • und-based St

Station

  • ns
  • Consistency in Ground-based (GB) and satellite trends

provide confidence in derived trends

  • GB broad band trends are influenced by limited

sampling (even single-station coverage), thus larger uncertainties

  • However, GB ozone observations in the upper and

middle stratosphere are representative of zonally averaged trends, but within narrow bands

1998-2015 SBUV Zonal averages Lidar stations Pressure, hPa Ozone Trend, %/decade Ozone Trend, %/decade

100 101 102

35N-60N, post 2000 trends

GMD Review and GMAC 2018 8

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SLIDE 9

GMD records: Measuring long-term changes in stratospheric and tropospheric ozone

9

  • LOTUS 2018 and Ozone

Assessment 2018 used GMD data.

  • GMD helped to develop statistical

models to interpret trends in

  • zone profiles and total column.
  • Lower stratosphere and

troposphere – larger variability and thus harder to detect trends and attribute sources.

  • Ozonesonde homogenization

improves confidence in trends

  • Further work is needed

Oral presentations on Wed by A. Gaudel, D. Tarasick, A. Langford Poster: A. McClure, K-L Chang, K. Miyagawa, K. Minschwanner Boulder, 2000-2016

40 50 30 20 10

Altitude, km

  • 3 -2 -1 0 1 2 3

Ozone Trend, %/year Lower stratosphere Trend model fit: Trend + Solar + QBO + ENSO Sonde, 16-20 km

40 20

  • 20
  • 40

Ozone anomaly, % 1977 1987 1997 2007 2017 Year Sonde (2-5 km) Niwot Ridge (~3 km) Lower troposphere

40 20

  • 20
  • 40

Ozone anomaly, % 1977 1987 1997 2007 2017 Year

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SLIDE 10
  • Ozone is recovering in the upper stratosphere
  • Magnitude and patterns are consistent in different datasets and

in model simulations.

  • recovery trends (2-3 % per decade) in NH are the most significant.
  • Lower stratosphere
  • Large uncertainties and discrepancies between models and
  • bservations.
  • Complicated ozone variability due to dynamical effects or ODS

replacements (Ball et al., 2018).

  • Further analyses are needed – GMD ozone records can help!
  • WMO/SPARC LOTUS report to be published (May 2018)!
  • Future plans:
  • Thoroughly investigate drifts and implement corrections
  • Expand trend studies: total column data, tropospheric ozone and
  • zone in polar regions
  • Explore trends in UTLS in conjunction with other SPARC efforts,

i.e OCTAV-UTLS activity (I. Petropavlovskikh, G. Manney, P. Hoor)

  • – GMD ozonesonde records are essential!

Con Concl clusi sions a and nd N Next St Step eps

GMD Review and GMAC 2018 10

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SLIDE 11

B) Measuring long-term changes in stratospheric ozone

– To allow an understanding of ozone column changes by altitude (ODS+GHG+transport)

12

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

  • zone-sonde data in tropics

and middle latitudes.

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SLIDE 12

Negative trends in ozonesonde and models (Wargan, 2018)

GMD Review and GMAC 2018 13