Insights into Ozone from SHADOZ: Strategic Design, Variability & Role in Model-Observing Systems

Dr Anne Thompson

NASA/Goddard & SHADOZ Team

CMM-U Chile, Nov 04thompson@gator1.gsfc.nasa.gov

Presentation

Review O3 “Science Questions,” DefinitionsInteraction of Models & Observations

Design of SHADOZ Network and Key Discoveries =Challenges for Models!

> Match Science Questions & Sampling (1998->)Comparison with Satellite OzoneSolve “Wave-one Mystery”Variability in tropospheric ozone

(classification need) “Atlantic Paradox” complexity of processes

> Review Science Questions & Modify Network (2004)

Preview Integrated Approach: Sondes-Models-Aircraft-Satellites

Issues: - Ozone and Aerosols – Climate, Oxidation, Pollution on Global-Regional-Urban scales

- Need predictive capability (models)

INTERACTION OF OBSERVATIONS & MODELS:Can O3 Pollution Formation & Transport be: Measured from Satellite, Ground, Sondes? Quantified? Predicted?

Lifetime, Scientific Issue Define Observing Requirement

“Junge” diagram - key species in long-range pollution transport, radiation-climate have days-weeks lifetime: ozone, aerosols, CO

Require vertical profiles, weekly frequency or higher, depending on scale of phenomenon in question

TROPOSPHERIC OZONE UNITS Mixing ratio, ppbv; pollution > 40 ppbv, 0 km Column-integrated, DU; pollution > 25-30 DU

“Good ozone” in stratosphere“Bad ozone” in

troposphere

QUESTIONS MOTIVATING SHADOZ

O3 & Measurement Strategy Begun in 1998 > Tropical Questions SHADOZ network

1. Are ozone satellite columns accurate? √ High resolution, stratosphere and troposphere i.e. Soundings

2. Where is wave-one pattern observed in total equatorial ozone [Shiotani, 1992]? √

3. Which chemical-meteorological interactions govern ozone variability? Burning? Lightning? Urban?STE? Long-range transport? Time scale? √

Ozonesonde Instrument: Preparation & Packaging with Radiosonde

Design of Tropical Ozone Network

• What causes zonal wave-one pattern observed in total equatorial ozone [Shiotani, 1992]?

Full longitudinal coverage – selected 9 operational stations in 1998 (now 12)

• Which chemical-meteorological interactions govern tropospheric ozone variability? Time scale?

Practicality (cost, personnel) => weekly soundings

SHADOZ PROJECT(Southern Hemisphere Additional Ozonesondes)

• Operations in southern hemisphere (1998), then add two NH • Now > 2200 ozone profiles: http://croc.gsfc.nasa.gov/shadoz. Refer to Thompson et al, JGR, 108, 8238, doi: 10.129/ 2001JD000967, 2003

Tropical Ozone Answers from SHADOZ

• Are ozone satellite columns accurate? √Good Agreement at Nairobi

SHADOZ SAMOA, TOMS, DOBSON

1) TOMS comparisons valid 1998-2001

2) v 7 TOMS, v8 ozone > sonde, Dobson - left

3) TOMS overestimate at low-tropo.-O3 sites, (eg Samoa, Fiji) - below

√ Wave-One in Tropospheric Ozone, Stratospheric Ozone Longitudinally Invariant – Interaction of General Circulation, Convection + O3 from Fires, Lightning (via NO)

•Unique SHADOZ view shows wavepresent all year (Thompson et al, JGR, 108, D2, 8241 2002JD002241, 2003).

Convective influence over western Pacific, subsidence over Atlantic

√ Week-to-week variability, Nairobi: Low ozone in free troposphere (left, blue) coincides with convection & Indian Ocean Transport (higher humidity, right, red).

Wavelet, other statistics (Thompson, Chatfield) show distinct 3-7-day periodicity from convection, advection

Nairobi, 1998-2001-Seasonal “Means?”• Tropospheric column ozone

is higher in S-O-N than M-A-M, but extremes are similar “Meaningless means”From Thompson et al [Bull. Am. Meteor. Soc., 2004]

- Cf Variability defined bysynoptic regime [Diab et al., Atmos. Chem. Phys., 2003; JGR, 2004].

Profile Classification: Two DJF patterns at Irene, So. Africa ***

Mean Profile (3a - class 1)

0100020003000400050006000700080009000

100001100012000

0 10 20 30 40 50 60 70 80 90 100

110

120

Ozone in ppbv

Alti

tude

in m

Graphs

MEAN 3a

Mean Profile (3b - class 2)

0100020003000400050006000700080009000

100001100012000

0 10 20 30 40 50 60 70 80 90 100

110

120

Ozone in ppbv

Alti

tude

in m

Graphs

MEAN 3b

• Search for pattern and order.• Multivariate cluster analyses technique• Profiles group according to magnitude and altitude of ozone• Highlight need to account for temporal variability, I.e. stratification?

*** Diab et al., Atmos. Chem. Phys., 3, 713-723, 2003

Looking Ahead! – Now in Aura Era> What is Aura? Launched 15/7/04, 4 ozone sensors

-- Two (OMI/TES) oriented to troposphere> Ozonesonde needs for scientific issues:

Processes – Tropical*, Mid-latitudeValidation – TOMS/OMI retrievals

* Tropical – Re-examine SHADOZ to respond to new findings of “Paradox,” absence of NH wave-one

--- TES

HIRDLS

OMI--

MLS--

Atlantic “Ozone Paradox”

“Paradox” (left) – more DJF ozone over southern hemisphere when north tropics (west Africa) burning! Thompson et al. [2000]

Mechanisms: Interhemispheric transport, subsidence of ozone over So. Atlantic (middle), lightning (right)

How much of each?

Atlantic “Ozone Paradox” Not Seen over Africa

Re-evaluate SHADOZ Design – 2004Over African continent no DJF “Paradox” (Note! NH is at

right, SH is left) [Sauvage at al., Thesis, 2004].

Paramaribo (Surinam, 5N) O3 differs from SH O3 [Peters et al., 2004]

• All SHADOZ sites, distinct 3-7-day periodicity weekly sampling ok; 2/week better; 2/month inadequate

• Urban fires cause 30-50% of surface 90 ppbv ozone [Thompson et al., GRL, 29, 1976, doi: 10.129/2002GL015399, 2002]

Issues: Aerosol interferes with uv ozone satellite retrieval. Algorithms need profile data in regions with smokePollution-level surface ozone absent from SHADOZ stations because most are far fromsources Need more Polluted Sites

SAFARI-2000 Lusaka, Zambia (15S, 28E) (9/2000)

Sounding Strategies in AURA

Profile interactively guides satellite (OMI/TES) derivation of tropospheric ozone and assimilation

Simultaneously engage other EOS/A-train sensors (eg H2O, AIRS) Full range of radicals, ozone precursors, deposited species (ground-

based), plus aircraft/uav data constrain Models, Assimilation

Other Ground-based,BL Aircraft

Models, assimilation

SatelliteSONDE

Synergism of Ground-based-Models-Balloon-Aircraft Observations with Modeling & Assimilation

Summary

O3 & Measurement Strategy Design

> Tropical Questions SHADOZ network• Spatial, temporal resolution in network must match scientific question (for O3,, scales of dominant meteorological processes) • Regional-to-global scale of tropical issues

define SHADOZ (~12 global sites, 1/wk)

Integrated Observing Strategies Required – Sondes-aircraft-satellite-ground-based

Analyses, Predictions require multiple statistical, modeling approaches, all scales!

Thank you for Attention!

Thank You L Gallardo (U Chile-CMM)

Acknowledgments: Jacquelyn Witte for Graphics, Analysis NASA Program Sponsors for SHADOZ SHADOZ Team – NASA Honor Awards Given in

2004 to > 40 individuals in 20 nations!