tropical tropospheric ozone: global measurements and modeling

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M. Newchurch1, D. Sun2, X. Liu2, L. Emmons3, D. Kinnison3, X. X. Tie3, L. Horowitz4, J. H. Kim5, K. Han5, S. Na5, G.

Brasseur6, D. Jacob7, J. Logan7, R.V. Martin7

1. U. Alabama in Huntsville, NSSTC 320 Sparkman Dr., Huntsville, AL 35805 and NCAR/ACD Boulder, CO United States 2. U. Alabama in Huntsville NSSTC, Huntsville, AL 35805 United States 3. NCAR/ACD, Boulder, CO United States 4. GFDL Princeton University, Princeton, NJ, United States 5. Pusan National University, Pusan, Korea, Korea, Republic of 6. Max Planck Institute for Meteorology Hamburg, Germany and NCAR/ACD 7. Harvard University, Cambridge, MA, United States

Tropical Tropospheric Ozone: Global Measurements and Modeling

http://vortex.nsstc.uah.edu/atmchem/

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Introduction

1. Due to the limited spatial coverage of in situ measurements, satellite techniques play an important role in deriving global tropospheric ozone.

2. Various satellite retrieval methods, however, vary in their derived values of tropospheric column ozone.

3. Evaluate the correspondence between various satellite derivation techniques and ozonesondes.

4. Evaluate this correspondence to model calculations in both the spatial and temporal morphology of ozone.

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Climate Application

Masatomo Fujiwara/RASC/Kyoto U/Japan notes today:

Indian Dipole Moment (IOD) seems to have started in June 2001.

Related to, but separate from, ENSO.

Results in significant impact on rainfall in Indian Ocean region: Drought in western Indonesia.

If both IOD and El Nino occur: large impact this year.

Significant enhancement in ozone occurred in 1997 due to both circulation changes and enhanced Biomass Burning [Thompson et al., Science, 2001]

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Cloud Distribution

55

CCD TechniqueZiemke et al., 1998

http://hyperion.gsfc.nasa.gov/Data_services/cloud_slice/index.html

(

(1) The high-reflectivity (R >0.9) cloud tops over the Western Pacific region usually lie near the tropopause.

(2) Stratospheric column ozone (as a function of latitude and time) is derived by averaging above-cloud column ozone amounts over the Western Pacific.

(3) Assumes zonal variability of stratospheric column ozone is

negligible.

66

CCP TechniqueNewchurch et al., 2001

http://vortex.nsstc.uah.edu/atmchem/

(1) Zonal wave structure of stratospheric ozone = 1/2 of total ~7 DU amplitude [Newchurch et al., 2001a](2) TOMS 380 nm Ref > 80%and THIR-derived cloud- top pressure <200 mb throughout tropics.(3) If no THIR, Low-pass filter applied to filter low-altitude clouds. Tested well during THIR period [Newchurch et al., 2001b].

77

Modified-Residual TechniqueHudson and Thompson, 1998

http://metosrv2.umd.edu/~tropo

(1) Assumes zonally flat stratospheric ozone.

(2) Assumes flat tropospheric background.

(3) Fits TOMS total O3 in zonal waves to a background wave and a ‘pollution’ excess amount.

88

Scan-Angle TechniqueKim et al., 2001

http://vortex.nsstc.uah.edu/atmchem/

(1) Normalized difference of Tropospheric Ozone Retrieval Efficiency (TORE) between nadir and high-scan positions as a function of altitude.

(2) This average kernel shows a broad response with its peak centered at 5-km altitude, indicating that the difference between total ozone retrieved at nadir and high scan angles contains information about tropospheric ozone.

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Tropospheric Ozone Residual (TOR) Technique

Fishman and Larsen, 1987

(1) The original TOMS technique.

(2) Tropospheric ozone the difference between TOMS total ozone and collocated SAGE integrated stratospheric ozone.

(3) Also computed with SBUV stratospheric ozone.

1010

CCP-SAGE TechniqueNewchurch et al., 2001

http://vortex.nsstc.uah.edu/atmchem/

(1) This method is the same as the CCP technique, except that SAGE measurements are used for stratospheric columns when high-altitude clouds are absent.

(2) The significant influence is areas with low frequency of high-altitude clouds, such as the Atlantic Ocean and east Pacific Ocean.

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Lower Tropospheric Ozone(LTO) Derived from Topographic Contrast Method(TCM)

http://vortex.nsstc.uah.edu/atmchem/

(1) Assumes that the stratospheric ozone and upper tropospheric ozone (above mountain top level) is the same at mountainous regions and its neighboring oceanic regions.

(2) The difference in the total ozone between mountain-top and sea level is the LTO from sea level to mountain-top.

(3) TCM has been applied to both TOMS Level-3 and Level-2 data to derive LTO west and east of Andes, Mexican and Rocky Mountains, African and Arabian Peninsula, New Guinea, and Himalayas.

(4)This method suffers from limited spatial coverage.

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Seasonal variation of LTO derived from TOMS V7 Level-2 data (1979-1999)

http://vortex.nsstc.uah.edu/atmchem/

(1) The LTO seasonality west and east of the Andes, east of the Mexican Mountains, South Sudan, South Africa, and west of New Guinea is consistent with the biomass burning seasons in these regions.

(2) Spring maximum west of the Mexican Mountains, in western China, and west of the Andes is consistent with a stratospheric intrusion source.

(3) East of the Mexican Mountains, both west and east of the Rocky Mountains, in north Sudan and Iraq, and in western China, high concentrations of ozone are found in these continental and coastal regions which are affected by anthropogenic sources.

(4) Comparisons of LTO to 5 ozonesonde records indicates good agreement [Newchurch et al., 2001]

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Six TOMS-based MethodsSeptember 1997

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Monthly CCP1997 - 2000

Click here to view Monthly CCP Movies

(Recommendation: Right-click and select “Open in New Window”)

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Average Range of Trop Ozone from Six TOMS-based Methods

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Mean Square Difference of CCD-MR Tropospheric Ozone

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Mean Square Difference of CCP-CCD Tropospheric Ozone

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Mean Square Difference of CCP-MRTropospheric Ozone

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6 Methods Max/Min Compared to SHADOZ Ozonesonde (1)

Max and Min curves of the six TOMS derivation methods compared to the ozonesonde observations at four SHADOZ sites.

2020

6 Methods Max/Min Compared to SHADOZ Ozonesonde (2)

Max and Min curves of the six indicated TOMS derivation methods compared to the ozonesonde observations at four SHADOZ sites.

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6 Individual Methods Compared to SHADOZ Ozonesonde (1)

Time series of the six indicated TOMS derivation methods compared to the ozonesonde observations at four SHADOZ sites.

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6 Individual Methods Compared to SHADOZ Ozonesonde (2)

Time series of the six indicated TOMS derivation methods compared to the ozonesonde observations at four SHADOZ sites.

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The Average Differences (SONDE - METHOD) 1 Standard Deviation and Standard Error of the

Mean

D i f f e r e n c e ± 1 S . D . S t d . E r r o r o f M e a nS H A D O Z

S t a t i o n C C P C C D T O RS A G E

C C PM R S C A N C C P C C D T O R

S A G EC C P

M R S C A N

A s c e n s i o n 6 5 - 2 5 1 5 3 6 5 7 1 1 7 1 . 0 1 . 2 1 . 1 1 . 4 1 . 7 1 . 8

C r i s t o b a l - 1 2 - 3 3 - 4 4 - 2 5 0 4 9 7 0 . 5 0 . 7 1 . 1 1 . 4 1 . 0 2 . 0

N a t a l 1 6 - 5 6 - 6 3 - 4 4 3 8 9 8 1 . 6 1 . 6 1 . 2 1 . 6 2 . 4 2 . 6

N a i r o b i 1 3 - 4 3 - 4 4 - 2 4 - 1 8 5 5 0 . 6 0 . 6 0 . 9 1 . 2 1 . 8 1 . 4

J a v a - 3 6 - 5 6 - 3 6 - 5 6 2 1 0 3 9 1 . 1 1 . 3 1 . 4 1 . 6 2 . 2 2 . 4

F i j i - 2 6 - 3 5 0 8 - 3 8 5 9 9 7 1 . 1 1 . 1 1 . 8 1 . 9 1 . 9 2 . 0

S a m o a - 5 4 - 6 4 - 3 6 - 7 7 1 9 1 5 1 . 1 1 . 1 1 . 8 2 . 2 2 . 2 2 . 0

T a h i t i - 4 6 - 6 6 - 4 7 - 6 7 2 7 9 7 1 . 3 1 . 2 1 . 7 1 . 8 1 . 7 1 . 9

A v e r a g e - 1 5 - 4 5 - 3 5 - 3 6 2 8 7 7 1 . 0 1 . 1 1 . 4 1 . 6 1 . 9 2 . 0

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MOZAIC ozone column in December 1987 and January 1991.

The maximum flight height is at least 8Km

CCP Method Compared to MOZAIC min Column

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Scan-Angle Method Jan 1999

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PEM DIAL O3 ColumnsBrowell web site + Emmons composites

PEM Tropics A

Aug-Sept 1996

PEM Tropics B

Mar-Apr 1999

TRACE-A

Sept-Oct 1992

PEM West-A

Sep-Oct 1991

PEM West-B

Feb-Mar 1994

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Daily MOZART Tropical Ozone, NOx, and CO

1997

O3 is green on an isosurface of 30 ppbv O3

NOx is blue on an isosurface of 300 pptv.

CO is red on an isosurface of 200 ppbv.

Credit: NCAR/SCD

Click here to play the Movie(Right click + “Open in New Window” recommended)

2828

MOZART-2 Tropospheric Ozonew/ NCEP winds, 1997

Lightning NOx = 9 TgN/yr

Monthly tropical tropospheric ozone calculated by MOZART-2 for 1997. (Lighting NOx =

9TgN/y)

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MOZART-2 Tropospheric Ozonew/ NCEP winds, 1997

Lightning NOx = 3 TgN/yr

Monthly tropical tropospheric ozone calculated by MOZART-2 for 1997. (Lighting NOx =

3TgN/y)

3030

Harvard GEOS Tropospheric Ozonew/ DAO winds, 1997,

Lightning NOx = 6 TgN/yr

Monthly tropical tropospheric ozone from GEOS over Dec 1996-Nov 1997.(Lightning NOx =

6TgN/y)

3131

Harvard GEOS Tropospheric Ozonew/ DAO winds, 1997,

Lightning NOx = 3 TgN/yr

Monthly tropical tropospheric ozone from GEOS over Dec 1996-Nov 1997. (Lightning NOx = 3 TgN/y)

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CCP Tropospheric Ozone in 1997

3333

Harvard GEOS 6 TgN/yr- 3 TgN/yr

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CCP - MOZART (Lightning NOx = 3 TgN/yr)

The difference between monthly CCP and MOZART (CCP-MOZART) tropospheric ozone in

1997.

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The difference between monthly CCP and GEOS-CHEM (CCP-GEOS: Nox=3Tg)

tropospheric ozone in December 1996 – November 1997.

CCP - Harvard GEOS 3 TgN/yr

3636

Monthly mean of ozonesonde (pink) observations at eight SHADOZ sites and model output from GEOS-CHEM (3 (blue) and 6(black) TgN/yr) and MOZART (9TgN/yr).

MOZART-2 (9), Harvard GEOS (6 & 3 TgN/yr) Vs. Monthly Average SHADOZ

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Conclusions

Several satellite methods are available to estimate Tropical Tropospheric Ozone: cloud difference, sat-sat residual, total column fitting, scan-angle.

Some systematic differences in bias and wave-1 structure between methods.

Envelope of methods agrees with sondes in magnitude and annual variation.

RSS of each method agrees with sondes within 1-7 DU.

Could we combine strengths of several methods to a superior composite method? Current research to retrieve at higher latitudes.

2 global models are similar within lightning NOx differences.

Largest model/measurement differences in N. Equatorial Africa burning season; most likely a TOMS derivative problem.

All methods and models see the ENSO signal in Indonesian ozone to some extent.