In Situ Measurements of Ozone during Hibiscus 2004

Contributions through provision of data and discussions:

Niels Larsen (DMI ozonesondes)Gerhard Held, José Mauricio Leite, Bruno Biazon, Pierre Dedieu (preparation and processing of IPMet RS80 & O3 sondes)Georges Durry, Nadir Amarouche (SDLA)Tom Gardiner, Nigel Swann (TDLAS)Alain Hauchcorne (MIMOSA)

G. M. Hansford, R. A. Freshwater, R. L. Jones

Outline

• Assessment of 13 Ozonesondes (DMI/IPMet) launched during Hibiscus– TTL characteristics: temperature, lapse rate, saturated water

vapour mixing ratio profiles and their relation to ozone– Definition of the TTL appropriate to Bauru– Individual flights: anomalies, relation to PV

• Assessment of UCAM solid-state ozone sensor measurements on SF flights– Correlations with other tracers: CH4, H2O, CO2

– Comparison with Theseo 2000 correlations

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0.01 0.1 1 10

Ozone /ppmv

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/km

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Ozone /mPa

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/km

DMI 10 Feb04 00:59

DMI 11 Feb04 23:57

DMI 13 Feb04 22:35

DMI 16 Feb04 00:07

DMI 17 Feb04 00:05

DMI 19 Feb04 00:07

DMI 20 Feb04 23:58

DMI 21 Feb04 22:24

DMI 23 Feb04 22:41

DMI 24 Feb04 22:30

Ipmet 20 Feb04 15:36

Ipmet 26 Feb04 23:25

Ipmet 6 Mar04 15:42

All Ozonesondes launched during Hibiscus

• Flat mixing ratio in the troposphere

• 11th Feb and 6th Mar are anomalous in the altitude range 12 – 16 km

MIMOSA PV Maps at 350K: Selected Dates

11th Feb

6th Mar

16th Feb

• 350K corresponds to ~13.6 km, 165 hPa

• 11th Feb and 6th Mar show high PV at this level

• other dates show normal PV characteristic of the tropics

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Ozone /mPa

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Standard Deviation %

Average

Average + SD

Average - SD

Standard Deviation %

SD% w/o 11Feb, 6Mar

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Ozone /ppmv

-80 -60 -40 -20 0 20

Ambient Temperature /oC

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Standard Deviation /oC

Average

Average + SD

Average - SD

Standard Deviation %

SD% w/o 11Feb, 6Mar

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Ambient Temperature /oC

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DMI 10 Feb04 00:59

DMI 11 Feb04 23:57

DMI 13 Feb04 22:35

DMI 16 Feb04 00:07

DMI 17 Feb04 00:05

DMI 19 Feb04 00:07

DMI 20 Feb04 23:58

DMI 21 Feb04 22:24

DMI 23 Feb04 22:41

DMI 24 Feb04 22:30

Ipmet 20 Feb04 15:36

Ipmet 26 Feb04 23:25

Ipmet 6 Mar04 15:42

Ozonesondes: Averages and Ambient Temperature

• Ozonopause in the average profile occurs at 13.66 km

• Except for the boundary layer, the TTL shows greatest variability

• Standard deviation is only ~5% above 20 km

• Broad temperature minimum in individual and average profiles

• Cold-point tropopause at 17.56 km (-75.9ºC) in the average profile

• Variability also greatest in the TTL, though less pronounced than ozone

Ozonesondes: Lapse Rate and Saturated Water Vapour MR

• Clear TTL signature 13.4 – 17.8 km

• Local minimum in the average lapse rate at 13.42 km

• Lapse rate profiles very noisy

• Very flat SWVMR between 15.0 – 17.8 km

• Minimum in the average profile is 12.2 ppmv

• Individual minima are more important? Dataset minimum is 6.0 ppmv on the 20th Feb

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Lapse Rate K/km

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Ambient Temperature /oC

Average Lapse Rate

Average + SD

Average - SD

Average Temperature

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Saturated Water Vapour Mixing Ratio /ppmv

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DMI 10 Feb04 00:59

DMI 11 Feb04 23:57

DMI 13 Feb04 22:35

DMI 16 Feb04 00:07

DMI 17 Feb04 00:05

DMI 19 Feb04 00:07

DMI 20 Feb04 23:58

DMI 21 Feb04 22:24

DMI 23 Feb04 22:41

DMI 24 Feb04 22:30

Ipmet 20 Feb04 15:36

Ipmet 26 Feb04 23:25

Ipmet 6 Mar04 15:42

1 10 100 1000 10000 100000

Saturated Water Vapour Mixing Ratio /ppmv

TTL Statistics from Ozonesonde Series

Definitions of the TTL

• Highwood and Hoskins (1998): extending from the main convective outflow to the cold point.

• Sherwood and Dessler (2001): the region where convection overshoots its level of neutral buoyancy.

• Vömel et al. (2002): TTL lower boundary can be defined by a local minimum in relative humidity.

• Thuburn and Craig (2002): region where radiation is more important than convection, but convection is more important than chemical ozone production.

• Gettelman and Forster (2002): lower boundary marked by the lapse rate minimum, upper boundary by the cold point.

The TTL above Bauru

Lower boundary

Lapse rate minimum 13.42 km

Ozone minimum 13.66 km

Upper boundary

Cold-point 17.56 km

BUT, a secondary local minimum (within 3ºC) is frequently found in the range 18 – 19 km

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Ozone /mPa, Lapse Rate K/km

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-80 -60 -40 -20 0 20 40

Ambient Temperature /oC

OzoneLapse RateTemperature

Individual Profile: 16th February 2004

• TTL extends from 14.2 – 19.2 km (lapse rate minimum to secondary temperature minimum)

• Cold-point at 16.4 km

• Although a clear lapse rate minimum is apparent in this dataset, many show multiple local minima in the range 10 – 15 km

Conclusion

The Gettelman and Forster criteria for the TTL boundaries are not appropriate for this region of the tropics.

TTL definition appropriate for Bauru? – Lower boundary: change in gradient in ozone mixing ratio. Upper boundary: decrease in ozone variability. 14.0 – 17.9 km

This definition reflects the potentially greater role of horizontal transport/mixing at TTL altitudes relative to sites closer to the equator.

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Ozone /mPa

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Methane /ppmv, Carbon Dioxide/200 /ppmv

Ozone

Methane

Carbon Dioxide

SF4 24th Feb 2004: O3 (O3-SSS), CH4, CO2 (SDLA)

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-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4

Deviations from Trend: Ozone /mPa, Methane*2 /ppmv, Carbon Dioxide/50 /ppmv

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Ozone

Methane

Carbon Dioxide

Ascent Profiles

• No clear correlations between any of these tracers

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-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4

Deviations from trends: Ozone /mPa, 2*LOG(H2O/ppmv)

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Ozone

Water Vapour

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Ozone /mPa

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Water Vapour Mixing Ratio /ppmv

Ozone

Water Vapour

SF4 24th Feb 2004: O3 (O3-SSS), H2O (SDLA)

Descent Profiles

• Anti-correlation between ozone and water vapour 16.5 – 19 km

• Major features occur at similar altitudes

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Deviations from trend: Ozone /mPa, Methane*2 or *4 /ppmv

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Ozone

Methane

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Ozone /mPa

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1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2

Methane /ppmv

Ozone

Methane

SF2 13th Feb 2004: O3 (O3-SSS), CH4 (SDLA)

Ascent Profiles

• No significant correlations over any extended altitude range

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-0.6 -0.4 -0.2 0 0.2 0.4 0.6

Deviation from trend: Ozone /mPa, LOG(H2O/ppmv)*4 or *1

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Ozone

Water Vapour

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Ozone /mPa

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Water Vapour /ppmv

Ozone

Water Vapour

SF2 13th Feb 2004: O3 (O3-SSS), H2O (SDLA)

Descent Profiles

• No significant correlations over any extended altitude range (large feature at 6 km correlated?)

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Ozone /mPa

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Water Vapour /ppmv

Ozone Ascent

Ozone Descent

Water Vapour Ascent

Water Vapour Descent

SF3 26th Feb 2004: O3 (O3-SSS), H2O (TDLAS)

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-0.6 -0.4 -0.2 0 0.2 0.4 0.6

Deviation from trend: Ozone /mPa, LOG(H2O/ppmv)

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Water Vapour

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Deviation from trend: Ozone /mPa, LOG(H2O/ppmv)

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Ozone

Water Vapour

• Anti-correlation during descent between 10.5 and 13.5 km

• No other significant correlations

THESEO-2000: O3 (O3-SSS), CH4 (TDLAS)

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Deviation from Smooth Profile

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Methane

Ozone

9th Feb 2000: Outside Vortex

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Deviation from Smooth Profile

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Methane

Ozone

27th Feb 2000: Inside Vortex

• Much more obvious (anti-)correlations seen between ozone and methane above Kiruna

• But, these profiles represent mostly stratospheric air

Summary of Tracer Correlations on SF Flights

Tracers SF2 SF3 SF4

O3/CO2 X

O3/CH4 X X

O3/H2O XAnti-correlation

10.5 – 13.5 km (descent only)

Anti-correlation

16.5 – 19 km (descent)

• These results need to be interpreted in terms of origin of air – are any (anti-)correlations expected?

Future Work

Ozonesondes– Calculate photochemical ozone production rates in the lower

TTL, and check for a positive correlation between ozone and lapse rate above ~14 km (Folkins et al, 1999)

– Check ancillary data for 11th Feb and 6th Mar to understand elevated ozone in the 12 - 16 km range on these dates

SF flights– Interpretation of (lack of) correlations between ozone and other

tracers– Comparison with back-trajectories

Folkins, JAS, 2001

Folkins et al, 1999

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Ozone /ppmv

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Ambient Temperature /oC

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Standard Deviation /oC