Natural variability of the atmospheric composition Natural variability of the atmospheric composition

(1)

Natural variability of the atmospheric composition Natural variability of the atmospheric composition

and anthropogenic influence in Patagonia.

Contribution to the study of the transport along Contribution to the study of the transport along

the Equator-Mid latitudes-Pole the Equator-Mid latitudes-Pole

Isabel Moreno

Direction: Jean-Robert Petit Co-direction: Françoise Vimeux Scientific advice: Martine de Angelis

Grenoble, 19 january 2011

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The ice-archive

0^o S

20^o S

60^o S Huascarán

Quelccaya Sajama CerroTapado

Chimborazo

Illimani Coropuna

Cerro Mercedario

Lange Glacier (KGI) James Ross Island Berkner Island

Talos Dome

Vostok Byrd

Dome C San Valentin

Pio XI

Fine resolution for paleo environmental reconstructions

Southern mid-

latitudes information gap

35º-60ºS

AAO

ENSO PDO

46 ºS

(3)

Monte San Valentín 46ºS 73ºW

(Lopez et al. 2008)

Temperate sites + percolation

Pacific Ocean (west) behind the summit

2005 15 m firn core

Cold site

4023 masl

3723 masl

(4)

Main results form the 2005 core:

1. Low mean net accumulation [2005-1965]

(Vimeux et al 2008)

19 cm w.e. yr ^-1 (36 cm snow yr ^-1 )

(5)

Main results form the 2005 core:

2. Important continental register for a site under marine influence

Depth [m]

Westerlies 30- 50ºS

(Vimeux et al. 2008)

Polar front

Alternation of marine Na

⁺

& continental nssCa

²⁺

(6)

Hypothesis 2005

• Low accumulation + continental signal

→ A deep ice core could cover the last millenium

• No years missing

• Marine storms partly eroded

• Continental inputs rather conserved

The SANVALLOR project

35º-60ºS gap

 generate

environmental data

Document southern hemisphere mid-latitudes

 climatic variability?

 proxies for paleo environmental reconstructions?

 anthropogenic influence? sources?

 teleconnections ENSO-AAO?

(7)

The SANVALLOR project

• 20 m firn cores (5) → Pollen, algae, ions, δ D, δ ¹⁸ O

• 50 m ice core

• 70 m ice core → Radiogenic species, metals

• 120 m ice core → Soluble ions, δ D, δ ¹⁸ O LGGE, LSCE

LAMA, LMTG CECs

U.Bern 2007

(Photo: P.Ginot)

(8)

The SANVALLOR project

• 20 m firn cores (5) → Pollen, algae, ions, δ D, δ ¹⁸ O

• 50 m ice core

• 70 m ice core → Radiogenic species, metals

• 120 m ice core → Soluble ions, δ D, δ ¹⁸ O LGGE, LSCE

LAMA, LMTG CECs

U.Bern 2007

(Photo: P.Ginot)

(9)

Objectives of this work

1. To reconstruct the paleoenvironnmental conditions at southern mid-latitudes

• Holocene?

• Source identification LGGE:

• 120 m core inorganic/organic ions (high resolution)

• Comparison with other available ice-core

records

(10)

Objectives of this work

2. To understand the processes

responsible of the continental input

• Air masses origin?

• Precipitation conditions?

University of Chile, Geophysics Department :

Backtrajectories + precipitation

(11)

Ion chromatography (IC)

• Decontamination

• Soluble ions trace & ultratrace level: ng/g

– Major ions Na

⁺

,Cl

^-

,Mg

²⁺

,Ca

²⁺

,NO

₃^-

,SO

₄^2-

… – Other trace ions: K

⁺

, Br

^-

, NO

₂^-

, mono

and dicarboxylic acids

87 meters of ice

> 4000 samples

> 1 year analyses

(12)

Datasets

Precipitation Temperature

Chilean stations observations

Regional model outputs

1960 1990 2005 2007

ERA-40

(2.5º)

ERA Interim

(1.5º)

NCEP-NCAR

(2.5º)

Long term mean Daily

Wind Temperature Moisture

Precipitation Temperature

GFS

(0.5º)

Daily PRECIS

(0.25º)

Long term mean

Reanalysis

Regional climatology Forecast

(13)

Datasets

Precipitation Temperature

Chilean stations observations

Regional model outputs

1960 1990 2005 2007

ERA-40

(2.5º)

ERA Interim

(1.5º)

NCEP-NCAR

(2.5º)

Long term mean Daily

Wind Temperature Moisture

Precipitation Temperature

GFS

(0.5º)

Daily PRECIS

(0.25º)

Long term mean

Reanalysis

Regional climatology Forecast

(14)

Plan

• Climate basis for the archive interpretation

• Complete chemical profile 2007 + comparison with 15m shallow core

• Marine contributions

– Primary aerosol & biogenic (sources + seasonality)

• Continental contributions

– Events (type + seasonality?)

– Background trends

(15)

(Lopez et al. 2008) Climatology

15 120 m ice-core

Marine contribution

Continental contribution

Conclusions

δD, δ

¹⁸

O = seasonal temperature

cycles

(stations)

(16)

Annual pp 4000 to 8000 mm

Climatology

16 120 m ice-core

Marine contribution

Conclusions

(17)

V wind 700 hPa [m.s

^-1

]

Precipitation events vs. wind

speed (GFS) _{U zonal} ^{V merid.}

U wind 700 hPa [m.s

^-1

] MAM, SON: snowiest seasons

DJF: less cloudiness, less pp + strong wind -- less conservation JJA : more calm events -- better conservation

NW

SW,SE, E NW

Climatology

17 120 m ice-core

Marine contribution

Conclusions

SON (spring) MAM (fall) DJF (summer)

JJA (hiver)

(18)

V wind 700 hPa [m.s

^-1

]

Precipitation events vs. wind

speed (GFS) _{U zonal} ^{V merid.}

U wind 700 hPa [m.s

^-1

] MAM, SON: snowiest seasons

DJF: less cloudiness, less pp + strong wind -- less conservation JJA : more calm events -- better conservation

NW

SW,SE, E NW

Climatology

18 120 m ice-core

Marine contribution

Conclusions

SON (spring) MAM (fall) DJF (summer)

JJA (hiver)

(19)

V wind 700 hPa [m.s

^-1

]

Precipitation events vs. wind

speed (GFS) _{U zonal} ^{V merid.}

U wind 700 hPa [m.s

^-1

]

NW

SW,SE, E NW

Climatology

19 120 m ice-core

Marine contribution

Conclusions

SON (spring) MAM (fall) DJF (summer)

JJA (hiver)

(20)

Direction

NCEP-NCAR

backtrajectories Approximate (regional)

2005-2007

3% N, NE 5% E, SE, S 92% SW, W, NW

Climatology

20 120 m ice-core

Marine contribution

Conclusions

(21)

Direction

Easterly

transport Northerly: NW,

N Westerly: W, NW,

SW Marine storms:

Wide peaks No precipitation

Dry deposit Continental:

Wide peaks

Climatology

21 120 m ice-core

Marine contribution

Conclusions

(22)

Conserved signal

Lower precipitation / dry deposit Lower zonal wind → conservation

Wide peaks: not seasons but events

19 cm w.e. Mean net accumulation

11 cm w.e. A single large biomass burning event 25 cm w.e. A single large marine event

Important wind blowing

Continental contribution: S, NE, N, NW

But no missing years.

Climatology

22 120 m ice-core

Marine contribution

Conclusions

(23)

Chemical analysis

Climatology

23 120 m ice-core

Marine contribution

Conclusions

(24)

Climatology

24 120 m ice-core

Marine contribution

Conclusions

Chemical profile 120 m Chemical profile 120 m

3H, β, γ

Depth (m)

Brittle

zone Older ice?

max. age 4kyr (δ¹⁸O air)

1965

(25)

Climatology

25 120 m ice-core

Marine contribution

Conclusions

Chemical profile 120 m Chemical profile 120 m

3H, β, γ

Depth (m)

• Reliable paleo-register

• 12-meter of snow between both profiles

Brittle

zone Older ice?

max. age 4kyr (δ¹⁸O air)

Depth (m)

2005 1965

1965

(26)

Current

hypothesis:

Geophysical effect

N

Spatial

variation of the net

accumulation

Wind erosion

N

Climatology

26 120 m ice-core

Marine contribution

Conclusions

(27)

General view of the flow line

Flow line

Summit (4032 m

a.s.l.)

Rock wall: no snow

Ice cores

(P.Ginot, pers comm.)

N

(28)

General view of the flow line

Flow line

Summit (4032 m

a.s.l.)

Minor peak

Rock wall: no snow

Ice cores

CC4 CC5 CL122

N

(29)

General view of the flow line

Flow line

Summit (4032 m

a.s.l.)

Minor peak

Rock wall: no snow

Ice cores

CC4 CC5 CL122

Estimated net accumulation

N

(30)

B08 B03 B09

CL122

Fresh snow

CC5

CL122

SV 2005

CC4

Surface

(M. de Angelis, pers comm.) (G.Cassasa, pers comm.)

(31)

Implications

• Glaciological study ongoing: elements for dating

• This work:

– Events

– Sources identification + transport – Possible dating horizons

Climatology

31 120 m ice-core

Marine contribution

Conclusions

(32)

Major Minor Minor

Methodology

• Proxies:

– Marine: Na ⁺ , MSA

– Continental: NH ₄ ⁺ , nssSO ₄ ^2- , nssCa ²⁺ , F ^-

• Peak sorting

• Correlation matrices

Background

Climatology

32 120 m ice-core

Marine contribution

Conclusions

(33)

The marine component

Climatology

33 120 m ice-core

Marine contribution

Conclusions

(34)

Primary marine inputs

Bubble bursting:

primary marine aerosol Na

⁺

, Cl

^-

, Mg

²⁺

, SO

₄²⁺

,…

Na

⁺

peak → marine storm

~30 % of the register

16ºS Coropuna 0.8 46ºS San Valentin 1.4 65ºS James Ross I. ~5 Climatology

34 120 m ice-core

Marine contribution

Conclusions

•Uplift by cyclonic perturbations

•Transport by Westerlies

[Na⁺]µeq.L^-1

(35)

Primary marine inputs

Na ⁺ , Cl ^- , Mg ²⁺ …

Na/Cl close to sea water

→ fast transport

Na ⁺ , Cl ^- , Mg ²⁺ … NH ₄ ⁺ , SO ₄ ^2- , NO ₃ ^-

Major peaks

Organic species NH ₄ ⁺ , SO ₄ ^2- , NO ₃ ^-

Minor peaks

Background

Climatology

35 120 m ice-core

Marine contribution

Conclusions

(36)

Marine biogenic aerosol

CH

₃

DMS -S-CH

₃

bacteria Phytoplancton

(+algues+autres)

SO

₄^2-

CH MSA

₃

SO

₃^-

[O] 

_atm

DMSP

Fraction not related to sea-salt:

[nssSO

₄^2-

] = [SO

₄^2-

]

_T

 – R

_BSW

 * [Na

⁺

] Many sources

Climatology

36 120 m ice-core

Marine contribution

Conclusions

Depth (m)

(37)

Marine biogenic aerosol origin?

MOCAGE simulations (M.Ménégoz, pers. comm.) JJA

Total MSA kg.m-2

SON DJF MAM

Regional T?Source?

Climatology

37 120 m ice-core

Marine contribution

Conclusions

(38)

Secondary marine aerosol

MSA:nssSO

MSA:nssSO ₄ ₄ ^2- ^2- = 0.10 - 0.16 (molar) = 0.10 - 0.16 (molar)

→ mid-latitudes → mid-latitudes

>90% marine transport expected

45% important contributions observed

30% Na 15% MSA

Antarctic Peninsula

New Zealand

Climatology

38 120 m ice-core

Marine contribution

Conclusions

(39)

The continental component

Climatology

39 120 m ice-core

Marine contribution

Conclusions

(40)

Continental inputs

• nssCa ²⁺

– almost insoluble – 5-20% IC/ICPMS

• nssSO ₄ ^2-

– 50-70% non marine biogenic

– various sources influence

• volcanisme

• urban/industrial (?) – SO

₄^2-

, NH

₄⁺

, NO

₃^-

,

HCl

Climatology

40 120 m ice-core

Marine contribution

Conclusions

(Map: J.Gardelle.)

(41)

Volcanic contributions

• F ^- + SO ₄ ^2-

• Secondary gypsum formation

• NH ₃ neutralization

Quizapu?: 1915-1932 35-40 m w.e.

Climatology

41 120 m ice-core

Marine contribution

Conclusions

(42)

Volcanic background

• Secondary gypsum

formation

nssCa

²⁺

acid attack:

solubilisation

• Dry deposit?

Climatology

42 120 m ice-core

Marine contribution

Conclusions

(43)

Volcanic H ₂ SO ₄

G = secondary

gypsum formation H = halite

formation

Climatology

43 120 m ice-core

Marine contribution

Conclusions

(44)

Query of combustion events

• NH ₄ ⁺ complex proxy

– Associated with high SO ₄ ^2- (unusual) – Neutralized by volcanic SO ₄ ^2-

Climatology

44 120 m ice-core

Marine contribution

Conclusions

(45)

Intricate continental fingerprint

Biomass burning (atmosphere)

NO

₃^-

Climatology

45 120 m ice-core

Marine contribution

Conclusions

Ice-cores

Fires more oxidized

Polluted rain

(46)

Intricate continental fingerprint

Biomass burning (atmosphere)

NO

₃^-

Volcanoes SV

Combustion events SV

Climatology

46 120 m ice-core

Marine contribution

Conclusions

Ice-cores

Fires more oxidized

Polluted rain

(47)

Biomass burning

Absent:

- Marine markers

- Monocarboxylic acids - H

⁺

>10 µeq.L

^-1

Present: - Levoglucosan - BC

- Soot

- Dicarboxylic acids

Climatology

47 120 m ice-core

Marine contribution

Conclusions

(48)

Biomass burning

Absent:

- Marine markers

- Monocarboxylic acids - H

⁺

>10 µeq.L

^-1

Present: - Levoglucosan - BC

- Soot

- Dicarboxylic acids

Climatology

48 120 m ice-core

Marine contribution

Conclusions

S

S S

S

S S

S

(49)

Continental background

NH ₄ ⁺

Soils emissions

NO ₃ ^- , nssSO ₄ ^2-

Car exhaust

Industrial emissions

•Not recorded at this altitude?

•Atmospheric dilution?

•Sources?

•Accumulation?

Fertilizer use?

Climatology

49 120 m ice-core

Marine contribution

Conclusions

(50)

Proposed dating horizons

1937

Old ice Brittle

zone

Climatology

50 120 m ice-core

Marine contribution

Conclusions

Settlers?

(51)

Proposed dating horizons

1937

Old ice

1915-1932

Brittle zone

Quizapu?

Climatology

51 120 m ice-core

Marine contribution

Conclusions

Settlers?

(52)

Proposed dating horizons

1937 1908

Old ice

1915-1932

Brittle zone

Quizapu?

Climatology

52 120 m ice-core

Marine contribution

Conclusions

Settlers? Start oil extraction?

(53)

Conclusions

- Holocene? → 73 m → 120 years

- Ice-core interpretation in terms of events - Site under strong marine influence

Expected : 90% (backtrajectories) Conserved: 45%

- MSA:nssSO

₄^2-

molar ratio (0.10-0.16) is closer to the mid- latitudes marine values than Antarctic peninsula values

Complete ionic dataset produced + General transport

(54)

Conclusions

Continental sources: N, NE, NW SO

₄^2-

, NO

₃^-,

HCl?

SO

₄^2-

ubiquitous:

* Volcanic events, background,

* Fires NH

₄⁺

complex:

* Ammoniac neutralization by volcanic H

₂

SO

₄

* Fires, anthropogenic (settlers arrival) influence

Complete ionic dataset produced + General transport

(55)

Perspectives…

 73-120 m Bottom ice

 Flow model, glaciological setting needed

Basis for climatic interpretation

 New elements: trace elements LMTG

 Climatic modes, isotopes: ENSO, AAO

 Which is the origin of the association of SO

₄^2-

, NO

₃^-,

HCl?

Sources?

Mechanisms?

Regional chemical models?

 Stable isotopes: S, N

(56)

Thank you for your attention

(57)

Continental ubiquitous

cluster:

NO ₃ ^- , SO ₄ ^2- ,

HCl

(58)

What can we expect from stable isotopes?

(Herreros, pers. comm.IAEA data)

• Clear isotopic seasonal cycles for

precipitation collected at Coyhaique [45°50S;

75°70W, 310m]. Cycles at the summit also expected.

• Correction for isotopic diffusion needed.

• Ground temperature is representative for high altitude sites at mid-latitudes

(Falvey et al.,2008)

(Lopez, pers. comm.)

Natural variability of the atmospheric composition Natural variability of the atmospheric composition