Arctic Troposphere Transport

and Air Quality Theme

Jim SloanUniversity of Waterloo

CANDAC WorkshopToronto 24 October 2007

Arctic Troposphere Transport and Air Quality

Participants: CANDAC: A. Manson, B. McArthur, N. O’Neill, J. Sloan, K. Strong Collaborators: J. McConnell, T. Uttal

Scientific Interests (focus on aerosols)

Arctic Pollutants and deposition. Arctic Haze Chemical Contaminants

– Persistent Organic Pollutants, heavy metals, etc. Polar sunrise chemistry

Meteorology and modelling Transport and chemistry of PM

– Source identification

– Size distributions, compositions, etc.

ATTAQ at PEARL

Current activities: In situ PM monitoring by Aerosol Mass Spectrometer

Size distributions: 0 to ~700 nm Chemical composition

Sun, star photometers Aerosol Optical Depth measurements

Wish list: Addition of conventional aerosol measurements

Size distribution: SMPS Total local aerosol loading (CPC/TEOM… ?)

Primary Arctic Pollutants

Found in surface snowpack measurementsTransported from lower latitudes and

deposited to surface – no local sources

POPsHg and

heavy metals

Secondary Pollutants

Found in lower troposphereAtmospheric reactions at source or in transit

Arctic Haze, Barrow

Transport & General Circulation

(long term transport)

Westerlies transport mid-latitude air towards poles

Polar front dynamics and polar cells contribute

Mechanisms for Arctic Transport

AMAP 2002

“Grasshopper” mechanism(Semi-volatile gas phase)

High latitude averaged transport

Transport of Anthropogenic Pollutants

Anthropogenic contaminants atmospherically transported thousands of kilometres from mid- and low-latitude sources to the Arctic troposphere SOx, heavy metals, POPs

Sulphur aerosols, cause acid rain; climate change

Heavy metals and POPs are biomagnified, causing Arctic predators such as seals, cetacea, and polar bears to have high levels of contamination,, affecting the health of Northern indigenous communities

Bard, S. M., “Global transport of anthropogenic contaminants and the consequences for the Arctic marine ecosystem”, Marine Pollution Bulletin, 38, 356-379, 1999.

Ozone transport into the Arctic

Jan W. Bottenheim and Elton Chan “A trajectory study into the origin of spring time Arctic boundary layer ozone depletion” JGR (D111), D19301, doi:10.1029/2006JD007055, 2006

Trajectory study of ozone transport after polar sunrise surface depletions. April 1992–2000. The maps link specific regions in the Arctic with the observed O3 mole fractions (nmol mol-1) at Alert. The colours show the calculated average mole fractions in air that traversed the area. Contour lines indicate the average travel distance in days to the measurement location.

Transport from European Sources

CTM study of export pathways of pollution from Europe from 1987 to 1997 Winter pathways are advection to the (1) middle/high

latitudes of the North Atlantic Ocean, (2) Russia and the Russian Arctic,

Summer export occurs by both advection and convection; advection predominantly to Russia

Two major regions of convection in summer that loft European pollution into the free troposphere, one centered over Germany and the other over the Ural Mountains in Russia.

Duncan, B. N. and I. Bey, A modeling study of the export pathways of pollution from Europe: Seasonal and interannual variations (1987-1997), Journal of Geophysical Research-Atmospheres, 109, 2004..

Identification of source regions

(Flexpart footprints for BC sources)

Importance of different locations as sources for anthropogenic BC that appears at latitudes north of 70o

(= time spent in a specific location x emission at that location)Integrated for 30 days

A . Stohl, “Characteristics of atmospheric transport into the Arctic troposphere” JGR (D) 111, D11306, doi:10.1029/2005JD006888, (2006)

Cross-Tropopause Transport

Lagrangian analyses of upward troposphere to stratosphere exchange (TSE) and downward stratosphere to troposphere exchange (STE) in the extratropical Northern Hemisphere from May 1995 to April 1996 Chemical implications of extratropical cross-tropopause

transport The meridional distribution of the net flux is upward in

subtropics, downward in mid-latitudes and weakly upward in the Arctic region.

The localized source regions for deep TSE indicate that pollutants emitted in eastern North America and Asia have an enhanced potential for being rapidly transported into the lowermost stratosphere

Wernli, H. and M. Bourqui, A Lagrangian "1-year climatology'' of (deep) cross-tropopause exchange in the extratropical Northern Hemisphere, Journal of Geophysical Research-Atmospheres, 107, 2002.

Dynamics and transportNAO and transport from Europe.

(a) Residual NO2 columns [1014 molecules cm−2] retrieved from GOME satellite observations for (NAO+ - NAO−) composites during (1996–2002) winters.(b) Simulated NO2 columns [mg m-2] for a European emission tracer with a 1-day lifetime.White lines: correlation coefficients with the NAO index.

S. Eckhardt, et al., “The North Atlantic Oscillation controls air pollution transport to the Arctic” Atmos. Chem. Phys., 3, 1769-1778, 2003.

AMS Report

Arrival August 2006

AMS at PEARL

Instrument location

Inlet and calibration system

Aerosol Mass Spectrometer Components

1ATM

1Torr

10-8 Torr

10-7 Torr

10-5 Torr

~10-3 Torr

QMS

Ionizer

Aerodynamic Lens TOF Chopper

Heater

Inlet

CFD to design sampling from cold source

e.g. -40C to 20 C

Cylindrically-symmetric heater gives turbulence due to differential expansion

Localized heating gives recirculation

Installation of External Inlet

The worker The supervisors

Survival of External Inlet

After Installation (2006) At Polar Sunrise (2007)

Survived the winter but modifications are needed to provide better temperature control

Example Results: Four 1-Week Time Series

Measurements of Sulfate & Organics29 Aug – 5 Sept

5 – 12 Sept.

Sulfate

Organic

13 – 20 Sept.6 – 13 Oct.

Aerodynamic Radii

Only small particles are observed

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

Ma

ss C

on

ce

ntr

atio

n (

µg

m-3)

8/11/2006 8/21/2006 8/31/2006 9/10/2006 9/20/2006Date and Time

Water Ammonium Nitrate Sulphate Chloride Organics

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

Ma

ss C

on

ce

ntr

atio

n (

µg

m-3)

8/11/2006 8/21/2006 8/31/2006 9/10/2006 9/20/2006Date and Time

Water Ammonium Nitrate Sulphate Chloride Organics

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

Ma

ss C

on

ce

ntr

atio

n (

µg

m-3)

8/11/2006 8/21/2006 8/31/2006 9/10/2006 9/20/2006Date and Time

Water Ammonium Nitrate Sulphate Chloride Organics

0.5

0.4

0.3

0.2

0.1

0.0

-0.1

-0.2

dM/d

log

Dva

(µg

m-3

)

102 3 4 5 6 7 8 9

1002 3 4 5 6 7 8 9

10002

Vacuum Aerodynamic Diameter (nm)

Water Ammonium Nitrate Sulphate Chloride Organics

0.5

0.4

0.3

0.2

0.1

0.0

-0.1

-0.2

dM/d

log

Dva

(µg

m-3

)

102 3 4 5 6 7 8 9

1002 3 4 5 6 7 8 9

10002

Vacuum Aerodynamic Diameter (nm)

Water Ammonium Nitrate Sulphate Chloride Organics

Approx. lens transmission limit

AOD Measurements with Sun Photometers

In operation at 0PAL and PEARL

0PAL – CIMEL 327 PEARL – CIMEL 401

Early AOD Results2 April 2007: 0PAL – Fine and coarse; PEARL mostly

fine

June 29

fine mode

smokecloud

Resolute Bay optical depths, June 29

0

0.02

0.04

0.06

0.08

0.1

180.5 180.6 180.7 180.8 180.9 181 181.1 181.2 181.3 181.4 181.5 181.6 181.7 181.8 181.9 182 182.1 182.2 182.3

fine mode OD coarse mode OD total ODPEARL optical depths

Cloud &

smoke

smoke

Smoke

layercloud

June 29, 30