Part 1. Black Carbon in Arctic snow: concentrations and effect on surface albedo

Tom Grenfell & Steve WarrenUniversity of Washington

Tony Clarke (University of Hawaii)Vladimir Radionov (AARI, St. Petersburg)

Other UW participants:Dean Hegg, Richard Brandt,Sarah Doherty, Steve Hudson,

Mike Town, Hyun-Seung Kim, Lora Koenig, Ron Sletten (ESS) Jamie Morison, Andy Heiberg, Mike Steele (APL)

Project website: www.atmos.washington.edu/sootinsnowIntro 1

Sn

ow A

lbed

o

0.5ppm 0.05ppm

5 ppm

5 ppm

0.05 ppm

0.5 ppm

Primary influence of BC on Spectral Albedo was first characterized by Warren and Wiscombe 1980.(i) visible wavelengths(ii) grain radius

Where and when does variation of snow albedo matter for climate?

Whenever large areas of snow are exposed to significant solar energy

Arctic snow- Tundra in spring- Sea ice in spring (covered with snow)- Greenland Ice Sheet in spring (cold snow)- Greenland Ice Sheet in summer (melting snow)

Glacier ice and sea ice:- Ablation zone of Greenland Ice Sheet in summer- Arctic sea ice in summer

Non-Arctic snow- Great Plains of North America- Steppes of Asia: Kazakhstan, Mongolia, Xinjiang, Tibet

Where and when does this matter (?)

Pioneering Effort – 1983/4 Survey

1983

Soot in snow 1983-4 (Clarke & Noone) Most amounts are 5-50 parts per billion.

Clarke & Noone Sites

Warren & Wiscombe (1985);

Warren &Clarke(1986)

Soot contents from Clarke & Noone (1985)

Expected magnitude of albedo reduction

Difficulties in the use of remote sensing to determine BC's effect on snow albedo

1. It's hard to distinguish snow from clouds-over-snow, which hide the surface. Thin near-surface layers of atmospheric ice crystals ("diamond-dust") are common in the Arctic.

2. The bidirectional reflectance (BRDF) is affected by: a. small-scale surface roughness: ripples, sastrugi, suncups, pressure-ridges. (The effects of

sastrugi on BRDF are different at different wavelengths, because they depend on the ratio of sastrugi width to flux-penetration depth.)

b. when thin surface-fog (or diamond-dust layer) covers the rough snow, the forward peak is enhanced and the nadir view is darker. This darkening at nadir could be mistaken for BC contamination.

c. Grain shape

3. Albedo reduction by BC in snow can be mimicked by:- thin snow. Sooty snow has the same spectral signature as thin snow.

- increase of grain size with depth (common situation) preferentially reduces visible albedo - sub-grid-scale leads in the Arctic Ocean. - BC in the atmosphere above the snow (Arctic haze).

Difficulties with remote sensing

Our 4-year project (begunin spring 2006): a comprehensive surface-based survey of BC in Arctic snow,to repeat and extend Clarke & Noone’ssurvey from 1983/4.

Our Sites

Yukon River

Baker Lake

Kugluktuk

Petermann

GITS

NASA-SE

SaddleDye-2

South D

Petermann ELASummit

NASA-E

Thule

SGW-NE

Nar'yan Mar

VorkutaNoril'sk

Khatanga

Dikson

Tiksi

Pevek

Anady r

Chersky

Uelen

Yakutsk

Magadan

50

N

60

N

70

N

80

N

90 N

Sampling Profiles

Filter Apparatus deployed in the field

Filters are compared to standard calibration filters. They will be scanned with a spectrophotometer to quantify BC, dust, & other components – different spectral absorption curves.

Filters

BC in snow (ppb)Median valuesK. Steffen automaticweather stations +

Greenland Sector

22

Petermann10

GITS6

NASA-SE1

Saddle

1

Dye-2

3->9

South D

7

Petermann ELA

1

Summit2

NASA-E

1

Thule4

SGW-NE

2

BC in Snow (ppb)M. Sturm (CRREL)+

Canada Sector

Yukon River

15

7 25

10 5576712

70

156

812

2325

8179 5 10

6 1154 4 6

Baker Lake

Kugluktuk

3

5

9

22

3

7

5

3

7

4,6

150 W

140 W

130 W

120 W 110

W 100

W

90 W

80 W

70 W

60 N

70 N

80 N

90 N

T. Grenfell and Steve Hudson, Western Arctic Russia March-May 2007Permissions were granted to enter restricted border areas; International Polar Year (IPY) has prominence in Russia.

Nar'yan Mar

10Vorkuta

220

Noril'skKhatanga

30

Dikson

9

Tiksi

Pevek

Anadyr

Chersky

Uelen

Yakutsk Magadan

45 E

75 E

105 E

135 E

165 E

50 N

60 N

70 N

80 N

Russian Sector

Representative Profile - Khatanga

IPY News Information Bulletin June 2007

Stephen Hudson (left), a graduate student at the University of Washington, traveling up the Khatanga River

Новости МПГ

Table of Results*strong haze event

*

(1) Do particles collect at the surface as the snow melts?

Greenland (Dye-2) August 2007, melting snow: surface 9 ppb, subsurface 3 ppb

Enhancements

(2) Snow grain size increases markedly with spring melt onset magnifying the effect of a given soot load – accelerating melt. Δ(albedo) changes from -0.01 to -0.03 for 35 ngC/g

Spectral albedo of snow observed at selected sites for closure - soot observations, RT modeling, and spectral albedo. Svalbard, March 2007

New Snow Loading and Scavenging Experiments - Tony Clarke

January: Artificial snowpack to quantify effect of soot on snow albedo with homogeneous grain size and known BC loading - (Rich Brandt, Steve Warren – Adirondacks)

March-May: Snow sampling in Eastern Siberia (Grenfell & Warren)

April: Albedo & BC intercomparison with Norwegian Polar Institute (Gerland, Brandt)

April-May: Redistribution of BC during melt (Sanja Forsstrøm at Tromsø)

July: Greenland melting-snow zone: redistribution study - fine vertical BC sampling of top 20 cm; spectral albedo (Brandt & Warren)

Calibrate new spectrophotometer; quantify BC, dust, other components (Sarah Doherty, Tom Grenfell); further comparisons with SP2 (Joe McConnell, Tony Clarke)

Scanning Electron Microscope and chemical analysis of samples to investigate source signatures (Hegg, Grenfell, Warren)

Plans for 2008

Jim Hansen for inspiring us to take on this project

Clean Air Task Force and NSF Arctic Program for support

Thanks to:

This project has benefited from the increased scientific activity in the Arctic, 2007-9.

Collaborations:Norwegian Polar Institute (Svalbard) Sebastian GerlandDanish Polar Center (Northeast Greenland) Carl-Egede Bøggild Arctic and Antarctic Research Institute (Russia) Vladimir Radionov Volunteers who have collected snow for this project in 2007:

Konrad Steffen & Thomas Phillips (Univ. Colorado). Automatic weather stations in GreenlandMatthew Sturm (U.S. Army Cold Regions Lab, Fairbanks, Alaska). Snowmobile traverse of Arctic Alaska and CanadaJacqueline Richter-Menge (U.S. Army Cold Regions Lab, Hanover, NH). Snow on sea ice in the Beaufort SeaJamie Morison, Andy Heiberg & Mike Steele (UW Applied Physics Lab). North Pole Environmental Observatory and Switchyard Expt, Arctic Ocean.Matt Nolan (Univ. Alaska). McCall Glacier, northern AlaskaVon Walden (Univ. Idaho). Ellesmere Island, CanadaShawn Marshall (Univ. Calgary). Devon Island Ice Cap, Canada.

International Polar Year Collaborations

Part 2. Source Attribution of Black Carbon in Arctic SnowDean Hegg, Tom Grenfell, Steve Warren

U. of Washington, Seattle, WA

Yukon River

Baker Lake

Kugluktuk

Petermann

GITS

NASA-SE

SaddleDye-2

South D

Petermann ELASummit

NASA-ESGW-NE

Nar'yan Mar

VorkutaNoril'sk

Khatanga

Dikson

Tiksi

Pevek

Anadyr

Chersky

Uelen

Yakutsk

Magadan

50

N

60

N

70

N

80

N

90 N

Current Data Base

• 36 sites - Canada, Greenland, Russia, North Pole

• BC estimates from filter samples

• 26 soluble co-analytes from filtered, melted snow

a. Anions – ion chromatography

b. Hydrocarbons – liquid chromatography, mass spectrometer detection

c. Elements – ICP-OES (inductively coupled plasma with optical emission spectroscopy)

BC concentration, 3 most highly correlated analytes, and a biomass fire tracer (Levoglucosan)

Levoglucosan is not simply correlated with BC but is identified by the factor analysis.

PMF (Positive matrix factorization) model results (tentative) for available data base. The five most significant factors explained 90% of variance.

90 % of the mass of BC is associated with this and the next factor.

PMF Results continued. Factor shown had next highest BC loading. These two factors accounted for over 90% of the BC

90 % of the mass of BC is associated with this and the previous factor.

Preliminary Interpretation•Both factors had appreciable levoglucosan, suggesting a strong biomass component to the BC

Preliminary Interpretation•Both factors had appreciable levoglucosan, suggesting a strong biomass component to the BC•The 1st factor was associated primarily with the Russian sites, the 2nd with the Canadian sites

Preliminary Interpretation•Both factors had appreciable levoglucosan, suggesting a strong biomass component to the BC•The 1st factor was associated primarily with the Russian sites, the 2nd with the Canadian sites•Both factors also indicated a pollution component of different composition for the two locales. This is expected and may be a geographic discriminator.• More species are needed to explore the attribution in detail.

Further Analysis• Analysis of non-filtered snow melt

• Chemical analysis of snow filters for insoluble tracers.

• In particular, analysis of filter deposits for PAH’s (polycyclic aromatic hydrocarbons).

• More elaborate receptor modeling