Direct radiative forcing and BC on snow in the Arctic region

Bjørn H. Samset, Gunnar Myhre, Ragnhild B. Skeie, …

Outline:

- BC on snow in the Arctic region

- RF from shipping and petroleum activities in current and future arctic

- AeroCom direct RF update

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BC on snow in the Arctic region(”Black carbon in the atmosphere and snow, from preindustrial times to the present”, R. B. Skeie et al., in prep.)• Study of BC from fossil

fuel, biofuel and biomassburning in the atmosphere and on snow, from 1750 through 2000

• Chemical transport modelled with OsloCTM2

• Includes new code for BC aging, aerosol microphysics (M7)

• RF calculated via a disort code

• Data comparisons on EC concentrations in 3D, BC in snow

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Modelled BC on snow for 2006, and model comaprison with ground observations

R. B. Skeie et al. (in prep.)

Observed (red) vs modelled (green) springtime BC concentration in surface snow

Modelled springtime concentration of BC in surface snow, 2006

Model estimates are fairlycompatible with data fromDoherty et al. (2010), butsome regions warrant a moredetailed study.

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• Concl…

RF from FFBF BC in the atmosphere and on snow

R. B. Skeie et al. (in prep.)

• Change in effect of BC on snow is weaker than change in direct RF

• Strong deposition in Himalaya/ Tibet region, max RF from BC here in 2000

• Global annual mean RF is only ~10mW/m2

• Arctic region around ~150mW/m2

BC on snow concentration for four regions, 1750-2000

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ArcAct – unlocking the Arctic oceanThe climate impact of increased shipping and petroleum activities(CICERO, NILU, DNV)• Project funded by the Norwegian Researc Council

Petroleum and shipping activities at higher latitudes have increased considerably over recent years, and a significant further increase is expected. Melting of sea ice will open opportunities for new shipping routes and lengthen the navigation season of existing routes, as well as open new areas for oil/gas production. We will assess, in terms of radiative forcing, the climate impact of increased oil/gas and shipping activity in the Arctic.

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Arctic SW RF from shipping and petroleum activities – 2004 data

50-90

Burden AOD RF NRF NRF

mg/m2 (550nm) mW/m2 W/g W/m2

Sulphate 0,0078 1,6E-04 -1,73 -221 -11

Nitrate -0,0001 -1,6E-06 0,02 -192 -14

BC 0,0034 4,1E-05 5,66 1680 139

OC 0,0037 2,4E-05 -0,39 -106 -17

Total 0,0148 2,2E-04 3,56 241 16

50-90

Burden AOD RF NRF NRF

mg/m2 (550nm) mW/m2 W/g W/m2

Sulphate 0,01700 0,000596 -5,08 -299 -9

Nitrate 0,00091 0,000009 -0,17 -190 -19

BC 0,00033 0,000004 0,51 1570 133

OC 0,00119 0,000008 -0,13 -105 -15

Total 0,01940 0,000617 -4,86 -251 -8

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Zonal means, comparing shipping to petroleum activities

• Numbers are for a year 2004 emission inventory• Studies of emission estimates for 2030 and 2050 are

under ways• Also have projections for extent of arctic sea ice decline

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March

Sep

tem

ber

Arctic sea ice estimatesFuture estimates from DNV (Det Norske Veritas)

1988 2030 2050

Plan to study SW+LW forcing, cloud effects, seasonal variations…,use sea ice cover in conjunction with the other ArcAct results.Interesting to compare this to other estimates of sea ice decline

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Direct RF model comparisons from AeroCom

• The AEROCOM-project is an open international initiative of scientists interested in the advancement of the understanding of the global aerosol and its impact on climate. A large number of observations (including MODIS, POLDER, MISR, AVHHR, SEAWIFS, TOMS, AERONET and surface concentrations) and results from more than 14 global models have been assembled to document and compare state of the art modeling of the global aerosol. A common protocol has been established and models are asked to make use of the AEROCOM emission inventories for the year 2000 and preindustrial times. Results are documented via interactive websites which give access to 2D fields and standard comparisons to observations. Regular workshops are held to discuss findings and future directions.

• Pre-AR4 AEROCOM publication: M. Schultz et al, Radiative forcing by aerosols as derived from the AeroCom present-day and pre-industrial simulations, Atmos. Chem. Phys., 6, 5225-5246, 2006.

• Prescribed aerosol direct RF experiment V2 ongoing – so far have data from: CAM4-Oslo, HadGEM2, MPIHAM_V2, OsloCTM2, SPRINTARS-v384Expect more models to join the new comparison

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AeroCom direct RF [W/m2]Status as of January 2010

W/m2

All SO4 BCFF OAFF BB SOA NO3 CSum

-0.80

-0.60

-0.40

-0.20

0.00

0.20

0.40

0.60

CAM4-OsloHadGEM2-ESMPIHAM_V2_KZOsloCTM2SPRINTARS-v384

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Do the models treat all regions in the same way? Example comparison:

Comparisons of model treatments of arctic regions will give valuable input towards constraining current differences

Global RFs:CAM4-Oslo -0.05 W/m2

MPIHAM -0.15 W/m2

Four models

Four models

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Summary and further plans

BC on snow• Detailed study of BC in the atmosphere

and deposition of snow to be submitted shortly (R. B. Skeie et al.)

• Will perform further comparisons of model output with published and upcoming data on BC deposition and its effects on snow albedo

ArcAct• Have emissions database for shipping and

petroleum activities for arctic region, plus estimates for 2030, 2050.

• Detailed chemical transport modelling ongoing, will provide RF maps for BC, OC, SO4, NH3, O3, …

CICERO has expertise on aerosol physics, chemistry and modelling,will participate in relevant efforts within CRAICC. Main emphasis: RF calculations

Sea ice and RF• Detailed arctic sea ice estimates have

been provided by DNV • Direct RF estimates from sea ice change

alone, then in conjunction with other results like ArcAct

AeroCom• Prescribed emissions studied by a range

of models. Have input from five groups, expect (hope for) 2-3 (5-6) more.

• Can the arctic area be used to understand model differences?

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Backups

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2004 emissions in the Arctic due to shipping and petroleum acivitiesStudied: SO4, BC, OC, NO3, O3

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Arctic RF from shipping and petroleum activities