Direct radiative forcing and BC on snow in the Arctic region

1. Directradiativeforcing and BC onsnow in the Arctic region Bjørn H. Samset, Gunnar Myhre, Ragnhild B. Skeie, … Outline: BC onsnow in the Arctic region RF from shipping and petroleum activitiesin current and futurearctic AeroComdirect RF update

2. BC onsnow in the Arctic region(”Black carbon in theatmosphere 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 theatmosphere and onsnow, from 1750 through 2000 • Chemical transport modelledwith OsloCTM2 • Includesnewcode for BC aging, aerosol microphysics (M7) • RF calculated via a disortcode • Data comparisonson EC concentrations in 3D, BC in snow

3. Modelled BC onsnow for 2006, and modelcomaprisonwithgroundobservations Modelled springtime concentrationof BC in surfacesnow, 2006 Modelestimatesarefairlycompatiblewith data fromDoherty et al. (2010), butsome regions warrant a moredetailedstudy. Observed (red) vsmodelled (green) springtime BC concentration in surfacesnow R. B. Skeie et al. (in prep.)

4. R. B. Skeie et al. (in prep.) RF from FFBF BC in theatmosphere and onsnow • Concl… BC onsnowconcentration for four regions, 1750-2000 • Change in effectof BC onsnow is weakerthanchange in direct RF • Strongdeposition in Himalaya/ Tibet region, max RF from BChere in 2000 • Global annualmean RF is only ~10mW/m2 • Arctic region around ~150mW/m2

5. ArcAct – unlockingthe Arctic oceanThe climateimpactofincreased shipping and petroleum activities(CICERO, NILU, DNV) • Project funded by the Norwegian Researc CouncilPetroleum 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.

6. Arctic SW RF from shipping and petroleum activities – 2004 data

7. Zonalmeans, comparing shipping to petroleum activities • Numbersare for a year 2004 emissioninventory • Studies ofemissionestimates for 2030 and 2050 are under ways • Also have projections for extentofarcticseaicedecline

8. Arctic seaiceestimatesFutureestimates from DNV (Det Norske Veritas) 1988 2030 2050 March September Plan to studySW+LW forcing, cloudeffects, seasonalvariations…, useseaice cover in conjunctionwiththeotherArcActresults. Interesting to comparethis to otherestimatesofseaicedecline

9. Direct RF modelcomparisons 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 directRF experimentV2 ongoing – so far have data from: CAM4-Oslo, HadGEM2, MPIHAM_V2, OsloCTM2, SPRINTARS-v384Expect more models to jointhenewcomparison

10. AeroComdirect RF [W/m2]Status as ofJanuary 2010 W/m2

11. Do themodelstreat all regions in the same way? Examplecomparison: Four models Global RFs: CAM4-Oslo -0.05 W/m2 MPIHAM -0.15 W/m2 Four models Comparisonsofmodeltreatmentsofarctic regions willgive valuable input towardsconstrainingcurrentdifferences

12. Summary and further plans • BC onsnow • Detailedstudyof BC in theatmosphere and depositionofsnow to be submittedshortly (R. B. Skeie et al.) • Willperformfurthercomparisonsofmodel output withpublished and upcoming data on BC deposition and itseffectsonsnowalbedo • ArcAct • Have emissions database for shipping and petroleum activities for arctic region, plusestimates for 2030, 2050. • Detailedchemical transport modellingongoing, willprovide RF maps for BC, OC, SO4, NH3, O3, … • CICERO has expertiseon aerosol physics, chemistry and modelling,willparticipate in relevant effortswithinCRAICC. Main emphasis: RF calculations • Seaice and RF • Detailedarcticseaiceestimates havebeenprovided by DNV • Direct RF estimates from seaicechangealone, then in conjunctionwithotherresults like ArcAct • AeroCom • Prescribedemissionsstudied by a rangeofmodels. Have input from fivegroups,expect (hope for) 2-3 (5-6) more. • Canthearctic area be used to understand modeldifferences?

13. Backups

14. 2004 emissions in the Arctic due to shipping and petroleum acivitiesStudied: SO4, BC, OC, NO3, O3

15. Arctic RF from shipping and petroleum activities