How do regional aerosol emissions affect climate?

Matthew Kasoar

With: Apostolos Voulgarakis (Imperial), Drew Shindell (NASA GISS/Duke), Greg Faluvegi (NASA GISS), Jean-Francois Lamarque (NCAR), and Dill

Shawki (Imperial)

SO2, BCSO2 SO2, BCSO2, BC

SO2

BC

N96L85 configuration (1.875°x1.25°, 85 levels up to 85km)1° NEMO oceanCLASSIC aerosol scheme

100/200 year simulations, repeat year 2000 emissionsRemove emission of interest from individual regions

HADGEM3-AOSimulations with

BC vs. SO2

TOA

SWTe

mp

US vs. China SO2

TOA

SWTe

mp

India vs. China SO2

TOA

SWTe

mp

Dynamical changes in above SO2 cases

Similarity in pattern of US and China responses corresponds to similar dynamical structure

Indian SO2 removal produces different pattern

ChinaUS

India

3X AS MANY MODELSInvestigating US and China SO2 removals with

HadGEM31.875° x 1.25°; 85 vertical levels

CESM12.5° x 1.875°; 30 vertical levels

GISS-E22.5° x 2°; 40 vertical levels

HadG

EM3

CESM

1GI

SS-E

2US CHINA

1.57 Tg HadGEM3

1.09 Tg GISS-E2

Differences between HadGEM3 and GISS-E2

SO2 dry deposition: HadGEM3 = 406.2 kg(S)/s GISS-E2 = 1399 kg(S)/s

SO2 dry oxidation: HadGEM3 = 609.3 kg(S)/s GISS-E2 = 681.9 kg(S)/s

SO2 wet removal/oxidation: HadGEM3 = 1419 kg(S)/s GISS-E2 = 742.5 kg(S)/s

0.64 Tg HadGEM3

1.15 Tg GISS-E2

SO2

SO4

Present-day BC effects are negligible compared to SO2 in HadGEM3/CLASSIC

Strong hemisphere-wide response to localised mid-latitude forcing

Mechanism of remote temperature responses

Which model is right?

Substantial model diversity in sensitivity to SO2 emission reductions

Models vary in both aerosol quantity and radiative efficiency

Conclusions

Questions

THANK YOU

EXTRA SLIDES:

AERONET comparison

Biases in aerosol amount explain some of the discrepancies

OBS

HadGEM3GISS-E2

Biases in aerosol amount explain some of the discrepancies

But differences in radiative efficiency as well

AERONET comparison

OBS

CESM1GISS-E2

Map of regionsChina (NCAR/GISS) = 80E-120E, 20N-50NSA = 70E-90E, 10N-30NEA = 105E-145E, 20N-45NUS = 70W-125W, 30N-50NNHML = 30N-60N

SO2, BCSO2 SO2, BCSO2SO2, BC

US vs. EA SO2

TOA

SWTe

mp

India vs. EA SO2

TOA

SWTe

mp