Assessment of aerosol direct effects on surface radiation in the northern hemisphere

using two-way WRF-CMAQ model

Jia Xing, Jonathan Pleim, Rohit Mathur, David Wong, George Pouliot, Christian Hogrefe, Chuen-Meei Gan, Chao Wei

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA12th Annual CMAS Conference, October 30, 2013

• To extend the applicability of the two-way WRF-CMAQ model to hemispheric scales

• To assess the model’s ability in reproducing the decadal changes in surface radiation (e.g. dimming and brightening) in the north hemisphere from 1990-2010 when significant of changes in emissions occurred

• To provide boundary conditions for long-term regional-scale CMAQ simulations at finer resolution

• Emission processing & model configuration

• Result discussion Trends in AOD & Clear-sky Shortwave radiation (SWR)

Aerosol impacts on T2, PBL Height, SWR, PM2.5 and O3

Dust aerosol direct effects on clear-sky SWR

• Summary

Emission processing

0

10

20

30

40

50

1990 1995 2000 2005

SO2

annu

al e

mis

sion

(Tg)

USChinaOECD+Central Europe

0

10

20

30

1990 1995 2000 2005

NO

xan

nual

em

issi

on (T

g)

USChinaOECD+Central Europe

0

5

10

15

20

1990 1995 2000 2005

PM10

annu

al e

mis

sion

(Tg)

USChinaOECD+CentralEurope

Historic anthropogenic emissions in three regions over the past two decades

Anthropogenic emissions were derived from EDGAR (Emission Database for Global Atmospheric Research); Biogenic VOC and lightning NOx emissions were obtained from GEIA (Global Emission Inventory Activity); Temporal distribution was referred to EDGAR default profile; Speciation was referred to SMOKE profile; Vertical allocation was referred to SMOKE plume-rise and EMEP profile.

SO2 NOxPrimary PM10

Model Setup

Simulation period: from 1990 to 2009 (summer time-JJA)

Two scenarios:

WRF-CMAQ(nf): no-feedback

WRF-CMAQ(sf): with shortwave feedback (-aerosol direct effects)

Hemispheric WRF-CMAQ two-way model─WRF3.4: NCEP/NCAR Reanalysis data with 2.5 degree spatial and 6-hour temporal resolution; NCEP ADP Operational Global Surface/ Upper Air Observations with 6 hour intervals, MODIS land-use type, RRTMg radiation scheme, ACM2 (Pleim) PBL, PX LSM.

─CMAQ5.0: Cb05-AERO6 chemistry, tropopause ozone calculated from PV (potential vorticity), inline photolysis, inline dust emission module.

East China

Europe

East US

Simulation domain:

108×108 km resolution over northern hemisphere

44 layers from surface to 50mb

Three sub-regions will be analyzed

Trend in Aerosol Optical Depth (AOD)

2000MODIS+ SeaWiFS

WRF-CMAQ (sf)

JJA-average

MODIS - level 3 TerraSeaWiFS - level 3 Deep BlueMissing value in MODIS (mostly in Sahara Desert) was filled by SeaWiFS (550nm)

533nm

2009

Trend in Aerosol Optical Depth (AOD)

MODIS+ SeaWiFS WRF-CMAQ(sf)

East China East US Europe

JJA-average

(2009 minus 2000)

from 1990 to 2009

Trend in clear-sky shortwave radiation

CERES

East China East US Europe

JJA-average (2009 minus 2000)

WRF-CMAQ(sf)

WRF-CMAQ(nf)

brig

hten

ing

Dim

min

g

from 1990 to 2009

Unit: W m-2

Aerosol impacts on Surface SW-radiation

1990JJA-average from WRF-CMAQ

difference between sf and nf (i.e., sf - nf )

Unit: W m-2

1990-2009

2009

Aerosol impacts on Surface Temperature

1990 JJA-average from WRF-CMAQ

difference between sf and nf (i.e., sf - nf )

Unit: K

1990-2009

2009

Aerosol impacts on PBL Height

1990JJA-average from WRF-CMAQ

difference between sf and nf (i.e., sf - nf )

Unit: meter

1990-2009

2009

Simulated surface PM2.5 conc.

1990

2009

JJA-average from WRF-CMAQ(sf)

Unit: µg m-3

1990-2009

Aerosol impacts on PM2.5 conc.

1990

2009

difference between sf and nf (i.e., sf - nf )

Unit: µg m-3

1990-2009

Simulated surface O3 mixing ratio

1990

2009

JJA 24 hour-average from WRF-CMAQ(sf)

Unit: ppbV1990-2009

Aerosol impacts on O3 mixing ratio

1990difference between sf and nf (i.e., sf - nf )

Unit: ppbV

1990-2009

2009

WRF-CMAQ (nf)WRF-CMAQ (sf)CERES

(2006 minus 2000) Unit: W m-2

Dust Aerosol impacts on Clear-sky SSRJu

neJu

ly

brig

hten

ing

Dim

min

gbr

ight

enin

gD

imm

ing

AOD

200

0 SW

R 20

06-2

000

AOD

200

6 Satellite (June) Model (June) Satellite (July) Model (July)

brig

hten

ing

Dim

min

g

Summary

• Hemispheric WRF-CMAQ model system was successfully set up. Results of magnitude and spatial distribution of AOD generally agree

with MODIS satellite retrievals; Trends of clear-sky SW-radiation roughly reflect the brightening &

dimming in three regions.

• Aerosol direct impacts were evaluated. The reductions in surface solar radiation, surface-level temperature, and

PBL height arising from aerosol direct effects show distinct trends in response to changes in regional aerosol loading

PM2.5 will be enhanced in industrial regions, but reduced in windblown dust area.

• Capability of two-way coupled WRF-CMAQ model to represent the aerosol direct effects and to reproduce the observed changes in radiation was performed through comparison with CERES satellite retrieval.

Thank you for your time!

Acknowledgement This work was supported through and Inter-Agency Agreement between

the EPA and DOE and does not represent the views of either Agency. We also acknowledge the free use of EDGAR, GEIA, MODIS, SeaWiFS and

CERES product.

EDGAR v42 gridded annual

sectoral emissions 1990-2008

EDGAR v42 gridded annual

sectoral emissions 1990-2008

SO2SO2

NOxNOx

COCO

NH3NH3

CH4CH4

PM10PM10

PM2.5PM2.5

SULFSULF

NO2NO2 NONO

PFINEPFINE

PNO3PNO3 PSO4PSO4

POCPOC PECPEC

VOCVOC

EDGAR HTAPv1 gridded annual

sectoral emissions 2000-2005

EDGAR HTAPv1 gridded annual

sectoral emissions 2000-2005

Hemisphere-CMAQ

Hemisphere-CMAQ

Projection system

conversion, incl.:

Horizontal & Vertical

distribution

Projection system

conversion, incl.:

Horizontal & Vertical

distribution

Monthly/Weekly/Hourly

variation

Monthly/Weekly/Hourly

variationSpeciationSpeciation

SMOKE - default

SMOKE - default

CB05 speciesCB05 species

EDGAR -default

EDGAR -default

PMCPMC

SO2SO2

GEIAGEIAFramework of emission processing