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Impacts of snow darkening by absorbing aerosols on Eurasian climate Kyu-Myong Kim (NASA/GSFC) William K-M Lau (UMD/ESSIC), Teppei J. Yasunari (Hokkaido University) Maeng-Ki Kim, Jeong Sang (Kongju Natioanl University) Randal D. Koster (NASA/GSFC) https://ntrs.nasa.gov/search.jsp?R=20160003308 2020-04-02T15:03:51+00:00Z

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Page 1: Impacts of snow darkening by absorbing aerosols on ... · Impacts of snow darkening by absorbing aerosols are examined based on two sets of 10 member 10-year simulations of NASA/GEOS-5

Impacts of snow darkening by absorbing

aerosols on Eurasian climate

Kyu-Myong Kim (NASA/GSFC)

William K-M Lau (UMD/ESSIC), Teppei J. Yasunari (Hokkaido University)

Maeng-Ki Kim, Jeong Sang (Kongju Natioanl University)

Randal D. Koster (NASA/GSFC)

https://ntrs.nasa.gov/search.jsp?R=20160003308 2020-04-02T15:03:51+00:00Z

Page 2: Impacts of snow darkening by absorbing aerosols on ... · Impacts of snow darkening by absorbing aerosols are examined based on two sets of 10 member 10-year simulations of NASA/GEOS-5

Background:

Snow darkening effect

Deposition of absorbing aerosols on snow

surfaces reduces snow-albedo and allows

snowpack to absorb more sunlight (Warren

and Wiscombe 1980; Hansen and Nazarenko

2004), accelerates snow melting and leads to

surface warming in spring (Flanner et al.

2009; Qian et al. 2015).

Spectral snow albedos changes due to

snow density (b) and snow impurity (c)

(From Yasunari et al. 2011)

Terra/MODIS image of the dust-laden southern Alps

and MODIS spectral surface reflectance. Courtesy of

Ritesh Gautum (IIT-Bombay)

Snow

density

Snow

impurity

Page 3: Impacts of snow darkening by absorbing aerosols on ... · Impacts of snow darkening by absorbing aerosols are examined based on two sets of 10 member 10-year simulations of NASA/GEOS-5

Did spring dryness and associated increase of aerosols provide favorable land

surface conditions for the development of a mega heat wave in summer 2010?

AIRS surface temperature anomaly (shading)

and MODIS fire pixel (green dots) for 1 June

– 27 August 2010 (From Lau and Kim 2012)

Aerosol layer fraction from CALIPSOMotivation:

The Russian Heat Waves of 2010MAM2010 (30-70E)

MAM2010 – MAM2008

Did spring dryness and associated increase of aerosols provide favorable land

surface conditions for the development of a mega heat wave in summer 2010?

Page 4: Impacts of snow darkening by absorbing aerosols on ... · Impacts of snow darkening by absorbing aerosols are examined based on two sets of 10 member 10-year simulations of NASA/GEOS-5

Hypothesis:

Effect of snow darkening on regional climate

Snow

darkening

Page 5: Impacts of snow darkening by absorbing aerosols on ... · Impacts of snow darkening by absorbing aerosols are examined based on two sets of 10 member 10-year simulations of NASA/GEOS-5

NASA/GEOS-5 GCM Experiments

with/without snow darkening effect (SDE)

• Horizontally 2°x2.5°; vertically 72 layers

• Dust, BC, and OC depositions from GOCART (e.g., Ginoux et al.,

2001, JGR; Chin et al., 2000, JGR, & 2002, JAS; Colarco et al., 2010,

JGR)

• The GOddard SnoW Impurity Module (GOSWIM, Yasunari et al.

2014) is used in the Catchment land surface model (seasonal snowpack

only)

• Prescribed observed SST (Reynolds et al., 2002, J. Clim.)

• Biofuel and fossil fuel emissions until 2006 based on the emission

dataset (A2-MAP-v1; Diehl et al., 2012, ACPD; data in 2006 used after

2006). Biomass burning emissions based on the Quick Fire Emission

Data set (QFED; Petrenko et al., 2012, JGR, and Darmenov and da

Silva, NASA Tech. Rep. Ser. GMDA, in preparation)

• 10 member, 10-year simulations with and without SDE.

Page 6: Impacts of snow darkening by absorbing aerosols on ... · Impacts of snow darkening by absorbing aerosols are examined based on two sets of 10 member 10-year simulations of NASA/GEOS-5

Masses of Dust/BC/OC in the top snow layer (MAM)

Dust

Black

Carbon

Organic

Carbon

Page 7: Impacts of snow darkening by absorbing aerosols on ... · Impacts of snow darkening by absorbing aerosols are examined based on two sets of 10 member 10-year simulations of NASA/GEOS-5

Simulated Snow-Darkening Effect (MAM)

Surface

Albedo

Net downward

SW flux at SFC

(W/m2)

Snow cover

(%)

Surface

Temperature (K)

Yasunari et al.(2015) Reproduced.

Page 8: Impacts of snow darkening by absorbing aerosols on ... · Impacts of snow darkening by absorbing aerosols are examined based on two sets of 10 member 10-year simulations of NASA/GEOS-5

Surface Energy Budget (MAM)

Page 9: Impacts of snow darkening by absorbing aerosols on ... · Impacts of snow darkening by absorbing aerosols are examined based on two sets of 10 member 10-year simulations of NASA/GEOS-5

Surface Energy Budget and Snow Melting (MAM)

Net energy at

surface (W/m2)

Snow melt

flux (mm/day)

Page 10: Impacts of snow darkening by absorbing aerosols on ... · Impacts of snow darkening by absorbing aerosols are examined based on two sets of 10 member 10-year simulations of NASA/GEOS-5

Surface Water Budget (MAM)

Page 11: Impacts of snow darkening by absorbing aerosols on ... · Impacts of snow darkening by absorbing aerosols are examined based on two sets of 10 member 10-year simulations of NASA/GEOS-5

Surface Water Budget and Surface Wetness (MAM)

Net water budget

at surface

(mm/day)

Surface Wetness

(shading) &

snow melt flux

(contour)

Page 12: Impacts of snow darkening by absorbing aerosols on ... · Impacts of snow darkening by absorbing aerosols are examined based on two sets of 10 member 10-year simulations of NASA/GEOS-5

Surface Water Budget and Surface Wetness (JJA)

Page 13: Impacts of snow darkening by absorbing aerosols on ... · Impacts of snow darkening by absorbing aerosols are examined based on two sets of 10 member 10-year simulations of NASA/GEOS-5

(℃)

An

nu

al m

ea

n(

)

Surface air temperature (shading) &

Net SW flux (contour) change due to snow darkening

Page 14: Impacts of snow darkening by absorbing aerosols on ... · Impacts of snow darkening by absorbing aerosols are examined based on two sets of 10 member 10-year simulations of NASA/GEOS-5

Snow darkening effect on the occurrence of heat waves

Early snowmelt leads to drier land surface that favors more

frequent occurrence of heatwaves.

Definition of heat waves (Stefanon et al. 2012)

Page 15: Impacts of snow darkening by absorbing aerosols on ... · Impacts of snow darkening by absorbing aerosols are examined based on two sets of 10 member 10-year simulations of NASA/GEOS-5

Impacts of snow darkening by absorbing aerosols are examined based on two sets of 10 member 10-

year simulations of NASA/GEOS-5 model coupled with a snow darkening module, GOddard SnoW

Impurity Module (GOSWIM, Yasunari et al. 2014).

Reduced snow albedo increase shortwave downward flux and accelerate snow melting during boreal

spring

Early snowmelt leads to drier land surface that favors more frequent occurrence of heat waves.

Summary