Aerosol effect on cloud cover and cloud height

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Aerosol effect on cloud cover and cloud
height Kaufman, Koren, Remer, Rosenfeld Martins
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1. Koren, I., Y. J. Kaufman L. A. Remer and J.V.
   Martins, Measurement of the effect of Amazon
   smoke on inhibition of cloud formation, Science,
   303, 1342-1344, 2004. http//climate.gsfc.nasa.gov
   /publications/fulltext/Koren_et_al._(2004).pdf
2. Kaufman, Y. J., I. Koren, L. A. Remer, D.
   Rosenfeld and Y. Rudich, The effect of smoke,
   dust, and pollution aerosol on shallow cloud
   development over the Atlantic Ocean, Proc. Nat.
   Acad. Scie., 102, 11207-11212, 2005
   http//climate.gsfc.nasa.gov/publications/fulltext
   /PNAS-shallow_clouds.pdf
3. Koren, I. Y. J. Kaufman, L. A. Remer, D.
   Rosenfeld and Y. Rudich Aerosol impact on the
   development and coverage of Convective clouds,
   Geoph. Res. Lett. 32 (14) Art. No. L14828 JUL 30
   2005 http//climate.gsfc.nasa.gov/publications/ful
   ltext/2005GL023187.pdf

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1. Smoke inhibition of cloud formation over the
Amazon
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Koren et al Science, 2004 Cloud fraction as
function of aerosol optical depth (OD). The cloud
fraction decreases almost linearly with
increasing OD.
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Clouds only
8w/m2
-28w/m2
Smoke only
Impacts smoke instantaneous forcing -28w/m2
--gt 8w/m2 smoke 24hrs forcing -11w/m2 --gt
-5w/m2 less radiation at the surface gt less
evaporation smaller boundary layer cloud
fraction
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2. Aerosol effects on cloud cover - shallow
clouds The Atlantic Ocean - several aerosol types
interacting with clouds June-Aug 2002 Pollution
zone Dust zone Smoke zone Marine aerosol
pollution
dust
smoke
Sea salt
convective
convective
stratiform
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Dust
Stratus and trade cumulus Clouds
Smoke
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3. Convective Clouds
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clean
hazy
Cloud fraction
Cloud fraction
clean
hazy
Cloud top pressure
Cloud top pressure
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What does it mean to climate? The aerosol
forcing corresponding to the increase in cloud
cover is 6w/m2 in the June-Aug period over the
Atlantic Ocean We see similar increases in other
locations, depending on the aerosol content of
black carbon. How does it reconcile with global
warming?
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x. What is the response of the cloud water path
to 50 yr increase in aerosol concentration? A.
Fixed ocean temperature
B. feedback through ocean temperature
Takemura, Kaufman, Remer, Nakajima, submitted
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The aerosol roadmap
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Aerosol effect on cloud cover and cloud height
MODIS is in unique position to measure the
correlation of aerosol AOT and properties to
cloud cover height We find increases in
cloud cover on average of 0.05 ? 6 W/m2 We
find an average increase in cloud height of 400
m (-40 mb) Model shows that long term aerosol
cooling of the ocean may compensate the aerosol
effect on cloud cover through impact on cloud
microphysics