# Presentation: 775569

## Aerosol effect on cloud cover and cloud height

**Aerosol effect on cloud cover and cloud height**
- Kaufman, Koren, Remer, Rosenfeld & Martins

## 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

- 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.](http://climate.gsfc.nasa.gov/publications/fulltext/PNAS-shallow_clouds.pdf)__[gsfc](http://climate.gsfc.nasa.gov/publications/fulltext/PNAS-shallow_clouds.pdf)__[.](http://climate.gsfc.nasa.gov/publications/fulltext/PNAS-shallow_clouds.pdf)__[nasa](http://climate.gsfc.nasa.gov/publications/fulltext/PNAS-shallow_clouds.pdf)__[.](http://climate.gsfc.nasa.gov/publications/fulltext/PNAS-shallow_clouds.pdf)__[gov/publications/fulltext/PNAS-shallow_clouds](http://climate.gsfc.nasa.gov/publications/fulltext/PNAS-shallow_clouds.pdf)__[.pdf](http://climate.gsfc.nasa.gov/publications/fulltext/PNAS-shallow_clouds.pdf)_
- 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.](http://climate.gsfc.nasa.gov/publications/fulltext/2005GL023187.pdf)__[gsfc](http://climate.gsfc.nasa.gov/publications/fulltext/2005GL023187.pdf)__[.](http://climate.gsfc.nasa.gov/publications/fulltext/2005GL023187.pdf)__[nasa](http://climate.gsfc.nasa.gov/publications/fulltext/2005GL023187.pdf)__[.gov/publications/fulltext/2005GL023187.pdf](http://climate.gsfc.nasa.gov/publications/fulltext/2005GL023187.pdf)_

## 1. Smoke inhibition of cloud formation over the Amazon

## Slide 4

## Koren et al Science, 2004; 

- Koren et al Science, 2004;
- Cloud fraction as function of aerosol optical depth (OD). The cloud fraction decreases almost linearly with increasing OD.

## • smoke instantaneous forcing -28w/m2 --> +8w/m2

- Clouds only

- Smoke only

**Impacts:**
**• ****smoke instantaneous forcing ****-28w/m****2**** --> +8w/m****2**
**• ****smoke 24hrs forcing ****-11w/m****2**** --> -5w/m****2**** **
**• ****less radiation at the surface => less evaporation**
**• ****smaller boundary layer cloud fraction **

**-28w/m****2**

**+8w/m****2**

## Pollution zone

- dust

- smoke

- pollution

- Sea salt

- stratiform

- convective

- convective

**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**

## Stratus and trade cumulus

- Clouds

- Dust

- Smoke

## 3. Convective  Clouds

## clean

**clean**

**hazy**

- hazy

- Cloud fraction

- Cloud fraction

- Cloud top pressure

- Cloud top pressure

## 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?

## 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

## “The aerosol roadmap”

## Slide 14

## Aerosol effect on cloud cover and cloud 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

**Aerosol effect on cloud cover and cloud height**