# Presentation: 353495

## Satellite Data and Model Integration of Global Distribution  of Aerosols to Estimate the Aerosol Radiative Effect

***Hongbin Yu***
***GEST, UMBC & NASA GSFC***
***M. Chin, Y. Kaufman, L. Remer ***
***NASA/GSFC***
***M. Zhou, R.E. Dickinson, Q. Tan ***
***Georgia Tech***

## Motivation & Objective

**IPCC report summarizes that the uncertainty for the aerosol direct forcing is about a factor of 2-3, based largely on model simulations. **
**In recent years, a great deal of effort has gone into improving measurements and data sets. **
**It is feasible to shift the estimates of direct effect from largely model-based to increasingly measurement-based.**
** **
**Observations can also be used to improve and constrain model simulations through synthesis and integration.**

**MISR**

## Integrated Study of Global Aerosols and Direct Effect

**     ********2**** = ***********2****** + (f************)******2***

-  **AERONET**
-  **MODIS *****(Remer)***
-  **CERES *****(Loeb)***

**Integrated Study of Global Aerosols ****and Direct Effect**

**MISR**

**Aerosol Direct Radiative Effect**
**(clear-sky)**

_**MODIS **_*** ***
***surface albedo****** ***

**    ****Radiative Transfer Model**

**Integrated AOT**

**SSA, g**

**Inter-comparisons**

## MODIS
 ±0.03 ± 0.05 (Ocean)
 ±0.05 ± 0.20 (Land), gaps over deserts
MISR
 +0.038 (Ocean)
 ±0.20  or ±0.05 (Land)
GOCART: Goddard Global Ozone Chemistry Aerosol Radiation & Transport 
 Sulfate, OC, BC, dust, Sea-salt  
 driven by the assimilated metorology
 30 layers, 2.5x2                     [1.25x1 ongoing] 
 ±0.01 ± 0.46 (Ocean), ±0.04 ± 0.31 (Land)  

				 	MO_MI_GO

** ****±0.03 ± 0.05******** (Ocean)**
** ****±0.05 ± 0.20******** (Land), gaps over deserts**
**MISR**
** ****+0.038 (Ocean)**
** ****±0.20********  or ±0.05 (Land)**
**GOCART: ****Goddard ****Global Ozone Chemistry Aerosol Radiation & Transport **
** ****Sulfate, OC, BC, dust, Sea-salt  **
** ****driven by the assimilated metorology**
** ****30 layers, ****2.5********x2********                     *****[1.25************x1************ ongoing]***** **
** ****±0.01 ± 0.46******** (Ocean), ±0.04 ± 0.31******** (Land)  **
- 				****** ****	****MO_MI_GO**

**Data and Model**

****

****

****

## Annual ave. AOT, 2001

| MODIS | 0.188 |
| --- | --- |
| MISR | 0.199 |
| MO_MI_GO | 0.151 |
| GOCART | 0.134 |

**60********S ~ 60********N  **

## Before Integration

**After Integration**

**Angstrom exponent < 1.5**

**Angstrom exponent > 1.5**

**Comparisons with AERONET measurements**

## Clear-sky Aerosol Direct Effect

**MO_MI_GO - GOCART**

**Clear-sky Aerosol Direct Effect**

**Annual Average, 2001**

**TOA**

**SURFACE**

**-4.1 W/m2**

**-7.8 W/m2**

** ****= - 0.8 W/m2**
**      ****(20%)**

** ****= - 1.5 W/m2**
**      ****(20%)**

## Comparisons with AERONET 

**r =**** ****0.54****            ****r = 0.39**

**r =**** ****0.67****         ****r = 0.44 **

*** Integration increases correlation;**
*** Integration overall brings the direct effect estimates closer to AERONET measurements;**
*** Significant low biases. Part of them could result from mismatching between points and 2.5********x2******** grids.**** **

## AOD < 0.4

**AOD < 0.4**

**r =**** ****0.68****                  ****r =**** ****0.56**

**r = 0.69****                   ****r = 0.52**

## Seasonal averages over 13 zones  (Land & Ocean separately)

**60********N**

**60********S**

**EQ.**

## CERES flux + MODIS aerosol: Loeb & Manalo-Smith, 2005

**CERES flux + MODIS aerosol: *****Loeb & Manalo-Smith, 2005***

**  ****r = 0.92,  B=0.92± 0.17**** **
**  ****r = 0.83,  B=0.74± 0.23 **

**13 oceanic zones, seasonal averages of TOA aerosol effect**

**B=1, no bias**

## MODIS AOT + MODIS aerosol models: Remer & Kaufman, 2005

**MODIS AOT + MODIS aerosol models: *****Remer & Kaufman, 2005***

**  ****r = 0.86,  B=0.91± 0.22**** **
**  ****r = 0.80,  B=0.71± 0.20 **

**13 oceanic zones, seasonal averages of TOA aerosol effect**

**B=1, no bias**

## Summary

- Integrating MODIS *(ocean)* and MISR *(land)* measurements of optical depth into GOCART simulations increases the GOCART clear-sky direct effect estimate by ~20%.
- The integration can improve the agreement with measurement-based estimates of aerosol direct effect, including AERONET, MODIS, and CERES.