# Presentation: 749931

## New Developments in AERONET aerosol retrievals

**Outlines:**
***Improving operational retrieval software***
***Aerosol particle non-sphericity***
***Inversion of combined AERONET/satellite observations******  ***
***	***

- Oleg Dubovik  (Code 614.4)

**New Developments in**** AERONET aerosol retrievals**

## INPUT of Forward Model

**Particle Size Distribution:**
**0.05 ********m ≤ R (22 bins) ≤ 15 ********m**

**Complex Refractive Index at **
****** ****= 0.44; 0.67; 0.87; 1.02 ********m**

_***INPUT***__* of Forward Model*_

- Smoke

- Desert Dust

- Maritime

**Aerosol characterization form AERONET retrievals**

## AERONET Inversion 2

**Flexibility and refinements of the algorithm:**
-     - any number of spectral channel (from 0.34 to 1.64 m)
-     - any measurements geometry (almucantar, principle plane, etc.)
-     - dynamic error estimates for all retrieval products
-     - improved assumptions about surface reflectance (Moody et al. 2005)
-      - utilizing measurements of polarization (not operational yet)
**New products from retrievals:**
-     - particle non-sphericity
-     - direct aerosol radiative forcing computations
-     - degree of polarization, phase function, etc.
**New concepts in the retrieval:**
-     - non-spherical aerosols
-     - using co-incident satellite observations in the retrievals

## AERONET model of aerosol

***spherical:***

***Randomly oriented***
***spheroids :***
***(Mishchenko et al., 1997)***

_***AERONET***__*** model of aerosol***_

## Single Scattering  using spheroids

- Basic Model by Mishchenko et al. 1997:
- randomly oriented homogeneous spheroids
-  ***(****)* - size independent shape distribution

***Single Scattering  using ******spheroids***

**K** - pre-computed
- kernel matrices:
- Input: n and k

**Input:** p (*N*p =11),
-            V(ri) (*N*i =22 -26)

**Output:** (), 0(),
- F11(), F12(),F22(),
- F33(),F34(),F44()

*Time:** < *_*one sec.*_
*Accuracy:** < *_*1-3 %*_
*Range of applicability:*
*0.15 ≤ 2****r/****≤ *_*280 *_*(26 bins)*
*0.4 ≤ ****≤ 2.4 **(11 bins)*
*1.33 ≤ n ≤ 1.6 *
*0.0005 ≤ k ≤ 0.5*

## NEW CONCEPT - retrieving degree of non-sphericity as an additional parameter

**spheres**

**Non-**
**spheres**

- Retrieved aspect ratio

- The retrieval is possible for aerosols with pronounced coarse fraction, i. e. desert dust and maritime ( < ~ 1.2)

**Notes:**
Illustration of retrieval of degree of non-sphericity. We can retrieve shape distribution (these figures are for regular almucantars).
In version 2, we can implements a version of such tretieval. The sensitivity to the shape is only for aerosols with pronounced coarse mode).

## AERONET-MSP(multispectral polarization)

- Spectral Percent linear Polarization hourly
- Standard Products
- L(nm):  340, 380, 440, 500, 675, 870, 940, 1020, 1640
- AERONET testing (Feb. to May 2006)
- Operational products:  June 2006

- Dual filter wheel, top for polarizers
- bottom for IAD filters

*B.N. Holben*

## Sensitivity of polarization to  particle shape

**Coarse **
**aerosol**

**-P****12****(********)/P****11 ****(********)**

**-P****12****(********)/P****11 ****(********)**

## (spheroids)~ 5%; (spheres)~ 10%

- (spheroids)~ 5%; (spheres)~ 10%

- (spheroids) < 0.01; (spheres)~ 0.05

**Notes:**
This slide show that with newly developed software we can reproduce both intensity and polarization at many wavelengths.
In principle, these is no established model for simulating both intensity and polarization of non-spherical dust. Here we show that it seems like our development allow to use spehroids very successfully for that.

## Simultaneous Inversion of intensity and 

**Simultaneous Inversion of intensity and **
**Polarization measured in principle plane at 5 channels (0.44; 0.5; 067; 0.87; 1.02)**

- Maarco, August 8, 2004

**Notes:**
These are characteristics retrieved for dust dominated case observed during UAE2 experiment with new polarized instrument

## Combining of observations:

**Combining of observations:**
**satellite, ground-based and aircraft**

_***Retrieved:***_

_***AEROSOL***_***:***
* **Size Distribution*
*- Real Refractive Index*
* **Absorption*
* **Vertical variability*

**CALIPSO**

**LIDAR**

**size**

**concentration**

**concentration**

**altitude**

_***SURFACE ***_***:***
* **Albedo *
*- Bi-directional reflectance*

**CALIPSO**

**LIDAR**

## Simultaneous fitting

- August 9, 2003
- (0.44) ~ 0.3

**AERONET**

**MISR-MODIS**

- MODIS

## Comparisons of Surface Retrievals (with improved vertical profile)

**Surface BRDF:**

**Comparisons of Surface ****Retrievals ****(with improved vertical profile)**

## Surface Effect on Retrievals of  the fine mode aerosols (low aerosol loading)

- POLDER: June 24, 2003
- (0.44) ~ 0.26 , SZA=470

## 	Version 2 operational retrieval

**	****Version 2 operational retrieval**
***More ******robust******, more ******accurate****** and ******better characterized****** results ***
***Utilize new types of measurements (******polarization******, ******principle plane******, etc)***
***       ***
***Provide new retrieval products: ******particle shape, forcing******, etc.***
**Plans:**
***Using co-incident observations of MODIS, MISR and POLDER ***
***Including ******Lidar information ****** into retrievals***