# Presentation: 232715

## Synergy of MODIS Deep Blue and Operational Aerosol Products with MISR and SeaWiFS

_***N. Christina Hsu***_* ****and***
***S.-C. Tsay******, M. D. King, M.-J. Jeong***
***NASA Goddard Space Flight Center***
***Greenbelt, Maryland  USA***

## Solar radiation is the sole large-scale source of diabatic heating that drives the weather & climate system on planet Earth.
Terrestrial radiation keeps the planet in balance to make Earth habitable for all forms of life.

***NASA’s Vision:***
***To improve life here,***
***To extend life to there,***
***To find life beyond.***

***Solar radiation is the sole large-scale source of diabatic heating that drives the weather & climate system on planet Earth.***
***Terrestrial radiation keeps the planet in balance to make Earth habitable for all forms of life.***

***Aerosols may play an ***
***  ******important role in modifying ***
***  ******solar and terrestrial radiation.***
***Understanding that role is critical to understanding the energy balance that shapes our weather/climate.***

- 3-D Clouds

- Ozone

- Irradiance

- Precip

- NPP

- Brightness Temp

- Altimetry

## Understanding how the properties of those aerosols...

***Understanding how the properties of those aerosols...***
***refractive index***
***species***
***mixture***
***hygroscopicity***
***size distribution***
***shape***

***...******afffect various aspects of solar and terrestrial radiation...***
***spectral (************)***
***spatial (x, y, z)***
***angular (q, f)***
***temporal (t)***

***...******for each type of aerosol that occurs in the atmosphere***
***Dust Particles***
***Biomass Burning Smoke***
***Air Pollutants***
***Sea Salts***

***Understanding the role of aerosols means***

## Aerosol Remote Sensing & Retrieval

**Optical Thickness**

**Fine-mode Fraction**

**August 2003 Monthly Mean**

**August 2003 Monthly Mean**

***The current days of MODIS, since 2000: Remer, Kaufman, Tanré, et al.,***
*** ******J. Atmos. Sci., 2004.***

********* ******= 0.55 μm***

## reflectance taken over the Sahara MODIS 

***superimposed on the GOME spectral ***
***reflectance taken over ******the Sahara ******MODIS****** ***

## Viewing Geometry Differences

*View Angle vs. Relative Azimuth Angle*

## Slide 7

## Flowchart for Deep Blue Algorithm

***Flowchart for Deep Blue Algorithm***

**Radiances**
**412, 490, 670 nm**

## Phase Function for Dust Model

***Phase Function for Dust Model***

## In areas of mixed aerosol types, we linearly mix radiances from the dust aerosol model, Rdust, with those from the smoke aerosol model, Rsmoke 

**Aerosol**
**Mode**l

******412**

******470**

******490**

******470**

**Refractive Index**
**412 nm**

**Refractive Index**
**490 nm**

******0**
**412 nm**

******0**
**490 nm**

**Dust**

**Smoke**

**1.00**

**1.00**

**1.55 – 0.020i**

**1.55 – 0.022i**

**1.55 – 0.008i**

**1.55 – 0.026i**

**0.91**

**0.96**

**0.89**

**0.90**

**1.30**

**0.92**

**The aerosol characteristics used to generate the simulated radiances in these two figures are shown below**

**In areas of mixed aerosol types, we linearly mix radiances from the dust aerosol model, R****dust****, with those from the smoke aerosol model, R****smoke**** **

**= aR****dust**** + (1-a)R****smoke**

**Gaussian distribution with a peak at 3 km and a width of 1 km was assumed**

## Deep Blue Algorithm for SeaWiFS/MODIS

***Deep Blue Algorithm for SeaWiFS/MODIS***

** ****Utilize solar reflectance at ********= 412, 490, ****and**** 670 nm**** to retrieve aerosol optical thickness (********a****) and single scattering albedo (********o****).**
** ****Less sensitive to aerosol ****height****, compared to UV methods.**
** ****Works well on retrieving aerosol properties over various types of  surfaces, including very ****bright desert****.**

******0****(dust****670nm****)=1.0**

********

********

******a**

******a**

## Aerosol Optical Thickness Retrieved from Deep Blue Algorithm:

- Dust plumes in Africa

******a**

## Validation: Comparisons with AERONET 

***Aerosol Optical Thickness***

## Deep Blue Algorithm

**AERO****NET**** ****(500nm)**
**= 0.66**

**0.56**

**0.36**

**0.61**

**1.01**

**0.88**

**1.04**

**0.66**

** ****0.43**

**AERONET = 0.44**

**0.71**

**0.61**

**1.13**

**1.30**

**0.23**

**September**** 12, 2004**

- SeaWiFS retrieved aerosol
- optical thickness and Angstrom
- exponent showing a dust front
- pushing the air mass with small
- particle air pollution over both
- water and land on this day.

## Validation During UAE2 Experiment

- Harmim

- Mezaira

***Validation During UAE2 Experiment***
***August – September 2004***

## Aerosol Observation Strategy

***Satellite***
***Observations***
***A***

***Aerosol Product***
***Intercomparisons***

***Improvements of***
***Retrieval Products***

***Satellite***
***Observations***
***B***

***Synergy***

***Constraining***
***Models***

***Reducing Uncertainty***
***Of Climate Forcing***

***Aerosol Observation Strategy***

## Slide 17

## Slide 18

## Slide 19

## Tracking Movements and Evolutions of Aerosol Plumes

***Tracking Movements and Evolutions of Aerosol Plumes***

## Slide 21

## Summary

***Deep Blue algorithm *****provides aerosol *****optical thickness*****, *****Angstrom exponent***** and *****single scattering albedo***** for both land and water.**

***Deep Blue algorithm *****successfully applied to SeaWiFS and MODIS: *****evolution***** (spatial & temporal) of aerosols can be studied for the first time over deserts using one consistent algorithm.**

** ****Compared *****well***** with AERONET aerosol products:**
**Separate dust *****well***** from other anthropogenic sources**
**Aerosol optical thickness agree with AERONET values**
**within 10-20% over water and 20-30% over deserts**

## Summary (continued)

***Current Issues****** in Aerosol Product Synergy:***

*•  ****Presences of**** ****Clouds****:** ****requires careful selection ***
***in geolocation to conduct intercomparisons;***
*•  ****Variability of Aerosol Loading****:** ****requires spatial coverage;***
*•*  ***Accurate and Consistent Calibration**** ****across each individual sensors.  ***