Retrieval of Aerosol Optical Properties using the Multi-angle Imaging Spectro-Radiometer (MISR)

A contribution to ACCENT-TROPOSAT-2, Task Group 1

Johannes Keller

Laboratory of Atmospheric Chemistry (LAC), Paul Scherrer Institute (PSI) Switzerland
Tel.:  +41-56-310-2065
Fax:  +41-56-310-4525

MISR onboard NASA’s satellite TERRA observes the earth from 9 different view angles and in 4 spectral bands in the visible and near-infrared spectrum. This instrument is particularly suited to retrieve the angular pattern of radiation scattered by aerosols. An operational product for aerosols over flat terrain is already available on a spatial resolution of 17.6 km.

For aerosol observations over complex terrain a new retrieval algorithm with a spatial resolution of 1 km was developed at PSI. MODTRAN 4 is currently used as atmospheric radiation transfer model. The algorithm yields realistic aerosol optical depths (AOD) over inland water bodies compared to sun-photometer data. Over land, however, the influence of the non-lambertian behavior of vegetation (bi-directional reflectance distribution function, BRDF) is not yet fully taken into account.

In the frame of ACCENT / TROPOSAT we will

improve the new algorithm in view of its application over land;

test the algorithm for water and for various land covers -> AOD and aerosol composition over lakes, various vegetation types and urban areas;

derive PM10 data assuming pre-defined vertical aerosol profiles;

apply the algorithm to a 3 months period of the hot summer 2003. The main domain of interest is Central Europe and Northern Italy.

The improved retrieval algorithm will be validated by comparing

the retrieved AODs with AODs of the MISR operational aerosol product,

the retrieved AODs with sun-photometer AODs of AERONET and the Swiss network CHARM,

the derived PM10 data with data of the Swiss NABEL network and other monitoring stations.

In the view of synergistic use of different sensors, results of the improved MISR retrieval algorithm can be compared to various aerosol products dealt with in and outside AT-2, e.g.: ATSR/AATSR (G..de Leeuw, TNO), SCIAMACHY (T. Holzer-Popp, DLR; W. von Hoyningen-Huene, Uni Bremen), NOAA AVHRR (S.Wunderle, Uni Bern), MISR and MODIS operational products.

Time schedule

 

2004

2005

2006

2007

algorithm improvement

*

***

***

*

validation

 

*

***

**

Achievement after 18 months

Inclusion of appropriate BRDFs for inland water bodies and for land to match the AODs over water and over land.

Approximate manpower and cost

 

2004

2005

2006

2007

total

Personnel / man-years

0.1

0.75

0.75

0.6

2.2

Yearly cost (kECU)

12

108

108

96

324

Likely funding agencies

EU 6th FP (questionable), PSI

Co-workers

Dr. Urs Baltensperger, PSI

Dr. Andre Prevot, PSI

 

 


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