MODIS aerosol optical depth Retrievals with high spatial resolution over an urban area using the critical reflectance


Autoria(s): CASTANHO, Andrea D. de Almeida; MARTINS, J. Vanderlei; Artaxo Netto, Paulo Eduardo
Contribuinte(s)

UNIVERSIDADE DE SÃO PAULO

Data(s)

20/10/2012

20/10/2012

2008

Resumo

[1] The retrieval of aerosol optical depth (Ta) over land by satellite remote sensing is still a challenge when a high spatial resolution is required. This study presents a tool that uses satellite measurements to dynamically identify the aerosol optical model that best represents the optical properties of the aerosol present in the atmosphere. We use aerosol critical reflectance to identify the single scattering albedo of the aerosol layer. Two case studies show that the Sao Paulo region can have different aerosol properties and demonstrates how the dynamic methodology works to identify those differences to obtain a better T a retrieval. The methodology assigned the high single scattering albedo aerosol model (pi o( lambda = 0.55) = 0.90) to the case where the aerosol source was dominated by biomass burning and the lower pi(o) model (pi(o) (lambda = 0.55) = 0.85) to the case where the local urban aerosol had the dominant influence on the region, as expected. The dynamic methodology was applied using cloud-free data from 2002 to 2005 in order to retrieve Ta with Moderate Resolution Imaging Spectroradiometer ( MODIS). These results were compared with collocated data measured by AERONET in Sao Paulo. The comparison shows better results when the dynamic methodology using two aerosol optical models is applied (slope 1.06 +/- 0.08 offset 0.01 +/- 0.02 r(2) 0.6) than when a single and fixed aerosol model is used (slope 1.48 +/- 0.11 and offset - 0.03 +/- 0.03 r(2) 0.6). In conclusion the dynamical methodology is shown to work well with two aerosol models. Further studies are necessary to evaluate the methodology in other regions and under different conditions.

Identificador

JOURNAL OF GEOPHYSICAL RESEARCH, v.113, n.D2, 2008

0148-0227

http://producao.usp.br/handle/BDPI/29085

10.1029/2007JD008751

http://dx.doi.org/10.1029/2007JD008751

Idioma(s)

eng

Publicador

AMER GEOPHYSICAL UNION

Relação

Journal of Geophysical Research

Direitos

closedAccess

Copyright AMER GEOPHYSICAL UNION

Palavras-Chave #IMAGING SPECTRORADIOMETER #TROPOSPHERIC AEROSOL #ALGORITHM #VALIDATION #ABSORPTION #AMAZONIA #WATER #LAND #Meteorology & Atmospheric Sciences
Tipo

article

original article

publishedVersion