ATMOSPHERIC CONSTITUENTS IN SOUTH AMERICA

Description:

The atmospheric products available in this webpage, so-called AtmC - Atmospheric Constituents, include water vapor (CWV), aerosol optical depth (AOD) and fraction of cloud cover (CLOUD). These products were derived from historical MODIS data based on MAIAC algorithm (Multi-Angle Implementation of Atmospheric Correction) and validated with in-situ sites (AERONET). Mapping of atmospheric constituents with continental coverage was developed to assess the seasonal and spatial distribution of key constituents and their implications for optical remote sensing, especially, in the Amazon region. In general, users can explore (i) the constituent features in the Landsat grid with 1 km resolution, (ii) the critical periods of aerosol loading and water vapor concentrations, and (iii) understand limitations of optical remote sensing due to high cloud coverage (Martins et al., 2017, in progress). The image processing was performed by Vitor S. Martins, member of LabISA group as part of his Master's student at the Remote Sensing Program (INPE), under supervision of Dr. Claudio C.F. Barbosa (INPE) and Dr. Lino A. S. de Carvalho (INPE) and extensive collaboration of Dr. Evlyn Novo (INPE) e Dr. Alexei Lyapustin (NASA). For more details about validation in South America and application in Amazon region, click here.

The available data in website represent the monthly average of time series within 2000-2015 of atmospheric products retrieved from MAIAC algorithm (Multi-Angle Implementation of Atmospheric Correction) using MODIS sensor (Lyapustin et al., 2011; 2012; Hilker et al., 2012). The comprehensive validation of AOD product (550 nm) in the South America is described in Martins et al. (2017, in review). For additional information of this product, access here. The image processing of monthly average of MAIAC products generates products with nominal spatial resolution of 1 km (although MODIS pixel size increases towards swath edges):

(iv) Aerosol optical depth, AOD em 550 nm;
(v) Columnar water vapor, CWV (g.cm-2); and
(vi) Fraction of cloud cover; CLOUD (%).

Data download:

User Notes:

The monthly products are available for download based on the Landsat-8 grid (path/row) and file names are organized as follows:

CCC_M#_pPPPrRRR
where, CCC represents atmospheric constituents (AOD, CWV e CLOUD); M# is the month (M1 is January, M2 is February,..., M12 is December); PPP is the path and RRR is the row of Landsat-8 tiles (access the shapefile here). For additional information, click on a region on the map below, and then, click on the URL with dataset (.zip) with all constituents throughout the year. For more information, contact atmc@dpi.inpe.br.

Direct data access here

Example of AOD, CWV and cloud cover products:


Figure 1. Quarter average of atmospheric constituents (AOD e water vapor) and fraction of cloud cover across the South America based on MAIAC/MODIS products.

Validation of AOD:


Figure 2. Validation of aerosol optical depth (AOD) from MAIAC retrievals (y-axis) versus ground-truth AERONET measurements (x-axis).

Validation of CWV:


Figure 3. Validation of columnar water vapor (CWV) from MAIAC retrievals (y-axis) versus ground-truth AERONET measurements (x-axis).

References:
Lyapustin, A., Wang, Y., & Frey, R. An automatic cloud mask algorithm based on time series of MODIS measurements. Journal of Geophysical Research: Atmospheres, v. 113, n. D16, 2008.

Lyapustin, A., Wang, Y., Laszlo, I., Kahn, R., Korkin, S., Remer, L., ... & Reid, J. S.. Multiangle implementation of atmospheric correction (MAIAC): 2. Aerosol algorithm. Journal of Geophysical Research: Atmospheres, v. 116, n. D3, 2011.

Hilker, T., Lyapustin, A. I., Tucker, C. J., Sellers, P. J., Hall, F. G., & Wang, Y.. Remote sensing of tropical ecosystems: Atmospheric correction and cloud masking matter. Remote Sensing of Environment, v. 127, p. 370-384, 2012.

Martins, V.S., Carvalho, L.A.S., Lyapustin, A., Barbosa, C. C. F., de Moraes Novo, E. M. L. Validation of high-resolution MAIAC aerosol product over South America. Journal of Geophysical Research: Atmospheres. (under review).

This work is licensed under foi licenciado com uma Licença Creative Commons - Atribution 4.0.
Use the following credit when these data are displayed: www.dpi.inpe.br/atmc
Use the following credit when these data are cited: Martins, V.S., Carvalho, L.A.S., Lyapustin, A., Barbosa, C.C.F., Novo, E.M.L.M., Validation of high-resolution MAIAC aerosol product over South America, Journal of Geophysical Research - Atmospheres, 2017.(In review).